Mark for 0.31

Update Adler32 from ImageSharp v2.1.0

.github/workflows/dotnetcore.yml

@@ -12,13 +12,9 @@ jobs:
     - uses: actions/checkout@v1
     - uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 5.0.101
+        dotnet-version: 5.0.401
     - run: dotnet run -p build/build.csproj
     - uses: actions/upload-artifact@v2
       with:
         name: ${{ matrix.os }}-sharpcompress.nupkg
         path: artifacts/*
-    - uses: actions/upload-artifact@v2
-      with:
-        name: ${{ matrix.os }}-sharpcompress.snupkg
-        path: artifacts/*

FORMATS.md

@@ -19,7 +19,6 @@
 | Tar.XZ                 | LZMA2                                             | Decompress          | TarArchive      | TarReader  | TarWriter (3) |
 | GZip (single file)     | DEFLATE                                           | Both                | GZipArchive     | GZipReader | GZipWriter    |
 | 7Zip (4)               | LZMA, LZMA2, BZip2, PPMd, BCJ, BCJ2, Deflate      | Decompress          | SevenZipArchive | N/A        | N/A           |
-| LZip (single file) (5) | LZip (LZMA)                                       | Both                | LZipArchive     | LZipReader | LZipWriter    |
 
 1. SOLID Rars are only supported in the RarReader API.
 2. Zip format supports pkware and WinzipAES encryption. However, encrypted LZMA is not supported. Zip64 reading/writing is supported but only with seekable streams as the Zip spec doesn't support Zip64 data in post data descriptors. Deflate64 is only supported for reading.

build/Program.cs

@@ -49,20 +49,20 @@ class Program
         Target(Build, DependsOn(Format),
                framework =>
                {
-                   if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && framework == "net46")
-                   {
-                       return;
-                   }
                    Run("dotnet", "build src/SharpCompress/SharpCompress.csproj -c Release");
                });
 
-        Target(Test, DependsOn(Build), ForEach("net5.0"),
+        Target(Test, DependsOn(Build), ForEach("net5.0", "net461"),
                framework =>
                {
                    IEnumerable<string> GetFiles(string d)
                    {
                        return Glob.Files(".", d);
                    }
+                   if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && framework == "net461")
+                   {
+                       return;
+                   }
 
                    foreach (var file in GetFiles("**/*.Test.csproj"))
                    {

build/build.csproj

@@ -6,9 +6,9 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Bullseye" Version="3.6.0" />
+    <PackageReference Include="Bullseye" Version="3.8.0" />
     <PackageReference Include="Glob" Version="1.1.8" />
-    <PackageReference Include="SimpleExec" Version="6.4.0" />
+    <PackageReference Include="SimpleExec" Version="8.0.0" />
   </ItemGroup>
 
 </Project>

global.json

@@ -1,5 +1,6 @@
 {
   "sdk": {
-    "version": "5.0.101"
+    "version": "5.0.300",
+    "rollForward": "latestFeature"
   }
 }

src/SharpCompress/Algorithms/Adler32.cs

@@ -0,0 +1,420 @@
+// Copyright (c) Six Labors.
+// Licensed under the Apache License, Version 2.0.
+
+#if !NETSTANDARD2_0 && !NETSTANDARD2_1 && !NETFRAMEWORK
+#define SUPPORTS_RUNTIME_INTRINSICS
+#define SUPPORTS_HOTPATH
+#endif
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+#if SUPPORTS_RUNTIME_INTRINSICS
+using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.X86;
+#endif
+
+#pragma warning disable IDE0007 // Use implicit type
+namespace SharpCompress.Algorithms
+{
+    /// <summary>
+    /// Calculates the 32 bit Adler checksum of a given buffer according to
+    /// RFC 1950. ZLIB Compressed Data Format Specification version 3.3)
+    /// </summary>
+    internal static class Adler32 // From https://github.com/SixLabors/ImageSharp/blob/main/src/ImageSharp/Compression/Zlib/Adler32.cs
+    {
+        /// <summary>
+        /// Global inlining options. Helps temporarily disable inlining for better profiler output.
+        /// </summary>
+        private static class InliningOptions // From https://github.com/SixLabors/ImageSharp/blob/main/src/ImageSharp/Common/Helpers/InliningOptions.cs
+        {
+            /// <summary>
+            /// <see cref="MethodImplOptions.AggressiveInlining"/> regardless of the build conditions.
+            /// </summary>
+            public const MethodImplOptions AlwaysInline = MethodImplOptions.AggressiveInlining;
+#if PROFILING
+            public const MethodImplOptions HotPath = MethodImplOptions.NoInlining;
+            public const MethodImplOptions ShortMethod = MethodImplOptions.NoInlining;
+#else
+#if SUPPORTS_HOTPATH
+            public const MethodImplOptions HotPath = MethodImplOptions.AggressiveOptimization;
+#else
+            public const MethodImplOptions HotPath = MethodImplOptions.AggressiveInlining;
+#endif
+            public const MethodImplOptions ShortMethod = MethodImplOptions.AggressiveInlining;
+#endif
+            public const MethodImplOptions ColdPath = MethodImplOptions.NoInlining;
+        }
+
+#if SUPPORTS_RUNTIME_INTRINSICS
+        /// <summary>
+        /// Provides optimized static methods for trigonometric, logarithmic,
+        /// and other common mathematical functions.
+        /// </summary>
+        private static class Numerics // From https://github.com/SixLabors/ImageSharp/blob/main/src/ImageSharp/Common/Helpers/Numerics.cs
+        {
+            /// <summary>
+            /// Reduces elements of the vector into one sum.
+            /// </summary>
+            /// <param name="accumulator">The accumulator to reduce.</param>
+            /// <returns>The sum of all elements.</returns>
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public static int ReduceSum(Vector256<int> accumulator)
+            {
+                // Add upper lane to lower lane.
+                Vector128<int> vsum = Sse2.Add(accumulator.GetLower(), accumulator.GetUpper());
+
+                // Add odd to even.
+                vsum = Sse2.Add(vsum, Sse2.Shuffle(vsum, 0b_11_11_01_01));
+
+                // Add high to low.
+                vsum = Sse2.Add(vsum, Sse2.Shuffle(vsum, 0b_11_10_11_10));
+
+                return Sse2.ConvertToInt32(vsum);
+            }
+
+            /// <summary>
+            /// Reduces even elements of the vector into one sum.
+            /// </summary>
+            /// <param name="accumulator">The accumulator to reduce.</param>
+            /// <returns>The sum of even elements.</returns>
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            public static int EvenReduceSum(Vector256<int> accumulator)
+            {
+                Vector128<int> vsum = Sse2.Add(accumulator.GetLower(), accumulator.GetUpper()); // add upper lane to lower lane
+                vsum = Sse2.Add(vsum, Sse2.Shuffle(vsum, 0b_11_10_11_10));                      // add high to low
+
+                // Vector128<int>.ToScalar() isn't optimized pre-net5.0 https://github.com/dotnet/runtime/pull/37882
+                return Sse2.ConvertToInt32(vsum);
+            }
+        }
+#endif
+
+        /// <summary>
+        /// The default initial seed value of a Adler32 checksum calculation.
+        /// </summary>
+        public const uint SeedValue = 1U;
+
+        // Largest prime smaller than 65536
+        private const uint BASE = 65521;
+
+        // NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1
+        private const uint NMAX = 5552;
+
+#if SUPPORTS_RUNTIME_INTRINSICS
+        private const int MinBufferSize = 64;
+
+        private const int BlockSize = 1 << 5;
+
+        // The C# compiler emits this as a compile-time constant embedded in the PE file.
+        private static ReadOnlySpan<byte> Tap1Tap2 => new byte[]
+        {
+            32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, // tap1
+            16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 // tap2
+        };
+#endif
+
+        /// <summary>
+        /// Calculates the Adler32 checksum with the bytes taken from the span.
+        /// </summary>
+        /// <param name="buffer">The readonly span of bytes.</param>
+        /// <returns>The <see cref="uint"/>.</returns>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public static uint Calculate(ReadOnlySpan<byte> buffer)
+            => Calculate(SeedValue, buffer);
+
+        /// <summary>
+        /// Calculates the Adler32 checksum with the bytes taken from the span and seed.
+        /// </summary>
+        /// <param name="adler">The input Adler32 value.</param>
+        /// <param name="buffer">The readonly span of bytes.</param>
+        /// <returns>The <see cref="uint"/>.</returns>
+        [MethodImpl(InliningOptions.HotPath | InliningOptions.ShortMethod)]
+        public static uint Calculate(uint adler, ReadOnlySpan<byte> buffer)
+        {
+            if (buffer.IsEmpty)
+            {
+                return adler;
+            }
+
+#if SUPPORTS_RUNTIME_INTRINSICS
+            if (Avx2.IsSupported && buffer.Length >= MinBufferSize)
+            {
+                return CalculateAvx2(adler, buffer);
+            }
+
+            if (Ssse3.IsSupported && buffer.Length >= MinBufferSize)
+            {
+                return CalculateSse(adler, buffer);
+            }
+
+            return CalculateScalar(adler, buffer);
+#else
+            return CalculateScalar(adler, buffer);
+#endif
+        }
+
+        // Based on https://github.com/chromium/chromium/blob/master/third_party/zlib/adler32_simd.c
+#if SUPPORTS_RUNTIME_INTRINSICS
+        [MethodImpl(InliningOptions.HotPath | InliningOptions.ShortMethod)]
+        private static unsafe uint CalculateSse(uint adler, ReadOnlySpan<byte> buffer)
+        {
+            uint s1 = adler & 0xFFFF;
+            uint s2 = (adler >> 16) & 0xFFFF;
+
+            // Process the data in blocks.
+            uint length = (uint)buffer.Length;
+            uint blocks = length / BlockSize;
+            length -= blocks * BlockSize;
+
+            fixed (byte* bufferPtr = &MemoryMarshal.GetReference(buffer))
+            {
+                fixed (byte* tapPtr = &MemoryMarshal.GetReference(Tap1Tap2))
+                {
+                    byte* localBufferPtr = bufferPtr;
+
+                    // _mm_setr_epi8 on x86
+                    Vector128<sbyte> tap1 = Sse2.LoadVector128((sbyte*)tapPtr);
+                    Vector128<sbyte> tap2 = Sse2.LoadVector128((sbyte*)(tapPtr + 0x10));
+                    Vector128<byte> zero = Vector128<byte>.Zero;
+                    var ones = Vector128.Create((short)1);
+
+                    while (blocks > 0)
+                    {
+                        uint n = NMAX / BlockSize;  /* The NMAX constraint. */
+                        if (n > blocks)
+                        {
+                            n = blocks;
+                        }
+
+                        blocks -= n;
+
+                        // Process n blocks of data. At most NMAX data bytes can be
+                        // processed before s2 must be reduced modulo BASE.
+                        Vector128<uint> v_ps = Vector128.CreateScalar(s1 * n);
+                        Vector128<uint> v_s2 = Vector128.CreateScalar(s2);
+                        Vector128<uint> v_s1 = Vector128<uint>.Zero;
+
+                        do
+                        {
+                            // Load 32 input bytes.
+                            Vector128<byte> bytes1 = Sse3.LoadDquVector128(localBufferPtr);
+                            Vector128<byte> bytes2 = Sse3.LoadDquVector128(localBufferPtr + 0x10);
+
+                            // Add previous block byte sum to v_ps.
+                            v_ps = Sse2.Add(v_ps, v_s1);
+
+                            // Horizontally add the bytes for s1, multiply-adds the
+                            // bytes by [ 32, 31, 30, ... ] for s2.
+                            v_s1 = Sse2.Add(v_s1, Sse2.SumAbsoluteDifferences(bytes1, zero).AsUInt32());
+                            Vector128<short> mad1 = Ssse3.MultiplyAddAdjacent(bytes1, tap1);
+                            v_s2 = Sse2.Add(v_s2, Sse2.MultiplyAddAdjacent(mad1, ones).AsUInt32());
+
+                            v_s1 = Sse2.Add(v_s1, Sse2.SumAbsoluteDifferences(bytes2, zero).AsUInt32());
+                            Vector128<short> mad2 = Ssse3.MultiplyAddAdjacent(bytes2, tap2);
+                            v_s2 = Sse2.Add(v_s2, Sse2.MultiplyAddAdjacent(mad2, ones).AsUInt32());
+
+                            localBufferPtr += BlockSize;
+                        }
+                        while (--n > 0);
+
+                        v_s2 = Sse2.Add(v_s2, Sse2.ShiftLeftLogical(v_ps, 5));
+
+                        // Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
+                        const byte S2301 = 0b1011_0001;  // A B C D -> B A D C
+                        const byte S1032 = 0b0100_1110;  // A B C D -> C D A B
+
+                        v_s1 = Sse2.Add(v_s1, Sse2.Shuffle(v_s1, S1032));
+
+                        s1 += v_s1.ToScalar();
+
+                        v_s2 = Sse2.Add(v_s2, Sse2.Shuffle(v_s2, S2301));
+                        v_s2 = Sse2.Add(v_s2, Sse2.Shuffle(v_s2, S1032));
+
+                        s2 = v_s2.ToScalar();
+
+                        // Reduce.
+                        s1 %= BASE;
+                        s2 %= BASE;
+                    }
+
+                    if (length > 0)
+                    {
+                        HandleLeftOver(localBufferPtr, length, ref s1, ref s2);
+                    }
+
+                    return s1 | (s2 << 16);
+                }
+            }
+        }
+
+        // Based on: https://github.com/zlib-ng/zlib-ng/blob/develop/arch/x86/adler32_avx2.c
+        [MethodImpl(InliningOptions.HotPath | InliningOptions.ShortMethod)]
+        public static unsafe uint CalculateAvx2(uint adler, ReadOnlySpan<byte> buffer)
+        {
+            uint s1 = adler & 0xFFFF;
+            uint s2 = (adler >> 16) & 0xFFFF;
+            uint length = (uint)buffer.Length;
+
+            fixed (byte* bufferPtr = &MemoryMarshal.GetReference(buffer))
+            {
+                byte* localBufferPtr = bufferPtr;
+
+                Vector256<byte> zero = Vector256<byte>.Zero;
+                var dot3v = Vector256.Create((short)1);
+                var dot2v = Vector256.Create(32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
+
+                // Process n blocks of data. At most NMAX data bytes can be
+                // processed before s2 must be reduced modulo BASE.
+                var vs1 = Vector256.CreateScalar(s1);
+                var vs2 = Vector256.CreateScalar(s2);
+
+                while (length >= 32)
+                {
+                    int k = length < NMAX ? (int)length : (int)NMAX;
+                    k -= k % 32;
+                    length -= (uint)k;
+
+                    Vector256<uint> vs10 = vs1;
+                    Vector256<uint> vs3 = Vector256<uint>.Zero;
+
+                    while (k >= 32)
+                    {
+                        // Load 32 input bytes.
+                        Vector256<byte> block = Avx.LoadVector256(localBufferPtr);
+
+                        // Sum of abs diff, resulting in 2 x int32's
+                        Vector256<ushort> vs1sad = Avx2.SumAbsoluteDifferences(block, zero);
+
+                        vs1 = Avx2.Add(vs1, vs1sad.AsUInt32());
+                        vs3 = Avx2.Add(vs3, vs10);
+
+                        // sum 32 uint8s to 16 shorts.
+                        Vector256<short> vshortsum2 = Avx2.MultiplyAddAdjacent(block, dot2v);
+
+                        // sum 16 shorts to 8 uint32s.
+                        Vector256<int> vsum2 = Avx2.MultiplyAddAdjacent(vshortsum2, dot3v);
+
+                        vs2 = Avx2.Add(vsum2.AsUInt32(), vs2);
+                        vs10 = vs1;
+
+                        localBufferPtr += BlockSize;
+                        k -= 32;
+                    }
+
+                    // Defer the multiplication with 32 to outside of the loop.
+                    vs3 = Avx2.ShiftLeftLogical(vs3, 5);
+                    vs2 = Avx2.Add(vs2, vs3);
+
+                    s1 = (uint)Numerics.EvenReduceSum(vs1.AsInt32());
+                    s2 = (uint)Numerics.ReduceSum(vs2.AsInt32());
+
+                    s1 %= BASE;
+                    s2 %= BASE;
+
+                    vs1 = Vector256.CreateScalar(s1);
+                    vs2 = Vector256.CreateScalar(s2);
+                }
+
+                if (length > 0)
+                {
+                    HandleLeftOver(localBufferPtr, length, ref s1, ref s2);
+                }
+
+                return s1 | (s2 << 16);
+            }
+        }
+
+        private static unsafe void HandleLeftOver(byte* localBufferPtr, uint length, ref uint s1, ref uint s2)
+        {
+            if (length >= 16)
+            {
+                s2 += s1 += localBufferPtr[0];
+                s2 += s1 += localBufferPtr[1];
+                s2 += s1 += localBufferPtr[2];
+                s2 += s1 += localBufferPtr[3];
+                s2 += s1 += localBufferPtr[4];
+                s2 += s1 += localBufferPtr[5];
+                s2 += s1 += localBufferPtr[6];
+                s2 += s1 += localBufferPtr[7];
+                s2 += s1 += localBufferPtr[8];
+                s2 += s1 += localBufferPtr[9];
+                s2 += s1 += localBufferPtr[10];
+                s2 += s1 += localBufferPtr[11];
+                s2 += s1 += localBufferPtr[12];
+                s2 += s1 += localBufferPtr[13];
+                s2 += s1 += localBufferPtr[14];
+                s2 += s1 += localBufferPtr[15];
+
+                localBufferPtr += 16;
+                length -= 16;
+            }
+
+            while (length-- > 0)
+            {
+                s2 += s1 += *localBufferPtr++;
+            }
+
+            if (s1 >= BASE)
+            {
+                s1 -= BASE;
+            }
+
+            s2 %= BASE;
+        }
+#endif
+
+        [MethodImpl(InliningOptions.HotPath | InliningOptions.ShortMethod)]
+        private static unsafe uint CalculateScalar(uint adler, ReadOnlySpan<byte> buffer)
+        {
+            uint s1 = adler & 0xFFFF;
+            uint s2 = (adler >> 16) & 0xFFFF;
+            uint k;
+
+            fixed (byte* bufferPtr = buffer)
+            {
+                var localBufferPtr = bufferPtr;
+                uint length = (uint)buffer.Length;
+
+                while (length > 0)
+                {
+                    k = length < NMAX ? length : NMAX;
+                    length -= k;
+
+                    while (k >= 16)
+                    {
+                        s2 += s1 += localBufferPtr[0];
+                        s2 += s1 += localBufferPtr[1];
+                        s2 += s1 += localBufferPtr[2];
+                        s2 += s1 += localBufferPtr[3];
+                        s2 += s1 += localBufferPtr[4];
+                        s2 += s1 += localBufferPtr[5];
+                        s2 += s1 += localBufferPtr[6];
+                        s2 += s1 += localBufferPtr[7];
+                        s2 += s1 += localBufferPtr[8];
+                        s2 += s1 += localBufferPtr[9];
+                        s2 += s1 += localBufferPtr[10];
+                        s2 += s1 += localBufferPtr[11];
+                        s2 += s1 += localBufferPtr[12];
+                        s2 += s1 += localBufferPtr[13];
+                        s2 += s1 += localBufferPtr[14];
+                        s2 += s1 += localBufferPtr[15];
+
+                        localBufferPtr += 16;
+                        k -= 16;
+                    }
+
+                    while (k-- > 0)
+                    {
+                        s2 += s1 += *localBufferPtr++;
+                    }
+
+                    s1 %= BASE;
+                    s2 %= BASE;
+                }
+
+                return (s2 << 16) | s1;
+            }
+        }
+    }
+}

src/SharpCompress/Algorithms/Alder32.cs

@@ -1,285 +0,0 @@
-// Copyright (c) Six Labors and contributors.
-// Licensed under the GNU Affero General Public License, Version 3.
-
-using System;
-using System.Runtime.CompilerServices;
-using System.Runtime.InteropServices;
-#if !NETSTANDARD2_0 && !NETSTANDARD2_1
-using System.Runtime.Intrinsics;
-using System.Runtime.Intrinsics.X86;
-#endif
-
-namespace SharpCompress.Algorithms
-{
-    /// <summary>
-    /// Calculates the 32 bit Adler checksum of a given buffer according to
-    /// RFC 1950. ZLIB Compressed Data Format Specification version 3.3)
-    /// </summary>
-    internal static class Adler32
-    {
-        /// <summary>
-        /// The default initial seed value of a Adler32 checksum calculation.
-        /// </summary>
-        public const uint SeedValue = 1U;
-
-#if !NETSTANDARD2_0 && !NETSTANDARD2_1
-        private const int MinBufferSize = 64;
-#endif
-
-        // Largest prime smaller than 65536
-        private const uint BASE = 65521;
-
-        // NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1
-        private const uint NMAX = 5552;
-
-        /// <summary>
-        /// Calculates the Adler32 checksum with the bytes taken from the span.
-        /// </summary>
-        /// <param name="buffer">The readonly span of bytes.</param>
-        /// <returns>The <see cref="uint"/>.</returns>
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        public static uint Calculate(ReadOnlySpan<byte> buffer)
-        {
-            return Calculate(SeedValue, buffer);
-        }
-
-        /// <summary>
-        /// Calculates the Adler32 checksum with the bytes taken from the span and seed.
-        /// </summary>
-        /// <param name="adler">The input Adler32 value.</param>
-        /// <param name="buffer">The readonly span of bytes.</param>
-        /// <returns>The <see cref="uint"/>.</returns>
-        public static uint Calculate(uint adler, ReadOnlySpan<byte> buffer)
-        {
-            if (buffer.IsEmpty)
-            {
-                return SeedValue;
-            }
-
-#if !NETSTANDARD2_0 && !NETSTANDARD2_1
-            if (Sse3.IsSupported && buffer.Length >= MinBufferSize)
-            {
-                return CalculateSse(adler, buffer);
-            }
-
-            return CalculateScalar(adler, buffer);
-#else
-            return CalculateScalar(adler, buffer);
-#endif
-        }
-
-        // Based on https://github.com/chromium/chromium/blob/master/third_party/zlib/adler32_simd.c
-#if !NETSTANDARD2_0 && !NETSTANDARD2_1
-        private static unsafe uint CalculateSse(uint adler, ReadOnlySpan<byte> buffer)
-        {
-            uint s1 = adler & 0xFFFF;
-            uint s2 = (adler >> 16) & 0xFFFF;
-
-            // Process the data in blocks.
-            const int BLOCK_SIZE = 1 << 5;
-
-            uint length = (uint)buffer.Length;
-            uint blocks = length / BLOCK_SIZE;
-            length -= blocks * BLOCK_SIZE;
-
-            int index = 0;
-            fixed (byte* bufferPtr = &buffer[0])
-            {
-                index += (int)blocks * BLOCK_SIZE;
-                var localBufferPtr = bufferPtr;
-
-                // _mm_setr_epi8 on x86
-                var tap1 = Vector128.Create(32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17);
-                var tap2 = Vector128.Create(16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1);
-                Vector128<byte> zero = Vector128<byte>.Zero;
-                var ones = Vector128.Create((short)1);
-
-                while (blocks > 0)
-                {
-                    uint n = NMAX / BLOCK_SIZE;  /* The NMAX constraint. */
-                    if (n > blocks)
-                    {
-                        n = blocks;
-                    }
-
-                    blocks -= n;
-
-                    // Process n blocks of data. At most NMAX data bytes can be
-                    // processed before s2 must be reduced modulo BASE.
-                    Vector128<int> v_ps = Vector128.CreateScalar(s1 * n).AsInt32();
-                    Vector128<int> v_s2 = Vector128.CreateScalar(s2).AsInt32();
-                    Vector128<int> v_s1 = Vector128<int>.Zero;
-
-                    do
-                    {
-                        // Load 32 input bytes.
-                        Vector128<byte> bytes1 = Sse3.LoadDquVector128(localBufferPtr);
-                        Vector128<byte> bytes2 = Sse3.LoadDquVector128(localBufferPtr + 16);
-
-                        // Add previous block byte sum to v_ps.
-                        v_ps = Sse2.Add(v_ps, v_s1);
-
-                        // Horizontally add the bytes for s1, multiply-adds the
-                        // bytes by [ 32, 31, 30, ... ] for s2.
-                        v_s1 = Sse2.Add(v_s1, Sse2.SumAbsoluteDifferences(bytes1, zero).AsInt32());
-                        Vector128<short> mad1 = Ssse3.MultiplyAddAdjacent(bytes1, tap1);
-                        v_s2 = Sse2.Add(v_s2, Sse2.MultiplyAddAdjacent(mad1, ones));
-
-                        v_s1 = Sse2.Add(v_s1, Sse2.SumAbsoluteDifferences(bytes2, zero).AsInt32());
-                        Vector128<short> mad2 = Ssse3.MultiplyAddAdjacent(bytes2, tap2);
-                        v_s2 = Sse2.Add(v_s2, Sse2.MultiplyAddAdjacent(mad2, ones));
-
-                        localBufferPtr += BLOCK_SIZE;
-                    }
-                    while (--n > 0);
-
-                    v_s2 = Sse2.Add(v_s2, Sse2.ShiftLeftLogical(v_ps, 5));
-
-                    // Sum epi32 ints v_s1(s2) and accumulate in s1(s2).
-                    const byte S2301 = 0b1011_0001;  // A B C D -> B A D C
-                    const byte S1032 = 0b0100_1110;  // A B C D -> C D A B
-
-                    v_s1 = Sse2.Add(v_s1, Sse2.Shuffle(v_s1, S2301));
-                    v_s1 = Sse2.Add(v_s1, Sse2.Shuffle(v_s1, S1032));
-
-                    s1 += (uint)v_s1.ToScalar();
-
-                    v_s2 = Sse2.Add(v_s2, Sse2.Shuffle(v_s2, S2301));
-                    v_s2 = Sse2.Add(v_s2, Sse2.Shuffle(v_s2, S1032));
-
-                    s2 = (uint)v_s2.ToScalar();
-
-                    // Reduce.
-                    s1 %= BASE;
-                    s2 %= BASE;
-                }
-            }
-
-            ref byte bufferRef = ref MemoryMarshal.GetReference(buffer);
-
-            if (length > 0)
-            {
-                if (length >= 16)
-                {
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    length -= 16;
-                }
-
-                while (length-- > 0)
-                {
-                    s2 += s1 += Unsafe.Add(ref bufferRef, index++);
-                }
-
-                if (s1 >= BASE)
-                {
-                    s1 -= BASE;
-                }
-
-                s2 %= BASE;
-            }
-
-            return s1 | (s2 << 16);
-        }
-#endif
-
-        private static uint CalculateScalar(uint adler, ReadOnlySpan<byte> buffer)
-        {
-            uint s1 = adler & 0xFFFF;
-            uint s2 = (adler >> 16) & 0xFFFF;
-            uint k;
-
-            ref byte bufferRef = ref MemoryMarshal.GetReference<byte>(buffer);
-            uint length = (uint)buffer.Length;
-            int index = 0;
-
-            while (length > 0)
-            {
-                k = length < NMAX ? length : NMAX;
-                length -= k;
-
-                while (k >= 16)
-                {
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    s1 += Unsafe.Add(ref bufferRef, index++);
-                    s2 += s1;
-                    k -= 16;
-                }
-
-                if (k != 0)
-                {
-                    do
-                    {
-                        s1 += Unsafe.Add(ref bufferRef, index++);
-                        s2 += s1;
-                    }
-                    while (--k != 0);
-                }
-
-                s1 %= BASE;
-                s2 %= BASE;
-            }
-
-            return (s2 << 16) | s1;
-        }
-    }
-}

src/SharpCompress/Archives/AbstractArchive.cs

@@ -2,25 +2,29 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Readers;
 
 namespace SharpCompress.Archives
 {
-    public abstract class AbstractArchive<TEntry, TVolume> : IArchive
+    public abstract class AbstractArchive<TEntry, TVolume> : IArchive, IArchiveExtractionListener
         where TEntry : IArchiveEntry
         where TVolume : IVolume
     {
         private readonly LazyReadOnlyCollection<TVolume> lazyVolumes;
         private readonly LazyReadOnlyCollection<TEntry> lazyEntries;
 
-        protected ReaderOptions ReaderOptions { get; } = new ();
+        public event EventHandler<ArchiveExtractionEventArgs<IArchiveEntry>>? EntryExtractionBegin;
+        public event EventHandler<ArchiveExtractionEventArgs<IArchiveEntry>>? EntryExtractionEnd;
+
+        public event EventHandler<CompressedBytesReadEventArgs>? CompressedBytesRead;
+        public event EventHandler<FilePartExtractionBeginEventArgs>? FilePartExtractionBegin;
+
+        protected ReaderOptions ReaderOptions { get; }
 
         private bool disposed;
 
-        internal AbstractArchive(ArchiveType type, FileInfo fileInfo, ReaderOptions readerOptions, CancellationToken cancellationToken)
+        internal AbstractArchive(ArchiveType type, FileInfo fileInfo, ReaderOptions readerOptions)
         {
             Type = type;
             if (!fileInfo.Exists)
@@ -29,30 +33,42 @@ namespace SharpCompress.Archives
             }
             ReaderOptions = readerOptions;
             readerOptions.LeaveStreamOpen = false;
-            lazyVolumes = new LazyReadOnlyCollection<TVolume>(LoadVolumes(fileInfo, cancellationToken));
-            lazyEntries = new LazyReadOnlyCollection<TEntry>(LoadEntries(Volumes, cancellationToken));
+            lazyVolumes = new LazyReadOnlyCollection<TVolume>(LoadVolumes(fileInfo));
+            lazyEntries = new LazyReadOnlyCollection<TEntry>(LoadEntries(Volumes));
         }
 
 
-        protected abstract IAsyncEnumerable<TVolume> LoadVolumes(FileInfo file, CancellationToken cancellationToken);
+        protected abstract IEnumerable<TVolume> LoadVolumes(FileInfo file);
 
-        internal AbstractArchive(ArchiveType type, IAsyncEnumerable<Stream> streams, ReaderOptions readerOptions, CancellationToken cancellationToken)
+        internal AbstractArchive(ArchiveType type, IEnumerable<Stream> streams, ReaderOptions readerOptions)
         {
             Type = type;
             ReaderOptions = readerOptions;
-            lazyVolumes = new LazyReadOnlyCollection<TVolume>(LoadVolumes(streams.Select(CheckStreams), cancellationToken));
-            lazyEntries = new LazyReadOnlyCollection<TEntry>(LoadEntries(Volumes, cancellationToken));
+            lazyVolumes = new LazyReadOnlyCollection<TVolume>(LoadVolumes(streams.Select(CheckStreams)));
+            lazyEntries = new LazyReadOnlyCollection<TEntry>(LoadEntries(Volumes));
         }
 
+#nullable disable
         internal AbstractArchive(ArchiveType type)
         {
             Type = type;
-            lazyVolumes = new LazyReadOnlyCollection<TVolume>( AsyncEnumerable.Empty<TVolume>());
-            lazyEntries = new LazyReadOnlyCollection<TEntry>(AsyncEnumerable.Empty<TEntry>());
+            lazyVolumes = new LazyReadOnlyCollection<TVolume>(Enumerable.Empty<TVolume>());
+            lazyEntries = new LazyReadOnlyCollection<TEntry>(Enumerable.Empty<TEntry>());
         }
+#nullable enable
 
         public ArchiveType Type { get; }
 
+        void IArchiveExtractionListener.FireEntryExtractionBegin(IArchiveEntry entry)
+        {
+            EntryExtractionBegin?.Invoke(this, new ArchiveExtractionEventArgs<IArchiveEntry>(entry));
+        }
+
+        void IArchiveExtractionListener.FireEntryExtractionEnd(IArchiveEntry entry)
+        {
+            EntryExtractionEnd?.Invoke(this, new ArchiveExtractionEventArgs<IArchiveEntry>(entry));
+        }
+
         private static Stream CheckStreams(Stream stream)
         {
             if (!stream.CanSeek || !stream.CanRead)
@@ -65,48 +81,63 @@ namespace SharpCompress.Archives
         /// <summary>
         /// Returns an ReadOnlyCollection of all the RarArchiveEntries across the one or many parts of the RarArchive.
         /// </summary>
-        public virtual IAsyncEnumerable<TEntry> Entries => lazyEntries;
+        public virtual ICollection<TEntry> Entries => lazyEntries;
 
         /// <summary>
         /// Returns an ReadOnlyCollection of all the RarArchiveVolumes across the one or many parts of the RarArchive.
         /// </summary>
-        public IAsyncEnumerable<TVolume> Volumes => lazyVolumes;
+        public ICollection<TVolume> Volumes => lazyVolumes;
 
         /// <summary>
         /// The total size of the files compressed in the archive.
         /// </summary>
-        public virtual async ValueTask<long> TotalSizeAsync()
-        {
-            await EnsureEntriesLoaded();
-            return await Entries.AggregateAsync(0L, (total, cf) => total + cf.CompressedSize);
-        }
+        public virtual long TotalSize => Entries.Aggregate(0L, (total, cf) => total + cf.CompressedSize);
 
         /// <summary>
         /// The total size of the files as uncompressed in the archive.
         /// </summary>
-        public virtual async ValueTask<long> TotalUncompressedSizeAsync()
-        {
-            await EnsureEntriesLoaded();
-            return await Entries.AggregateAsync(0L, (total, cf) => total + cf.Size);
-        }
+        public virtual long TotalUncompressSize => Entries.Aggregate(0L, (total, cf) => total + cf.Size);
 
-        protected abstract IAsyncEnumerable<TVolume> LoadVolumes(IAsyncEnumerable<Stream> streams, CancellationToken cancellationToken);
-        protected abstract IAsyncEnumerable<TEntry> LoadEntries(IAsyncEnumerable<TVolume> volumes, CancellationToken cancellationToken);
+        protected abstract IEnumerable<TVolume> LoadVolumes(IEnumerable<Stream> streams);
+        protected abstract IEnumerable<TEntry> LoadEntries(IEnumerable<TVolume> volumes);
 
-        IAsyncEnumerable<IArchiveEntry> IArchive.Entries => Entries.Select(x => (IArchiveEntry)x);
+        IEnumerable<IArchiveEntry> IArchive.Entries => Entries.Cast<IArchiveEntry>();
 
-        IAsyncEnumerable<IVolume> IArchive.Volumes => lazyVolumes.Select(x => (IVolume)x);
+        IEnumerable<IVolume> IArchive.Volumes => lazyVolumes.Cast<IVolume>();
 
-        public virtual async ValueTask DisposeAsync()
+        public virtual void Dispose()
         {
             if (!disposed)
             {
-                await lazyVolumes.ForEachAsync(async v => await v.DisposeAsync());
-                await lazyEntries.GetLoaded().Cast<Entry>().ForEachAsync(async x => await x.CloseAsync());
+                lazyVolumes.ForEach(v => v.Dispose());
+                lazyEntries.GetLoaded().Cast<Entry>().ForEach(x => x.Close());
                 disposed = true;
             }
         }
 
+        void IArchiveExtractionListener.EnsureEntriesLoaded()
+        {
+            lazyEntries.EnsureFullyLoaded();
+            lazyVolumes.EnsureFullyLoaded();
+        }
+
+        void IExtractionListener.FireCompressedBytesRead(long currentPartCompressedBytes, long compressedReadBytes)
+        {
+            CompressedBytesRead?.Invoke(this, new CompressedBytesReadEventArgs(
+                currentFilePartCompressedBytesRead: currentPartCompressedBytes,
+                compressedBytesRead: compressedReadBytes
+            ));
+        }
+
+        void IExtractionListener.FireFilePartExtractionBegin(string name, long size, long compressedSize)
+        {
+            FilePartExtractionBegin?.Invoke(this, new FilePartExtractionBeginEventArgs(
+                compressedSize: compressedSize,
+                size: size,
+                name: name
+            ));
+        }
+
         /// <summary>
         /// Use this method to extract all entries in an archive in order.
         /// This is primarily for SOLID Rar Archives or 7Zip Archives as they need to be
@@ -118,32 +149,29 @@ namespace SharpCompress.Archives
         /// occur if this is used at the same time as other extraction methods on this instance.
         /// </summary>
         /// <returns></returns>
-        public async ValueTask<IReader> ExtractAllEntries()
+        public IReader ExtractAllEntries()
         {
-            await EnsureEntriesLoaded();
-            return await CreateReaderForSolidExtraction();
-        }
-        
-        public async ValueTask EnsureEntriesLoaded()
-        {
-            await lazyEntries.EnsureFullyLoaded();
-            await lazyVolumes.EnsureFullyLoaded();
+            ((IArchiveExtractionListener)this).EnsureEntriesLoaded();
+            return CreateReaderForSolidExtraction();
         }
 
-        protected abstract ValueTask<IReader> CreateReaderForSolidExtraction();
+        protected abstract IReader CreateReaderForSolidExtraction();
 
         /// <summary>
         /// Archive is SOLID (this means the Archive saved bytes by reusing information which helps for archives containing many small files).
         /// </summary>
-        public virtual ValueTask<bool> IsSolidAsync() => new(false);
+        public virtual bool IsSolid => false;
 
         /// <summary>
         /// The archive can find all the parts of the archive needed to fully extract the archive.  This forces the parsing of the entire archive.
         /// </summary>
-        public async ValueTask<bool> IsCompleteAsync()
+        public bool IsComplete
         {
-            await EnsureEntriesLoaded();
-            return await Entries.AllAsync(x => x.IsComplete);
+            get
+            {
+                ((IArchiveExtractionListener)this).EnsureEntriesLoaded();
+                return Entries.All(x => x.IsComplete);
+            }
         }
     }
 }

src/SharpCompress/Archives/AbstractWritableArchive.cs

@@ -2,8 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Readers;
 using SharpCompress.Writers;
@@ -14,7 +12,7 @@ namespace SharpCompress.Archives
         where TEntry : IArchiveEntry
         where TVolume : IVolume
     {
-        private class RebuildPauseDisposable : IAsyncDisposable
+        private class RebuildPauseDisposable : IDisposable
         {
             private readonly AbstractWritableArchive<TEntry, TVolume> archive;
 
@@ -24,16 +22,16 @@ namespace SharpCompress.Archives
                 archive.pauseRebuilding = true;
             }
 
-            public async ValueTask DisposeAsync()
+            public void Dispose()
             {
                 archive.pauseRebuilding = false;
-                await archive.RebuildModifiedCollection();
+                archive.RebuildModifiedCollection();
             }
         }
-        private readonly List<TEntry> newEntries = new();
-        private readonly List<TEntry> removedEntries = new();
+        private readonly List<TEntry> newEntries = new List<TEntry>();
+        private readonly List<TEntry> removedEntries = new List<TEntry>();
 
-        private readonly List<TEntry> modifiedEntries = new();
+        private readonly List<TEntry> modifiedEntries = new List<TEntry>();
         private bool hasModifications;
         private bool pauseRebuilding;
 
@@ -42,36 +40,34 @@ namespace SharpCompress.Archives
         {
         }
 
-        internal AbstractWritableArchive(ArchiveType type, Stream stream, ReaderOptions readerFactoryOptions,
-                                         CancellationToken cancellationToken)
-            : base(type, stream.AsAsyncEnumerable(), readerFactoryOptions, cancellationToken)
+        internal AbstractWritableArchive(ArchiveType type, Stream stream, ReaderOptions readerFactoryOptions)
+            : base(type, stream.AsEnumerable(), readerFactoryOptions)
         {
         }
 
-        internal AbstractWritableArchive(ArchiveType type, FileInfo fileInfo, ReaderOptions readerFactoryOptions,
-                                         CancellationToken cancellationToken)
-            : base(type, fileInfo, readerFactoryOptions, cancellationToken)
+        internal AbstractWritableArchive(ArchiveType type, FileInfo fileInfo, ReaderOptions readerFactoryOptions)
+            : base(type, fileInfo, readerFactoryOptions)
         {
         }
 
-        public override IAsyncEnumerable<TEntry> Entries
+        public override ICollection<TEntry> Entries
         {
             get
             {
                 if (hasModifications)
                 {
-                    return modifiedEntries.ToAsyncEnumerable();
+                    return modifiedEntries;
                 }
                 return base.Entries;
             }
         }
 
-        public IAsyncDisposable PauseEntryRebuilding()
+        public IDisposable PauseEntryRebuilding()
         {
             return new RebuildPauseDisposable(this);
         }
 
-        private async ValueTask RebuildModifiedCollection()
+        private void RebuildModifiedCollection()
         {
             if (pauseRebuilding)
             {
@@ -80,57 +76,56 @@ namespace SharpCompress.Archives
             hasModifications = true;
             newEntries.RemoveAll(v => removedEntries.Contains(v));
             modifiedEntries.Clear();
-            modifiedEntries.AddRange(await OldEntries.Concat(newEntries.ToAsyncEnumerable()).ToListAsync());
+            modifiedEntries.AddRange(OldEntries.Concat(newEntries));
         }
 
-        private IAsyncEnumerable<TEntry> OldEntries { get { return base.Entries.Where(x => !removedEntries.Contains(x)); } }
+        private IEnumerable<TEntry> OldEntries { get { return base.Entries.Where(x => !removedEntries.Contains(x)); } }
 
-        public async ValueTask RemoveEntryAsync(TEntry entry)
+        public void RemoveEntry(TEntry entry)
         {
             if (!removedEntries.Contains(entry))
             {
                 removedEntries.Add(entry);
-                await RebuildModifiedCollection();
+                RebuildModifiedCollection();
             }
         }
 
-        ValueTask IWritableArchive.RemoveEntryAsync(IArchiveEntry entry, CancellationToken cancellationToken)
+        void IWritableArchive.RemoveEntry(IArchiveEntry entry)
         {
-            return RemoveEntryAsync((TEntry)entry);
+            RemoveEntry((TEntry)entry);
         }
 
-        public ValueTask<TEntry>  AddEntryAsync(string key, Stream source,
-                                                       long size = 0, DateTime? modified = null, 
-                                                       CancellationToken cancellationToken = default)
+        public TEntry AddEntry(string key, Stream source,
+                               long size = 0, DateTime? modified = null)
         {
-            return AddEntryAsync(key, source, false, size, modified, cancellationToken);
+            return AddEntry(key, source, false, size, modified);
         }
 
-        async ValueTask<IArchiveEntry> IWritableArchive.AddEntryAsync(string key, Stream source, bool closeStream, long size, DateTime? modified, CancellationToken cancellationToken)
+        IArchiveEntry IWritableArchive.AddEntry(string key, Stream source, bool closeStream, long size, DateTime? modified)
         {
-            return await AddEntryAsync(key, source, closeStream, size, modified, cancellationToken);
+            return AddEntry(key, source, closeStream, size, modified);
         }
 
-        public async ValueTask<TEntry> AddEntryAsync(string key, Stream source, bool closeStream,
-                                    long size = 0, DateTime? modified = null, CancellationToken cancellationToken = default)
+        public TEntry AddEntry(string key, Stream source, bool closeStream,
+                               long size = 0, DateTime? modified = null)
         {
             if (key.Length > 0 && key[0] is '/' or '\\')
             {
                 key = key.Substring(1);
             }
-            if (await DoesKeyMatchExisting(key))
+            if (DoesKeyMatchExisting(key))
             {
                 throw new ArchiveException("Cannot add entry with duplicate key: " + key);
             }
-            var entry = await CreateEntry(key, source, size, modified, closeStream, cancellationToken);
+            var entry = CreateEntry(key, source, size, modified, closeStream);
             newEntries.Add(entry);
-            await RebuildModifiedCollection();
+            RebuildModifiedCollection();
             return entry;
         }
 
-        private async ValueTask<bool> DoesKeyMatchExisting(string key)
+        private bool DoesKeyMatchExisting(string key)
         {
-            await foreach (var path in Entries.Select(x => x.Key))
+            foreach (var path in Entries.Select(x => x.Key))
             {
                 var p = path.Replace('/', '\\');
                 if (p.Length > 0 && p[0] == '\\')
@@ -142,35 +137,34 @@ namespace SharpCompress.Archives
             return false;
         }
 
-        public async ValueTask SaveToAsync(Stream stream, WriterOptions options, CancellationToken cancellationToken = default)
+        public void SaveTo(Stream stream, WriterOptions options)
         {
             //reset streams of new entries
             newEntries.Cast<IWritableArchiveEntry>().ForEach(x => x.Stream.Seek(0, SeekOrigin.Begin));
-            await SaveToAsync(stream, options, OldEntries, newEntries.ToAsyncEnumerable(), cancellationToken);
+            SaveTo(stream, options, OldEntries, newEntries);
         }
 
-        protected ValueTask<TEntry> CreateEntry(string key, Stream source, long size, DateTime? modified,
-                                                bool closeStream, CancellationToken cancellationToken)
+        protected TEntry CreateEntry(string key, Stream source, long size, DateTime? modified,
+                                     bool closeStream)
         {
             if (!source.CanRead || !source.CanSeek)
             {
                 throw new ArgumentException("Streams must be readable and seekable to use the Writing Archive API");
             }
-            return CreateEntryInternal(key, source, size, modified, closeStream, cancellationToken);
+            return CreateEntryInternal(key, source, size, modified, closeStream);
         }
 
-        protected abstract ValueTask<TEntry> CreateEntryInternal(string key, Stream source, long size, DateTime? modified,
-                                                      bool closeStream, CancellationToken cancellationToken);
+        protected abstract TEntry CreateEntryInternal(string key, Stream source, long size, DateTime? modified,
+                                                      bool closeStream);
 
-        protected abstract ValueTask SaveToAsync(Stream stream, WriterOptions options, IAsyncEnumerable<TEntry> oldEntries, IAsyncEnumerable<TEntry> newEntries,
-                                                 CancellationToken cancellationToken = default);
+        protected abstract void SaveTo(Stream stream, WriterOptions options, IEnumerable<TEntry> oldEntries, IEnumerable<TEntry> newEntries);
 
-        public override async ValueTask DisposeAsync()
+        public override void Dispose()
         {
-            await base.DisposeAsync();
-            await newEntries.Cast<Entry>().ForEachAsync(async x => await x.CloseAsync());
-            await removedEntries.Cast<Entry>().ForEachAsync(async x => await x.CloseAsync());
-            await modifiedEntries.Cast<Entry>().ForEachAsync(async x => await x.CloseAsync());
+            base.Dispose();
+            newEntries.Cast<Entry>().ForEach(x => x.Close());
+            removedEntries.Cast<Entry>().ForEach(x => x.Close());
+            modifiedEntries.Cast<Entry>().ForEach(x => x.Close());
         }
     }
 }

src/SharpCompress/Archives/ArchiveFactory.cs

@@ -1,10 +1,8 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Archives.GZip;
-//using SharpCompress.Archives.Rar;
-//using SharpCompress.Archives.SevenZip;
+using SharpCompress.Archives.Rar;
+using SharpCompress.Archives.SevenZip;
 using SharpCompress.Archives.Tar;
 using SharpCompress.Archives.Zip;
 using SharpCompress.Common;
@@ -20,7 +18,7 @@ namespace SharpCompress.Archives
         /// <param name="stream"></param>
         /// <param name="readerOptions"></param>
         /// <returns></returns>
-        public static async ValueTask<IArchive> OpenAsync(Stream stream, ReaderOptions? readerOptions = null, CancellationToken cancellationToken = default)
+        public static IArchive Open(Stream stream, ReaderOptions? readerOptions = null)
         {
             stream.CheckNotNull(nameof(stream));
             if (!stream.CanRead || !stream.CanSeek)
@@ -28,35 +26,35 @@ namespace SharpCompress.Archives
                 throw new ArgumentException("Stream should be readable and seekable");
             }
             readerOptions ??= new ReaderOptions();
-            if (await ZipArchive.IsZipFileAsync(stream, null, cancellationToken))
+            if (ZipArchive.IsZipFile(stream, null))
             {
                 stream.Seek(0, SeekOrigin.Begin);
                 return ZipArchive.Open(stream, readerOptions);
             }
             stream.Seek(0, SeekOrigin.Begin);
-            /*if (SevenZipArchive.IsSevenZipFile(stream))
+            if (SevenZipArchive.IsSevenZipFile(stream))
             {
                 stream.Seek(0, SeekOrigin.Begin);
                 return SevenZipArchive.Open(stream, readerOptions);
             }
-            stream.Seek(0, SeekOrigin.Begin);  */
-            if (await GZipArchive.IsGZipFileAsync(stream, cancellationToken))
+            stream.Seek(0, SeekOrigin.Begin);
+            if (GZipArchive.IsGZipFile(stream))
             {
                 stream.Seek(0, SeekOrigin.Begin);
                 return GZipArchive.Open(stream, readerOptions);
             }
             stream.Seek(0, SeekOrigin.Begin);
-           /* if (RarArchive.IsRarFile(stream, readerOptions))
+            if (RarArchive.IsRarFile(stream, readerOptions))
             {
                 stream.Seek(0, SeekOrigin.Begin);
                 return RarArchive.Open(stream, readerOptions);
             }
-            stream.Seek(0, SeekOrigin.Begin);  */
-            if (await TarArchive.IsTarFileAsync(stream, cancellationToken))
+            stream.Seek(0, SeekOrigin.Begin);
+            if (TarArchive.IsTarFile(stream))
             {
                 stream.Seek(0, SeekOrigin.Begin);
                 return TarArchive.Open(stream, readerOptions);
-            }                    
+            }
             throw new InvalidOperationException("Cannot determine compressed stream type. Supported Archive Formats: Zip, GZip, Tar, Rar, 7Zip, LZip");
         }
 
@@ -65,7 +63,7 @@ namespace SharpCompress.Archives
             return type switch
             {
                 ArchiveType.Zip => ZipArchive.Create(),
-                //ArchiveType.Tar => TarArchive.Create(),
+                ArchiveType.Tar => TarArchive.Create(),
                 ArchiveType.GZip => GZipArchive.Create(),
                 _ => throw new NotSupportedException("Cannot create Archives of type: " + type)
             };
@@ -76,10 +74,10 @@ namespace SharpCompress.Archives
         /// </summary>
         /// <param name="filePath"></param>
         /// <param name="options"></param>
-        public static ValueTask<IArchive> OpenAsync(string filePath, ReaderOptions? options = null)
+        public static IArchive Open(string filePath, ReaderOptions? options = null)
         {
             filePath.CheckNotNullOrEmpty(nameof(filePath));
-            return OpenAsync(new FileInfo(filePath), options);
+            return Open(new FileInfo(filePath), options);
         }
 
         /// <summary>
@@ -87,28 +85,28 @@ namespace SharpCompress.Archives
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="options"></param>
-        public static async ValueTask<IArchive> OpenAsync(FileInfo fileInfo, ReaderOptions? options = null, CancellationToken cancellationToken = default)
+        public static IArchive Open(FileInfo fileInfo, ReaderOptions? options = null)
         {
             fileInfo.CheckNotNull(nameof(fileInfo));
             options ??= new ReaderOptions { LeaveStreamOpen = false };
 
-            await using var stream = fileInfo.OpenRead();
-            if (await ZipArchive.IsZipFileAsync(stream, null, cancellationToken))
+            using var stream = fileInfo.OpenRead();
+            if (ZipArchive.IsZipFile(stream, null))
             {
                 return ZipArchive.Open(fileInfo, options);
             }
             stream.Seek(0, SeekOrigin.Begin);
-            /*if (SevenZipArchive.IsSevenZipFile(stream))
+            if (SevenZipArchive.IsSevenZipFile(stream))
             {
                 return SevenZipArchive.Open(fileInfo, options);
             }
-            stream.Seek(0, SeekOrigin.Begin);     */
-            if (await GZipArchive.IsGZipFileAsync(stream, cancellationToken))
+            stream.Seek(0, SeekOrigin.Begin);
+            if (GZipArchive.IsGZipFile(stream))
             {
                 return GZipArchive.Open(fileInfo, options);
             }
             stream.Seek(0, SeekOrigin.Begin);
-            /*if (RarArchive.IsRarFile(stream, options))
+            if (RarArchive.IsRarFile(stream, options))
             {
                 return RarArchive.Open(fileInfo, options);
             }
@@ -116,22 +114,20 @@ namespace SharpCompress.Archives
             if (TarArchive.IsTarFile(stream))
             {
                 return TarArchive.Open(fileInfo, options);
-            }                          */
+            }
             throw new InvalidOperationException("Cannot determine compressed stream type. Supported Archive Formats: Zip, GZip, Tar, Rar, 7Zip");
         }
 
         /// <summary>
         /// Extract to specific directory, retaining filename
         /// </summary>
-        public static async ValueTask WriteToDirectory(string sourceArchive, 
-                                                       string destinationDirectory,
-                                                 ExtractionOptions? options = null, 
-                                                 CancellationToken cancellationToken = default)
+        public static void WriteToDirectory(string sourceArchive, string destinationDirectory,
+                                            ExtractionOptions? options = null)
         {
-            await using IArchive archive = await OpenAsync(sourceArchive);
-            await foreach (IArchiveEntry entry in archive.Entries.WithCancellation(cancellationToken))
+            using IArchive archive = Open(sourceArchive);
+            foreach (IArchiveEntry entry in archive.Entries)
             {
-                await entry.WriteEntryToDirectoryAsync(destinationDirectory, options, cancellationToken);
+                entry.WriteToDirectory(destinationDirectory, options);
             }
         }
     }

src/SharpCompress/Archives/GZip/GZipArchive.cs

@@ -1,11 +1,7 @@
 using System;
-using System.Buffers;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Common.GZip;
 using SharpCompress.Readers;
@@ -33,11 +29,10 @@ namespace SharpCompress.Archives.GZip
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="readerOptions"></param>
-        public static GZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null,
-                                       CancellationToken cancellationToken = default)
+        public static GZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
         {
             fileInfo.CheckNotNull(nameof(fileInfo));
-            return new GZipArchive(fileInfo, readerOptions ?? new ReaderOptions(), cancellationToken);
+            return new GZipArchive(fileInfo, readerOptions ?? new ReaderOptions());
         }
 
         /// <summary>
@@ -45,11 +40,10 @@ namespace SharpCompress.Archives.GZip
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="readerOptions"></param>
-        public static GZipArchive Open(Stream stream, ReaderOptions? readerOptions = null,
-                                       CancellationToken cancellationToken = default)
+        public static GZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
         {
             stream.CheckNotNull(nameof(stream));
-            return new GZipArchive(stream, readerOptions ?? new ReaderOptions(), cancellationToken);
+            return new GZipArchive(stream, readerOptions ?? new ReaderOptions());
         }
 
         public static GZipArchive Create()
@@ -62,58 +56,57 @@ namespace SharpCompress.Archives.GZip
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="options"></param>
-        internal GZipArchive(FileInfo fileInfo, ReaderOptions options,
-                             CancellationToken cancellationToken)
-            : base(ArchiveType.GZip, fileInfo, options, cancellationToken)
+        internal GZipArchive(FileInfo fileInfo, ReaderOptions options)
+            : base(ArchiveType.GZip, fileInfo, options)
         {
         }
 
-        protected override IAsyncEnumerable<GZipVolume> LoadVolumes(FileInfo file,
-                                                                    CancellationToken cancellationToken)
+        protected override IEnumerable<GZipVolume> LoadVolumes(FileInfo file)
         {
-            return  new GZipVolume(file, ReaderOptions).AsAsyncEnumerable();
+            return new GZipVolume(file, ReaderOptions).AsEnumerable();
         }
 
-        public static ValueTask<bool> IsGZipFileAsync(string filePath, CancellationToken cancellationToken = default)
+        public static bool IsGZipFile(string filePath)
         {
-            return IsGZipFileAsync(new FileInfo(filePath), cancellationToken);
+            return IsGZipFile(new FileInfo(filePath));
         }
 
-        public static async ValueTask<bool> IsGZipFileAsync(FileInfo fileInfo, CancellationToken cancellationToken = default)
+        public static bool IsGZipFile(FileInfo fileInfo)
         {
             if (!fileInfo.Exists)
             {
                 return false;
             }
 
-            await using Stream stream = fileInfo.OpenRead();
-            return await IsGZipFileAsync(stream, cancellationToken);
+            using Stream stream = fileInfo.OpenRead();
+            return IsGZipFile(stream);
         }
 
-        public Task SaveToAsync(string filePath, CancellationToken cancellationToken = default)
+        public void SaveTo(string filePath)
         {
-            return SaveToAsync(new FileInfo(filePath), cancellationToken);
+            SaveTo(new FileInfo(filePath));
         }
 
-        public async Task SaveToAsync(FileInfo fileInfo, CancellationToken cancellationToken = default)
+        public void SaveTo(FileInfo fileInfo)
         {
-            await using var stream = fileInfo.Open(FileMode.Create, FileAccess.Write);
-            await SaveToAsync(stream, new WriterOptions(CompressionType.GZip), cancellationToken);
+            using (var stream = fileInfo.Open(FileMode.Create, FileAccess.Write))
+            {
+                SaveTo(stream, new WriterOptions(CompressionType.GZip));
+            }
         }
 
-        public static async ValueTask<bool> IsGZipFileAsync(Stream stream, CancellationToken cancellationToken = default)
+        public static bool IsGZipFile(Stream stream)
         {
             // read the header on the first read
-            using var header = MemoryPool<byte>.Shared.Rent(10);
-            var slice = header.Memory.Slice(0, 10);
+            Span<byte> header = stackalloc byte[10];
 
             // workitem 8501: handle edge case (decompress empty stream)
-            if (await stream.ReadAsync(slice, cancellationToken) != 10)
+            if (!stream.ReadFully(header))
             {
                 return false;
             }
 
-            if (slice.Span[0] != 0x1F || slice.Span[1] != 0x8B || slice.Span[2] != 8)
+            if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
             {
                 return false;
             }
@@ -126,9 +119,8 @@ namespace SharpCompress.Archives.GZip
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="options"></param>
-        internal GZipArchive(Stream stream, ReaderOptions options,
-                             CancellationToken cancellationToken)
-            : base(ArchiveType.GZip, stream, options, cancellationToken)
+        internal GZipArchive(Stream stream, ReaderOptions options)
+            : base(ArchiveType.GZip, stream, options)
         {
         }
 
@@ -137,54 +129,51 @@ namespace SharpCompress.Archives.GZip
         {
         }
 
-        protected override async ValueTask<GZipArchiveEntry> CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
-                                                                bool closeStream, CancellationToken cancellationToken = default)
+        protected override GZipArchiveEntry CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
+                                                                bool closeStream)
         {
-            if (await Entries.AnyAsync(cancellationToken: cancellationToken))
+            if (Entries.Any())
             {
                 throw new InvalidOperationException("Only one entry is allowed in a GZip Archive");
             }
             return new GZipWritableArchiveEntry(this, source, filePath, size, modified, closeStream);
         }
 
-        protected override async ValueTask SaveToAsync(Stream stream, WriterOptions options,
-                                            IAsyncEnumerable<GZipArchiveEntry> oldEntries,
-                                            IAsyncEnumerable<GZipArchiveEntry> newEntries, 
-                                            CancellationToken cancellationToken = default)
+        protected override void SaveTo(Stream stream, WriterOptions options,
+                                       IEnumerable<GZipArchiveEntry> oldEntries,
+                                       IEnumerable<GZipArchiveEntry> newEntries)
         {
-            if (await Entries.CountAsync(cancellationToken: cancellationToken) > 1)
+            if (Entries.Count > 1)
             {
                 throw new InvalidOperationException("Only one entry is allowed in a GZip Archive");
             }
-
-            await using var writer = new GZipWriter(stream, new GZipWriterOptions(options));
-            await foreach (var entry in oldEntries.Concat(newEntries)
-                                                  .Where(x => !x.IsDirectory)
-                                                  .WithCancellation(cancellationToken))
+            using (var writer = new GZipWriter(stream, new GZipWriterOptions(options)))
             {
-                await using var entryStream = await entry.OpenEntryStreamAsync(cancellationToken);
-                await writer.WriteAsync(entry.Key, entryStream, entry.LastModifiedTime, cancellationToken);
+                foreach (var entry in oldEntries.Concat(newEntries)
+                                                .Where(x => !x.IsDirectory))
+                {
+                    using (var entryStream = entry.OpenEntryStream())
+                    {
+                        writer.Write(entry.Key, entryStream, entry.LastModifiedTime);
+                    }
+                }
             }
         }
 
-        protected override async IAsyncEnumerable<GZipVolume> LoadVolumes(IAsyncEnumerable<Stream> streams,
-                                                                          [EnumeratorCancellation]CancellationToken cancellationToken)
+        protected override IEnumerable<GZipVolume> LoadVolumes(IEnumerable<Stream> streams)
         {
-            yield return new GZipVolume(await streams.FirstAsync(cancellationToken: cancellationToken), ReaderOptions);
+            return new GZipVolume(streams.First(), ReaderOptions).AsEnumerable();
         }
 
-        protected override async IAsyncEnumerable<GZipArchiveEntry> LoadEntries(IAsyncEnumerable<GZipVolume> volumes,
-                                                                                [EnumeratorCancellation]CancellationToken cancellationToken)
+        protected override IEnumerable<GZipArchiveEntry> LoadEntries(IEnumerable<GZipVolume> volumes)
         {
-            Stream stream = (await volumes.SingleAsync(cancellationToken: cancellationToken)).Stream;
-            var part = new GZipFilePart(ReaderOptions.ArchiveEncoding);
-            await part.Initialize(stream, cancellationToken);
-            yield return new GZipArchiveEntry(this, part);
+            Stream stream = volumes.Single().Stream;
+            yield return new GZipArchiveEntry(this, new GZipFilePart(stream, ReaderOptions.ArchiveEncoding));
         }
 
-        protected override async ValueTask<IReader> CreateReaderForSolidExtraction()
+        protected override IReader CreateReaderForSolidExtraction()
         {
-            var stream = (await Volumes.SingleAsync()).Stream;
+            var stream = Volumes.Single().Stream;
             stream.Position = 0;
             return GZipReader.Open(stream);
         }

src/SharpCompress/Archives/GZip/GZipArchiveEntry.cs

@@ -1,7 +1,5 @@
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.GZip;
 
 namespace SharpCompress.Archives.GZip
@@ -14,7 +12,7 @@ namespace SharpCompress.Archives.GZip
             Archive = archive;
         }
 
-        public virtual async ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public virtual Stream OpenEntryStream()
         {
             //this is to reset the stream to be read multiple times
             var part = (GZipFilePart)Parts.Single();
@@ -22,7 +20,7 @@ namespace SharpCompress.Archives.GZip
             {
                 part.GetRawStream().Position = part.EntryStartPosition;
             }
-            return await Parts.Single().GetCompressedStreamAsync(cancellationToken);
+            return Parts.Single().GetCompressedStream();
         }
 
         #region IArchiveEntry Members

src/SharpCompress/Archives/GZip/GZipWritableArchiveEntry.cs

@@ -3,8 +3,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.IO;
 
@@ -52,18 +50,18 @@ namespace SharpCompress.Archives.GZip
 
         Stream IWritableArchiveEntry.Stream => stream;
 
-        public override ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public override Stream OpenEntryStream()
         {
             //ensure new stream is at the start, this could be reset
             stream.Seek(0, SeekOrigin.Begin);
-            return new(new NonDisposingStream(stream));
+            return new NonDisposingStream(stream);
         }
 
-        internal override async ValueTask CloseAsync()
+        internal override void Close()
         {
             if (closeStream)
             {
-                await stream.DisposeAsync();
+                stream.Dispose();
             }
         }
     }

src/SharpCompress/Archives/IArchive.cs

@@ -1,44 +1,49 @@
 using System;
 using System.Collections.Generic;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Readers;
 
 namespace SharpCompress.Archives
 {
-    public interface IArchive : IAsyncDisposable
+    public interface IArchive : IDisposable
     {
-        IAsyncEnumerable<IArchiveEntry> Entries { get; }
-        IAsyncEnumerable<IVolume> Volumes { get; }
+        event EventHandler<ArchiveExtractionEventArgs<IArchiveEntry>> EntryExtractionBegin;
+        event EventHandler<ArchiveExtractionEventArgs<IArchiveEntry>> EntryExtractionEnd;
+
+        event EventHandler<CompressedBytesReadEventArgs> CompressedBytesRead;
+        event EventHandler<FilePartExtractionBeginEventArgs> FilePartExtractionBegin;
+
+        IEnumerable<IArchiveEntry> Entries { get; }
+        IEnumerable<IVolume> Volumes { get; }
 
         ArchiveType Type { get; }
-        ValueTask EnsureEntriesLoaded();
+
         /// <summary>
         /// Use this method to extract all entries in an archive in order.
         /// This is primarily for SOLID Rar Archives or 7Zip Archives as they need to be 
         /// extracted sequentially for the best performance.
         /// </summary>
-        ValueTask<IReader> ExtractAllEntries();
+        IReader ExtractAllEntries();
 
         /// <summary>
         /// Archive is SOLID (this means the Archive saved bytes by reusing information which helps for archives containing many small files).
         /// Rar Archives can be SOLID while all 7Zip archives are considered SOLID.
         /// </summary>
-        ValueTask<bool> IsSolidAsync();
+        bool IsSolid { get; }
 
         /// <summary>
         /// This checks to see if all the known entries have IsComplete = true
         /// </summary>
-        ValueTask<bool> IsCompleteAsync();
+        bool IsComplete { get; }
 
         /// <summary>
         /// The total size of the files compressed in the archive.
         /// </summary>
-        ValueTask<long> TotalSizeAsync();
+        long TotalSize { get; }
 
         /// <summary>
         /// The total size of the files as uncompressed in the archive.
         /// </summary>
-        ValueTask<long> TotalUncompressedSizeAsync();
+        long TotalUncompressSize { get; }
     }
 }

src/SharpCompress/Archives/IArchiveEntry.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 
 namespace SharpCompress.Archives
@@ -11,7 +9,7 @@ namespace SharpCompress.Archives
         /// Opens the current entry as a stream that will decompress as it is read.
         /// Read the entire stream or use SkipEntry on EntryStream.
         /// </summary>
-        ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default);
+        Stream OpenEntryStream();
 
         /// <summary>
         /// The archive can find all the parts of the archive needed to extract this entry.

src/SharpCompress/Archives/IArchiveEntryExtensions.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.IO;
 
@@ -8,53 +6,58 @@ namespace SharpCompress.Archives
 {
     public static class IArchiveEntryExtensions
     {
-        public static async ValueTask WriteToAsync(this IArchiveEntry archiveEntry, Stream streamToWriteTo, CancellationToken cancellationToken = default)
+        public static void WriteTo(this IArchiveEntry archiveEntry, Stream streamToWriteTo)
         {
             if (archiveEntry.IsDirectory)
             {
                 throw new ExtractionException("Entry is a file directory and cannot be extracted.");
             }
 
-            var archive = archiveEntry.Archive;
-            await archive.EnsureEntriesLoaded();
-            var entryStream = await archiveEntry.OpenEntryStreamAsync(cancellationToken);
+            var streamListener = (IArchiveExtractionListener)archiveEntry.Archive;
+            streamListener.EnsureEntriesLoaded();
+            streamListener.FireEntryExtractionBegin(archiveEntry);
+            streamListener.FireFilePartExtractionBegin(archiveEntry.Key, archiveEntry.Size, archiveEntry.CompressedSize);
+            var entryStream = archiveEntry.OpenEntryStream();
             if (entryStream is null)
             {
                 return;
             }
-            await using (entryStream)
+            using (entryStream)
             {
-                await entryStream.TransferToAsync(streamToWriteTo, cancellationToken);
+                using (Stream s = new ListeningStream(streamListener, entryStream))
+                {
+                    s.TransferTo(streamToWriteTo);
+                }
             }
+            streamListener.FireEntryExtractionEnd(archiveEntry);
         }
 
         /// <summary>
         /// Extract to specific directory, retaining filename
         /// </summary>
-        public static ValueTask WriteEntryToDirectoryAsync(this IArchiveEntry entry, 
-                                                           string destinationDirectory,
-                                                           ExtractionOptions? options = null, 
-                                                           CancellationToken cancellationToken = default)
+        public static void WriteToDirectory(this IArchiveEntry entry, string destinationDirectory,
+                                            ExtractionOptions? options = null)
         {
-            return ExtractionMethods.WriteEntryToDirectoryAsync(entry, destinationDirectory, options,
-                                              entry.WriteToFileAsync, cancellationToken);
+            ExtractionMethods.WriteEntryToDirectory(entry, destinationDirectory, options,
+                                              entry.WriteToFile);
         }
 
         /// <summary>
         /// Extract to specific file
         /// </summary>
-        public static ValueTask WriteToFileAsync(this IArchiveEntry entry,
+        public static void WriteToFile(this IArchiveEntry entry,
                                        string destinationFileName,
-                                       ExtractionOptions? options = null, 
-                                       CancellationToken cancellationToken = default)
+                                       ExtractionOptions? options = null)
         {
 
-            return ExtractionMethods.WriteEntryToFileAsync(entry, destinationFileName, options,
-                                               async (x, fm, ct) =>
+            ExtractionMethods.WriteEntryToFile(entry, destinationFileName, options,
+                                               (x, fm) =>
                                                {
-                                                   await using FileStream fs = File.Open(x, fm);
-                                                   await entry.WriteToAsync(fs, ct);
-                                               }, cancellationToken);
+                                                   using (FileStream fs = File.Open(destinationFileName, fm))
+                                                   {
+                                                       entry.WriteTo(fs);
+                                                   }
+                                               });
         }
     }
 }

src/SharpCompress/Archives/IArchiveExtensions.cs

@@ -1,6 +1,4 @@
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 
 namespace SharpCompress.Archives
@@ -10,14 +8,12 @@ namespace SharpCompress.Archives
         /// <summary>
         /// Extract to specific directory, retaining filename
         /// </summary>
-        public static async ValueTask WriteToDirectoryAsync(this IArchive archive, 
-                                            string destinationDirectory,
-                                            ExtractionOptions? options = null,
-                                            CancellationToken cancellationToken = default)
+        public static void WriteToDirectory(this IArchive archive, string destinationDirectory,
+                                            ExtractionOptions? options = null)
         {
-            await foreach (IArchiveEntry entry in archive.Entries.Where(x => !x.IsDirectory).WithCancellation(cancellationToken))
+            foreach (IArchiveEntry entry in archive.Entries.Where(x => !x.IsDirectory))
             {
-                await entry.WriteEntryToDirectoryAsync(destinationDirectory, options, cancellationToken);
+                entry.WriteToDirectory(destinationDirectory, options);
             }
         }
     }

src/SharpCompress/Archives/IArchiveExtractionListener.cs

@@ -0,0 +1,11 @@
+using SharpCompress.Common;
+
+namespace SharpCompress.Archives
+{
+    internal interface IArchiveExtractionListener : IExtractionListener
+    {
+        void EnsureEntriesLoaded();
+        void FireEntryExtractionBegin(IArchiveEntry entry);
+        void FireEntryExtractionEnd(IArchiveEntry entry);
+    }
+}

src/SharpCompress/Archives/IWritableArchive.cs

@@ -1,23 +1,21 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Writers;
 
 namespace SharpCompress.Archives
 {
     public interface IWritableArchive : IArchive
     {
-        ValueTask RemoveEntryAsync(IArchiveEntry entry, CancellationToken cancellationToken = default);
+        void RemoveEntry(IArchiveEntry entry);
 
-        ValueTask<IArchiveEntry> AddEntryAsync(string key, Stream source, bool closeStream, long size = 0, DateTime? modified = null, CancellationToken cancellationToken = default);
+        IArchiveEntry AddEntry(string key, Stream source, bool closeStream, long size = 0, DateTime? modified = null);
 
-        ValueTask SaveToAsync(Stream stream, WriterOptions options, CancellationToken cancellationToken = default);
+        void SaveTo(Stream stream, WriterOptions options);
 
         /// <summary>
         /// Use this to pause entry rebuilding when adding large collections of entries.  Dispose when complete.  A  using statement is recommended.
         /// </summary>
         /// <returns>IDisposeable to resume entry rebuilding</returns>
-        IAsyncDisposable PauseEntryRebuilding();
+        IDisposable PauseEntryRebuilding();
     }
 }

src/SharpCompress/Archives/IWritableArchiveExtensions.cs

@@ -1,62 +1,57 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Writers;
 
 namespace SharpCompress.Archives
 {
     public static class IWritableArchiveExtensions
     {
-        public static async ValueTask AddEntryAsync(this IWritableArchive writableArchive,
-                                         string entryPath, string filePath, 
-                                         CancellationToken cancellationToken = default)
+        public static void AddEntry(this IWritableArchive writableArchive,
+                                                     string entryPath, string filePath)
         {
             var fileInfo = new FileInfo(filePath);
             if (!fileInfo.Exists)
             {
                 throw new FileNotFoundException("Could not AddEntry: " + filePath);
             }
-            await writableArchive.AddEntryAsync(entryPath, new FileInfo(filePath).OpenRead(), true, fileInfo.Length,
-                                     fileInfo.LastWriteTime, cancellationToken);
+            writableArchive.AddEntry(entryPath, new FileInfo(filePath).OpenRead(), true, fileInfo.Length,
+                                     fileInfo.LastWriteTime);
         }
 
-        public static Task SaveToAsync(this IWritableArchive writableArchive, string filePath, WriterOptions options, CancellationToken cancellationToken = default)
+        public static void SaveTo(this IWritableArchive writableArchive, string filePath, WriterOptions options)
         {
-            return writableArchive.SaveToAsync(new FileInfo(filePath), options, cancellationToken);
+            writableArchive.SaveTo(new FileInfo(filePath), options);
         }
 
-        public static async Task SaveToAsync(this IWritableArchive writableArchive, FileInfo fileInfo, WriterOptions options, CancellationToken cancellationToken = default)
+        public static void SaveTo(this IWritableArchive writableArchive, FileInfo fileInfo, WriterOptions options)
         {
-            await using var stream = fileInfo.Open(FileMode.Create, FileAccess.Write);
-            await writableArchive.SaveToAsync(stream, options, cancellationToken);
+            using (var stream = fileInfo.Open(FileMode.Create, FileAccess.Write))
+            {
+                writableArchive.SaveTo(stream, options);
+            }
         }
 
-        public static async ValueTask AddAllFromDirectoryAsync(
+        public static void AddAllFromDirectory(
             this IWritableArchive writableArchive,
-            string filePath, string searchPattern = "*.*", 
-            SearchOption searchOption = SearchOption.AllDirectories,
-            CancellationToken cancellationToken = default)
+            string filePath, string searchPattern = "*.*", SearchOption searchOption = SearchOption.AllDirectories)
         {
-            await using (writableArchive.PauseEntryRebuilding())
+            using (writableArchive.PauseEntryRebuilding())
             {
                 foreach (var path in Directory.EnumerateFiles(filePath, searchPattern, searchOption))
                 {
                     var fileInfo = new FileInfo(path);
-                    await writableArchive.AddEntryAsync(path.Substring(filePath.Length), fileInfo.OpenRead(), true, fileInfo.Length,
-                                            fileInfo.LastWriteTime,
-                                            cancellationToken);
+                    writableArchive.AddEntry(path.Substring(filePath.Length), fileInfo.OpenRead(), true, fileInfo.Length,
+                                            fileInfo.LastWriteTime);
                 }
             }
         }
-        public static ValueTask<IArchiveEntry> AddEntryAsync(this IWritableArchive writableArchive, string key, FileInfo fileInfo,
-                                                  CancellationToken cancellationToken = default)
+        public static IArchiveEntry AddEntry(this IWritableArchive writableArchive, string key, FileInfo fileInfo)
         {
             if (!fileInfo.Exists)
             {
                 throw new ArgumentException("FileInfo does not exist.");
             }
-            return writableArchive.AddEntryAsync(key, fileInfo.OpenRead(), true, fileInfo.Length, fileInfo.LastWriteTime, cancellationToken);
+            return writableArchive.AddEntry(key, fileInfo.OpenRead(), true, fileInfo.Length, fileInfo.LastWriteTime);
         }
     }
 }

src/SharpCompress/Archives/Rar/RarArchive.cs

@@ -10,7 +10,7 @@ using SharpCompress.Readers.Rar;
 
 namespace SharpCompress.Archives.Rar
 {
-    public class 
+    public class
         RarArchive : AbstractArchive<RarArchiveEntry, RarVolume>
     {
         internal Lazy<IRarUnpack> UnpackV2017 { get; } = new Lazy<IRarUnpack>(() => new SharpCompress.Compressors.Rar.UnpackV2017.Unpack());

src/SharpCompress/Archives/Tar/TarArchive.cs

@@ -2,9 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Common.Tar;
 using SharpCompress.Common.Tar.Headers;
@@ -34,11 +31,10 @@ namespace SharpCompress.Archives.Tar
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="readerOptions"></param>
-        public static TarArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null,
-                                      CancellationToken cancellationToken = default)
+        public static TarArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
         {
             fileInfo.CheckNotNull(nameof(fileInfo));
-            return new TarArchive(fileInfo, readerOptions ?? new ReaderOptions(), cancellationToken);
+            return new TarArchive(fileInfo, readerOptions ?? new ReaderOptions());
         }
 
         /// <summary>
@@ -46,35 +42,35 @@ namespace SharpCompress.Archives.Tar
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="readerOptions"></param>
-        public static TarArchive Open(Stream stream, ReaderOptions? readerOptions = null,
-                    CancellationToken cancellationToken = default)
+        public static TarArchive Open(Stream stream, ReaderOptions? readerOptions = null)
         {
             stream.CheckNotNull(nameof(stream));
-            return new TarArchive(stream, readerOptions ?? new ReaderOptions(), cancellationToken);
+            return new TarArchive(stream, readerOptions ?? new ReaderOptions());
         }
 
-        public static ValueTask<bool> IsTarFileAsync(string filePath, CancellationToken cancellationToken = default)
+        public static bool IsTarFile(string filePath)
         {
-            return IsTarFileAsync(new FileInfo(filePath), cancellationToken);
+            return IsTarFile(new FileInfo(filePath));
         }
 
-        public static async ValueTask<bool> IsTarFileAsync(FileInfo fileInfo, CancellationToken cancellationToken = default)
+        public static bool IsTarFile(FileInfo fileInfo)
         {
             if (!fileInfo.Exists)
             {
                 return false;
             }
-
-            await using Stream stream = fileInfo.OpenRead();
-            return await IsTarFileAsync(stream, cancellationToken);
+            using (Stream stream = fileInfo.OpenRead())
+            {
+                return IsTarFile(stream);
+            }
         }
 
-        public static async ValueTask<bool> IsTarFileAsync(Stream stream, CancellationToken cancellationToken = default)
+        public static bool IsTarFile(Stream stream)
         {
             try
             {
-                TarHeader tarHeader = new(new ArchiveEncoding());
-                bool readSucceeded = await tarHeader.Read(stream, cancellationToken);
+                TarHeader tarHeader = new TarHeader(new ArchiveEncoding());
+                bool readSucceeded = tarHeader.Read(new BinaryReader(stream));
                 bool isEmptyArchive = tarHeader.Name.Length == 0 && tarHeader.Size == 0 && Enum.IsDefined(typeof(EntryType), tarHeader.EntryType);
                 return readSucceeded || isEmptyArchive;
             }
@@ -89,15 +85,14 @@ namespace SharpCompress.Archives.Tar
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="readerOptions"></param>
-        internal TarArchive(FileInfo fileInfo, ReaderOptions readerOptions,
-                            CancellationToken cancellationToken)
-            : base(ArchiveType.Tar, fileInfo, readerOptions, cancellationToken)
+        internal TarArchive(FileInfo fileInfo, ReaderOptions readerOptions)
+            : base(ArchiveType.Tar, fileInfo, readerOptions)
         {
         }
 
-        protected override IAsyncEnumerable<TarVolume> LoadVolumes(FileInfo file, CancellationToken cancellationToken)
+        protected override IEnumerable<TarVolume> LoadVolumes(FileInfo file)
         {
-            return new TarVolume(file.OpenRead(), ReaderOptions).AsAsyncEnumerable();
+            return new TarVolume(file.OpenRead(), ReaderOptions).AsEnumerable();
         }
 
         /// <summary>
@@ -105,9 +100,8 @@ namespace SharpCompress.Archives.Tar
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="readerOptions"></param>
-        internal TarArchive(Stream stream, ReaderOptions readerOptions,
-                            CancellationToken cancellationToken)
-            : base(ArchiveType.Tar, stream, readerOptions, cancellationToken)
+        internal TarArchive(Stream stream, ReaderOptions readerOptions)
+            : base(ArchiveType.Tar, stream, readerOptions)
         {
         }
 
@@ -116,18 +110,16 @@ namespace SharpCompress.Archives.Tar
         {
         }
 
-        protected override async IAsyncEnumerable<TarVolume> LoadVolumes(IAsyncEnumerable<Stream> streams, 
-                                                                         [EnumeratorCancellation]CancellationToken cancellationToken)
+        protected override IEnumerable<TarVolume> LoadVolumes(IEnumerable<Stream> streams)
         {
-            yield return new TarVolume(await streams.FirstAsync(cancellationToken: cancellationToken), ReaderOptions);
+            return new TarVolume(streams.First(), ReaderOptions).AsEnumerable();
         }
 
-        protected override async IAsyncEnumerable<TarArchiveEntry> LoadEntries(IAsyncEnumerable<TarVolume> volumes, 
-                                                                               [EnumeratorCancellation]CancellationToken cancellationToken)
+        protected override IEnumerable<TarArchiveEntry> LoadEntries(IEnumerable<TarVolume> volumes)
         {
-            Stream stream = (await volumes.SingleAsync(cancellationToken: cancellationToken)).Stream;
+            Stream stream = volumes.Single().Stream;
             TarHeader? previousHeader = null;
-            await foreach (TarHeader? header in TarHeaderFactory.ReadHeader(StreamingMode.Seekable, stream, ReaderOptions.ArchiveEncoding, cancellationToken))
+            foreach (TarHeader? header in TarHeaderFactory.ReadHeader(StreamingMode.Seekable, stream, ReaderOptions.ArchiveEncoding))
             {
                 if (header != null)
                 {
@@ -144,11 +136,11 @@ namespace SharpCompress.Archives.Tar
 
                             var oldStreamPos = stream.Position;
 
-                            await using (var entryStream = await entry.OpenEntryStreamAsync(cancellationToken))
+                            using (var entryStream = entry.OpenEntryStream())
                             {
-                                await using (var memoryStream = new MemoryStream())
+                                using (var memoryStream = new MemoryStream())
                                 {
-                                    await entryStream.TransferToAsync(memoryStream, cancellationToken);
+                                    entryStream.TransferTo(memoryStream);
                                     memoryStream.Position = 0;
                                     var bytes = memoryStream.ToArray();
 
@@ -168,37 +160,38 @@ namespace SharpCompress.Archives.Tar
 
         public static TarArchive Create()
         {
-            return new();
+            return new TarArchive();
         }
 
-        protected override ValueTask<TarArchiveEntry> CreateEntryInternal(string filePath, Stream source,
-                                                               long size, DateTime? modified, bool closeStream,
-                                                               CancellationToken cancellationToken)
+        protected override TarArchiveEntry CreateEntryInternal(string filePath, Stream source,
+                                                               long size, DateTime? modified, bool closeStream)
         {
-            return new (new TarWritableArchiveEntry(this, source, CompressionType.Unknown, filePath, size, modified,
-                                               closeStream));
+            return new TarWritableArchiveEntry(this, source, CompressionType.Unknown, filePath, size, modified,
+                                               closeStream);
         }
 
-        protected override async ValueTask SaveToAsync(Stream stream, WriterOptions options,
-                                                       IAsyncEnumerable<TarArchiveEntry> oldEntries,
-                                                       IAsyncEnumerable<TarArchiveEntry> newEntries,
-                                                       CancellationToken cancellationToken = default)
+        protected override void SaveTo(Stream stream, WriterOptions options,
+                                       IEnumerable<TarArchiveEntry> oldEntries,
+                                       IEnumerable<TarArchiveEntry> newEntries)
         {
-            await using var writer = await TarWriter.CreateAsync(stream, new TarWriterOptions(options), cancellationToken);
-            await foreach (var entry in oldEntries.Concat(newEntries)
-                                                  .Where(x => !x.IsDirectory)
-                                                  .WithCancellation(cancellationToken))
+            using (var writer = new TarWriter(stream, new TarWriterOptions(options)))
             {
-                await using var entryStream = await entry.OpenEntryStreamAsync(cancellationToken);
-                await writer.WriteAsync(entry.Key, entryStream, entry.LastModifiedTime, entry.Size, cancellationToken);
+                foreach (var entry in oldEntries.Concat(newEntries)
+                                                .Where(x => !x.IsDirectory))
+                {
+                    using (var entryStream = entry.OpenEntryStream())
+                    {
+                        writer.Write(entry.Key, entryStream, entry.LastModifiedTime, entry.Size);
+                    }
+                }
             }
         }
 
-        protected override async ValueTask<IReader> CreateReaderForSolidExtraction()
+        protected override IReader CreateReaderForSolidExtraction()
         {
-            var stream = (await Volumes.SingleAsync()).Stream;
+            var stream = Volumes.Single().Stream;
             stream.Position = 0;
-            return await TarReader.OpenAsync(stream);
+            return TarReader.Open(stream);
         }
     }
 }

src/SharpCompress/Archives/Tar/TarArchiveEntry.cs

@@ -1,7 +1,5 @@
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Common.Tar;
 
@@ -15,9 +13,9 @@ namespace SharpCompress.Archives.Tar
             Archive = archive;
         }
 
-        public virtual async ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public virtual Stream OpenEntryStream()
         {
-            return await Parts.Single().GetCompressedStreamAsync(cancellationToken);
+            return Parts.Single().GetCompressedStream();
         }
 
         #region IArchiveEntry Members

src/SharpCompress/Archives/Tar/TarWritableArchiveEntry.cs

@@ -3,8 +3,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.IO;
 
@@ -51,18 +49,18 @@ namespace SharpCompress.Archives.Tar
         internal override IEnumerable<FilePart> Parts => throw new NotImplementedException();
         Stream IWritableArchiveEntry.Stream => stream;
 
-        public override ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public override Stream OpenEntryStream()
         {
             //ensure new stream is at the start, this could be reset
             stream.Seek(0, SeekOrigin.Begin);
-            return new(new NonDisposingStream(stream));
+            return new NonDisposingStream(stream);
         }
 
-        internal override async ValueTask CloseAsync()
+        internal override void Close()
         {
             if (closeStream)
             {
-                await stream.DisposeAsync();
+                stream.Dispose();
             }
         }
     }

src/SharpCompress/Archives/Zip/ZipArchive.cs

@@ -2,14 +2,10 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Common.Zip;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.Compressors.Deflate;
-using SharpCompress.IO;
 using SharpCompress.Readers;
 using SharpCompress.Readers.Zip;
 using SharpCompress.Writers;
@@ -45,11 +41,10 @@ namespace SharpCompress.Archives.Zip
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="readerOptions"></param>
-        public static ZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null,
-                                      CancellationToken cancellationToken = default)
+        public static ZipArchive Open(FileInfo fileInfo, ReaderOptions? readerOptions = null)
         {
             fileInfo.CheckNotNull(nameof(fileInfo));
-            return new ZipArchive(fileInfo, readerOptions ?? new ReaderOptions(), cancellationToken);
+            return new ZipArchive(fileInfo, readerOptions ?? new ReaderOptions());
         }
 
         /// <summary>
@@ -57,45 +52,35 @@ namespace SharpCompress.Archives.Zip
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="readerOptions"></param>
-        public static ZipArchive Open(Stream stream, ReaderOptions? readerOptions = null,
-                                      CancellationToken cancellationToken = default)
+        public static ZipArchive Open(Stream stream, ReaderOptions? readerOptions = null)
         {
             stream.CheckNotNull(nameof(stream));
-            return new ZipArchive(stream, readerOptions ?? new ReaderOptions(), cancellationToken);
+            return new ZipArchive(stream, readerOptions ?? new ReaderOptions());
         }
 
-        public static ValueTask<bool> IsZipFile(string filePath, string? password = null)
+        public static bool IsZipFile(string filePath, string? password = null)
         {
-            return IsZipFileAsync(new FileInfo(filePath), password);
+            return IsZipFile(new FileInfo(filePath), password);
         }
 
-        public static async ValueTask<bool> IsZipFileAsync(FileInfo fileInfo, string? password = null)
+        public static bool IsZipFile(FileInfo fileInfo, string? password = null)
         {
             if (!fileInfo.Exists)
             {
                 return false;
             }
-
-            await using Stream stream = fileInfo.OpenRead();
-            return await IsZipFileAsync(stream, password);
+            using (Stream stream = fileInfo.OpenRead())
+            {
+                return IsZipFile(stream, password);
+            }
         }
 
-        public static async ValueTask<bool> IsZipFileAsync(Stream stream, string? password = null, CancellationToken cancellationToken = default)
+        public static bool IsZipFile(Stream stream, string? password = null)
         {
-            StreamingZipHeaderFactory headerFactory = new(password, new ArchiveEncoding());
+            StreamingZipHeaderFactory headerFactory = new StreamingZipHeaderFactory(password, new ArchiveEncoding());
             try
             {
-                RewindableStream rewindableStream;
-                if (stream is RewindableStream rs)
-                {
-                    rewindableStream = rs;
-                }
-                else
-                {
-                    rewindableStream = new RewindableStream(stream);
-                }
-                ZipHeader? header = await headerFactory.ReadStreamHeader(rewindableStream, cancellationToken)
-                                                       .FirstOrDefaultAsync(x => x.ZipHeaderType != ZipHeaderType.Split, cancellationToken: cancellationToken);
+                ZipHeader? header = headerFactory.ReadStreamHeader(stream).FirstOrDefault(x => x.ZipHeaderType != ZipHeaderType.Split);
                 if (header is null)
                 {
                     return false;
@@ -117,17 +102,15 @@ namespace SharpCompress.Archives.Zip
         /// </summary>
         /// <param name="fileInfo"></param>
         /// <param name="readerOptions"></param>
-        internal ZipArchive(FileInfo fileInfo, ReaderOptions readerOptions,
-                            CancellationToken cancellationToken)
-            : base(ArchiveType.Zip, fileInfo, readerOptions, cancellationToken)
+        internal ZipArchive(FileInfo fileInfo, ReaderOptions readerOptions)
+            : base(ArchiveType.Zip, fileInfo, readerOptions)
         {
             headerFactory = new SeekableZipHeaderFactory(readerOptions.Password, readerOptions.ArchiveEncoding);
         }
 
-        protected override IAsyncEnumerable<ZipVolume> LoadVolumes(FileInfo file,
-                                                                   CancellationToken cancellationToken)
+        protected override IEnumerable<ZipVolume> LoadVolumes(FileInfo file)
         {
-            return new ZipVolume(file.OpenRead(), ReaderOptions).AsAsyncEnumerable();
+            return new ZipVolume(file.OpenRead(), ReaderOptions).AsEnumerable();
         }
 
         internal ZipArchive()
@@ -140,86 +123,82 @@ namespace SharpCompress.Archives.Zip
         /// </summary>
         /// <param name="stream"></param>
         /// <param name="readerOptions"></param>
-        internal ZipArchive(Stream stream, ReaderOptions readerOptions,
-                            CancellationToken cancellationToken)
-            : base(ArchiveType.Zip, stream, readerOptions, cancellationToken)
+        internal ZipArchive(Stream stream, ReaderOptions readerOptions)
+            : base(ArchiveType.Zip, stream, readerOptions)
         {
             headerFactory = new SeekableZipHeaderFactory(readerOptions.Password, readerOptions.ArchiveEncoding);
         }
 
-        protected override async IAsyncEnumerable<ZipVolume> LoadVolumes(IAsyncEnumerable<Stream> streams,
-                                                                         [EnumeratorCancellation]CancellationToken cancellationToken)
+        protected override IEnumerable<ZipVolume> LoadVolumes(IEnumerable<Stream> streams)
         {
-            yield return new ZipVolume(await streams.FirstAsync(cancellationToken: cancellationToken), ReaderOptions);
+            return new ZipVolume(streams.First(), ReaderOptions).AsEnumerable();
         }
 
-        protected override async IAsyncEnumerable<ZipArchiveEntry> LoadEntries(IAsyncEnumerable<ZipVolume> volumes,
-                                                                               [EnumeratorCancellation]CancellationToken cancellationToken)
+        protected override IEnumerable<ZipArchiveEntry> LoadEntries(IEnumerable<ZipVolume> volumes)
         {
-            await Task.CompletedTask;
-            var volume = await volumes.SingleAsync(cancellationToken: cancellationToken);
+            var volume = volumes.Single();
             Stream stream = volume.Stream;
-            await foreach (ZipHeader h in headerFactory.ReadSeekableHeader(stream, cancellationToken))
+            foreach (ZipHeader h in headerFactory.ReadSeekableHeader(stream))
             {
                 if (h != null)
                 {
                     switch (h.ZipHeaderType)
                     {
                         case ZipHeaderType.DirectoryEntry:
-                        {
-                            yield return new ZipArchiveEntry(this,
-                                                             new SeekableZipFilePart(headerFactory,
-                                                                                     (DirectoryEntryHeader)h,
-                                                                                     stream));
-                        }
+                            {
+                                yield return new ZipArchiveEntry(this,
+                                                                 new SeekableZipFilePart(headerFactory,
+                                                                                         (DirectoryEntryHeader)h,
+                                                                                         stream));
+                            }
                             break;
                         case ZipHeaderType.DirectoryEnd:
-                        {
-                            byte[] bytes = ((DirectoryEndHeader)h).Comment ?? Array.Empty<byte>();
-                            volume.Comment = ReaderOptions.ArchiveEncoding.Decode(bytes);
-                            yield break;
-                        }
+                            {
+                                byte[] bytes = ((DirectoryEndHeader)h).Comment ?? Array.Empty<byte>();
+                                volume.Comment = ReaderOptions.ArchiveEncoding.Decode(bytes);
+                                yield break;
+                            }
                     }
                 }
             }
         }
 
-        public ValueTask SaveToAsync(Stream stream, CancellationToken cancellationToken = default)
+        public void SaveTo(Stream stream)
         {
-            return SaveToAsync(stream, new WriterOptions(CompressionType.Deflate), cancellationToken);
+            SaveTo(stream, new WriterOptions(CompressionType.Deflate));
         }
 
-        protected override async ValueTask SaveToAsync(Stream stream, WriterOptions options, 
-                                                       IAsyncEnumerable<ZipArchiveEntry> oldEntries, 
-                                                       IAsyncEnumerable<ZipArchiveEntry> newEntries, 
-                                                       CancellationToken cancellationToken = default)
+        protected override void SaveTo(Stream stream, WriterOptions options,
+                                       IEnumerable<ZipArchiveEntry> oldEntries,
+                                       IEnumerable<ZipArchiveEntry> newEntries)
         {
-            await using var writer = new ZipWriter(stream, new ZipWriterOptions(options));
-            await foreach (var entry in oldEntries.Concat(newEntries)
-                                                  .Where(x => !x.IsDirectory)
-                                                  .WithCancellation(cancellationToken))
+            using (var writer = new ZipWriter(stream, new ZipWriterOptions(options)))
             {
-                await using (var entryStream = await entry.OpenEntryStreamAsync(cancellationToken))
+                foreach (var entry in oldEntries.Concat(newEntries)
+                                                .Where(x => !x.IsDirectory))
                 {
-                    await writer.WriteAsync(entry.Key, entryStream, entry.LastModifiedTime, cancellationToken);
+                    using (var entryStream = entry.OpenEntryStream())
+                    {
+                        writer.Write(entry.Key, entryStream, entry.LastModifiedTime);
+                    }
                 }
             }
         }
 
-        protected override ValueTask<ZipArchiveEntry> CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
-                                                               bool closeStream, CancellationToken cancellationToken = default)
+        protected override ZipArchiveEntry CreateEntryInternal(string filePath, Stream source, long size, DateTime? modified,
+                                                               bool closeStream)
         {
-            return new(new ZipWritableArchiveEntry(this, source, filePath, size, modified, closeStream));
+            return new ZipWritableArchiveEntry(this, source, filePath, size, modified, closeStream);
         }
 
         public static ZipArchive Create()
         {
-            return new();
+            return new ZipArchive();
         }
 
-        protected override async ValueTask<IReader> CreateReaderForSolidExtraction()
+        protected override IReader CreateReaderForSolidExtraction()
         {
-            var stream = (await Volumes.SingleAsync()).Stream;
+            var stream = Volumes.Single().Stream;
             stream.Position = 0;
             return ZipReader.Open(stream, ReaderOptions);
         }

src/SharpCompress/Archives/Zip/ZipArchiveEntry.cs

@@ -1,7 +1,5 @@
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Zip;
 
 namespace SharpCompress.Archives.Zip
@@ -14,9 +12,9 @@ namespace SharpCompress.Archives.Zip
             Archive = archive;
         }
 
-        public virtual ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public virtual Stream OpenEntryStream()
         {
-            return Parts.Single().GetCompressedStreamAsync(cancellationToken);
+            return Parts.Single().GetCompressedStream();
         }
 
         #region IArchiveEntry Members

src/SharpCompress/Archives/Zip/ZipWritableArchiveEntry.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.IO;
 
@@ -51,18 +49,18 @@ namespace SharpCompress.Archives.Zip
 
         Stream IWritableArchiveEntry.Stream => stream;
 
-        public override ValueTask<Stream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public override Stream OpenEntryStream()
         {
             //ensure new stream is at the start, this could be reset
             stream.Seek(0, SeekOrigin.Begin);
-            return new(new NonDisposingStream(stream));
+            return new NonDisposingStream(stream);
         }
 
-        internal override async ValueTask CloseAsync()
+        internal override void Close()
         {
             if (closeStream && !isDisposed)
             {
-                await stream.DisposeAsync();
+                stream.Dispose();
                 isDisposed = true;
             }
         }

src/SharpCompress/AsyncEnumerable.cs

@@ -1,25 +0,0 @@
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace SharpCompress
-{
-    public static class AsyncEnumerable
-    {
-        public static IAsyncEnumerable<T> Empty<T>() => EmptyAsyncEnumerable<T>.Instance;
-        
-
-        private class EmptyAsyncEnumerable<T> : IAsyncEnumerator<T>, IAsyncEnumerable<T>
-        {
-            public static readonly EmptyAsyncEnumerable<T> Instance = 
-                new();
-            public T Current => default!;
-            public ValueTask DisposeAsync() => default;
-            public ValueTask<bool> MoveNextAsync() => new(false);
-            public IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken = new CancellationToken())
-            {
-                return this;
-            }
-        }
-    }
-}

src/SharpCompress/Common/ArchiveEncoding.cs

@@ -24,7 +24,7 @@ namespace SharpCompress.Common
         /// Set this when you want to use a custom method for all decoding operations.
         /// </summary>
         /// <returns>string Func(bytes, index, length)</returns>
-        //public Func<byte[], int, int, string>? CustomDecoder { get; set; }
+        public Func<byte[], int, int, string>? CustomDecoder { get; set; }
 
         public ArchiveEncoding()
         : this(Encoding.Default, Encoding.Default)
@@ -36,7 +36,7 @@ namespace SharpCompress.Common
             Password = password;
         }
 
-#if !NET461
+#if !NETFRAMEWORK
         static ArchiveEncoding()
         {
             Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
@@ -50,12 +50,7 @@ namespace SharpCompress.Common
 
         public string Decode(byte[] bytes, int start, int length)
         {
-            return GetEncoding().GetString(bytes, start, length);
-        }
-        
-        public string Decode(ReadOnlySpan<byte> span)
-        {
-            return GetEncoding().GetString(span);
+            return GetDecoder().Invoke(bytes, start, length);
         }
 
         public string DecodeUTF8(byte[] bytes)
@@ -72,5 +67,10 @@ namespace SharpCompress.Common
         {
             return Forced ?? Default ?? Encoding.UTF8;
         }
+
+        public Func<byte[], int, int, string> GetDecoder()
+        {
+            return CustomDecoder ?? ((bytes, index, count) => GetEncoding().GetString(bytes, index, count));
+        }
     }
 }

src/SharpCompress/Common/Entry.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common
 {
@@ -78,9 +77,8 @@ namespace SharpCompress.Common
 
         internal bool IsSolid { get; set; }
 
-        internal virtual ValueTask CloseAsync()
+        internal virtual void Close()
         {
-            return new ();
         }
 
         /// <summary>

src/SharpCompress/Common/EntryStream.cs

@@ -1,13 +1,10 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 using SharpCompress.Readers;
 
 namespace SharpCompress.Common
 {
-    public class EntryStream : AsyncStream
+    public class EntryStream : Stream
     {
         private readonly IReader _reader;
         private readonly Stream _stream;
@@ -23,24 +20,25 @@ namespace SharpCompress.Common
         /// <summary>
         /// When reading a stream from OpenEntryStream, the stream must be completed so use this to finish reading the entire entry.
         /// </summary>
-        public async ValueTask SkipEntryAsync(CancellationToken cancellationToken = default)
+        public void SkipEntry()
         {
-            await this.SkipAsync(cancellationToken);
+            this.Skip();
             _completed = true;
         }
 
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
             if (!(_completed || _reader.Cancelled))
             {
-                await SkipEntryAsync();
+                SkipEntry();
             }
             if (_isDisposed)
             {
                 return;
             }
             _isDisposed = true;
-            await _stream.DisposeAsync();
+            base.Dispose(disposing);
+            _stream.Dispose();
         }
 
         public override bool CanRead => true;
@@ -48,13 +46,18 @@ namespace SharpCompress.Common
         public override bool CanSeek => false;
 
         public override bool CanWrite => false;
+
+        public override void Flush()
+        {
+        }
+
         public override long Length => _stream.Length;
 
         public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
 
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int Read(byte[] buffer, int offset, int count)
         {
-            int read = await _stream.ReadAsync(buffer, cancellationToken);
+            int read = _stream.Read(buffer, offset, count);
             if (read <= 0)
             {
                 _completed = true;
@@ -62,14 +65,14 @@ namespace SharpCompress.Common
             return read;
         }
 
-        public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int ReadByte()
         {
-            throw new NotSupportedException();
-        }
-
-        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            throw new NotSupportedException();
+            int value = _stream.ReadByte();
+            if (value == -1)
+            {
+                _completed = true;
+            }
+            return value;
         }
 
         public override long Seek(long offset, SeekOrigin origin)
@@ -81,5 +84,10 @@ namespace SharpCompress.Common
         {
             throw new NotSupportedException();
         }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
     }
 }

src/SharpCompress/Common/ExtractionMethods.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common
 {
@@ -10,21 +8,31 @@ namespace SharpCompress.Common
         /// <summary>
         /// Extract to specific directory, retaining filename
         /// </summary>
-        public static async ValueTask WriteEntryToDirectoryAsync(IEntry entry,
+        public static void WriteEntryToDirectory(IEntry entry,
                                                  string destinationDirectory,
                                                  ExtractionOptions? options,
-                                                 Func<string, ExtractionOptions?, CancellationToken, ValueTask> write,
-                                                 CancellationToken cancellationToken = default)
+                                                 Action<string, ExtractionOptions?> write)
         {
             string destinationFileName;
-            string file = Path.GetFileName(entry.Key);
             string fullDestinationDirectoryPath = Path.GetFullPath(destinationDirectory);
 
+            //check for trailing slash.
+            if (fullDestinationDirectoryPath[fullDestinationDirectoryPath.Length - 1] != Path.DirectorySeparatorChar)
+            {
+                fullDestinationDirectoryPath += Path.DirectorySeparatorChar;
+            }
+
+            if (!Directory.Exists(fullDestinationDirectoryPath))
+            {
+                throw new ExtractionException($"Directory does not exist to extract to: {fullDestinationDirectoryPath}");
+            }
+
             options ??= new ExtractionOptions()
             {
                 Overwrite = true
             };
 
+            string file = Path.GetFileName(entry.Key);
             if (options.ExtractFullPath)
             {
                 string folder = Path.GetDirectoryName(entry.Key)!;
@@ -55,7 +63,7 @@ namespace SharpCompress.Common
                 {
                     throw new ExtractionException("Entry is trying to write a file outside of the destination directory.");
                 }
-                await write(destinationFileName, options, cancellationToken);
+                write(destinationFileName, options);
             }
             else if (options.ExtractFullPath && !Directory.Exists(destinationFileName))
             {
@@ -63,12 +71,11 @@ namespace SharpCompress.Common
             }
         }
 
-        public static async ValueTask WriteEntryToFileAsync(IEntry entry, string destinationFileName,
+        public static void WriteEntryToFile(IEntry entry, string destinationFileName,
                                             ExtractionOptions? options,
-                                            Func<string, FileMode, CancellationToken, ValueTask> openAndWrite,
-                                            CancellationToken cancellationToken = default)
+                                            Action<string, FileMode> openAndWrite)
         {
-            if (entry.LinkTarget is not null)
+            if (entry.LinkTarget != null)
             {
                 if (options?.WriteSymbolicLink is null)
                 {
@@ -89,7 +96,7 @@ namespace SharpCompress.Common
                     fm = FileMode.CreateNew;
                 }
 
-                await openAndWrite(destinationFileName, fm, cancellationToken);
+                openAndWrite(destinationFileName, fm);
                 entry.PreserveExtractionOptions(destinationFileName, options);
             }
         }

src/SharpCompress/Common/FilePart.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common
 {
@@ -13,9 +11,9 @@ namespace SharpCompress.Common
 
         internal ArchiveEncoding ArchiveEncoding { get; }
 
-        internal abstract string? FilePartName { get; }
+        internal abstract string FilePartName { get; }
 
-        internal abstract ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken);
+        internal abstract Stream GetCompressedStream();
         internal abstract Stream? GetRawStream();
         internal bool Skipped { get; set; }
     }

src/SharpCompress/Common/GZip/GZipEntry.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Runtime.CompilerServices;
-using System.Threading;
 
 namespace SharpCompress.Common.GZip
 {
@@ -19,7 +17,7 @@ namespace SharpCompress.Common.GZip
 
         public override long Crc => _filePart.Crc ?? 0;
 
-        public override string Key => _filePart.FilePartName ?? string.Empty;
+        public override string Key => _filePart.FilePartName;
 
         public override string? LinkTarget => null;
 
@@ -43,12 +41,9 @@ namespace SharpCompress.Common.GZip
 
         internal override IEnumerable<FilePart> Parts => _filePart.AsEnumerable<FilePart>();
 
-        internal static async IAsyncEnumerable<GZipEntry> GetEntries(Stream stream, OptionsBase options,
-                                                                     [EnumeratorCancellation] CancellationToken cancellationToken)
+        internal static IEnumerable<GZipEntry> GetEntries(Stream stream, OptionsBase options)
         {
-            var part = new GZipFilePart(options.ArchiveEncoding);
-            await part.Initialize(stream, cancellationToken);
-            yield return new GZipEntry(part);
+            yield return new GZipEntry(new GZipFilePart(stream, options.ArchiveEncoding));
         }
     }
 }

src/SharpCompress/Common/GZip/GZipFilePart.cs

@@ -1,10 +1,7 @@
 using System;
-using System.Buffers;
 using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.Compressors;
 using SharpCompress.Compressors.Deflate;
@@ -14,44 +11,34 @@ namespace SharpCompress.Common.GZip
     internal sealed class GZipFilePart : FilePart
     {
         private string? _name;
-        //init only
-#nullable disable
-        private Stream _stream;
-#nullable enable
+        private readonly Stream _stream;
 
-        internal GZipFilePart(ArchiveEncoding archiveEncoding)
+        internal GZipFilePart(Stream stream, ArchiveEncoding archiveEncoding)
             : base(archiveEncoding)
-        {
-        }
-
-        internal async ValueTask Initialize(Stream stream, CancellationToken cancellationToken)
         {
             _stream = stream;
+            ReadAndValidateGzipHeader();
             if (stream.CanSeek)
             {
                 long position = stream.Position;
                 stream.Position = stream.Length - 8;
-                await ReadTrailerAsync(cancellationToken);
+                ReadTrailer();
                 stream.Position = position;
             }
             EntryStartPosition = stream.Position;
         }
 
-        internal long EntryStartPosition { get; private set; }
+        internal long EntryStartPosition { get; }
 
         internal DateTime? DateModified { get; private set; }
         internal int? Crc { get; private set; }
         internal int? UncompressedSize { get; private set; }
 
-        internal override string? FilePartName => _name;
+        internal override string FilePartName => _name!;
 
-        internal override async ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken)
+        internal override Stream GetCompressedStream()
         {
-            var stream = new GZipStream(_stream, CompressionMode.Decompress, CompressionLevel.Default);
-            await stream.ReadAsync(Array.Empty<byte>(), 0, 0, cancellationToken);
-            _name = stream.FileName;
-            DateModified = stream.LastModified;
-            return stream;
+            return new DeflateStream(_stream, CompressionMode.Decompress, CompressionLevel.Default);
         }
 
         internal override Stream GetRawStream()
@@ -59,12 +46,93 @@ namespace SharpCompress.Common.GZip
             return _stream;
         }
 
-        private async ValueTask ReadTrailerAsync(CancellationToken cancellationToken)
+        private void ReadTrailer()
         {
             // Read and potentially verify the GZIP trailer: CRC32 and  size mod 2^32
+            Span<byte> trailer = stackalloc byte[8];
+            int n = _stream.Read(trailer);
 
-            Crc = await _stream.ReadInt32(cancellationToken);
-            UncompressedSize = await _stream.ReadInt32(cancellationToken);
+            Crc = BinaryPrimitives.ReadInt32LittleEndian(trailer);
+            UncompressedSize = BinaryPrimitives.ReadInt32LittleEndian(trailer.Slice(4));
+        }
+
+        private void ReadAndValidateGzipHeader()
+        {
+            // read the header on the first read
+            Span<byte> header = stackalloc byte[10];
+            int n = _stream.Read(header);
+
+            // workitem 8501: handle edge case (decompress empty stream)
+            if (n == 0)
+            {
+                return;
+            }
+
+            if (n != 10)
+            {
+                throw new ZlibException("Not a valid GZIP stream.");
+            }
+
+            if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
+            {
+                throw new ZlibException("Bad GZIP header.");
+            }
+
+            int timet = BinaryPrimitives.ReadInt32LittleEndian(header.Slice(4));
+            DateModified = TarHeader.EPOCH.AddSeconds(timet);
+            if ((header[3] & 0x04) == 0x04)
+            {
+                // read and discard extra field
+                n = _stream.Read(header.Slice(0, 2)); // 2-byte length field
+
+                short extraLength = (short)(header[0] + header[1] * 256);
+                byte[] extra = new byte[extraLength];
+
+                if (!_stream.ReadFully(extra))
+                {
+                    throw new ZlibException("Unexpected end-of-file reading GZIP header.");
+                }
+                n = extraLength;
+            }
+            if ((header[3] & 0x08) == 0x08)
+            {
+                _name = ReadZeroTerminatedString(_stream);
+            }
+            if ((header[3] & 0x10) == 0x010)
+            {
+                ReadZeroTerminatedString(_stream);
+            }
+            if ((header[3] & 0x02) == 0x02)
+            {
+                _stream.ReadByte(); // CRC16, ignore
+            }
+        }
+
+        private string ReadZeroTerminatedString(Stream stream)
+        {
+            Span<byte> buf1 = stackalloc byte[1];
+            var list = new List<byte>();
+            bool done = false;
+            do
+            {
+                // workitem 7740
+                int n = stream.Read(buf1);
+                if (n != 1)
+                {
+                    throw new ZlibException("Unexpected EOF reading GZIP header.");
+                }
+                if (buf1[0] == 0)
+                {
+                    done = true;
+                }
+                else
+                {
+                    list.Add(buf1[0]);
+                }
+            }
+            while (!done);
+            byte[] buffer = list.ToArray();
+            return ArchiveEncoding.Decode(buffer);
         }
     }
 }

src/SharpCompress/Common/IVolume.cs

@@ -2,7 +2,7 @@
 
 namespace SharpCompress.Common
 {
-    public interface IVolume : IAsyncDisposable
+    public interface IVolume : IDisposable
     {
     }
 }

src/SharpCompress/Common/Rar/RarEntry.cs

@@ -10,7 +10,7 @@ namespace SharpCompress.Common.Rar
         /// <summary>
         /// As the V2017 port isn't complete, add this check to use the legacy Rar code.
         /// </summary>
-        internal bool IsRarV3 => FileHeader.CompressionAlgorithm == 29 || FileHeader.CompressionAlgorithm == 36;
+        internal bool IsRarV3 => FileHeader.CompressionAlgorithm == 20 || FileHeader.CompressionAlgorithm == 26 || FileHeader.CompressionAlgorithm == 29 || FileHeader.CompressionAlgorithm == 36; //Nanook - Added 20+26 as Test arc from WinRar2.8 (algo 20) was failing with 2017 code
 
         /// <summary>
         /// The File's 32 bit CRC Hash

src/SharpCompress/Common/SevenZip/ArchiveReader.cs

@@ -5,8 +5,6 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Compressors.LZMA;
 using SharpCompress.Compressors.LZMA.Utilites;
 using SharpCompress.IO;
@@ -785,7 +783,7 @@ namespace SharpCompress.Common.SevenZip
             }
         }
 
-        private async ValueTask<List<byte[]>> ReadAndDecodePackedStreams(long baseOffset, IPasswordProvider pass, CancellationToken cancellationToken)
+        private List<byte[]> ReadAndDecodePackedStreams(long baseOffset, IPasswordProvider pass)
         {
 #if DEBUG
             Log.WriteLine("-- ReadAndDecodePackedStreams --");
@@ -817,8 +815,8 @@ namespace SharpCompress.Common.SevenZip
                         dataStartPos += packSize;
                     }
 
-                    var outStream = await DecoderStreamHelper.CreateDecoderStream(_stream, oldDataStartPos, myPackSizes,
-                                                                            folder, pass, cancellationToken);
+                    var outStream = DecoderStreamHelper.CreateDecoderStream(_stream, oldDataStartPos, myPackSizes,
+                                                                            folder, pass);
 
                     int unpackSize = checked((int)folder.GetUnpackSize());
                     byte[] data = new byte[unpackSize];
@@ -847,7 +845,7 @@ namespace SharpCompress.Common.SevenZip
             }
         }
 
-        private async ValueTask ReadHeader(ArchiveDatabase db, IPasswordProvider getTextPassword, CancellationToken cancellationToken)
+        private void ReadHeader(ArchiveDatabase db, IPasswordProvider getTextPassword)
         {
 #if DEBUG
             Log.WriteLine("-- ReadHeader --");
@@ -866,7 +864,7 @@ namespace SharpCompress.Common.SevenZip
                 List<byte[]> dataVector = null;
                 if (type == BlockType.AdditionalStreamsInfo)
                 {
-                    dataVector = await ReadAndDecodePackedStreams(db._startPositionAfterHeader, getTextPassword, cancellationToken);
+                    dataVector = ReadAndDecodePackedStreams(db._startPositionAfterHeader, getTextPassword);
                     type = ReadId();
                 }
 

src/SharpCompress/Common/SevenZip/SevenZipEntry.cs

@@ -32,7 +32,7 @@ namespace SharpCompress.Common.SevenZip
 
         public override DateTime? ArchivedTime => null;
 
-        public override bool IsEncrypted => false;
+        public override bool IsEncrypted => FilePart.IsEncrypted;
 
         public override bool IsDirectory => FilePart.Header.IsDir;
 

src/SharpCompress/Common/SevenZip/SevenZipFilePart.cs

@@ -1,8 +1,6 @@
 using System;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.IO;
 
 namespace SharpCompress.Common.SevenZip
@@ -37,11 +35,11 @@ namespace SharpCompress.Common.SevenZip
             return null;
         }
 
-        internal override async ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken)
+        internal override Stream GetCompressedStream()
         {
             if (!Header.HasStream)
             {
-                return Stream.Null;
+                return null!;
             }
             var folderStream = _database.GetFolderStream(_stream, Folder!, _database.PasswordProvider);
 
@@ -54,7 +52,7 @@ namespace SharpCompress.Common.SevenZip
             }
             if (skipSize > 0)
             {
-                await folderStream.SkipAsync(skipSize, cancellationToken);
+                folderStream.Skip(skipSize);
             }
             return new ReadOnlySubStream(folderStream, Header.Size);
         }
@@ -104,5 +102,7 @@ namespace SharpCompress.Common.SevenZip
                     throw new NotImplementedException();
             }
         }
+
+        internal bool IsEncrypted => Folder!._coders.FindIndex(c => c._methodId._id == CMethodId.K_AES_ID) != -1;
     }
 }

src/SharpCompress/Common/Tar/Headers/TarHeader.cs

@@ -1,12 +1,9 @@
 #nullable disable
 
 using System;
-using System.Buffers;
 using System.Buffers.Binary;
 using System.IO;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Tar.Headers
 {
@@ -35,48 +32,48 @@ namespace SharpCompress.Common.Tar.Headers
 
         internal const int BLOCK_SIZE = 512;
 
-        internal async Task WriteAsync(Stream output)
+        internal void Write(Stream output)
         {
-            using var buffer = MemoryPool<byte>.Shared.Rent(BLOCK_SIZE);
+            byte[] buffer = new byte[BLOCK_SIZE];
 
-            WriteOctalBytes(511, buffer.Memory.Span, 100, 8); // file mode
-            WriteOctalBytes(0, buffer.Memory.Span, 108, 8); // owner ID
-            WriteOctalBytes(0, buffer.Memory.Span, 116, 8); // group ID
+            WriteOctalBytes(511, buffer, 100, 8); // file mode
+            WriteOctalBytes(0, buffer, 108, 8); // owner ID
+            WriteOctalBytes(0, buffer, 116, 8); // group ID
 
             //ArchiveEncoding.UTF8.GetBytes("magic").CopyTo(buffer, 257);
             var nameByteCount = ArchiveEncoding.GetEncoding().GetByteCount(Name);
             if (nameByteCount > 100)
             {
                 // Set mock filename and filetype to indicate the next block is the actual name of the file
-                WriteStringBytes("././@LongLink", buffer.Memory.Span, 0, 100);
-                buffer.Memory.Span[156] = (byte)EntryType.LongName;
-                WriteOctalBytes(nameByteCount + 1, buffer.Memory.Span, 124, 12);
+                WriteStringBytes("././@LongLink", buffer, 0, 100);
+                buffer[156] = (byte)EntryType.LongName;
+                WriteOctalBytes(nameByteCount + 1, buffer, 124, 12);
             }
             else
             {
-                WriteStringBytes(ArchiveEncoding.Encode(Name), buffer.Memory, 100);
-                WriteOctalBytes(Size, buffer.Memory.Span, 124, 12);
+                WriteStringBytes(ArchiveEncoding.Encode(Name), buffer, 100);
+                WriteOctalBytes(Size, buffer, 124, 12);
                 var time = (long)(LastModifiedTime.ToUniversalTime() - EPOCH).TotalSeconds;
-                WriteOctalBytes(time, buffer.Memory.Span, 136, 12);
-                buffer.Memory.Span[156] = (byte)EntryType;
+                WriteOctalBytes(time, buffer, 136, 12);
+                buffer[156] = (byte)EntryType;
 
                 if (Size >= 0x1FFFFFFFF)
                 {
-                    using var bytes12 = MemoryPool<byte>.Shared.Rent(12);
-                    BinaryPrimitives.WriteInt64BigEndian(bytes12.Memory.Span.Slice(4), Size);
-                    bytes12.Memory.Span[0] |= 0x80;
-                    bytes12.Memory.CopyTo(buffer.Memory.Slice(124));
+                    Span<byte> bytes12 = stackalloc byte[12];
+                    BinaryPrimitives.WriteInt64BigEndian(bytes12.Slice(4), Size);
+                    bytes12[0] |= 0x80;
+                    bytes12.CopyTo(buffer.AsSpan(124));
                 }
             }
 
-            int crc = RecalculateChecksum(buffer.Memory);
-            WriteOctalBytes(crc, buffer.Memory.Span, 148, 8);
+            int crc = RecalculateChecksum(buffer);
+            WriteOctalBytes(crc, buffer, 148, 8);
 
-            await output.WriteAsync(buffer.Memory.Slice(0, BLOCK_SIZE));
+            output.Write(buffer, 0, buffer.Length);
 
             if (nameByteCount > 100)
             {
-                await WriteLongFilenameHeaderAsync(output);
+                WriteLongFilenameHeader(output);
                 // update to short name lower than 100 - [max bytes of one character].
                 // subtracting bytes is needed because preventing infinite loop(example code is here).
                 //
@@ -85,14 +82,14 @@ namespace SharpCompress.Common.Tar.Headers
                 //
                 // and then infinite recursion is occured in WriteLongFilenameHeader because truncated.Length is 102.
                 Name = ArchiveEncoding.Decode(ArchiveEncoding.Encode(Name), 0, 100 - ArchiveEncoding.GetEncoding().GetMaxByteCount(1));
-                await WriteAsync(output);
+                Write(output);
             }
         }
 
-        private async Task WriteLongFilenameHeaderAsync(Stream output)
+        private void WriteLongFilenameHeader(Stream output)
         {
             byte[] nameBytes = ArchiveEncoding.Encode(Name);
-            await output.WriteAsync(nameBytes.AsMemory());
+            output.Write(nameBytes, 0, nameBytes.Length);
 
             // pad to multiple of BlockSize bytes, and make sure a terminating null is added
             int numPaddingBytes = BLOCK_SIZE - (nameBytes.Length % BLOCK_SIZE);
@@ -100,56 +97,48 @@ namespace SharpCompress.Common.Tar.Headers
             {
                 numPaddingBytes = BLOCK_SIZE;
             }
-
-            using var padding = MemoryPool<byte>.Shared.Rent(numPaddingBytes);
-            padding.Memory.Span.Clear();
-            await output.WriteAsync(padding.Memory.Slice(0, numPaddingBytes));
+            output.Write(stackalloc byte[numPaddingBytes]);
         }
 
-        internal async ValueTask<bool> Read(Stream stream, CancellationToken cancellationToken)
+        internal bool Read(BinaryReader reader)
         {
-            var block = MemoryPool<byte>.Shared.Rent(BLOCK_SIZE);
-            bool readFullyAsync = await stream.ReadAsync(block.Memory.Slice(0, BLOCK_SIZE), cancellationToken) == BLOCK_SIZE;
-            if (readFullyAsync is false)
+            var buffer = ReadBlock(reader);
+            if (buffer.Length == 0)
             {
                 return false;
             }
 
             // for symlinks, additionally read the linkname
-            if (ReadEntryType(block.Memory.Span) == EntryType.SymLink)
+            if (ReadEntryType(buffer) == EntryType.SymLink)
             {
-                LinkName = ArchiveEncoding.Decode(block.Memory.Span.Slice(157, 100)).TrimNulls();
+                LinkName = ArchiveEncoding.Decode(buffer, 157, 100).TrimNulls();
             }
 
-            if (ReadEntryType(block.Memory.Span) == EntryType.LongName)
+            if (ReadEntryType(buffer) == EntryType.LongName)
             {
-                Name = await ReadLongName(stream, block.Memory.Slice(0,BLOCK_SIZE), cancellationToken);
-                readFullyAsync = await stream.ReadAsync(block.Memory.Slice(0, BLOCK_SIZE), cancellationToken) == BLOCK_SIZE;
-                if (readFullyAsync is false)
-                {
-                    return false;
-                }
+                Name = ReadLongName(reader, buffer);
+                buffer = ReadBlock(reader);
             }
             else
             {
-                Name = ArchiveEncoding.Decode(block.Memory.Span.Slice( 0, 100)).TrimNulls();
+                Name = ArchiveEncoding.Decode(buffer, 0, 100).TrimNulls();
             }
 
-            EntryType = ReadEntryType(block.Memory.Span);
-            Size = ReadSize(block.Memory.Slice(0, BLOCK_SIZE));
+            EntryType = ReadEntryType(buffer);
+            Size = ReadSize(buffer);
 
             //Mode = ReadASCIIInt32Base8(buffer, 100, 7);
             //UserId = ReadASCIIInt32Base8(buffer, 108, 7);
             //GroupId = ReadASCIIInt32Base8(buffer, 116, 7);
-            long unixTimeStamp = ReadAsciiInt64Base8(block.Memory.Span.Slice(136, 11));
+            long unixTimeStamp = ReadAsciiInt64Base8(buffer, 136, 11);
             LastModifiedTime = EPOCH.AddSeconds(unixTimeStamp).ToLocalTime();
 
-            Magic = ArchiveEncoding.Decode(block.Memory.Span.Slice( 257, 6)).TrimNulls();
+            Magic = ArchiveEncoding.Decode(buffer, 257, 6).TrimNulls();
 
             if (!string.IsNullOrEmpty(Magic)
                 && "ustar".Equals(Magic))
             {
-                string namePrefix = ArchiveEncoding.Decode(block.Memory.Span.Slice( 345, 157));
+                string namePrefix = ArchiveEncoding.Decode(buffer, 345, 157);
                 namePrefix = namePrefix.TrimNulls();
                 if (!string.IsNullOrEmpty(namePrefix))
                 {
@@ -164,46 +153,55 @@ namespace SharpCompress.Common.Tar.Headers
             return true;
         }
 
-        private async ValueTask<string> ReadLongName(Stream reader, ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken)
+        private string ReadLongName(BinaryReader reader, byte[] buffer)
         {
             var size = ReadSize(buffer);
             var nameLength = (int)size;
-            using var rented = MemoryPool<byte>.Shared.Rent(nameLength);
-            var nameBytes = rented.Memory.Slice(0, nameLength);
-            await reader.ReadAsync(nameBytes, cancellationToken);
+            var nameBytes = reader.ReadBytes(nameLength);
             var remainingBytesToRead = BLOCK_SIZE - (nameLength % BLOCK_SIZE);
 
             // Read the rest of the block and discard the data
             if (remainingBytesToRead < BLOCK_SIZE)
             {
-                using var remaining = MemoryPool<byte>.Shared.Rent(remainingBytesToRead);
-                await reader.ReadAsync(remaining.Memory.Slice(0, remainingBytesToRead), cancellationToken);
+                reader.ReadBytes(remainingBytesToRead);
             }
-            return ArchiveEncoding.Decode(nameBytes.Span).TrimNulls();
+            return ArchiveEncoding.Decode(nameBytes, 0, nameBytes.Length).TrimNulls();
         }
 
-        private static EntryType ReadEntryType(Span<byte> buffer)
+        private static EntryType ReadEntryType(byte[] buffer)
         {
             return (EntryType)buffer[156];
         }
 
-        private long ReadSize(ReadOnlyMemory<byte> buffer)
+        private long ReadSize(byte[] buffer)
         {
-            if ((buffer.Span[124] & 0x80) == 0x80) // if size in binary
+            if ((buffer[124] & 0x80) == 0x80) // if size in binary
             {
-                return BinaryPrimitives.ReadInt64BigEndian(buffer.Span.Slice(0x80));
+                return BinaryPrimitives.ReadInt64BigEndian(buffer.AsSpan(0x80));
             }
 
-            return ReadAsciiInt64Base8(buffer.Span.Slice(124, 11));
-        }
-        private static void WriteStringBytes(ReadOnlySpan<byte> name, Memory<byte> buffer, int length)
-        {
-            name.CopyTo(buffer.Span.Slice(0));
-            int i = Math.Min(length, name.Length);
-            buffer.Slice(i, length - i).Span.Clear();
+            return ReadAsciiInt64Base8(buffer, 124, 11);
         }
 
-        private static void WriteStringBytes(string name, Span<byte> buffer, int offset, int length)
+        private static byte[] ReadBlock(BinaryReader reader)
+        {
+            byte[] buffer = reader.ReadBytes(BLOCK_SIZE);
+
+            if (buffer.Length != 0 && buffer.Length < BLOCK_SIZE)
+            {
+                throw new InvalidOperationException("Buffer is invalid size");
+            }
+            return buffer;
+        }
+
+        private static void WriteStringBytes(ReadOnlySpan<byte> name, Span<byte> buffer, int length)
+        {
+            name.CopyTo(buffer);
+            int i = Math.Min(length, name.Length);
+            buffer.Slice(i, length - i).Clear();
+        }
+
+        private static void WriteStringBytes(string name, byte[] buffer, int offset, int length)
         {
             int i;
 
@@ -218,7 +216,7 @@ namespace SharpCompress.Common.Tar.Headers
             }
         }
 
-        private static void WriteOctalBytes(long value, Span<byte> buffer, int offset, int length)
+        private static void WriteOctalBytes(long value, byte[] buffer, int offset, int length)
         {
             string val = Convert.ToString(value, 8);
             int shift = length - val.Length - 1;
@@ -232,9 +230,19 @@ namespace SharpCompress.Common.Tar.Headers
             }
         }
 
-        private static long ReadAsciiInt64Base8(ReadOnlySpan<byte> buffer)
+        private static int ReadAsciiInt32Base8(byte[] buffer, int offset, int count)
         {
-            string s = Encoding.UTF8.GetString(buffer).TrimNulls();
+            string s = Encoding.UTF8.GetString(buffer, offset, count).TrimNulls();
+            if (string.IsNullOrEmpty(s))
+            {
+                return 0;
+            }
+            return Convert.ToInt32(s, 8);
+        }
+
+        private static long ReadAsciiInt64Base8(byte[] buffer, int offset, int count)
+        {
+            string s = Encoding.UTF8.GetString(buffer, offset, count).TrimNulls();
             if (string.IsNullOrEmpty(s))
             {
                 return 0;
@@ -258,20 +266,38 @@ namespace SharpCompress.Common.Tar.Headers
             (byte)' ', (byte)' ', (byte)' ', (byte)' '
         };
 
-        private static int RecalculateChecksum(Memory<byte> buf)
+        internal static int RecalculateChecksum(byte[] buf)
         {
             // Set default value for checksum. That is 8 spaces.
-            eightSpaces.CopyTo(buf.Slice(148));
+            eightSpaces.CopyTo(buf, 148);
 
             // Calculate checksum
             int headerChecksum = 0;
-            foreach (byte b in buf.Span)
+            foreach (byte b in buf)
             {
                 headerChecksum += b;
             }
             return headerChecksum;
         }
 
+        internal static int RecalculateAltChecksum(byte[] buf)
+        {
+            eightSpaces.CopyTo(buf, 148);
+            int headerChecksum = 0;
+            foreach (byte b in buf)
+            {
+                if ((b & 0x80) == 0x80)
+                {
+                    headerChecksum -= b ^ 0x80;
+                }
+                else
+                {
+                    headerChecksum += b;
+                }
+            }
+            return headerChecksum;
+        }
+
         public long? DataStartPosition { get; set; }
 
         public string Magic { get; set; }

src/SharpCompress/Common/Tar/TarEntry.cs

@@ -3,8 +3,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Runtime.CompilerServices;
-using System.Threading;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.IO;
 
@@ -48,11 +46,10 @@ namespace SharpCompress.Common.Tar
 
         internal override IEnumerable<FilePart> Parts => _filePart.AsEnumerable<FilePart>();
 
-        internal static async IAsyncEnumerable<TarEntry> GetEntries(StreamingMode mode, Stream stream,
-                                                         CompressionType compressionType, ArchiveEncoding archiveEncoding,
-                                                         [EnumeratorCancellation]CancellationToken cancellationToken)
+        internal static IEnumerable<TarEntry> GetEntries(StreamingMode mode, Stream stream,
+                                                         CompressionType compressionType, ArchiveEncoding archiveEncoding)
         {
-            await foreach (TarHeader h in TarHeaderFactory.ReadHeader(mode, stream, archiveEncoding, cancellationToken))
+            foreach (TarHeader h in TarHeaderFactory.ReadHeader(mode, stream, archiveEncoding))
             {
                 if (h != null)
                 {

src/SharpCompress/Common/Tar/TarFilePart.cs

@@ -1,7 +1,6 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Tar.Headers;
+using SharpCompress.IO;
 
 namespace SharpCompress.Common.Tar
 {
@@ -20,14 +19,14 @@ namespace SharpCompress.Common.Tar
 
         internal override string FilePartName => Header.Name;
 
-        internal override ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken)
+        internal override Stream GetCompressedStream()
         {
             if (_seekableStream != null)
             {
                 _seekableStream.Position = Header.DataStartPosition!.Value;
-                return new(new TarReadOnlySubStream(_seekableStream, Header.Size));
+                return new TarReadOnlySubStream(_seekableStream, Header.Size);
             }
-            return new(Header.PackedStream);
+            return Header.PackedStream;
         }
 
         internal override Stream? GetRawStream()

src/SharpCompress/Common/Tar/TarHeaderFactory.cs

@@ -1,7 +1,5 @@
 using System.Collections.Generic;
 using System.IO;
-using System.Runtime.CompilerServices;
-using System.Threading;
 using SharpCompress.Common.Tar.Headers;
 using SharpCompress.IO;
 
@@ -9,17 +7,17 @@ namespace SharpCompress.Common.Tar
 {
     internal static class TarHeaderFactory
     {
-        internal static async IAsyncEnumerable<TarHeader?> ReadHeader(StreamingMode mode, Stream stream, ArchiveEncoding archiveEncoding, 
-                                                                      [EnumeratorCancellation]CancellationToken cancellationToken)
+        internal static IEnumerable<TarHeader?> ReadHeader(StreamingMode mode, Stream stream, ArchiveEncoding archiveEncoding)
         {
             while (true)
             {
                 TarHeader? header = null;
                 try
                 {
+                    BinaryReader reader = new BinaryReader(stream);
                     header = new TarHeader(archiveEncoding);
 
-                    if (!await header.Read(stream, cancellationToken))
+                    if (!header.Read(reader))
                     {
                         yield break;
                     }
@@ -27,10 +25,10 @@ namespace SharpCompress.Common.Tar
                     {
                         case StreamingMode.Seekable:
                             {
-                                header.DataStartPosition = stream.Position;
+                                header.DataStartPosition = reader.BaseStream.Position;
 
                                 //skip to nearest 512
-                                stream.Position += PadTo512(header.Size);
+                                reader.BaseStream.Position += PadTo512(header.Size);
                             }
                             break;
                         case StreamingMode.Streaming:

src/SharpCompress/Common/Tar/TarReadOnlySubStream.cs

@@ -1,8 +1,6 @@
 using SharpCompress.IO;
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Tar
 {
@@ -16,7 +14,7 @@ namespace SharpCompress.Common.Tar
             BytesLeftToRead = bytesToRead;
         }
 
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
             if (_isDisposed)
             {
@@ -25,17 +23,22 @@ namespace SharpCompress.Common.Tar
 
             _isDisposed = true;
 
-            // Ensure we read all remaining blocks for this entry.
-            await Stream.SkipAsync(BytesLeftToRead);
-            _amountRead += BytesLeftToRead;
-
-            // If the last block wasn't a full 512 bytes, skip the remaining padding bytes.
-            var bytesInLastBlock = _amountRead % 512;
-
-            if (bytesInLastBlock != 0)
+            if (disposing)
             {
-                await Stream.SkipAsync(512 - bytesInLastBlock);
+                // Ensure we read all remaining blocks for this entry.
+                Stream.Skip(BytesLeftToRead);
+                _amountRead += BytesLeftToRead;
+
+                // If the last block wasn't a full 512 bytes, skip the remaining padding bytes.
+                var bytesInLastBlock = _amountRead % 512;
+
+                if (bytesInLastBlock != 0)
+                {
+                    Stream.Skip(512 - bytesInLastBlock);
+                }
             }
+
+            base.Dispose(disposing);
         }
 
         private long BytesLeftToRead { get; set; }
@@ -46,18 +49,22 @@ namespace SharpCompress.Common.Tar
 
         public override bool CanWrite => false;
 
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
         public override long Length => throw new NotSupportedException();
 
         public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
 
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int Read(byte[] buffer, int offset, int count)
         {
-            var count = buffer.Length;
-            if (BytesLeftToRead < buffer.Length)
+            if (BytesLeftToRead < count)
             {
                 count = (int)BytesLeftToRead;
             }
-            int read = await Stream.ReadAsync(buffer.Slice(0, count), cancellationToken);
+            int read = Stream.Read(buffer, offset, count);
             if (read > 0)
             {
                 BytesLeftToRead -= read;
@@ -66,9 +73,20 @@ namespace SharpCompress.Common.Tar
             return read;
         }
 
-        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int ReadByte()
         {
-            throw new NotSupportedException();
+            if (BytesLeftToRead <= 0)
+            {
+                return -1;
+            }
+            int value = Stream.ReadByte();
+            if (value != -1)
+            {
+                --BytesLeftToRead;
+                ++_amountRead;
+            }
+            return value;
+
         }
 
         public override long Seek(long offset, SeekOrigin origin)
@@ -80,5 +98,10 @@ namespace SharpCompress.Common.Tar
         {
             throw new NotSupportedException();
         }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
     }
 }

src/SharpCompress/Common/Volume.cs

@@ -1,5 +1,5 @@
-using System.IO;
-using System.Threading.Tasks;
+using System;
+using System.IO;
 using SharpCompress.IO;
 using SharpCompress.Readers;
 
@@ -33,10 +33,19 @@ namespace SharpCompress.Common
         /// RarArchive is part of a multi-part archive.
         /// </summary>
         public virtual bool IsMultiVolume => true;
-        
-        public ValueTask DisposeAsync()
+
+        protected virtual void Dispose(bool disposing)
         {
-            return _actualStream.DisposeAsync();
+            if (disposing)
+            {
+                _actualStream.Dispose();
+            }
+        }
+
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
         }
     }
 }

src/SharpCompress/Common/Zip/Headers/DirectoryEndHeader.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -11,29 +9,29 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override async ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
-            VolumeNumber = await stream.ReadUInt16(cancellationToken);
-            FirstVolumeWithDirectory = await stream.ReadUInt16(cancellationToken);
-            TotalNumberOfEntriesInDisk = await stream.ReadUInt16(cancellationToken);
-            TotalNumberOfEntries = await stream.ReadUInt16(cancellationToken);
-            DirectorySize = await stream.ReadUInt32(cancellationToken);
-            DirectoryStartOffsetRelativeToDisk = await stream.ReadUInt32(cancellationToken);
-            CommentLength = await stream.ReadUInt16(cancellationToken);
-            Comment = await stream.ReadBytes(CommentLength ?? 0, cancellationToken);
+            VolumeNumber = reader.ReadUInt16();
+            FirstVolumeWithDirectory = reader.ReadUInt16();
+            TotalNumberOfEntriesInDisk = reader.ReadUInt16();
+            TotalNumberOfEntries = reader.ReadUInt16();
+            DirectorySize = reader.ReadUInt32();
+            DirectoryStartOffsetRelativeToDisk = reader.ReadUInt32();
+            CommentLength = reader.ReadUInt16();
+            Comment = reader.ReadBytes(CommentLength);
         }
 
-        public ushort? VolumeNumber { get; private set; }
+        public ushort VolumeNumber { get; private set; }
 
-        public ushort? FirstVolumeWithDirectory { get; private set; }
+        public ushort FirstVolumeWithDirectory { get; private set; }
 
-        public ushort? TotalNumberOfEntriesInDisk { get; private set; }
+        public ushort TotalNumberOfEntriesInDisk { get; private set; }
 
-        public uint? DirectorySize { get; private set; }
+        public uint DirectorySize { get; private set; }
 
-        public uint? DirectoryStartOffsetRelativeToDisk { get; private set; }
+        public uint DirectoryStartOffsetRelativeToDisk { get; private set; }
 
-        public ushort? CommentLength { get; private set; }
+        public ushort CommentLength { get; private set; }
 
         public byte[]? Comment { get; private set; }
 

src/SharpCompress/Common/Zip/Headers/DirectoryEntryHeader.cs

@@ -1,7 +1,5 @@
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -12,28 +10,28 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override async ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
-            Version = await stream.ReadUInt16(cancellationToken);
-            VersionNeededToExtract = await stream.ReadUInt16(cancellationToken);
-            Flags = (HeaderFlags)await stream.ReadUInt16(cancellationToken);
-            CompressionMethod = (ZipCompressionMethod)await stream.ReadUInt16(cancellationToken);
-            LastModifiedTime = await stream.ReadUInt16(cancellationToken);
-            LastModifiedDate = await stream.ReadUInt16(cancellationToken);
-            Crc = await stream.ReadUInt32(cancellationToken);
-            CompressedSize = await stream.ReadUInt32(cancellationToken);
-            UncompressedSize = await stream.ReadUInt32(cancellationToken);
-            ushort nameLength = await stream.ReadUInt16(cancellationToken);
-            ushort extraLength = await stream.ReadUInt16(cancellationToken);
-            ushort commentLength = await stream.ReadUInt16(cancellationToken);
-            DiskNumberStart = await stream.ReadUInt16(cancellationToken);
-            InternalFileAttributes = await stream.ReadUInt16(cancellationToken);
-            ExternalFileAttributes = await stream.ReadUInt32(cancellationToken);
-            RelativeOffsetOfEntryHeader = await stream.ReadUInt32(cancellationToken);
+            Version = reader.ReadUInt16();
+            VersionNeededToExtract = reader.ReadUInt16();
+            Flags = (HeaderFlags)reader.ReadUInt16();
+            CompressionMethod = (ZipCompressionMethod)reader.ReadUInt16();
+            LastModifiedTime = reader.ReadUInt16();
+            LastModifiedDate = reader.ReadUInt16();
+            Crc = reader.ReadUInt32();
+            CompressedSize = reader.ReadUInt32();
+            UncompressedSize = reader.ReadUInt32();
+            ushort nameLength = reader.ReadUInt16();
+            ushort extraLength = reader.ReadUInt16();
+            ushort commentLength = reader.ReadUInt16();
+            DiskNumberStart = reader.ReadUInt16();
+            InternalFileAttributes = reader.ReadUInt16();
+            ExternalFileAttributes = reader.ReadUInt32();
+            RelativeOffsetOfEntryHeader = reader.ReadUInt32();
 
-            byte[] name = await stream.ReadBytes(nameLength, cancellationToken);
-            byte[] extra = await stream.ReadBytes(extraLength, cancellationToken);
-            byte[] comment = await stream.ReadBytes(commentLength, cancellationToken);
+            byte[] name = reader.ReadBytes(nameLength);
+            byte[] extra = reader.ReadBytes(extraLength);
+            byte[] comment = reader.ReadBytes(commentLength);
 
             // According to .ZIP File Format Specification
             //
@@ -65,6 +63,8 @@ namespace SharpCompress.Common.Zip.Headers
             var zip64ExtraData = Extra.OfType<Zip64ExtendedInformationExtraField>().FirstOrDefault();
             if (zip64ExtraData != null)
             {
+                zip64ExtraData.Process(UncompressedSize, CompressedSize, RelativeOffsetOfEntryHeader, DiskNumberStart);
+
                 if (CompressedSize == uint.MaxValue)
                 {
                     CompressedSize = zip64ExtraData.CompressedSize;

src/SharpCompress/Common/Zip/Headers/IgnoreHeader.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -11,9 +9,8 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
-            return new();
         }
     }
 }

src/SharpCompress/Common/Zip/Headers/LocalEntryHeader.cs

@@ -1,7 +1,5 @@
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -12,20 +10,20 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override async ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
-            Version = await stream.ReadUInt16(cancellationToken);
-            Flags = (HeaderFlags)await stream.ReadUInt16(cancellationToken);
-            CompressionMethod = (ZipCompressionMethod)await stream.ReadUInt16(cancellationToken);
-            LastModifiedTime = await stream.ReadUInt16(cancellationToken);
-            LastModifiedDate = await stream.ReadUInt16(cancellationToken);
-            Crc = await stream.ReadUInt32(cancellationToken);
-            CompressedSize = await stream.ReadUInt32(cancellationToken);
-            UncompressedSize = await stream.ReadUInt32(cancellationToken);
-            ushort nameLength = await stream.ReadUInt16(cancellationToken);
-            ushort extraLength = await stream.ReadUInt16(cancellationToken);
-            byte[] name = await stream.ReadBytes(nameLength, cancellationToken);
-            byte[] extra = await stream.ReadBytes(extraLength, cancellationToken);
+            Version = reader.ReadUInt16();
+            Flags = (HeaderFlags)reader.ReadUInt16();
+            CompressionMethod = (ZipCompressionMethod)reader.ReadUInt16();
+            LastModifiedTime = reader.ReadUInt16();
+            LastModifiedDate = reader.ReadUInt16();
+            Crc = reader.ReadUInt32();
+            CompressedSize = reader.ReadUInt32();
+            UncompressedSize = reader.ReadUInt32();
+            ushort nameLength = reader.ReadUInt16();
+            ushort extraLength = reader.ReadUInt16();
+            byte[] name = reader.ReadBytes(nameLength);
+            byte[] extra = reader.ReadBytes(extraLength);
 
             // According to .ZIP File Format Specification
             //
@@ -55,6 +53,8 @@ namespace SharpCompress.Common.Zip.Headers
             var zip64ExtraData = Extra.OfType<Zip64ExtendedInformationExtraField>().FirstOrDefault();
             if (zip64ExtraData != null)
             {
+                zip64ExtraData.Process(UncompressedSize, CompressedSize, 0, 0);
+
                 if (CompressedSize == uint.MaxValue)
                 {
                     CompressedSize = zip64ExtraData.CompressedSize;

src/SharpCompress/Common/Zip/Headers/LocalEntryHeaderExtraFactory.cs

@@ -66,46 +66,74 @@ namespace SharpCompress.Common.Zip.Headers
         public Zip64ExtendedInformationExtraField(ExtraDataType type, ushort length, byte[] dataBytes)
             : base(type, length, dataBytes)
         {
-            Process();
         }
 
-        private void Process()
+        // From the spec, values are only in the extradata if the standard
+        // value is set to 0xFFFFFFFF (or 0xFFFF for the Disk Start Number).
+        // Values, if present, must appear in the following order:
+        // - Original Size
+        // - Compressed Size
+        // - Relative Header Offset
+        // - Disk Start Number
+        public void Process(long uncompressedFileSize, long compressedFileSize, long relativeHeaderOffset, ushort diskNumber)
         {
-            if (DataBytes.Length >= 8)
+            var bytesRequired = ((uncompressedFileSize == uint.MaxValue) ? 8 : 0)
+                + ((compressedFileSize == uint.MaxValue) ? 8 : 0)
+                + ((relativeHeaderOffset == uint.MaxValue) ? 8 : 0)
+                + ((diskNumber == ushort.MaxValue) ? 4 : 0);
+            var currentIndex = 0;
+
+            if (bytesRequired > DataBytes.Length)
             {
-                UncompressedSize = BinaryPrimitives.ReadInt64LittleEndian(DataBytes);
+                throw new ArchiveException("Zip64 extended information extra field is not large enough for the required information");
             }
 
-            if (DataBytes.Length >= 16)
+            if (uncompressedFileSize == uint.MaxValue)
             {
-                CompressedSize = BinaryPrimitives.ReadInt64LittleEndian(DataBytes.AsSpan(8));
+                UncompressedSize = BinaryPrimitives.ReadInt64LittleEndian(DataBytes.AsSpan(currentIndex));
+                currentIndex += 8;
             }
 
-            if (DataBytes.Length >= 24)
+            if (compressedFileSize == uint.MaxValue)
             {
-                RelativeOffsetOfEntryHeader = BinaryPrimitives.ReadInt64LittleEndian(DataBytes.AsSpan(16));
+                CompressedSize = BinaryPrimitives.ReadInt64LittleEndian(DataBytes.AsSpan(currentIndex));
+                currentIndex += 8;
             }
 
-            if (DataBytes.Length >= 28)
+            if (relativeHeaderOffset == uint.MaxValue)
             {
-                VolumeNumber = BinaryPrimitives.ReadUInt32LittleEndian(DataBytes.AsSpan(24));
+                RelativeOffsetOfEntryHeader = BinaryPrimitives.ReadInt64LittleEndian(DataBytes.AsSpan(currentIndex));
+                currentIndex += 8;
             }
 
-            switch (DataBytes.Length)
+            if (diskNumber == ushort.MaxValue)
             {
-                case 8:
-                case 16:
-                case 24:
-                case 28:
-                    break;
-                default:
-                    throw new ArchiveException($"Unexpected size of of Zip64 extended information extra field: {DataBytes.Length}");
+                VolumeNumber = BinaryPrimitives.ReadUInt32LittleEndian(DataBytes.AsSpan(currentIndex));
             }
         }
 
+        /// <summary>
+        /// Uncompressed file size. Only valid after <see cref="Process(long, long, long, ushort)"/> has been called and if the
+        /// original entry header had a corresponding 0xFFFFFFFF value.
+        /// </summary>
         public long UncompressedSize { get; private set; }
+
+        /// <summary>
+        /// Compressed file size. Only valid after <see cref="Process(long, long, long, ushort)"/> has been called and if the
+        /// original entry header had a corresponding 0xFFFFFFFF value.
+        /// </summary>
         public long CompressedSize { get; private set; }
+
+        /// <summary>
+        /// Relative offset of the entry header. Only valid after <see cref="Process(long, long, long, ushort)"/> has been called and if the
+        /// original entry header had a corresponding 0xFFFFFFFF value.
+        /// </summary>
         public long RelativeOffsetOfEntryHeader { get; private set; }
+
+        /// <summary>
+        /// Volume number. Only valid after <see cref="Process(long, long, long, ushort)"/> has been called and if the
+        /// original entry header had a corresponding 0xFFFF value.
+        /// </summary>
         public uint VolumeNumber { get; private set; }
     }
 

src/SharpCompress/Common/Zip/Headers/SplitHeader.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -12,7 +10,7 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
             throw new NotImplementedException();
         }

src/SharpCompress/Common/Zip/Headers/Zip64DirectoryEndHeader.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -11,18 +9,18 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override async ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
-            SizeOfDirectoryEndRecord = (long)await stream.ReadUInt64(cancellationToken);
-            VersionMadeBy = await stream.ReadUInt16(cancellationToken);
-            VersionNeededToExtract = await stream.ReadUInt16(cancellationToken);
-            VolumeNumber = await stream.ReadUInt32(cancellationToken);
-            FirstVolumeWithDirectory = await stream.ReadUInt32(cancellationToken);
-            TotalNumberOfEntriesInDisk = (long)await stream.ReadUInt64(cancellationToken);
-            TotalNumberOfEntries = (long)await stream.ReadUInt64(cancellationToken);
-            DirectorySize = (long)await stream.ReadUInt64(cancellationToken);
-            DirectoryStartOffsetRelativeToDisk = (long)await stream.ReadUInt64(cancellationToken);
-            DataSector = await stream.ReadBytes((int)(SizeOfDirectoryEndRecord - SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS), cancellationToken);
+            SizeOfDirectoryEndRecord = (long)reader.ReadUInt64();
+            VersionMadeBy = reader.ReadUInt16();
+            VersionNeededToExtract = reader.ReadUInt16();
+            VolumeNumber = reader.ReadUInt32();
+            FirstVolumeWithDirectory = reader.ReadUInt32();
+            TotalNumberOfEntriesInDisk = (long)reader.ReadUInt64();
+            TotalNumberOfEntries = (long)reader.ReadUInt64();
+            DirectorySize = (long)reader.ReadUInt64();
+            DirectoryStartOffsetRelativeToDisk = (long)reader.ReadUInt64();
+            DataSector = reader.ReadBytes((int)(SizeOfDirectoryEndRecord - SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS));
         }
 
         private const int SIZE_OF_FIXED_HEADER_DATA_EXCEPT_SIGNATURE_AND_SIZE_FIELDS = 44;

src/SharpCompress/Common/Zip/Headers/Zip64DirectoryEndLocatorHeader.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -11,11 +9,11 @@ namespace SharpCompress.Common.Zip.Headers
         {
         }
 
-        internal override async ValueTask Read(Stream stream, CancellationToken cancellationToken)
+        internal override void Read(BinaryReader reader)
         {
-            FirstVolumeWithDirectory = await stream.ReadUInt32(cancellationToken);
-            RelativeOffsetOfTheEndOfDirectoryRecord = (long)await stream.ReadUInt64(cancellationToken);
-            TotalNumberOfVolumes = await stream.ReadUInt32(cancellationToken);
+            FirstVolumeWithDirectory = reader.ReadUInt32();
+            RelativeOffsetOfTheEndOfDirectoryRecord = (long)reader.ReadUInt64();
+            TotalNumberOfVolumes = reader.ReadUInt32();
         }
 
         public uint FirstVolumeWithDirectory { get; private set; }

src/SharpCompress/Common/Zip/Headers/ZipFileEntry.cs

@@ -105,6 +105,6 @@ namespace SharpCompress.Common.Zip.Headers
 
         internal ZipFilePart Part { get; set; }
 
-        internal bool IsZip64 => CompressedSize == uint.MaxValue;
+        internal bool IsZip64 => CompressedSize >= uint.MaxValue;
     }
 }

src/SharpCompress/Common/Zip/Headers/ZipHeader.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Common.Zip.Headers
 {
@@ -14,7 +12,7 @@ namespace SharpCompress.Common.Zip.Headers
 
         internal ZipHeaderType ZipHeaderType { get; }
 
-        internal abstract ValueTask Read(Stream stream, CancellationToken cancellationToken);
+        internal abstract void Read(BinaryReader reader);
 
         internal bool HasData { get; set; }
     }

src/SharpCompress/Common/Zip/SeekableZipFilePart.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.IO;
 
@@ -19,22 +17,22 @@ namespace SharpCompress.Common.Zip
             _directoryEntryHeader = header;
         }
 
-        internal override async ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken)
+        internal override Stream GetCompressedStream()
         {
             if (!_isLocalHeaderLoaded)
             {
-                await LoadLocalHeader(cancellationToken);
+                LoadLocalHeader();
                 _isLocalHeaderLoaded = true;
             }
-            return await base.GetCompressedStreamAsync(cancellationToken);
+            return base.GetCompressedStream();
         }
 
         internal string? Comment => ((DirectoryEntryHeader)Header).Comment;
 
-        private async ValueTask LoadLocalHeader(CancellationToken cancellationToken)
+        private void LoadLocalHeader()
         {
             bool hasData = Header.HasData;
-            Header = await _headerFactory.GetLocalHeader(BaseStream, (DirectoryEntryHeader)Header, cancellationToken);
+            Header = _headerFactory.GetLocalHeader(BaseStream, ((DirectoryEntryHeader)Header));
             Header.HasData = hasData;
         }
 

src/SharpCompress/Common/Zip/SeekableZipHeaderFactory.cs

@@ -1,12 +1,7 @@
 using System;
-using System.Buffers;
 using System.Collections.Generic;
 using System.IO;
-using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Zip.Headers;
-using SharpCompress.Compressors.Xz;
 using SharpCompress.IO;
 
 namespace SharpCompress.Common.Zip
@@ -24,13 +19,15 @@ namespace SharpCompress.Common.Zip
         {
         }
 
-        internal async IAsyncEnumerable<ZipHeader> ReadSeekableHeader(Stream stream, [EnumeratorCancellation]CancellationToken cancellationToken)
+        internal IEnumerable<ZipHeader> ReadSeekableHeader(Stream stream)
         {
-            await SeekBackToHeaderAsync(stream);
+            var reader = new BinaryReader(stream);
+
+            SeekBackToHeader(stream, reader);
 
             var eocd_location = stream.Position;
             var entry = new DirectoryEndHeader();
-            await entry.Read(stream, cancellationToken);
+            entry.Read(reader);
 
             if (entry.IsZip64)
             {
@@ -38,37 +35,37 @@ namespace SharpCompress.Common.Zip
 
                 // ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR should be before the EOCD
                 stream.Seek(eocd_location - ZIP64_EOCD_LENGTH - 4, SeekOrigin.Begin);
-                uint zip64_locator = await stream.ReadUInt32(cancellationToken);
-                if( zip64_locator != ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR )
+                uint zip64_locator = reader.ReadUInt32();
+                if (zip64_locator != ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR)
                 {
                     throw new ArchiveException("Failed to locate the Zip64 Directory Locator");
                 }
 
                 var zip64Locator = new Zip64DirectoryEndLocatorHeader();
-                await zip64Locator.Read(stream, cancellationToken);
+                zip64Locator.Read(reader);
 
                 stream.Seek(zip64Locator.RelativeOffsetOfTheEndOfDirectoryRecord, SeekOrigin.Begin);
-                uint zip64Signature = await stream.ReadUInt32(cancellationToken);
+                uint zip64Signature = reader.ReadUInt32();
                 if (zip64Signature != ZIP64_END_OF_CENTRAL_DIRECTORY)
                 {
                     throw new ArchiveException("Failed to locate the Zip64 Header");
                 }
 
                 var zip64Entry = new Zip64DirectoryEndHeader();
-                await zip64Entry.Read(stream, cancellationToken);
+                zip64Entry.Read(reader);
                 stream.Seek(zip64Entry.DirectoryStartOffsetRelativeToDisk, SeekOrigin.Begin);
             }
             else
             {
-                stream.Seek(entry.DirectoryStartOffsetRelativeToDisk ?? 0, SeekOrigin.Begin);
+                stream.Seek(entry.DirectoryStartOffsetRelativeToDisk, SeekOrigin.Begin);
             }
 
             long position = stream.Position;
             while (true)
             {
                 stream.Position = position;
-                uint signature = await stream.ReadUInt32(cancellationToken);
-                var nextHeader = await ReadHeader(signature, stream, cancellationToken, _zip64);
+                uint signature = reader.ReadUInt32();
+                var nextHeader = ReadHeader(signature, reader, _zip64);
                 position = stream.Position;
 
                 if (nextHeader is null)
@@ -89,11 +86,11 @@ namespace SharpCompress.Common.Zip
             }
         }
 
-        private static bool IsMatch (Span<byte> haystack, int position, byte[] needle)
+        private static bool IsMatch(byte[] haystack, int position, byte[] needle)
         {
-            for( int i = 0; i < needle.Length; i++ )
+            for (int i = 0; i < needle.Length; i++)
             {
-                if( haystack[ position + i ] != needle[ i ] )
+                if (haystack[position + i] != needle[i])
                 {
                     return false;
                 }
@@ -101,7 +98,7 @@ namespace SharpCompress.Common.Zip
 
             return true;
         }
-        private static async ValueTask SeekBackToHeaderAsync(Stream stream)
+        private static void SeekBackToHeader(Stream stream, BinaryReader reader)
         {
             // Minimum EOCD length
             if (stream.Length < MINIMUM_EOCD_LENGTH)
@@ -115,18 +112,17 @@ namespace SharpCompress.Common.Zip
 
             stream.Seek(-len, SeekOrigin.End);
 
-            using var rented = MemoryPool<byte>.Shared.Rent(len);
-            var buffer = rented.Memory.Slice(0, len);
-            await stream.ReadAsync(buffer);
+            byte[] seek = reader.ReadBytes(len);
 
             // Search in reverse
-            buffer.Span.Reverse();
+            Array.Reverse(seek);
 
-            var max_search_area = len - MINIMUM_EOCD_LENGTH;
+            // don't exclude the minimum eocd region, otherwise you fail to locate the header in empty zip files
+            var max_search_area = len; // - MINIMUM_EOCD_LENGTH;
 
-            for( int pos_from_end = 0; pos_from_end < max_search_area; ++pos_from_end)
+            for (int pos_from_end = 0; pos_from_end < max_search_area; ++pos_from_end)
             {
-                if( IsMatch( buffer.Span, pos_from_end, needle) )
+                if (IsMatch(seek, pos_from_end, needle))
                 {
                     stream.Seek(-pos_from_end, SeekOrigin.End);
                     return;
@@ -136,11 +132,12 @@ namespace SharpCompress.Common.Zip
             throw new ArchiveException("Failed to locate the Zip Header");
         }
 
-        internal async ValueTask<LocalEntryHeader> GetLocalHeader(Stream stream, DirectoryEntryHeader directoryEntryHeader, CancellationToken cancellationToken)
+        internal LocalEntryHeader GetLocalHeader(Stream stream, DirectoryEntryHeader directoryEntryHeader)
         {
             stream.Seek(directoryEntryHeader.RelativeOffsetOfEntryHeader, SeekOrigin.Begin);
-            uint signature = await stream.ReadUInt32(cancellationToken);
-            var localEntryHeader = await ReadHeader(signature, stream, cancellationToken, _zip64) as LocalEntryHeader;
+            BinaryReader reader = new BinaryReader(stream);
+            uint signature = reader.ReadUInt32();
+            var localEntryHeader = ReadHeader(signature, reader, _zip64) as LocalEntryHeader;
             if (localEntryHeader is null)
             {
                 throw new InvalidOperationException();

src/SharpCompress/Common/Zip/StreamingZipFilePart.cs

@@ -1,6 +1,4 @@
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.IO;
@@ -21,13 +19,13 @@ namespace SharpCompress.Common.Zip
             return Header.PackedStream;
         }
 
-        internal override async ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken)
+        internal override Stream GetCompressedStream()
         {
             if (!Header.HasData)
             {
                 return Stream.Null;
             }
-            _decompressionStream = await CreateDecompressionStream(GetCryptoStream(CreateBaseStream()), Header.CompressionMethod, cancellationToken);
+            _decompressionStream = CreateDecompressionStream(GetCryptoStream(CreateBaseStream()), Header.CompressionMethod);
             if (LeaveStreamOpen)
             {
                 return new NonDisposingStream(_decompressionStream);
@@ -35,17 +33,17 @@ namespace SharpCompress.Common.Zip
             return _decompressionStream;
         }
 
-        internal async ValueTask FixStreamedFileLocation(RewindableStream rewindableStream, CancellationToken cancellationToken)
+        internal BinaryReader FixStreamedFileLocation(ref RewindableStream rewindableStream)
         {
             if (Header.IsDirectory)
             {
-                return;
+                return new BinaryReader(rewindableStream);
             }
             if (Header.HasData && !Skipped)
             {
-                _decompressionStream ??= await GetCompressedStreamAsync(cancellationToken);
+                _decompressionStream ??= GetCompressedStream();
 
-                await _decompressionStream.SkipAsync(cancellationToken);
+                _decompressionStream.Skip();
 
                 if (_decompressionStream is DeflateStream deflateStream)
                 {
@@ -53,7 +51,9 @@ namespace SharpCompress.Common.Zip
                 }
                 Skipped = true;
             }
+            var reader = new BinaryReader(rewindableStream);
             _decompressionStream = null;
+            return reader;
         }
     }
 }

src/SharpCompress/Common/Zip/StreamingZipHeaderFactory.cs

@@ -1,6 +1,5 @@
 using System.Collections.Generic;
-using System.Runtime.CompilerServices;
-using System.Threading;
+using System.IO;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.IO;
 
@@ -13,36 +12,43 @@ namespace SharpCompress.Common.Zip
         {
         }
 
-        internal async IAsyncEnumerable<ZipHeader> ReadStreamHeader(RewindableStream rewindableStream, [EnumeratorCancellation] CancellationToken cancellationToken)
+        internal IEnumerable<ZipHeader> ReadStreamHeader(Stream stream)
         {
+            RewindableStream rewindableStream;
+
+            if (stream is RewindableStream rs)
+            {
+                rewindableStream = rs;
+            }
+            else
+            {
+                rewindableStream = new RewindableStream(stream);
+            }
             while (true)
             {
                 ZipHeader? header;
+                BinaryReader reader = new BinaryReader(rewindableStream);
                 if (_lastEntryHeader != null &&
                     (FlagUtility.HasFlag(_lastEntryHeader.Flags, HeaderFlags.UsePostDataDescriptor) || _lastEntryHeader.IsZip64))
                 {
-                    await ((StreamingZipFilePart)_lastEntryHeader.Part).FixStreamedFileLocation(rewindableStream, cancellationToken);
+                    reader = ((StreamingZipFilePart)_lastEntryHeader.Part).FixStreamedFileLocation(ref rewindableStream);
                     long? pos = rewindableStream.CanSeek ? (long?)rewindableStream.Position : null;
-                    uint crc = await rewindableStream.ReadUInt32(cancellationToken);
+                    uint crc = reader.ReadUInt32();
                     if (crc == POST_DATA_DESCRIPTOR)
                     {
-                        crc = await rewindableStream.ReadUInt32(cancellationToken);
+                        crc = reader.ReadUInt32();
                     }
                     _lastEntryHeader.Crc = crc;
-                    _lastEntryHeader.CompressedSize = await rewindableStream.ReadUInt32(cancellationToken);
-                    _lastEntryHeader.UncompressedSize = await rewindableStream.ReadUInt32(cancellationToken);
+                    _lastEntryHeader.CompressedSize = reader.ReadUInt32();
+                    _lastEntryHeader.UncompressedSize = reader.ReadUInt32();
                     if (pos.HasValue)
                     {
                         _lastEntryHeader.DataStartPosition = pos - _lastEntryHeader.CompressedSize;
                     }
                 }
                 _lastEntryHeader = null;
-                var headerBytes = await rewindableStream.ReadUInt32OrNull(cancellationToken);
-                if (headerBytes is null)
-                {
-                    yield break;
-                }
-                header = await ReadHeader(headerBytes.Value, rewindableStream, cancellationToken);
+                uint headerBytes = reader.ReadUInt32();
+                header = ReadHeader(headerBytes, reader);
                 if (header is null)
                 {
                     yield break;
@@ -65,10 +71,10 @@ namespace SharpCompress.Common.Zip
                         {
                             rewindableStream.StartRecording();
                         }
-                        uint nextHeaderBytes = await rewindableStream.ReadUInt32(cancellationToken);
+                        uint nextHeaderBytes = reader.ReadUInt32();
 
                         // Check if next data is PostDataDescriptor, streamed file with 0 length
-                        header.HasData = nextHeaderBytes != POST_DATA_DESCRIPTOR;
+                        header.HasData = !IsHeader(nextHeaderBytes);
                         rewindableStream.Rewind(!isRecording);
                     }
                     else // We are not streaming and compressed size is 0, we have no data

src/SharpCompress/Common/Zip/ZipFilePart.cs

@@ -2,15 +2,13 @@
 using System.Buffers.Binary;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.Compressors;
 using SharpCompress.Compressors.BZip2;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.Compressors.Deflate64;
 using SharpCompress.Compressors.LZMA;
-//using SharpCompress.Compressors.PPMd;
+using SharpCompress.Compressors.PPMd;
 using SharpCompress.IO;
 
 namespace SharpCompress.Common.Zip
@@ -30,13 +28,13 @@ namespace SharpCompress.Common.Zip
 
         internal override string FilePartName => Header.Name;
 
-        internal override async ValueTask<Stream> GetCompressedStreamAsync(CancellationToken cancellationToken)
+        internal override Stream GetCompressedStream()
         {
             if (!Header.HasData)
             {
                 return Stream.Null;
             }
-            Stream decompressionStream = await CreateDecompressionStream(GetCryptoStream(CreateBaseStream()), Header.CompressionMethod, cancellationToken);
+            Stream decompressionStream = CreateDecompressionStream(GetCryptoStream(CreateBaseStream()), Header.CompressionMethod);
             if (LeaveStreamOpen)
             {
                 return new NonDisposingStream(decompressionStream);
@@ -57,7 +55,7 @@ namespace SharpCompress.Common.Zip
 
         protected bool LeaveStreamOpen => FlagUtility.HasFlag(Header.Flags, HeaderFlags.UsePostDataDescriptor) || Header.IsZip64;
 
-        protected async ValueTask<Stream> CreateDecompressionStream(Stream stream, ZipCompressionMethod method, CancellationToken cancellationToken)
+        protected Stream CreateDecompressionStream(Stream stream, ZipCompressionMethod method)
         {
             switch (method)
             {
@@ -75,29 +73,30 @@ namespace SharpCompress.Common.Zip
                     }
                 case ZipCompressionMethod.BZip2:
                     {
-                        return await BZip2Stream.CreateAsync(stream, CompressionMode.Decompress, false, cancellationToken);
-                    }                                                                                          
+                        return new BZip2Stream(stream, CompressionMode.Decompress, false);
+                    }
                 case ZipCompressionMethod.LZMA:
                     {
                         if (FlagUtility.HasFlag(Header.Flags, HeaderFlags.Encrypted))
                         {
                             throw new NotSupportedException("LZMA with pkware encryption.");
                         }
-                        await stream.ReadUInt16(cancellationToken); //LZMA version
-                        var props = new byte[await stream.ReadUInt16(cancellationToken)];
-                        await stream.ReadAsync(props, 0, props.Length, cancellationToken);
-                        return await LzmaStream.CreateAsync(props, stream,
+                        var reader = new BinaryReader(stream);
+                        reader.ReadUInt16(); //LZMA version
+                        var props = new byte[reader.ReadUInt16()];
+                        reader.Read(props, 0, props.Length);
+                        return new LzmaStream(props, stream,
                                               Header.CompressedSize > 0 ? Header.CompressedSize - 4 - props.Length : -1,
                                               FlagUtility.HasFlag(Header.Flags, HeaderFlags.Bit1)
                                                   ? -1
-                                                  : (long)Header.UncompressedSize,
-                                              cancellationToken: cancellationToken);
+                                                  : (long)Header.UncompressedSize);
                     }
-              /*  case ZipCompressionMethod.PPMd:
-                {
-                    var props = await stream.ReadBytes(2, cancellationToken);
+                case ZipCompressionMethod.PPMd:
+                    {
+                        Span<byte> props = stackalloc byte[2];
+                        stream.ReadFully(props);
                         return new PpmdStream(new PpmdProperties(props), stream, false);
-                    }  */
+                    }
                 case ZipCompressionMethod.WinzipAes:
                     {
                         ExtraData? data = Header.Extra.SingleOrDefault(x => x.Type == ExtraDataType.WinZipAes);
@@ -121,7 +120,7 @@ namespace SharpCompress.Common.Zip
                         {
                             throw new InvalidFormatException("Unexpected vendor ID for WinZip AES metadata");
                         }
-                        return await CreateDecompressionStream(stream, (ZipCompressionMethod)BinaryPrimitives.ReadUInt16LittleEndian(data.DataBytes.AsSpan(5)), cancellationToken);
+                        return CreateDecompressionStream(stream, (ZipCompressionMethod)BinaryPrimitives.ReadUInt16LittleEndian(data.DataBytes.AsSpan(5)));
                     }
                 default:
                     {

src/SharpCompress/Common/Zip/ZipHeaderFactory.cs

@@ -1,8 +1,6 @@
 using System;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.Zip.Headers;
 using SharpCompress.IO;
 
@@ -32,15 +30,15 @@ namespace SharpCompress.Common.Zip
             this._archiveEncoding = archiveEncoding;
         }
 
-        protected async ValueTask<ZipHeader?> ReadHeader(uint headerBytes, Stream stream, CancellationToken cancellationToken, bool zip64 = false)
+        protected ZipHeader? ReadHeader(uint headerBytes, BinaryReader reader, bool zip64 = false)
         {
             switch (headerBytes)
             {
                 case ENTRY_HEADER_BYTES:
                     {
                         var entryHeader = new LocalEntryHeader(_archiveEncoding);
-                        await entryHeader.Read(stream, cancellationToken);
-                        await LoadHeader(entryHeader, stream, cancellationToken);
+                        entryHeader.Read(reader);
+                        LoadHeader(entryHeader, reader.BaseStream);
 
                         _lastEntryHeader = entryHeader;
                         return entryHeader;
@@ -48,20 +46,20 @@ namespace SharpCompress.Common.Zip
                 case DIRECTORY_START_HEADER_BYTES:
                     {
                         var entry = new DirectoryEntryHeader(_archiveEncoding);
-                        await entry.Read(stream, cancellationToken);
+                        entry.Read(reader);
                         return entry;
                     }
                 case POST_DATA_DESCRIPTOR:
                     {
                         if (FlagUtility.HasFlag(_lastEntryHeader!.Flags, HeaderFlags.UsePostDataDescriptor))
                         {
-                            _lastEntryHeader.Crc = await stream.ReadUInt32(cancellationToken);
-                            _lastEntryHeader.CompressedSize = zip64 ? (long)await stream.ReadUInt64(cancellationToken) : await stream.ReadUInt32(cancellationToken);
-                            _lastEntryHeader.UncompressedSize = zip64 ? (long)await stream.ReadUInt64(cancellationToken) : await stream.ReadUInt32(cancellationToken);
+                            _lastEntryHeader.Crc = reader.ReadUInt32();
+                            _lastEntryHeader.CompressedSize = zip64 ? (long)reader.ReadUInt64() : reader.ReadUInt32();
+                            _lastEntryHeader.UncompressedSize = zip64 ? (long)reader.ReadUInt64() : reader.ReadUInt32();
                         }
                         else
                         {
-                            await stream.ReadBytes(zip64 ? 20 : 12, cancellationToken);
+                            reader.ReadBytes(zip64 ? 20 : 12);
                         }
                         return null;
                     }
@@ -70,7 +68,7 @@ namespace SharpCompress.Common.Zip
                 case DIRECTORY_END_HEADER_BYTES:
                     {
                         var entry = new DirectoryEndHeader();
-                        await entry.Read(stream, cancellationToken);
+                        entry.Read(reader);
                         return entry;
                     }
                 case SPLIT_ARCHIVE_HEADER_BYTES:
@@ -80,13 +78,13 @@ namespace SharpCompress.Common.Zip
                 case ZIP64_END_OF_CENTRAL_DIRECTORY:
                     {
                         var entry = new Zip64DirectoryEndHeader();
-                        await entry.Read(stream, cancellationToken);
+                        entry.Read(reader);
                         return entry;
                     }
                 case ZIP64_END_OF_CENTRAL_DIRECTORY_LOCATOR:
                     {
                         var entry = new Zip64DirectoryEndLocatorHeader();
-                        await entry.Read(stream, cancellationToken);
+                        entry.Read(reader);
                         return entry;
                     }
                 default:
@@ -112,7 +110,7 @@ namespace SharpCompress.Common.Zip
             }
         }
 
-        private async ValueTask LoadHeader(ZipFileEntry entryHeader, Stream stream, CancellationToken cancellationToken)
+        private void LoadHeader(ZipFileEntry entryHeader, Stream stream)
         {
             if (FlagUtility.HasFlag(entryHeader.Flags, HeaderFlags.Encrypted))
             {
@@ -136,8 +134,10 @@ namespace SharpCompress.Common.Zip
                     {
                         var keySize = (WinzipAesKeySize)data.DataBytes[4];
 
-                        var salt = await stream.ReadBytes(WinzipAesEncryptionData.KeyLengthInBytes(keySize) / 2, cancellationToken);
-                        var passwordVerifyValue = await stream.ReadBytes(2, cancellationToken);
+                        var salt = new byte[WinzipAesEncryptionData.KeyLengthInBytes(keySize) / 2];
+                        var passwordVerifyValue = new byte[2];
+                        stream.Read(salt, 0, salt.Length);
+                        stream.Read(passwordVerifyValue, 0, 2);
                         entryHeader.WinzipAesEncryptionData =
                             new WinzipAesEncryptionData(keySize, salt, passwordVerifyValue, _password);
 

src/SharpCompress/Compressors/BZip2/BZip2Stream.cs

@@ -1,13 +1,9 @@
 using System;
-using System.Buffers;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.BZip2
 {
-    public sealed class BZip2Stream : AsyncStream
+    public sealed class BZip2Stream : Stream
     {
         private readonly Stream stream;
         private bool isDisposed;
@@ -37,14 +33,17 @@ namespace SharpCompress.Compressors.BZip2
             (stream as CBZip2OutputStream)?.Finish();
         }
 
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
             if (isDisposed)
             {
                 return;
             }
             isDisposed = true;
-            await stream.DisposeAsync();
+            if (disposing)
+            {
+                stream.Dispose();
+            }
         }
 
         public CompressionMode Mode { get; }
@@ -55,18 +54,23 @@ namespace SharpCompress.Compressors.BZip2
 
         public override bool CanWrite => stream.CanWrite;
 
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
-            return stream.FlushAsync(cancellationToken);
+            stream.Flush();
         }
 
         public override long Length => stream.Length;
 
         public override long Position { get => stream.Position; set => stream.Position = value; }
 
-        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int Read(byte[] buffer, int offset, int count)
         {
-            return stream.ReadAsync(buffer, cancellationToken);
+            return stream.Read(buffer, offset, count);
+        }
+
+        public override int ReadByte()
+        {
+            return stream.ReadByte();
         }
 
         public override long Seek(long offset, SeekOrigin origin)
@@ -79,14 +83,28 @@ namespace SharpCompress.Compressors.BZip2
             stream.SetLength(value);
         }
 
-        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+#if !NETFRAMEWORK && !NETSTANDARD2_0
+
+        public override int Read(Span<byte> buffer)
         {
-            return stream.WriteAsync(buffer, offset, count, cancellationToken);
+            return stream.Read(buffer);
         }
 
-        public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = new CancellationToken())
+        public override void Write(ReadOnlySpan<byte> buffer)
         {
-            return stream.WriteAsync(buffer, cancellationToken);
+            stream.Write(buffer);
+        }
+
+#endif
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            stream.Write(buffer, offset, count);
+        }
+
+        public override void WriteByte(byte value)
+        {
+            stream.WriteByte(value);
         }
 
         /// <summary>
@@ -94,16 +112,15 @@ namespace SharpCompress.Compressors.BZip2
         /// </summary>
         /// <param name="stream"></param>
         /// <returns></returns>
-        public static async ValueTask<bool> IsBZip2Async(Stream stream, CancellationToken cancellationToken)
+        public static bool IsBZip2(Stream stream)
         {
-            using var rented = MemoryPool<byte>.Shared.Rent(2);
-            var chars = rented.Memory.Slice(0, 2);
-            await stream.ReadAsync(chars, cancellationToken);
-            if (chars.Length < 2 || chars.Span[0] != 'B' || chars.Span[1] != 'Z')
+            BinaryReader br = new BinaryReader(stream);
+            byte[] chars = br.ReadBytes(2);
+            if (chars.Length < 2 || chars[0] != 'B' || chars[1] != 'Z')
             {
                 return false;
             }
             return true;
         }
     }
-}
+}

src/SharpCompress/Compressors/Deflate/DeflateStream.cs

@@ -27,13 +27,10 @@
 using System;
 using System.IO;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.Deflate
 {
-    public class DeflateStream : AsyncStream
+    public class DeflateStream : Stream
     {
         private readonly ZlibBaseStream _baseStream;
         private bool _disposed;
@@ -219,25 +216,35 @@ namespace SharpCompress.Compressors.Deflate
         /// <remarks>
         /// This may or may not result in a <c>Close()</c> call on the captive stream.
         /// </remarks>
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
-            if (!_disposed)
+            try
             {
-                await _baseStream.DisposeAsync();
-                _disposed = true;
+                if (!_disposed)
+                {
+                    if (disposing)
+                    {
+                        _baseStream?.Dispose();
+                    }
+                    _disposed = true;
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
             }
         }
 
         /// <summary>
         /// Flush the stream.
         /// </summary>
-        public override async Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("DeflateStream");
             }
-            await _baseStream.FlushAsync(cancellationToken);
+            _baseStream.Flush();
         }
 
         /// <summary>
@@ -266,14 +273,24 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="offset">the offset within that data array to put the first byte read.</param>
         /// <param name="count">the number of bytes to read.</param>
         /// <returns>the number of bytes actually read</returns>
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("DeflateStream");
             }
-            return await _baseStream.ReadAsync(buffer, offset, count, cancellationToken);
+            return _baseStream.Read(buffer, offset, count);
         }
+
+        public override int ReadByte()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException("DeflateStream");
+            }
+            return _baseStream.ReadByte();
+        }
+
         /// <summary>
         /// Calling this method always throws a <see cref="NotImplementedException"/>.
         /// </summary>
@@ -323,13 +340,22 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="buffer">The buffer holding data to write to the stream.</param>
         /// <param name="offset">the offset within that data array to find the first byte to write.</param>
         /// <param name="count">the number of bytes to write.</param>
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("DeflateStream");
             }
-            await _baseStream.WriteAsync(buffer, offset, count, cancellationToken);
+            _baseStream.Write(buffer, offset, count);
+        }
+
+        public override void WriteByte(byte value)
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException("DeflateStream");
+            }
+            _baseStream.WriteByte(value);
         }
 
         #endregion

src/SharpCompress/Compressors/Deflate/GZipStream.cs

@@ -27,25 +27,21 @@
 // ------------------------------------------------------------------
 
 using System;
-using System.Buffers;
 using System.Buffers.Binary;
 using System.IO;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.Deflate
 {
-    public class GZipStream : AsyncStream
+    public class GZipStream : Stream
     {
-        private static readonly DateTime UNIX_EPOCH = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
+        internal static readonly DateTime UNIX_EPOCH = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
 
         private string? _comment;
         private string? _fileName;
         private DateTime? _lastModified;
 
-        private readonly ZlibBaseStream _baseStream;
+        internal ZlibBaseStream BaseStream;
         private bool _disposed;
         private bool _firstReadDone;
         private int _headerByteCount;
@@ -64,7 +60,7 @@ namespace SharpCompress.Compressors.Deflate
 
         public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level, Encoding encoding)
         {
-            _baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.GZIP, encoding);
+            BaseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.GZIP, encoding);
             _encoding = encoding;
         }
 
@@ -72,27 +68,27 @@ namespace SharpCompress.Compressors.Deflate
 
         public virtual FlushType FlushMode
         {
-            get => (_baseStream._flushMode);
+            get => (BaseStream._flushMode);
             set
             {
                 if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
-                _baseStream._flushMode = value;
+                BaseStream._flushMode = value;
             }
         }
 
         public int BufferSize
         {
-            get => _baseStream._bufferSize;
+            get => BaseStream._bufferSize;
             set
             {
                 if (_disposed)
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
-                if (_baseStream._workingBuffer != null)
+                if (BaseStream._workingBuffer != null)
                 {
                     throw new ZlibException("The working buffer is already set.");
                 }
@@ -102,13 +98,13 @@ namespace SharpCompress.Compressors.Deflate
                                             String.Format("Don't be silly. {0} bytes?? Use a bigger buffer, at least {1}.", value,
                                                           ZlibConstants.WorkingBufferSizeMin));
                 }
-                _baseStream._bufferSize = value;
+                BaseStream._bufferSize = value;
             }
         }
 
-        internal virtual long TotalIn => _baseStream._z.TotalBytesIn;
+        internal virtual long TotalIn => BaseStream._z.TotalBytesIn;
 
-        internal virtual long TotalOut => _baseStream._z.TotalBytesOut;
+        internal virtual long TotalOut => BaseStream._z.TotalBytesOut;
 
         #endregion
 
@@ -128,7 +124,7 @@ namespace SharpCompress.Compressors.Deflate
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
-                return _baseStream._stream.CanRead;
+                return BaseStream._stream.CanRead;
             }
         }
 
@@ -154,7 +150,7 @@ namespace SharpCompress.Compressors.Deflate
                 {
                     throw new ObjectDisposedException("GZipStream");
                 }
-                return _baseStream._stream.CanWrite;
+                return BaseStream._stream.CanWrite;
             }
         }
 
@@ -178,13 +174,13 @@ namespace SharpCompress.Compressors.Deflate
         {
             get
             {
-                if (_baseStream._streamMode == ZlibBaseStream.StreamMode.Writer)
+                if (BaseStream._streamMode == ZlibBaseStream.StreamMode.Writer)
                 {
-                    return _baseStream._z.TotalBytesOut + _headerByteCount;
+                    return BaseStream._z.TotalBytesOut + _headerByteCount;
                 }
-                if (_baseStream._streamMode == ZlibBaseStream.StreamMode.Reader)
+                if (BaseStream._streamMode == ZlibBaseStream.StreamMode.Reader)
                 {
-                    return _baseStream._z.TotalBytesIn + _baseStream._gzipHeaderByteCount;
+                    return BaseStream._z.TotalBytesIn + BaseStream._gzipHeaderByteCount;
                 }
                 return 0;
             }
@@ -198,29 +194,36 @@ namespace SharpCompress.Compressors.Deflate
         /// <remarks>
         /// This may or may not result in a <c>Close()</c> call on the captive stream.
         /// </remarks>
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
+        {
+            try
             {
                 if (!_disposed)
                 {
-                    if (_baseStream is not null)
+                    if (disposing && (BaseStream != null))
                     {
-                        await _baseStream.DisposeAsync();
-                        Crc32 = _baseStream.Crc32;
+                        BaseStream.Dispose();
+                        Crc32 = BaseStream.Crc32;
                     }
                     _disposed = true;
                 }
             }
+            finally
+            {
+                base.Dispose(disposing);
+            }
+        }
 
         /// <summary>
         /// Flush the stream.
         /// </summary>
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("GZipStream");
             }
-            return _baseStream.FlushAsync(cancellationToken);
+            BaseStream.Flush();
         }
 
         /// <summary>
@@ -254,13 +257,13 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="offset">the offset within that data array to put the first byte read.</param>
         /// <param name="count">the number of bytes to read.</param>
         /// <returns>the number of bytes actually read</returns>
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("GZipStream");
             }
-            int n = await _baseStream.ReadAsync(buffer, offset, count, cancellationToken);
+            int n = BaseStream.Read(buffer, offset, count);
 
             // Console.WriteLine("GZipStream::Read(buffer, off({0}), c({1}) = {2}", offset, count, n);
             // Console.WriteLine( Util.FormatByteArray(buffer, offset, n) );
@@ -268,9 +271,9 @@ namespace SharpCompress.Compressors.Deflate
             if (!_firstReadDone)
             {
                 _firstReadDone = true;
-                FileName = _baseStream._GzipFileName;
-                Comment = _baseStream._GzipComment;
-                LastModified = _baseStream._GzipMtime;
+                FileName = BaseStream._GzipFileName;
+                Comment = BaseStream._GzipComment;
+                LastModified = BaseStream._GzipMtime;
             }
             return n;
         }
@@ -317,19 +320,19 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="buffer">The buffer holding data to write to the stream.</param>
         /// <param name="offset">the offset within that data array to find the first byte to write.</param>
         /// <param name="count">the number of bytes to write.</param>
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("GZipStream");
             }
-            if (_baseStream._streamMode == ZlibBaseStream.StreamMode.Undefined)
+            if (BaseStream._streamMode == ZlibBaseStream.StreamMode.Undefined)
             {
                 //Console.WriteLine("GZipStream: First write");
-                if (_baseStream._wantCompress)
+                if (BaseStream._wantCompress)
                 {
                     // first write in compression, therefore, emit the GZIP header
-                    _headerByteCount = await EmitHeaderAsync();
+                    _headerByteCount = EmitHeader();
                 }
                 else
                 {
@@ -337,7 +340,7 @@ namespace SharpCompress.Compressors.Deflate
                 }
             }
 
-            await _baseStream.WriteAsync(buffer, offset, count, cancellationToken);
+            BaseStream.Write(buffer, offset, count);
         }
 
         #endregion Stream methods
@@ -402,7 +405,7 @@ namespace SharpCompress.Compressors.Deflate
 
         public int Crc32 { get; private set; }
 
-        private async ValueTask<int> EmitHeaderAsync()
+        private int EmitHeader()
         {
             byte[]? commentBytes = (Comment is null) ? null
                 : _encoding.GetBytes(Comment);
@@ -471,7 +474,7 @@ namespace SharpCompress.Compressors.Deflate
                 header[i++] = 0; // terminate
             }
 
-            await _baseStream._stream.WriteAsync(header, 0, header.Length);
+            BaseStream._stream.Write(header, 0, header.Length);
 
             return header.Length; // bytes written
         }

src/SharpCompress/Compressors/Deflate/ZlibBaseStream.cs

@@ -27,15 +27,11 @@
 // ------------------------------------------------------------------
 
 using System;
-using System.Buffers;
 using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.IO;
 using SharpCompress.Common.Tar.Headers;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.Deflate
 {
@@ -46,18 +42,18 @@ namespace SharpCompress.Compressors.Deflate
         GZIP = 1952
     }
 
-    internal class ZlibBaseStream : AsyncStream
+    internal class ZlibBaseStream : Stream
     {
         protected internal ZlibCodec _z; // deferred init... new ZlibCodec();
 
         protected internal StreamMode _streamMode = StreamMode.Undefined;
         protected internal FlushType _flushMode;
-        private readonly ZlibStreamFlavor _flavor;
-        private readonly CompressionMode _compressionMode;
-        private readonly CompressionLevel _level;
+        protected internal ZlibStreamFlavor _flavor;
+        protected internal CompressionMode _compressionMode;
+        protected internal CompressionLevel _level;
         protected internal byte[] _workingBuffer;
         protected internal int _bufferSize = ZlibConstants.WorkingBufferSizeDefault;
-        private readonly byte[] _buf1 = new byte[1];
+        protected internal byte[] _buf1 = new byte[1];
 
         protected internal Stream _stream;
         protected internal CompressionStrategy Strategy = CompressionStrategy.Default;
@@ -120,13 +116,19 @@ namespace SharpCompress.Compressors.Deflate
             }
         }
 
-        private byte[] workingBuffer => _workingBuffer ??= new byte[_bufferSize];
+        private byte[] workingBuffer
+        {
+            get => _workingBuffer ??= new byte[_bufferSize];
+        }
 
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
             // workitem 7159
             // calculate the CRC on the unccompressed data  (before writing)
-            crc?.SlurpBlock(buffer, offset, count);
+            if (crc != null)
+            {
+                crc.SlurpBlock(buffer, offset, count);
+            }
 
             if (_streamMode == StreamMode.Undefined)
             {
@@ -146,7 +148,7 @@ namespace SharpCompress.Compressors.Deflate
             z.InputBuffer = buffer;
             _z.NextIn = offset;
             _z.AvailableBytesIn = count;
-            var done = false;
+            bool done = false;
             do
             {
                 _z.OutputBuffer = workingBuffer;
@@ -161,7 +163,7 @@ namespace SharpCompress.Compressors.Deflate
                 }
 
                 //if (_workingBuffer.Length - _z.AvailableBytesOut > 0)
-                await _stream.WriteAsync(_workingBuffer, 0, _workingBuffer.Length - _z.AvailableBytesOut, cancellationToken);
+                _stream.Write(_workingBuffer, 0, _workingBuffer.Length - _z.AvailableBytesOut);
 
                 done = _z.AvailableBytesIn == 0 && _z.AvailableBytesOut != 0;
 
@@ -174,7 +176,7 @@ namespace SharpCompress.Compressors.Deflate
             while (!done);
         }
 
-        private async Task FinishAsync()
+        private void finish()
         {
             if (_z is null)
             {
@@ -183,7 +185,7 @@ namespace SharpCompress.Compressors.Deflate
 
             if (_streamMode == StreamMode.Writer)
             {
-                var done = false;
+                bool done = false;
                 do
                 {
                     _z.OutputBuffer = workingBuffer;
@@ -198,14 +200,14 @@ namespace SharpCompress.Compressors.Deflate
                         string verb = (_wantCompress ? "de" : "in") + "flating";
                         if (_z.Message is null)
                         {
-                            throw new ZlibException($"{verb}: (rc = {rc})");
+                            throw new ZlibException(String.Format("{0}: (rc = {1})", verb, rc));
                         }
                         throw new ZlibException(verb + ": " + _z.Message);
                     }
 
                     if (_workingBuffer.Length - _z.AvailableBytesOut > 0)
                     {
-                        await _stream.WriteAsync(_workingBuffer, 0, _workingBuffer.Length - _z.AvailableBytesOut);
+                        _stream.Write(_workingBuffer, 0, _workingBuffer.Length - _z.AvailableBytesOut);
                     }
 
                     done = _z.AvailableBytesIn == 0 && _z.AvailableBytesOut != 0;
@@ -218,7 +220,7 @@ namespace SharpCompress.Compressors.Deflate
                 }
                 while (!done);
 
-                await FlushAsync();
+                Flush();
 
                 // workitem 7159
                 if (_flavor == ZlibStreamFlavor.GZIP)
@@ -226,13 +228,12 @@ namespace SharpCompress.Compressors.Deflate
                     if (_wantCompress)
                     {
                         // Emit the GZIP trailer: CRC32 and  size mod 2^32
-                        using var rented = MemoryPool<byte>.Shared.Rent(4);
-                        var intBuf = rented.Memory.Slice(0, 4);
-                        BinaryPrimitives.WriteInt32LittleEndian(intBuf.Span, crc.Crc32Result);
-                        await _stream.WriteAsync(intBuf, CancellationToken.None);
+                        Span<byte> intBuf = stackalloc byte[4];
+                        BinaryPrimitives.WriteInt32LittleEndian(intBuf, crc.Crc32Result);
+                        _stream.Write(intBuf);
                         int c2 = (int)(crc.TotalBytesRead & 0x00000000FFFFFFFF);
-                        BinaryPrimitives.WriteInt32LittleEndian(intBuf.Span, c2);
-                        await _stream.WriteAsync(intBuf, CancellationToken.None);
+                        BinaryPrimitives.WriteInt32LittleEndian(intBuf, c2);
+                        _stream.Write(intBuf);
                     }
                     else
                     {
@@ -255,41 +256,44 @@ namespace SharpCompress.Compressors.Deflate
                         }
 
                         // Read and potentially verify the GZIP trailer: CRC32 and  size mod 2^32
-                        using var rented = MemoryPool<byte>.Shared.Rent(8);
-                        var trailer = rented.Memory.Slice(0, 8);
+                        Span<byte> trailer = stackalloc byte[8];
 
                         // workitem 8679
                         if (_z.AvailableBytesIn != 8)
                         {
                             // Make sure we have read to the end of the stream
-                            _z.InputBuffer.AsSpan(_z.NextIn, _z.AvailableBytesIn).CopyTo(trailer.Span);
+                            _z.InputBuffer.AsSpan(_z.NextIn, _z.AvailableBytesIn).CopyTo(trailer);
                             int bytesNeeded = 8 - _z.AvailableBytesIn;
-                            int bytesRead = await _stream.ReadAsync(trailer.Slice(_z.AvailableBytesIn, bytesNeeded));
+                            int bytesRead = _stream.Read(trailer.Slice(_z.AvailableBytesIn, bytesNeeded));
                             if (bytesNeeded != bytesRead)
                             {
-                                throw new ZlibException($"Protocol error. AvailableBytesIn={_z.AvailableBytesIn + bytesRead}, expected 8");
+                                throw new ZlibException(String.Format(
+                                                                      "Protocol error. AvailableBytesIn={0}, expected 8",
+                                                                      _z.AvailableBytesIn + bytesRead));
                             }
                         }
                         else
                         {
-                            _z.InputBuffer.AsSpan(_z.NextIn, trailer.Length).CopyTo(trailer.Span);
+                            _z.InputBuffer.AsSpan(_z.NextIn, trailer.Length).CopyTo(trailer);
                         }
 
-                        Int32 crc32_expected = BinaryPrimitives.ReadInt32LittleEndian(trailer.Span);
+                        Int32 crc32_expected = BinaryPrimitives.ReadInt32LittleEndian(trailer);
                         Int32 crc32_actual = crc.Crc32Result;
-                        Int32 isize_expected = BinaryPrimitives.ReadInt32LittleEndian(trailer.Span.Slice(4));
+                        Int32 isize_expected = BinaryPrimitives.ReadInt32LittleEndian(trailer.Slice(4));
                         Int32 isize_actual = (Int32)(_z.TotalBytesOut & 0x00000000FFFFFFFF);
 
                         if (crc32_actual != crc32_expected)
                         {
                             throw new ZlibException(
-                                                    $"Bad CRC32 in GZIP stream. (actual({crc32_actual:X8})!=expected({crc32_expected:X8}))");
+                                                    String.Format("Bad CRC32 in GZIP stream. (actual({0:X8})!=expected({1:X8}))",
+                                                                  crc32_actual, crc32_expected));
                         }
 
                         if (isize_actual != isize_expected)
                         {
                             throw new ZlibException(
-                                                    $"Bad size in GZIP stream. (actual({isize_actual})!=expected({isize_expected}))");
+                                                    String.Format("Bad size in GZIP stream. (actual({0})!=expected({1}))", isize_actual,
+                                                                  isize_expected));
                         }
                     }
                     else
@@ -300,7 +304,7 @@ namespace SharpCompress.Compressors.Deflate
             }
         }
 
-        private void End()
+        private void end()
         {
             if (z is null)
             {
@@ -317,32 +321,36 @@ namespace SharpCompress.Compressors.Deflate
             _z = null;
         }
 
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
-            if (_isDisposed)
+            if (isDisposed)
             {
                 return;
             }
-            _isDisposed = true;
+            isDisposed = true;
+            base.Dispose(disposing);
+            if (disposing)
+            {
                 if (_stream is null)
                 {
                     return;
                 }
                 try
                 {
-                    await FinishAsync();
+                    finish();
                 }
                 finally
                 {
-                    End();
-                    _stream?.DisposeAsync();
+                    end();
+                    _stream?.Dispose();
                     _stream = null;
                 }
+            }
         }
 
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
-            return _stream.FlushAsync(cancellationToken);
+            _stream.Flush();
         }
 
         public override Int64 Seek(Int64 offset, SeekOrigin origin)
@@ -357,7 +365,7 @@ namespace SharpCompress.Compressors.Deflate
             _stream.SetLength(value);
         }
 
-/*
+#if NOT
         public int Read()
         {
             if (Read(_buf1, 0, 1) == 0)
@@ -367,19 +375,19 @@ namespace SharpCompress.Compressors.Deflate
                 crc.SlurpBlock(_buf1,0,1);
             return (_buf1[0] & 0xFF);
         }
-*/
+#endif
 
-        private bool _nomoreinput;
-        private bool _isDisposed;
+        private bool nomoreinput;
+        private bool isDisposed;
 
-        private async Task<string> ReadZeroTerminatedStringAsync()
+        private string ReadZeroTerminatedString()
         {
             var list = new List<byte>();
-            var done = false;
+            bool done = false;
             do
             {
                 // workitem 7740
-                int n = await _stream.ReadAsync(_buf1, 0, 1);
+                int n = _stream.Read(_buf1, 0, 1);
                 if (n != 1)
                 {
                     throw new ZlibException("Unexpected EOF reading GZIP header.");
@@ -398,14 +406,13 @@ namespace SharpCompress.Compressors.Deflate
             return _encoding.GetString(buffer, 0, buffer.Length);
         }
 
-        private async Task<int> ReadAndValidateGzipHeaderAsync(CancellationToken cancellationToken)
+        private int _ReadAndValidateGzipHeader()
         {
-            var totalBytesRead = 0;
+            int totalBytesRead = 0;
 
             // read the header on the first read
-            using var rented = MemoryPool<byte>.Shared.Rent(10);
-            var header = rented.Memory.Slice(0, 10);
-            int n = await _stream.ReadAsync(header, cancellationToken);
+            Span<byte> header = stackalloc byte[10];
+            int n = _stream.Read(header);
 
             // workitem 8501: handle edge case (decompress empty stream)
             if (n == 0)
@@ -418,46 +425,46 @@ namespace SharpCompress.Compressors.Deflate
                 throw new ZlibException("Not a valid GZIP stream.");
             }
 
-            if (header.Span[0] != 0x1F || header.Span[1] != 0x8B || header.Span[2] != 8)
+            if (header[0] != 0x1F || header[1] != 0x8B || header[2] != 8)
             {
                 throw new ZlibException("Bad GZIP header.");
             }
 
-            int timet = BinaryPrimitives.ReadInt32LittleEndian(header.Span.Slice(4));
+            int timet = BinaryPrimitives.ReadInt32LittleEndian(header.Slice(4));
             _GzipMtime = TarHeader.EPOCH.AddSeconds(timet);
             totalBytesRead += n;
-            if ((header.Span[3] & 0x04) == 0x04)
+            if ((header[3] & 0x04) == 0x04)
             {
                 // read and discard extra field
-                n = await _stream.ReadAsync(header.Slice(0, 2), cancellationToken); // 2-byte length field
+                n = _stream.Read(header.Slice(0, 2)); // 2-byte length field
                 totalBytesRead += n;
 
-                short extraLength = (short)(header.Span[0] + header.Span[1] * 256);
+                short extraLength = (short)(header[0] + header[1] * 256);
                 byte[] extra = new byte[extraLength];
-                n = await _stream.ReadAsync(extra, 0, extra.Length, cancellationToken);
+                n = _stream.Read(extra, 0, extra.Length);
                 if (n != extraLength)
                 {
                     throw new ZlibException("Unexpected end-of-file reading GZIP header.");
                 }
                 totalBytesRead += n;
             }
-            if ((header.Span[3] & 0x08) == 0x08)
+            if ((header[3] & 0x08) == 0x08)
             {
-                _GzipFileName = await ReadZeroTerminatedStringAsync();
+                _GzipFileName = ReadZeroTerminatedString();
             }
-            if ((header.Span[3] & 0x10) == 0x010)
+            if ((header[3] & 0x10) == 0x010)
             {
-                _GzipComment = await ReadZeroTerminatedStringAsync();
+                _GzipComment = ReadZeroTerminatedString();
             }
-            if ((header.Span[3] & 0x02) == 0x02)
+            if ((header[3] & 0x02) == 0x02)
             {
-                await ReadAsync(_buf1, 0, 1, cancellationToken); // CRC16, ignore
+                Read(_buf1, 0, 1); // CRC16, ignore
             }
 
             return totalBytesRead;
         }
 
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override Int32 Read(Byte[] buffer, Int32 offset, Int32 count)
         {
             // According to MS documentation, any implementation of the IO.Stream.Read function must:
             // (a) throw an exception if offset & count reference an invalid part of the buffer,
@@ -480,7 +487,7 @@ namespace SharpCompress.Compressors.Deflate
                 z.AvailableBytesIn = 0;
                 if (_flavor == ZlibStreamFlavor.GZIP)
                 {
-                    _gzipHeaderByteCount = await ReadAndValidateGzipHeaderAsync(cancellationToken);
+                    _gzipHeaderByteCount = _ReadAndValidateGzipHeader();
 
                     // workitem 8501: handle edge case (decompress empty stream)
                     if (_gzipHeaderByteCount == 0)
@@ -495,13 +502,37 @@ namespace SharpCompress.Compressors.Deflate
                 throw new ZlibException("Cannot Read after Writing.");
             }
 
+            int rc = 0;
+
+            // set up the output of the deflate/inflate codec:
+            _z.OutputBuffer = buffer;
+            _z.NextOut = offset;
+            _z.AvailableBytesOut = count;
+
             if (count == 0)
             {
                 return 0;
             }
-            if (_nomoreinput && _wantCompress)
+            if (nomoreinput && _wantCompress)
             {
-                return 0; // workitem 8557
+                // no more input data available; therefore we flush to
+                // try to complete the read
+                rc = _z.Deflate(FlushType.Finish);
+
+                if (rc != ZlibConstants.Z_OK && rc != ZlibConstants.Z_STREAM_END)
+                {
+                    throw new ZlibException(String.Format("Deflating:  rc={0}  msg={1}", rc, _z.Message));
+                }
+
+                rc = (count - _z.AvailableBytesOut);
+
+                // calculate CRC after reading
+                if (crc != null)
+                {
+                    crc.SlurpBlock(buffer, offset, rc);
+                }
+
+                return rc;
             }
             if (buffer is null)
             {
@@ -520,13 +551,6 @@ namespace SharpCompress.Compressors.Deflate
                 throw new ArgumentOutOfRangeException(nameof(count));
             }
 
-            var rc = 0;
-
-            // set up the output of the deflate/inflate codec:
-            _z.OutputBuffer = buffer;
-            _z.NextOut = offset;
-            _z.AvailableBytesOut = count;
-
             // This is necessary in case _workingBuffer has been resized. (new byte[])
             // (The first reference to _workingBuffer goes through the private accessor which
             // may initialize it.)
@@ -535,14 +559,14 @@ namespace SharpCompress.Compressors.Deflate
             do
             {
                 // need data in _workingBuffer in order to deflate/inflate.  Here, we check if we have any.
-                if ((_z.AvailableBytesIn == 0) && (!_nomoreinput))
+                if ((_z.AvailableBytesIn == 0) && (!nomoreinput))
                 {
                     // No data available, so try to Read data from the captive stream.
                     _z.NextIn = 0;
-                    _z.AvailableBytesIn = await _stream.ReadAsync(_workingBuffer, 0, _workingBuffer.Length, cancellationToken);
+                    _z.AvailableBytesIn = _stream.Read(_workingBuffer, 0, _workingBuffer.Length);
                     if (_z.AvailableBytesIn == 0)
                     {
-                        _nomoreinput = true;
+                        nomoreinput = true;
                     }
                 }
 
@@ -551,22 +575,23 @@ namespace SharpCompress.Compressors.Deflate
                          ? _z.Deflate(_flushMode)
                          : _z.Inflate(_flushMode);
 
-                if (_nomoreinput && (rc == ZlibConstants.Z_BUF_ERROR))
+                if (nomoreinput && (rc == ZlibConstants.Z_BUF_ERROR))
                 {
                     return 0;
                 }
 
                 if (rc != ZlibConstants.Z_OK && rc != ZlibConstants.Z_STREAM_END)
                 {
-                    throw new ZlibException($"{(_wantCompress ? "de" : "in")}flating:  rc={rc}  msg={_z.Message}");
+                    throw new ZlibException(String.Format("{0}flating:  rc={1}  msg={2}", (_wantCompress ? "de" : "in"),
+                                                          rc, _z.Message));
                 }
 
-                if ((_nomoreinput || rc == ZlibConstants.Z_STREAM_END) && (_z.AvailableBytesOut == count))
+                if ((nomoreinput || rc == ZlibConstants.Z_STREAM_END) && (_z.AvailableBytesOut == count))
                 {
                     break; // nothing more to read
                 }
             } //while (_z.AvailableBytesOut == count && rc == ZlibConstants.Z_OK);
-            while (_z.AvailableBytesOut > 0 && !_nomoreinput && rc == ZlibConstants.Z_OK);
+            while (_z.AvailableBytesOut > 0 && !nomoreinput && rc == ZlibConstants.Z_OK);
 
             // workitem 8557
             // is there more room in output?
@@ -578,7 +603,7 @@ namespace SharpCompress.Compressors.Deflate
                 }
 
                 // are we completely done reading?
-                if (_nomoreinput)
+                if (nomoreinput)
                 {
                     // and in compression?
                     if (_wantCompress)
@@ -589,7 +614,7 @@ namespace SharpCompress.Compressors.Deflate
 
                         if (rc != ZlibConstants.Z_OK && rc != ZlibConstants.Z_STREAM_END)
                         {
-                            throw new ZlibException($"Deflating:  rc={rc}  msg={_z.Message}");
+                            throw new ZlibException(String.Format("Deflating:  rc={0}  msg={1}", rc, _z.Message));
                         }
                     }
                 }
@@ -598,7 +623,10 @@ namespace SharpCompress.Compressors.Deflate
             rc = (count - _z.AvailableBytesOut);
 
             // calculate CRC after reading
-            crc?.SlurpBlock(buffer, offset, rc);
+            if (crc != null)
+            {
+                crc.SlurpBlock(buffer, offset, rc);
+            }
 
             return rc;
         }

src/SharpCompress/Compressors/Deflate/ZlibStream.cs

@@ -28,13 +28,10 @@
 using System;
 using System.IO;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.Deflate
 {
-    public class ZlibStream : AsyncStream
+    public class ZlibStream : Stream
     {
         private readonly ZlibBaseStream _baseStream;
         private bool _disposed;
@@ -207,25 +204,35 @@ namespace SharpCompress.Compressors.Deflate
         /// <remarks>
         /// This may or may not result in a <c>Close()</c> call on the captive stream.
         /// </remarks>
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
-            if (!_disposed)
+            try
             {
-                await _baseStream.DisposeAsync();
-                _disposed = true;
+                if (!_disposed)
+                {
+                    if (disposing)
+                    {
+                        _baseStream?.Dispose();
+                    }
+                    _disposed = true;
+                }
+            }
+            finally
+            {
+                base.Dispose(disposing);
             }
         }
 
         /// <summary>
         /// Flush the stream.
         /// </summary>
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("ZlibStream");
             }
-            return _baseStream.FlushAsync(cancellationToken);
+            _baseStream.Flush();
         }
 
         /// <summary>
@@ -254,13 +261,22 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="buffer">The buffer into which the read data should be placed.</param>
         /// <param name="offset">the offset within that data array to put the first byte read.</param>
         /// <param name="count">the number of bytes to read.</param>
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("ZlibStream");
             }
-            return await _baseStream.ReadAsync(buffer, offset, count, cancellationToken);
+            return _baseStream.Read(buffer, offset, count);
+        }
+
+        public override int ReadByte()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException("ZlibStream");
+            }
+            return _baseStream.ReadByte();
         }
 
         /// <summary>
@@ -305,14 +321,24 @@ namespace SharpCompress.Compressors.Deflate
         /// <param name="buffer">The buffer holding data to write to the stream.</param>
         /// <param name="offset">the offset within that data array to find the first byte to write.</param>
         /// <param name="count">the number of bytes to write.</param>
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
             if (_disposed)
             {
                 throw new ObjectDisposedException("ZlibStream");
             }
-            await _baseStream.WriteAsync(buffer, offset, count, cancellationToken);
+            _baseStream.Write(buffer, offset, count);
         }
+
+        public override void WriteByte(byte value)
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException("ZlibStream");
+            }
+            _baseStream.WriteByte(value);
+        }
+
         #endregion System.IO.Stream methods
     }
 }

src/SharpCompress/Compressors/LZMA/DecoderStream.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.SevenZip;
 using SharpCompress.Compressors.LZMA.Utilites;
 using SharpCompress.IO;
@@ -93,9 +91,8 @@ namespace SharpCompress.Compressors.LZMA
             }
         }
 
-        private static async ValueTask<Stream> CreateDecoderStream(Stream[] packStreams, long[] packSizes, Stream[] outStreams,
-                                                                   CFolder folderInfo, int coderIndex, IPasswordProvider pass,
-                                                                   CancellationToken cancellationToken)
+        private static Stream CreateDecoderStream(Stream[] packStreams, long[] packSizes, Stream[] outStreams,
+                                                  CFolder folderInfo, int coderIndex, IPasswordProvider pass)
         {
             var coderInfo = folderInfo._coders[coderIndex];
             if (coderInfo._numOutStreams != 1)
@@ -130,8 +127,8 @@ namespace SharpCompress.Compressors.LZMA
                     }
 
                     int otherCoderIndex = FindCoderIndexForOutStreamIndex(folderInfo, pairedOutIndex);
-                    inStreams[i] = await CreateDecoderStream(packStreams, packSizes, outStreams, folderInfo, otherCoderIndex,
-                                                       pass, cancellationToken);
+                    inStreams[i] = CreateDecoderStream(packStreams, packSizes, outStreams, folderInfo, otherCoderIndex,
+                                                       pass);
 
                     //inStreamSizes[i] = folderInfo.UnpackSizes[pairedOutIndex];
 
@@ -157,11 +154,11 @@ namespace SharpCompress.Compressors.LZMA
             }
 
             long unpackSize = folderInfo._unpackSizes[outStreamId];
-            return await DecoderRegistry.CreateDecoderStream(coderInfo._methodId, inStreams, coderInfo._props, pass, unpackSize, cancellationToken);
+            return DecoderRegistry.CreateDecoderStream(coderInfo._methodId, inStreams, coderInfo._props, pass, unpackSize);
         }
 
-        internal static async ValueTask<Stream> CreateDecoderStream(Stream inStream, long startPos, long[] packSizes, CFolder folderInfo,
-                                                   IPasswordProvider pass, CancellationToken cancellationToken)
+        internal static Stream CreateDecoderStream(Stream inStream, long startPos, long[] packSizes, CFolder folderInfo,
+                                                   IPasswordProvider pass)
         {
             if (!folderInfo.CheckStructure())
             {
@@ -179,7 +176,7 @@ namespace SharpCompress.Compressors.LZMA
 
             int primaryCoderIndex, primaryOutStreamIndex;
             FindPrimaryOutStreamIndex(folderInfo, out primaryCoderIndex, out primaryOutStreamIndex);
-            return await CreateDecoderStream(inStreams, packSizes, outStreams, folderInfo, primaryCoderIndex, pass, cancellationToken);
+            return CreateDecoderStream(inStreams, packSizes, outStreams, folderInfo, primaryCoderIndex, pass);
         }
     }
 }

src/SharpCompress/Compressors/LZMA/ICoder.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.LZMA
 {
@@ -61,8 +59,8 @@ namespace SharpCompress.Compressors.LZMA
         /// <param name="progress">
         /// callback progress reference.
         /// </param>
-        ValueTask CodeAsync(Stream inStream, Stream outStream,
-                  Int64 inSize, Int64 outSize, ICodeProgress progress, CancellationToken cancellationToken);
+        void Code(Stream inStream, Stream outStream,
+                  Int64 inSize, Int64 outSize, ICodeProgress progress);
     }
 
     /*

src/SharpCompress/Compressors/LZMA/LZipStream.cs

@@ -1,9 +1,6 @@
 using System;
-using System.Buffers;
 using System.Buffers.Binary;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Crypto;
 using SharpCompress.IO;
 
@@ -17,70 +14,61 @@ namespace SharpCompress.Compressors.LZMA
     /// <summary>
     /// Stream supporting the LZIP format, as documented at http://www.nongnu.org/lzip/manual/lzip_manual.html
     /// </summary>
-    public sealed class LZipStream : AsyncStream
+    public sealed class LZipStream : Stream
     {
-#nullable disable
-        private Stream _stream;
-#nullable enable
-        private CountingWritableSubStream? _countingWritableSubStream;
+        private readonly Stream _stream;
+        private readonly CountingWritableSubStream? _countingWritableSubStream;
         private bool _disposed;
         private bool _finished;
 
         private long _writeCount;
 
-        private LZipStream()
+        public LZipStream(Stream stream, CompressionMode mode)
         {
-            
-        }
-
-        public static async ValueTask<LZipStream> CreateAsync(Stream stream, CompressionMode mode)
-        {
-            var lzip = new LZipStream();
-            lzip.Mode = mode;
+            Mode = mode;
 
             if (mode == CompressionMode.Decompress)
             {
-                int dSize = await ValidateAndReadSize(stream);
+                int dSize = ValidateAndReadSize(stream);
                 if (dSize == 0)
                 {
                     throw new IOException("Not an LZip stream");
                 }
                 byte[] properties = GetProperties(dSize);
-                lzip._stream = await LzmaStream.CreateAsync(properties, stream);
+                _stream = new LzmaStream(properties, stream);
             }
             else
             {
                 //default
                 int dSize = 104 * 1024;
-                await WriteHeaderSizeAsync(stream);
+                WriteHeaderSize(stream);
 
-                lzip._countingWritableSubStream = new CountingWritableSubStream(stream);
-                lzip._stream = new Crc32Stream(new LzmaStream(new LzmaEncoderProperties(true, dSize), false, lzip._countingWritableSubStream));
+                _countingWritableSubStream = new CountingWritableSubStream(stream);
+                _stream = new Crc32Stream(new LzmaStream(new LzmaEncoderProperties(true, dSize), false, _countingWritableSubStream));
             }
-            return lzip;
         }
 
-        public async ValueTask FinishAsync()
+        public void Finish()
         {
             if (!_finished)
             {
                 if (Mode == CompressionMode.Compress)
                 {
                     var crc32Stream = (Crc32Stream)_stream;
-                    await crc32Stream.WrappedStream.DisposeAsync();
-                    await crc32Stream.DisposeAsync();
+                    crc32Stream.WrappedStream.Dispose();
+                    crc32Stream.Dispose();
                     var compressedCount = _countingWritableSubStream!.Count;
 
-                    byte[] intBuf = new byte[8];
+                    Span<byte> intBuf = stackalloc byte[8];
                     BinaryPrimitives.WriteUInt32LittleEndian(intBuf, crc32Stream.Crc);
-                    await _countingWritableSubStream.WriteAsync(intBuf, 0, 4);
+                    _countingWritableSubStream.Write(intBuf.Slice(0, 4));
 
                     BinaryPrimitives.WriteInt64LittleEndian(intBuf, _writeCount);
-                    await _countingWritableSubStream.WriteAsync(intBuf, 0, 8);
+                    _countingWritableSubStream.Write(intBuf);
 
                     //total with headers
                     BinaryPrimitives.WriteUInt64LittleEndian(intBuf, compressedCount + 6 + 20);
-                    await _countingWritableSubStream.WriteAsync(intBuf, 0, 8);
+                    _countingWritableSubStream.Write(intBuf);
                 }
                 _finished = true;
             }
@@ -88,18 +76,21 @@ namespace SharpCompress.Compressors.LZMA
 
         #region Stream methods
 
-        public override async ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
             if (_disposed)
             {
                 return;
             }
             _disposed = true;
-                await FinishAsync();
-                await _stream.DisposeAsync();
+            if (disposing)
+            {
+                Finish();
+                _stream.Dispose();
+            }
         }
 
-        public CompressionMode Mode { get; private set; }
+        public CompressionMode Mode { get; }
 
         public override bool CanRead => Mode == CompressionMode.Decompress;
 
@@ -107,38 +98,54 @@ namespace SharpCompress.Compressors.LZMA
 
         public override bool CanWrite => Mode == CompressionMode.Compress;
 
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
-            return _stream.FlushAsync(cancellationToken);
+            _stream.Flush();
         }
 
         // TODO: Both Length and Position are sometimes feasible, but would require
         // reading the output length when we initialize.
-        public override long Length => throw new NotSupportedException();
+        public override long Length => throw new NotImplementedException();
 
-        public override long Position { get => throw new NotImplementedException(); set => throw new NotSupportedException(); }
+        public override long Position { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
 
-        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = new CancellationToken())
-        {
-            return _stream.ReadAsync(buffer, cancellationToken);
-        }
+        public override int Read(byte[] buffer, int offset, int count) => _stream.Read(buffer, offset, count);
+
+        public override int ReadByte() => _stream.ReadByte();
 
         public override long Seek(long offset, SeekOrigin origin) => throw new NotSupportedException();
 
-        public override void SetLength(long value) => throw new NotSupportedException();
+        public override void SetLength(long value) => throw new NotImplementedException();
 
-        public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = new CancellationToken())
+
+#if !NETFRAMEWORK && !NETSTANDARD2_0
+
+        public override int Read(Span<byte> buffer)
         {
-            await _stream.WriteAsync(buffer, cancellationToken);
+            return _stream.Read(buffer);
+        }
+
+        public override void Write(ReadOnlySpan<byte> buffer)
+        {
+            _stream.Write(buffer);
+
             _writeCount += buffer.Length;
         }
 
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+#endif
+
+        public override void Write(byte[] buffer, int offset, int count)
         {
-            await _stream.WriteAsync(buffer, offset, count, cancellationToken);
+            _stream.Write(buffer, offset, count);
             _writeCount += count;
         }
 
+        public override void WriteByte(byte value)
+        {
+            _stream.WriteByte(value);
+            ++_writeCount;
+        }
+
         #endregion
 
         /// <summary>
@@ -148,14 +155,14 @@ namespace SharpCompress.Compressors.LZMA
         /// </summary>
         /// <param name="stream">The stream to read from. Must not be null.</param>
         /// <returns><c>true</c> if the given stream is an LZip file, <c>false</c> otherwise.</returns>
-        public static async ValueTask<bool> IsLZipFileAsync(Stream stream) => await ValidateAndReadSize(stream) != 0;
+        public static bool IsLZipFile(Stream stream) => ValidateAndReadSize(stream) != 0;
 
         /// <summary>
         /// Reads the 6-byte header of the stream, and returns 0 if either the header
         /// couldn't be read or it isn't a validate LZIP header, or the dictionary
         /// size if it *is* a valid LZIP file.
         /// </summary>
-        private static async ValueTask<int> ValidateAndReadSize(Stream stream)
+        public static int ValidateAndReadSize(Stream stream)
         {
             if (stream is null)
             {
@@ -163,9 +170,8 @@ namespace SharpCompress.Compressors.LZMA
             }
 
             // Read the header
-            using var buffer = MemoryPool<byte>.Shared.Rent(6);
-            var header = buffer.Memory.Slice(0,6);
-            int n = await stream.ReadAsync(header);
+            Span<byte> header = stackalloc byte[6];
+            int n = stream.Read(header);
 
             // TODO: Handle reading only part of the header?
 
@@ -174,18 +180,18 @@ namespace SharpCompress.Compressors.LZMA
                 return 0;
             }
 
-            if (header.Span[0] != 'L' || header.Span[1] != 'Z' || header.Span[2] != 'I' || header.Span[3] != 'P' || header.Span[4] != 1 /* version 1 */)
+            if (header[0] != 'L' || header[1] != 'Z' || header[2] != 'I' || header[3] != 'P' || header[4] != 1 /* version 1 */)
             {
                 return 0;
             }
-            int basePower = header.Span[5] & 0x1F;
-            int subtractionNumerator = (header.Span[5] & 0xE0) >> 5;
+            int basePower = header[5] & 0x1F;
+            int subtractionNumerator = (header[5] & 0xE0) >> 5;
             return (1 << basePower) - subtractionNumerator * (1 << (basePower - 4));
         }
 
         private static readonly byte[] headerBytes = new byte[6] { (byte)'L', (byte)'Z', (byte)'I', (byte)'P', 1, 113 };
 
-        public static async ValueTask WriteHeaderSizeAsync(Stream stream)
+        public static void WriteHeaderSize(Stream stream)
         {
             if (stream is null)
             {
@@ -193,7 +199,7 @@ namespace SharpCompress.Compressors.LZMA
             }
 
             // hard coding the dictionary size encoding
-            await stream.WriteAsync(headerBytes, 0, 6);
+            stream.Write(headerBytes, 0, 6);
         }
 
         /// <summary>

src/SharpCompress/Compressors/LZMA/LzmaDecoder.cs

@@ -1,7 +1,7 @@
+#nullable disable
+
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Compressors.LZMA.LZ;
 using SharpCompress.Compressors.LZMA.RangeCoder;
 
@@ -11,11 +11,11 @@ namespace SharpCompress.Compressors.LZMA
     {
         private class LenDecoder
         {
-            private BitDecoder _choice = new();
-            private BitDecoder _choice2 = new();
+            private BitDecoder _choice = new BitDecoder();
+            private BitDecoder _choice2 = new BitDecoder();
             private readonly BitTreeDecoder[] _lowCoder = new BitTreeDecoder[Base.K_NUM_POS_STATES_MAX];
             private readonly BitTreeDecoder[] _midCoder = new BitTreeDecoder[Base.K_NUM_POS_STATES_MAX];
-            private BitTreeDecoder _highCoder = new(Base.K_NUM_HIGH_LEN_BITS);
+            private BitTreeDecoder _highCoder = new BitTreeDecoder(Base.K_NUM_HIGH_LEN_BITS);
             private uint _numPosStates;
 
             public void Create(uint numPosStates)
@@ -40,21 +40,21 @@ namespace SharpCompress.Compressors.LZMA
                 _highCoder.Init();
             }
 
-            public async ValueTask<uint> DecodeAsync(RangeCoder.Decoder rangeDecoder, uint posState, CancellationToken cancellationToken)
+            public uint Decode(RangeCoder.Decoder rangeDecoder, uint posState)
             {
-                if (await _choice.DecodeAsync(rangeDecoder, cancellationToken) == 0)
+                if (_choice.Decode(rangeDecoder) == 0)
                 {
-                    return await _lowCoder[posState].DecodeAsync(rangeDecoder, cancellationToken);
+                    return _lowCoder[posState].Decode(rangeDecoder);
                 }
                 uint symbol = Base.K_NUM_LOW_LEN_SYMBOLS;
-                if (await _choice2.DecodeAsync(rangeDecoder, cancellationToken) == 0)
+                if (_choice2.Decode(rangeDecoder) == 0)
                 {
-                    symbol += await _midCoder[posState].DecodeAsync(rangeDecoder, cancellationToken);
+                    symbol += _midCoder[posState].Decode(rangeDecoder);
                 }
                 else
                 {
                     symbol += Base.K_NUM_MID_LEN_SYMBOLS;
-                    symbol += await _highCoder.DecodeAsync(rangeDecoder, cancellationToken);
+                    symbol += _highCoder.Decode(rangeDecoder);
                 }
                 return symbol;
             }
@@ -79,31 +79,31 @@ namespace SharpCompress.Compressors.LZMA
                     }
                 }
 
-                public async ValueTask<byte> DecodeNormalAsync(RangeCoder.Decoder rangeDecoder, CancellationToken cancellationToken)
+                public byte DecodeNormal(RangeCoder.Decoder rangeDecoder)
                 {
                     uint symbol = 1;
                     do
                     {
-                        symbol = (symbol << 1) | await _decoders[symbol].DecodeAsync(rangeDecoder, cancellationToken);
+                        symbol = (symbol << 1) | _decoders[symbol].Decode(rangeDecoder);
                     }
                     while (symbol < 0x100);
                     return (byte)symbol;
                 }
 
-                public async ValueTask<byte> DecodeWithMatchByteAsync(RangeCoder.Decoder rangeDecoder, byte matchByte, CancellationToken cancellationToken)
+                public byte DecodeWithMatchByte(RangeCoder.Decoder rangeDecoder, byte matchByte)
                 {
                     uint symbol = 1;
                     do
                     {
                         uint matchBit = (uint)(matchByte >> 7) & 1;
                         matchByte <<= 1;
-                        uint bit = await _decoders[((1 + matchBit) << 8) + symbol].DecodeAsync(rangeDecoder, cancellationToken);
+                        uint bit = _decoders[((1 + matchBit) << 8) + symbol].Decode(rangeDecoder);
                         symbol = (symbol << 1) | bit;
                         if (matchBit != bit)
                         {
                             while (symbol < 0x100)
                             {
-                                symbol = (symbol << 1) | await _decoders[symbol].DecodeAsync(rangeDecoder, cancellationToken);
+                                symbol = (symbol << 1) | _decoders[symbol].Decode(rangeDecoder);
                             }
                             break;
                         }
@@ -113,12 +113,12 @@ namespace SharpCompress.Compressors.LZMA
                 }
             }
 
-            private readonly Decoder2[]_coders;
-            private readonly int _numPrevBits;
-            private readonly int _numPosBits;
-            private readonly uint _posMask;
-            
-            public LiteralDecoder(int numPosBits, int numPrevBits)
+            private Decoder2[] _coders;
+            private int _numPrevBits;
+            private int _numPosBits;
+            private uint _posMask;
+
+            public void Create(int numPosBits, int numPrevBits)
             {
                 if (_coders != null && _numPrevBits == numPrevBits &&
                     _numPosBits == numPosBits)
@@ -150,18 +150,18 @@ namespace SharpCompress.Compressors.LZMA
                 return ((pos & _posMask) << _numPrevBits) + (uint)(prevByte >> (8 - _numPrevBits));
             }
 
-            public ValueTask<byte> DecodeNormalAsync(RangeCoder.Decoder rangeDecoder, uint pos, byte prevByte, CancellationToken cancellationToken)
+            public byte DecodeNormal(RangeCoder.Decoder rangeDecoder, uint pos, byte prevByte)
             {
-                return _coders[GetState(pos, prevByte)].DecodeNormalAsync(rangeDecoder, cancellationToken);
+                return _coders[GetState(pos, prevByte)].DecodeNormal(rangeDecoder);
             }
 
-            public ValueTask<byte> DecodeWithMatchByteAsync(RangeCoder.Decoder rangeDecoder, uint pos, byte prevByte, byte matchByte, CancellationToken cancellationToken)
+            public byte DecodeWithMatchByte(RangeCoder.Decoder rangeDecoder, uint pos, byte prevByte, byte matchByte)
             {
-                return _coders[GetState(pos, prevByte)].DecodeWithMatchByteAsync(rangeDecoder, matchByte, cancellationToken);
+                return _coders[GetState(pos, prevByte)].DecodeWithMatchByte(rangeDecoder, matchByte);
             }
         }
 
-        private OutWindow? _outWindow;
+        private OutWindow _outWindow;
 
         private readonly BitDecoder[] _isMatchDecoders = new BitDecoder[Base.K_NUM_STATES << Base.K_NUM_POS_STATES_BITS_MAX];
         private readonly BitDecoder[] _isRepDecoders = new BitDecoder[Base.K_NUM_STATES];
@@ -173,18 +173,18 @@ namespace SharpCompress.Compressors.LZMA
         private readonly BitTreeDecoder[] _posSlotDecoder = new BitTreeDecoder[Base.K_NUM_LEN_TO_POS_STATES];
         private readonly BitDecoder[] _posDecoders = new BitDecoder[Base.K_NUM_FULL_DISTANCES - Base.K_END_POS_MODEL_INDEX];
 
-        private BitTreeDecoder _posAlignDecoder = new(Base.K_NUM_ALIGN_BITS);
+        private BitTreeDecoder _posAlignDecoder = new BitTreeDecoder(Base.K_NUM_ALIGN_BITS);
 
-        private readonly LenDecoder _lenDecoder = new();
-        private readonly LenDecoder _repLenDecoder = new();
+        private readonly LenDecoder _lenDecoder = new LenDecoder();
+        private readonly LenDecoder _repLenDecoder = new LenDecoder();
 
-        private LiteralDecoder? _literalDecoder;
+        private readonly LiteralDecoder _literalDecoder = new LiteralDecoder();
 
         private int _dictionarySize;
 
         private uint _posStateMask;
 
-        private Base.State _state = new();
+        private Base.State _state = new Base.State();
         private uint _rep0, _rep1, _rep2, _rep3;
 
         public Decoder()
@@ -196,16 +196,15 @@ namespace SharpCompress.Compressors.LZMA
             }
         }
 
-        private OutWindow CreateDictionary()
+        private void CreateDictionary()
         {
             if (_dictionarySize < 0)
             {
                 throw new InvalidParamException();
             }
-            var outWindow = new OutWindow();
+            _outWindow = new OutWindow();
             int blockSize = Math.Max(_dictionarySize, (1 << 12));
-            outWindow.Create(blockSize);
-            return outWindow;
+            _outWindow.Create(blockSize);
         }
 
         private void SetLiteralProperties(int lp, int lc)
@@ -218,7 +217,7 @@ namespace SharpCompress.Compressors.LZMA
             {
                 throw new InvalidParamException();
             }
-            _literalDecoder = new(lp, lc);
+            _literalDecoder.Create(lp, lc);
         }
 
         private void SetPosBitsProperties(int pb)
@@ -250,7 +249,7 @@ namespace SharpCompress.Compressors.LZMA
                 _isRepG2Decoders[i].Init();
             }
 
-            _literalDecoder!.Init();
+            _literalDecoder.Init();
             for (i = 0; i < Base.K_NUM_LEN_TO_POS_STATES; i++)
             {
                 _posSlotDecoder[i].Init();
@@ -273,12 +272,12 @@ namespace SharpCompress.Compressors.LZMA
             _rep3 = 0;
         }
 
-        public async ValueTask CodeAsync(Stream inStream, Stream outStream,
-                         Int64 inSize, Int64 outSize, ICodeProgress progress, CancellationToken cancellationToken)
+        public void Code(Stream inStream, Stream outStream,
+                         Int64 inSize, Int64 outSize, ICodeProgress progress)
         {
             if (_outWindow is null)
             {
-                _outWindow = CreateDictionary();
+                CreateDictionary();
             }
             _outWindow.Init(outStream);
             if (outSize > 0)
@@ -291,9 +290,9 @@ namespace SharpCompress.Compressors.LZMA
             }
 
             RangeCoder.Decoder rangeDecoder = new RangeCoder.Decoder();
-            await rangeDecoder.InitAsync(inStream, cancellationToken);
+            rangeDecoder.Init(inStream);
 
-            await CodeAsync(_dictionarySize, _outWindow, rangeDecoder, cancellationToken);
+            Code(_dictionarySize, _outWindow, rangeDecoder);
 
             _outWindow.ReleaseStream();
             rangeDecoder.ReleaseStream();
@@ -309,9 +308,8 @@ namespace SharpCompress.Compressors.LZMA
             _outWindow = null;
         }
 
-        internal async ValueTask<bool> CodeAsync(int dictionarySize, OutWindow outWindow, RangeCoder.Decoder rangeDecoder, CancellationToken cancellationToken)
+        internal bool Code(int dictionarySize, OutWindow outWindow, RangeCoder.Decoder rangeDecoder)
         {
-            _literalDecoder ??= _literalDecoder.CheckNotNull(nameof(_literalDecoder));
             int dictionarySizeCheck = Math.Max(dictionarySize, 1);
 
             outWindow.CopyPending();
@@ -319,19 +317,19 @@ namespace SharpCompress.Compressors.LZMA
             while (outWindow.HasSpace)
             {
                 uint posState = (uint)outWindow._total & _posStateMask;
-                if (await _isMatchDecoders[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].DecodeAsync(rangeDecoder, cancellationToken) == 0)
+                if (_isMatchDecoders[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].Decode(rangeDecoder) == 0)
                 {
                     byte b;
                     byte prevByte = outWindow.GetByte(0);
                     if (!_state.IsCharState())
                     {
-                        b = await _literalDecoder.DecodeWithMatchByteAsync(rangeDecoder,
+                        b = _literalDecoder.DecodeWithMatchByte(rangeDecoder,
                                                                  (uint)outWindow._total, prevByte,
-                                                                 outWindow.GetByte((int)_rep0), cancellationToken);
+                                                                 outWindow.GetByte((int)_rep0));
                     }
                     else
                     {
-                        b = await _literalDecoder.DecodeNormalAsync(rangeDecoder, (uint)outWindow._total, prevByte, cancellationToken);
+                        b = _literalDecoder.DecodeNormal(rangeDecoder, (uint)outWindow._total, prevByte);
                     }
                     outWindow.PutByte(b);
                     _state.UpdateChar();
@@ -339,13 +337,13 @@ namespace SharpCompress.Compressors.LZMA
                 else
                 {
                     uint len;
-                    if (await _isRepDecoders[_state._index].DecodeAsync(rangeDecoder, cancellationToken) == 1)
+                    if (_isRepDecoders[_state._index].Decode(rangeDecoder) == 1)
                     {
-                        if (await _isRepG0Decoders[_state._index].DecodeAsync(rangeDecoder, cancellationToken) == 0)
+                        if (_isRepG0Decoders[_state._index].Decode(rangeDecoder) == 0)
                         {
                             if (
-                                await _isRep0LongDecoders[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].DecodeAsync(
-                                                                                                                              rangeDecoder, cancellationToken) == 0)
+                                _isRep0LongDecoders[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].Decode(
+                                                                                                                   rangeDecoder) == 0)
                             {
                                 _state.UpdateShortRep();
                                 outWindow.PutByte(outWindow.GetByte((int)_rep0));
@@ -355,13 +353,13 @@ namespace SharpCompress.Compressors.LZMA
                         else
                         {
                             UInt32 distance;
-                            if (await _isRepG1Decoders[_state._index].DecodeAsync(rangeDecoder, cancellationToken) == 0)
+                            if (_isRepG1Decoders[_state._index].Decode(rangeDecoder) == 0)
                             {
                                 distance = _rep1;
                             }
                             else
                             {
-                                if (await _isRepG2Decoders[_state._index].DecodeAsync(rangeDecoder, cancellationToken) == 0)
+                                if (_isRepG2Decoders[_state._index].Decode(rangeDecoder) == 0)
                                 {
                                     distance = _rep2;
                                 }
@@ -375,7 +373,7 @@ namespace SharpCompress.Compressors.LZMA
                             _rep1 = _rep0;
                             _rep0 = distance;
                         }
-                        len = await _repLenDecoder.DecodeAsync(rangeDecoder, posState, cancellationToken) + Base.K_MATCH_MIN_LEN;
+                        len = _repLenDecoder.Decode(rangeDecoder, posState) + Base.K_MATCH_MIN_LEN;
                         _state.UpdateRep();
                     }
                     else
@@ -383,22 +381,23 @@ namespace SharpCompress.Compressors.LZMA
                         _rep3 = _rep2;
                         _rep2 = _rep1;
                         _rep1 = _rep0;
-                        len = Base.K_MATCH_MIN_LEN + await _lenDecoder.DecodeAsync(rangeDecoder, posState, cancellationToken);
+                        len = Base.K_MATCH_MIN_LEN + _lenDecoder.Decode(rangeDecoder, posState);
                         _state.UpdateMatch();
-                        uint posSlot = await _posSlotDecoder[Base.GetLenToPosState(len)].DecodeAsync(rangeDecoder, cancellationToken);
+                        uint posSlot = _posSlotDecoder[Base.GetLenToPosState(len)].Decode(rangeDecoder);
                         if (posSlot >= Base.K_START_POS_MODEL_INDEX)
                         {
                             int numDirectBits = (int)((posSlot >> 1) - 1);
                             _rep0 = ((2 | (posSlot & 1)) << numDirectBits);
                             if (posSlot < Base.K_END_POS_MODEL_INDEX)
                             {
-                                _rep0 += await BitTreeDecoder.ReverseDecode(_posDecoders,
-                                                                     _rep0 - posSlot - 1, rangeDecoder, numDirectBits, cancellationToken);
+                                _rep0 += BitTreeDecoder.ReverseDecode(_posDecoders,
+                                                                     _rep0 - posSlot - 1, rangeDecoder, numDirectBits);
                             }
                             else
                             {
-                                _rep0 += (await rangeDecoder.DecodeDirectBitsAsync(numDirectBits - Base.K_NUM_ALIGN_BITS, cancellationToken) << Base.K_NUM_ALIGN_BITS);
-                                _rep0 += await _posAlignDecoder.ReverseDecode(rangeDecoder, cancellationToken);
+                                _rep0 += (rangeDecoder.DecodeDirectBits(
+                                                                       numDirectBits - Base.K_NUM_ALIGN_BITS) << Base.K_NUM_ALIGN_BITS);
+                                _rep0 += _posAlignDecoder.ReverseDecode(rangeDecoder);
                             }
                         }
                         else
@@ -451,7 +450,7 @@ namespace SharpCompress.Compressors.LZMA
         {
             if (_outWindow is null)
             {
-                _outWindow = CreateDictionary();
+                CreateDictionary();
             }
             _outWindow.Train(stream);
         }

src/SharpCompress/Compressors/LZMA/LzmaEncoder.cs

@@ -2,8 +2,6 @@
 
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Compressors.LZMA.LZ;
 using SharpCompress.Compressors.LZMA.RangeCoder;
 
@@ -63,7 +61,7 @@ namespace SharpCompress.Compressors.LZMA
             return (UInt32)(G_FAST_POS[pos >> 26] + 52);
         }
 
-        private Base.State _state = new();
+        private Base.State _state = new Base.State();
         private Byte _previousByte;
         private readonly UInt32[] _repDistances = new UInt32[Base.K_NUM_REP_DISTANCES];
 
@@ -99,18 +97,18 @@ namespace SharpCompress.Compressors.LZMA
                     }
                 }
 
-                public async ValueTask EncodeAsync(RangeCoder.Encoder rangeEncoder, byte symbol)
+                public void Encode(RangeCoder.Encoder rangeEncoder, byte symbol)
                 {
                     uint context = 1;
                     for (int i = 7; i >= 0; i--)
                     {
                         uint bit = (uint)((symbol >> i) & 1);
-                        await _encoders[context].EncodeAsync(rangeEncoder, bit);
+                        _encoders[context].Encode(rangeEncoder, bit);
                         context = (context << 1) | bit;
                     }
                 }
 
-                public async ValueTask EncodeMatchedAsync(RangeCoder.Encoder rangeEncoder, byte matchByte, byte symbol)
+                public void EncodeMatched(RangeCoder.Encoder rangeEncoder, byte matchByte, byte symbol)
                 {
                     uint context = 1;
                     bool same = true;
@@ -124,7 +122,7 @@ namespace SharpCompress.Compressors.LZMA
                             state += ((1 + matchBit) << 8);
                             same = (matchBit == bit);
                         }
-                        await _encoders[state].EncodeAsync(rangeEncoder, bit);
+                        _encoders[state].Encode(rangeEncoder, bit);
                         context = (context << 1) | bit;
                     }
                 }
@@ -198,11 +196,11 @@ namespace SharpCompress.Compressors.LZMA
 
         private class LenEncoder
         {
-            private BitEncoder _choice = new();
-            private BitEncoder _choice2 = new();
+            private BitEncoder _choice = new BitEncoder();
+            private BitEncoder _choice2 = new BitEncoder();
             private readonly BitTreeEncoder[] _lowCoder = new BitTreeEncoder[Base.K_NUM_POS_STATES_ENCODING_MAX];
             private readonly BitTreeEncoder[] _midCoder = new BitTreeEncoder[Base.K_NUM_POS_STATES_ENCODING_MAX];
-            private BitTreeEncoder _highCoder = new(Base.K_NUM_HIGH_LEN_BITS);
+            private BitTreeEncoder _highCoder = new BitTreeEncoder(Base.K_NUM_HIGH_LEN_BITS);
 
             public LenEncoder()
             {
@@ -225,26 +223,26 @@ namespace SharpCompress.Compressors.LZMA
                 _highCoder.Init();
             }
 
-            public async ValueTask EncodeAsync(RangeCoder.Encoder rangeEncoder, UInt32 symbol, UInt32 posState)
+            public void Encode(RangeCoder.Encoder rangeEncoder, UInt32 symbol, UInt32 posState)
             {
                 if (symbol < Base.K_NUM_LOW_LEN_SYMBOLS)
                 {
-                    await _choice.EncodeAsync(rangeEncoder, 0);
-                    await _lowCoder[posState].EncodeAsync(rangeEncoder, symbol);
+                    _choice.Encode(rangeEncoder, 0);
+                    _lowCoder[posState].Encode(rangeEncoder, symbol);
                 }
                 else
                 {
                     symbol -= Base.K_NUM_LOW_LEN_SYMBOLS;
-                    await  _choice.EncodeAsync(rangeEncoder, 1);
+                    _choice.Encode(rangeEncoder, 1);
                     if (symbol < Base.K_NUM_MID_LEN_SYMBOLS)
                     {
-                        await    _choice2.EncodeAsync(rangeEncoder, 0);
-                       await _midCoder[posState].EncodeAsync(rangeEncoder, symbol);
+                        _choice2.Encode(rangeEncoder, 0);
+                        _midCoder[posState].Encode(rangeEncoder, symbol);
                     }
                     else
                     {
-                        await   _choice2.EncodeAsync(rangeEncoder, 1);
-                        await _highCoder.EncodeAsync(rangeEncoder, symbol - Base.K_NUM_MID_LEN_SYMBOLS);
+                        _choice2.Encode(rangeEncoder, 1);
+                        _highCoder.Encode(rangeEncoder, symbol - Base.K_NUM_MID_LEN_SYMBOLS);
                     }
                 }
             }
@@ -311,9 +309,9 @@ namespace SharpCompress.Compressors.LZMA
                 }
             }
 
-            public new async ValueTask EncodeAsync(RangeCoder.Encoder rangeEncoder, UInt32 symbol, UInt32 posState)
+            public new void Encode(RangeCoder.Encoder rangeEncoder, UInt32 symbol, UInt32 posState)
             {
-                await base.EncodeAsync(rangeEncoder, symbol, posState);
+                base.Encode(rangeEncoder, symbol, posState);
                 if (--_counters[posState] == 0)
                 {
                     UpdateTable(posState);
@@ -363,7 +361,7 @@ namespace SharpCompress.Compressors.LZMA
 
         private readonly Optimal[] _optimum = new Optimal[K_NUM_OPTS];
         private BinTree _matchFinder;
-        private readonly RangeCoder.Encoder _rangeEncoder = new();
+        private readonly RangeCoder.Encoder _rangeEncoder = new RangeCoder.Encoder();
 
         private readonly BitEncoder[] _isMatch =
             new BitEncoder[Base.K_NUM_STATES << Base.K_NUM_POS_STATES_BITS_MAX];
@@ -381,12 +379,12 @@ namespace SharpCompress.Compressors.LZMA
         private readonly BitEncoder[] _posEncoders =
             new BitEncoder[Base.K_NUM_FULL_DISTANCES - Base.K_END_POS_MODEL_INDEX];
 
-        private BitTreeEncoder _posAlignEncoder = new(Base.K_NUM_ALIGN_BITS);
+        private BitTreeEncoder _posAlignEncoder = new BitTreeEncoder(Base.K_NUM_ALIGN_BITS);
 
-        private readonly LenPriceTableEncoder _lenEncoder = new();
-        private readonly LenPriceTableEncoder _repMatchLenEncoder = new();
+        private readonly LenPriceTableEncoder _lenEncoder = new LenPriceTableEncoder();
+        private readonly LenPriceTableEncoder _repMatchLenEncoder = new LenPriceTableEncoder();
 
-        private readonly LiteralEncoder _literalEncoder = new();
+        private readonly LiteralEncoder _literalEncoder = new LiteralEncoder();
 
         private readonly UInt32[] _matchDistances = new UInt32[Base.K_MATCH_MAX_LEN * 2 + 2];
 
@@ -1191,40 +1189,40 @@ namespace SharpCompress.Compressors.LZMA
             return (smallDist < ((UInt32)(1) << (32 - kDif)) && bigDist >= (smallDist << kDif));
         }
 
-        private async ValueTask WriteEndMarkerAsync(UInt32 posState)
+        private void WriteEndMarker(UInt32 posState)
         {
             if (!_writeEndMark)
             {
                 return;
             }
 
-            await _isMatch[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].EncodeAsync(_rangeEncoder, 1);
-            await _isRep[_state._index].EncodeAsync(_rangeEncoder, 0);
+            _isMatch[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].Encode(_rangeEncoder, 1);
+            _isRep[_state._index].Encode(_rangeEncoder, 0);
             _state.UpdateMatch();
             UInt32 len = Base.K_MATCH_MIN_LEN;
-            await _lenEncoder.EncodeAsync(_rangeEncoder, len - Base.K_MATCH_MIN_LEN, posState);
+            _lenEncoder.Encode(_rangeEncoder, len - Base.K_MATCH_MIN_LEN, posState);
             UInt32 posSlot = (1 << Base.K_NUM_POS_SLOT_BITS) - 1;
             UInt32 lenToPosState = Base.GetLenToPosState(len);
-            await _posSlotEncoder[lenToPosState].EncodeAsync(_rangeEncoder, posSlot);
+            _posSlotEncoder[lenToPosState].Encode(_rangeEncoder, posSlot);
             int footerBits = 30;
             UInt32 posReduced = (((UInt32)1) << footerBits) - 1;
-            await _rangeEncoder.EncodeDirectBits(posReduced >> Base.K_NUM_ALIGN_BITS, footerBits - Base.K_NUM_ALIGN_BITS);
-            await _posAlignEncoder.ReverseEncodeAsync(_rangeEncoder, posReduced & Base.K_ALIGN_MASK);
+            _rangeEncoder.EncodeDirectBits(posReduced >> Base.K_NUM_ALIGN_BITS, footerBits - Base.K_NUM_ALIGN_BITS);
+            _posAlignEncoder.ReverseEncode(_rangeEncoder, posReduced & Base.K_ALIGN_MASK);
         }
 
-        private async ValueTask FlushAsync(UInt32 nowPos)
+        private void Flush(UInt32 nowPos)
         {
             ReleaseMfStream();
-            await WriteEndMarkerAsync(nowPos & _posStateMask);
-            await _rangeEncoder.FlushData();
-            await _rangeEncoder.FlushAsync();
+            WriteEndMarker(nowPos & _posStateMask);
+            _rangeEncoder.FlushData();
+            _rangeEncoder.FlushStream();
         }
 
-        public async ValueTask<(Int64, Int64, bool)> CodeOneBlockAsync()
+        public void CodeOneBlock(out Int64 inSize, out Int64 outSize, out bool finished)
         {
-            long inSize = 0;
-            long outSize = 0;
-            var finished = true;
+            inSize = 0;
+            outSize = 0;
+            finished = true;
 
             if (_inStream != null)
             {
@@ -1235,7 +1233,7 @@ namespace SharpCompress.Compressors.LZMA
 
             if (_finished)
             {
-                return (inSize, outSize, finished);
+                return;
             }
             _finished = true;
 
@@ -1256,20 +1254,20 @@ namespace SharpCompress.Compressors.LZMA
                 if (_processingMode && _matchFinder.IsDataStarved)
                 {
                     _finished = false;
-                    return (inSize, outSize, finished);
+                    return;
                 }
                 if (_matchFinder.GetNumAvailableBytes() == 0)
                 {
-                    await FlushAsync((UInt32)_nowPos64);
-                    return (inSize, outSize, finished);
+                    Flush((UInt32)_nowPos64);
+                    return;
                 }
                 UInt32 len, numDistancePairs; // it's not used
                 ReadMatchDistances(out len, out numDistancePairs);
                 UInt32 posState = (UInt32)(_nowPos64) & _posStateMask;
-                await _isMatch[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].EncodeAsync(_rangeEncoder, 0);
+                _isMatch[(_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState].Encode(_rangeEncoder, 0);
                 _state.UpdateChar();
                 Byte curByte = _matchFinder.GetIndexByte((Int32)(0 - _additionalOffset));
-                await _literalEncoder.GetSubCoder((UInt32)(_nowPos64), _previousByte).EncodeAsync(_rangeEncoder, curByte);
+                _literalEncoder.GetSubCoder((UInt32)(_nowPos64), _previousByte).Encode(_rangeEncoder, curByte);
                 _previousByte = curByte;
                 _additionalOffset--;
                 _nowPos64++;
@@ -1277,19 +1275,19 @@ namespace SharpCompress.Compressors.LZMA
             if (_processingMode && _matchFinder.IsDataStarved)
             {
                 _finished = false;
-                return (inSize, outSize, finished);
+                return;
             }
             if (_matchFinder.GetNumAvailableBytes() == 0)
             {
-                await FlushAsync((UInt32)_nowPos64);
-                return (inSize, outSize, finished);
+                Flush((UInt32)_nowPos64);
+                return;
             }
             while (true)
             {
                 if (_processingMode && _matchFinder.IsDataStarved)
                 {
                     _finished = false;
-                    return (inSize, outSize, finished);
+                    return;
                 }
 
                 UInt32 pos;
@@ -1299,51 +1297,51 @@ namespace SharpCompress.Compressors.LZMA
                 UInt32 complexState = (_state._index << Base.K_NUM_POS_STATES_BITS_MAX) + posState;
                 if (len == 1 && pos == 0xFFFFFFFF)
                 {
-                    await _isMatch[complexState].EncodeAsync(_rangeEncoder, 0);
+                    _isMatch[complexState].Encode(_rangeEncoder, 0);
                     Byte curByte = _matchFinder.GetIndexByte((Int32)(0 - _additionalOffset));
                     LiteralEncoder.Encoder2 subCoder = _literalEncoder.GetSubCoder((UInt32)_nowPos64, _previousByte);
                     if (!_state.IsCharState())
                     {
                         Byte matchByte =
                             _matchFinder.GetIndexByte((Int32)(0 - _repDistances[0] - 1 - _additionalOffset));
-                        await subCoder.EncodeMatchedAsync(_rangeEncoder, matchByte, curByte);
+                        subCoder.EncodeMatched(_rangeEncoder, matchByte, curByte);
                     }
                     else
                     {
-                        await  subCoder.EncodeAsync(_rangeEncoder, curByte);
+                        subCoder.Encode(_rangeEncoder, curByte);
                     }
                     _previousByte = curByte;
                     _state.UpdateChar();
                 }
                 else
                 {
-                    await  _isMatch[complexState].EncodeAsync(_rangeEncoder, 1);
+                    _isMatch[complexState].Encode(_rangeEncoder, 1);
                     if (pos < Base.K_NUM_REP_DISTANCES)
                     {
-                        await  _isRep[_state._index].EncodeAsync(_rangeEncoder, 1);
+                        _isRep[_state._index].Encode(_rangeEncoder, 1);
                         if (pos == 0)
                         {
-                            await  _isRepG0[_state._index].EncodeAsync(_rangeEncoder, 0);
+                            _isRepG0[_state._index].Encode(_rangeEncoder, 0);
                             if (len == 1)
                             {
-                                await _isRep0Long[complexState].EncodeAsync(_rangeEncoder, 0);
+                                _isRep0Long[complexState].Encode(_rangeEncoder, 0);
                             }
                             else
                             {
-                                await  _isRep0Long[complexState].EncodeAsync(_rangeEncoder, 1);
+                                _isRep0Long[complexState].Encode(_rangeEncoder, 1);
                             }
                         }
                         else
                         {
-                            await  _isRepG0[_state._index].EncodeAsync(_rangeEncoder, 1);
+                            _isRepG0[_state._index].Encode(_rangeEncoder, 1);
                             if (pos == 1)
                             {
-                                await _isRepG1[_state._index].EncodeAsync(_rangeEncoder, 0);
+                                _isRepG1[_state._index].Encode(_rangeEncoder, 0);
                             }
                             else
                             {
-                                await _isRepG1[_state._index].EncodeAsync(_rangeEncoder, 1);
-                                await _isRepG2[_state._index].EncodeAsync(_rangeEncoder, pos - 2);
+                                _isRepG1[_state._index].Encode(_rangeEncoder, 1);
+                                _isRepG2[_state._index].Encode(_rangeEncoder, pos - 2);
                             }
                         }
                         if (len == 1)
@@ -1352,7 +1350,7 @@ namespace SharpCompress.Compressors.LZMA
                         }
                         else
                         {
-                            await _repMatchLenEncoder.EncodeAsync(_rangeEncoder, len - Base.K_MATCH_MIN_LEN, posState);
+                            _repMatchLenEncoder.Encode(_rangeEncoder, len - Base.K_MATCH_MIN_LEN, posState);
                             _state.UpdateRep();
                         }
                         UInt32 distance = _repDistances[pos];
@@ -1367,13 +1365,13 @@ namespace SharpCompress.Compressors.LZMA
                     }
                     else
                     {
-                        await _isRep[_state._index].EncodeAsync(_rangeEncoder, 0);
+                        _isRep[_state._index].Encode(_rangeEncoder, 0);
                         _state.UpdateMatch();
-                        await _lenEncoder.EncodeAsync(_rangeEncoder, len - Base.K_MATCH_MIN_LEN, posState);
+                        _lenEncoder.Encode(_rangeEncoder, len - Base.K_MATCH_MIN_LEN, posState);
                         pos -= Base.K_NUM_REP_DISTANCES;
                         UInt32 posSlot = GetPosSlot(pos);
                         UInt32 lenToPosState = Base.GetLenToPosState(len);
-                        await _posSlotEncoder[lenToPosState].EncodeAsync(_rangeEncoder, posSlot);
+                        _posSlotEncoder[lenToPosState].Encode(_rangeEncoder, posSlot);
 
                         if (posSlot >= Base.K_START_POS_MODEL_INDEX)
                         {
@@ -1383,15 +1381,15 @@ namespace SharpCompress.Compressors.LZMA
 
                             if (posSlot < Base.K_END_POS_MODEL_INDEX)
                             {
-                                await BitTreeEncoder.ReverseEncodeAsync(_posEncoders,
-                                                                        baseVal - posSlot - 1, _rangeEncoder, footerBits,
-                                                                        posReduced);
+                                BitTreeEncoder.ReverseEncode(_posEncoders,
+                                                             baseVal - posSlot - 1, _rangeEncoder, footerBits,
+                                                             posReduced);
                             }
                             else
                             {
-                                await _rangeEncoder.EncodeDirectBits(posReduced >> Base.K_NUM_ALIGN_BITS,
+                                _rangeEncoder.EncodeDirectBits(posReduced >> Base.K_NUM_ALIGN_BITS,
                                                                footerBits - Base.K_NUM_ALIGN_BITS);
-                                await _posAlignEncoder.ReverseEncodeAsync(_rangeEncoder, posReduced & Base.K_ALIGN_MASK);
+                                _posAlignEncoder.ReverseEncode(_rangeEncoder, posReduced & Base.K_ALIGN_MASK);
                                 _alignPriceCount++;
                             }
                         }
@@ -1423,19 +1421,19 @@ namespace SharpCompress.Compressors.LZMA
                     if (_processingMode && _matchFinder.IsDataStarved)
                     {
                         _finished = false;
-                        return (inSize, outSize, finished);
+                        return;
                     }
                     if (_matchFinder.GetNumAvailableBytes() == 0)
                     {
-                        await FlushAsync((UInt32)_nowPos64);
-                        return (inSize, outSize, finished);
+                        Flush((UInt32)_nowPos64);
+                        return;
                     }
 
                     if (_nowPos64 - progressPosValuePrev >= (1 << 12))
                     {
                         _finished = false;
                         finished = false;
-                        return (inSize, outSize, finished);
+                        return;
                     }
                 }
             }
@@ -1490,8 +1488,8 @@ namespace SharpCompress.Compressors.LZMA
             _nowPos64 = 0;
         }
 
-        public async ValueTask CodeAsync(Stream inStream, Stream outStream,
-                         Int64 inSize, Int64 outSize, ICodeProgress progress, CancellationToken cancellationToken)
+        public void Code(Stream inStream, Stream outStream,
+                         Int64 inSize, Int64 outSize, ICodeProgress progress)
         {
             _needReleaseMfStream = false;
             _processingMode = false;
@@ -1500,7 +1498,10 @@ namespace SharpCompress.Compressors.LZMA
                 SetStreams(inStream, outStream, inSize, outSize);
                 while (true)
                 {
-                    var (processedInSize, processedOutSize, finished) = await CodeOneBlockAsync();
+                    Int64 processedInSize;
+                    Int64 processedOutSize;
+                    bool finished;
+                    CodeOneBlock(out processedInSize, out processedOutSize, out finished);
                     if (finished)
                     {
                         return;
@@ -1517,7 +1518,7 @@ namespace SharpCompress.Compressors.LZMA
             }
         }
 
-        public async ValueTask<long> CodeAsync(Stream inStream, bool final)
+        public long Code(Stream inStream, bool final)
         {
             _matchFinder.SetStream(inStream);
             _processingMode = !final;
@@ -1525,7 +1526,10 @@ namespace SharpCompress.Compressors.LZMA
             {
                 while (true)
                 {
-                    var (processedInSize, processedOutSize, finished) = await CodeOneBlockAsync();
+                    Int64 processedInSize;
+                    Int64 processedOutSize;
+                    bool finished;
+                    CodeOneBlock(out processedInSize, out processedOutSize, out finished);
                     if (finished)
                     {
                         return processedInSize;

src/SharpCompress/Compressors/LZMA/LzmaStream.cs

@@ -1,25 +1,21 @@
 #nullable disable
 
 using System;
-using System.Buffers;
 using System.Buffers.Binary;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Compressors.LZMA.LZ;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.LZMA
 {
-    public class LzmaStream : AsyncStream
+    public class LzmaStream : Stream
     {
-        private Stream _inputStream;
-        private long _inputSize;
-        private long _outputSize;
+        private readonly Stream _inputStream;
+        private readonly long _inputSize;
+        private readonly long _outputSize;
 
-        private int _dictionarySize;
-        private OutWindow _outWindow = new OutWindow();
-        private RangeCoder.Decoder _rangeDecoder = new RangeCoder.Decoder();
+        private readonly int _dictionarySize;
+        private readonly OutWindow _outWindow = new OutWindow();
+        private readonly RangeCoder.Decoder _rangeDecoder = new RangeCoder.Decoder();
         private Decoder _decoder;
 
         private long _position;
@@ -29,60 +25,70 @@ namespace SharpCompress.Compressors.LZMA
         private long _inputPosition;
 
         // LZMA2
-        private bool _isLzma2;
+        private readonly bool _isLzma2;
         private bool _uncompressedChunk;
         private bool _needDictReset = true;
         private bool _needProps = true;
 
         private readonly Encoder _encoder;
         private bool _isDisposed;
-        
-        private LzmaStream() {}
 
-        public static async ValueTask<LzmaStream> CreateAsync(byte[] properties, Stream inputStream, long inputSize = -1, long outputSize = -1,
-                                                       Stream presetDictionary = null, bool? isLzma2 = null, CancellationToken cancellationToken = default)
+        public LzmaStream(byte[] properties, Stream inputStream)
+            : this(properties, inputStream, -1, -1, null, properties.Length < 5)
         {
-            var ls = new LzmaStream();
-            ls._inputStream = inputStream;
-            ls._inputSize = inputSize;
-            ls._outputSize = outputSize;
-            ls._isLzma2 = isLzma2 ?? properties.Length < 5;
+        }
 
-            if (!ls._isLzma2)
+        public LzmaStream(byte[] properties, Stream inputStream, long inputSize)
+            : this(properties, inputStream, inputSize, -1, null, properties.Length < 5)
+        {
+        }
+
+        public LzmaStream(byte[] properties, Stream inputStream, long inputSize, long outputSize)
+            : this(properties, inputStream, inputSize, outputSize, null, properties.Length < 5)
+        {
+        }
+
+        public LzmaStream(byte[] properties, Stream inputStream, long inputSize, long outputSize,
+                          Stream presetDictionary, bool isLzma2)
+        {
+            _inputStream = inputStream;
+            _inputSize = inputSize;
+            _outputSize = outputSize;
+            _isLzma2 = isLzma2;
+
+            if (!isLzma2)
             {
-                ls._dictionarySize = BinaryPrimitives.ReadInt32LittleEndian(properties.AsSpan(1));
-                ls._outWindow.Create(ls._dictionarySize);
+                _dictionarySize = BinaryPrimitives.ReadInt32LittleEndian(properties.AsSpan(1));
+                _outWindow.Create(_dictionarySize);
                 if (presetDictionary != null)
                 {
-                    ls._outWindow.Train(presetDictionary);
+                    _outWindow.Train(presetDictionary);
                 }
 
-                await ls._rangeDecoder.InitAsync(inputStream, cancellationToken);
+                _rangeDecoder.Init(inputStream);
 
-                ls._decoder = new Decoder();
-                ls._decoder.SetDecoderProperties(properties);
-                ls.Properties = properties;
+                _decoder = new Decoder();
+                _decoder.SetDecoderProperties(properties);
+                Properties = properties;
 
-                ls._availableBytes = outputSize < 0 ? long.MaxValue : outputSize;
-                ls._rangeDecoderLimit = inputSize;
+                _availableBytes = outputSize < 0 ? long.MaxValue : outputSize;
+                _rangeDecoderLimit = inputSize;
             }
             else
             {
-                ls. _dictionarySize = 2 | (properties[0] & 1);
-                ls. _dictionarySize <<= (properties[0] >> 1) + 11;
+                _dictionarySize = 2 | (properties[0] & 1);
+                _dictionarySize <<= (properties[0] >> 1) + 11;
 
-                ls._outWindow.Create(ls._dictionarySize);
+                _outWindow.Create(_dictionarySize);
                 if (presetDictionary != null)
                 {
-                    ls._outWindow.Train(presetDictionary);
-                    ls._needDictReset = false;
+                    _outWindow.Train(presetDictionary);
+                    _needDictReset = false;
                 }
 
-                ls. Properties = new byte[1];
-                ls._availableBytes = 0;
+                Properties = new byte[1];
+                _availableBytes = 0;
             }
-
-            return ls;
         }
 
         public LzmaStream(LzmaEncoderProperties properties, bool isLzma2, Stream outputStream)
@@ -120,25 +126,33 @@ namespace SharpCompress.Compressors.LZMA
 
         public override bool CanWrite => _encoder != null;
 
-        public override async ValueTask DisposeAsync()
+        public override void Flush()
+        {
+        }
+
+        protected override void Dispose(bool disposing)
         {
             if (_isDisposed)
             {
                 return;
             }
             _isDisposed = true;
-            if (_encoder != null)
+            if (disposing)
             {
-                _position = await _encoder.CodeAsync(null, true);
+                if (_encoder != null)
+                {
+                    _position = _encoder.Code(null, true);
+                }
+                _inputStream?.Dispose();
             }
-            _inputStream?.DisposeAsync();
+            base.Dispose(disposing);
         }
 
         public override long Length => _position + _availableBytes;
 
         public override long Position { get => _position; set => throw new NotSupportedException(); }
 
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             if (_endReached)
             {
@@ -152,7 +166,7 @@ namespace SharpCompress.Compressors.LZMA
                 {
                     if (_isLzma2)
                     {
-                        await DecodeChunkHeader(cancellationToken);
+                        DecodeChunkHeader();
                     }
                     else
                     {
@@ -175,7 +189,7 @@ namespace SharpCompress.Compressors.LZMA
                 {
                     _inputPosition += _outWindow.CopyStream(_inputStream, toProcess);
                 }
-                else if (await _decoder.CodeAsync(_dictionarySize, _outWindow, _rangeDecoder, cancellationToken)
+                else if (_decoder.Code(_dictionarySize, _outWindow, _rangeDecoder)
                          && _outputSize < 0)
                 {
                     _availableBytes = _outWindow.AvailableBytes;
@@ -217,7 +231,7 @@ namespace SharpCompress.Compressors.LZMA
             return total;
         }
 
-        private async ValueTask DecodeChunkHeader(CancellationToken cancellationToken)
+        private void DecodeChunkHeader()
         {
             int control = _inputStream.ReadByte();
             _inputPosition++;
@@ -269,7 +283,7 @@ namespace SharpCompress.Compressors.LZMA
                     _decoder.SetDecoderProperties(Properties);
                 }
 
-                await _rangeDecoder.InitAsync(_inputStream, cancellationToken);
+                _rangeDecoder.Init(_inputStream);
             }
             else if (control > 0x02)
             {
@@ -293,25 +307,14 @@ namespace SharpCompress.Compressors.LZMA
             throw new NotSupportedException();
         }
 
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
             if (_encoder != null)
             {
-                _position = await _encoder.CodeAsync(new MemoryStream(buffer, offset, count), false);
+                _position = _encoder.Code(new MemoryStream(buffer, offset, count), false);
             }
         }
 
-        public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = new CancellationToken())
-        {
-            if (_encoder != null)
-            {
-                 var m = ArrayPool<byte>.Shared.Rent(buffer.Length);
-                 buffer.CopyTo(m.AsMemory().Slice(0, buffer.Length));
-                _position = await _encoder.CodeAsync(new MemoryStream(m, 0, buffer.Length), false);
-                ArrayPool<byte>.Shared.Return(m);
-            }
-        }
-
-        public byte[] Properties { get; private set; }
+        public byte[] Properties { get; } = new byte[5];
     }
 }

src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoder.cs

@@ -1,14 +1,11 @@
 #nullable disable
 
 using System;
-using System.Buffers;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.LZMA.RangeCoder
 {
-    internal class Encoder : IAsyncDisposable
+    internal class Encoder
     {
         public const uint K_TOP_VALUE = (1 << 24);
 
@@ -41,46 +38,43 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             _cache = 0;
         }
 
-        public async ValueTask FlushData()
+        public void FlushData()
         {
             for (int i = 0; i < 5; i++)
             {
-                await ShiftLowAsync();
+                ShiftLow();
             }
         }
 
-        public Task FlushAsync()
+        public void FlushStream()
         {
-            return _stream.FlushAsync();
+            _stream.Flush();
         }
 
-        public ValueTask DisposeAsync()
+        public void CloseStream()
         {
-            return _stream.DisposeAsync();
+            _stream.Dispose();
         }
 
-        public async ValueTask EncodeAsync(uint start, uint size, uint total)
+        public void Encode(uint start, uint size, uint total)
         {
             _low += start * (_range /= total);
             _range *= size;
             while (_range < K_TOP_VALUE)
             {
                 _range <<= 8;
-                await ShiftLowAsync();
+                ShiftLow();
             }
         }
 
-        public async ValueTask ShiftLowAsync()
+        public void ShiftLow()
         {
             if ((uint)_low < 0xFF000000 || (uint)(_low >> 32) == 1)
             {
-                using var buffer = MemoryPool<byte>.Shared.Rent(1);
-                var b = buffer.Memory.Slice(0,1);
                 byte temp = _cache;
                 do
                 {
-                    b.Span[0] = (byte)(temp + (_low >> 32));
-                    await _stream.WriteAsync(b);
+                    _stream.WriteByte((byte)(temp + (_low >> 32)));
                     temp = 0xFF;
                 }
                 while (--_cacheSize != 0);
@@ -90,7 +84,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             _low = ((uint)_low) << 8;
         }
 
-        public async ValueTask EncodeDirectBits(uint v, int numTotalBits)
+        public void EncodeDirectBits(uint v, int numTotalBits)
         {
             for (int i = numTotalBits - 1; i >= 0; i--)
             {
@@ -102,12 +96,12 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
                 if (_range < K_TOP_VALUE)
                 {
                     _range <<= 8;
-                    await ShiftLowAsync();
+                    ShiftLow();
                 }
             }
         }
 
-        public async ValueTask EncodeBitAsync(uint size0, int numTotalBits, uint symbol)
+        public void EncodeBit(uint size0, int numTotalBits, uint symbol)
         {
             uint newBound = (_range >> numTotalBits) * size0;
             if (symbol == 0)
@@ -122,7 +116,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             while (_range < K_TOP_VALUE)
             {
                 _range <<= 8;
-                await ShiftLowAsync();
+                ShiftLow();
             }
         }
 
@@ -135,7 +129,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
         }
     }
 
-    internal class Decoder: IAsyncDisposable
+    internal class Decoder
     {
         public const uint K_TOP_VALUE = (1 << 24);
         public uint _range;
@@ -145,7 +139,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
         public Stream _stream;
         public long _total;
 
-        public async ValueTask InitAsync(Stream stream, CancellationToken cancellationToken)
+        public void Init(Stream stream)
         {
             // Stream.Init(stream);
             _stream = stream;
@@ -154,7 +148,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             _range = 0xFFFFFFFF;
             for (int i = 0; i < 5; i++)
             {
-                _code = (_code << 8) | await _stream.ReadByteAsync(cancellationToken);
+                _code = (_code << 8) | (byte)_stream.ReadByte();
             }
             _total = 5;
         }
@@ -165,34 +159,44 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             _stream = null;
         }
 
-        public ValueTask DisposeAsync()
+        public void CloseStream()
         {
-            return _stream.DisposeAsync();
+            _stream.Dispose();
         }
 
-        public async ValueTask NormalizeAsync(CancellationToken cancellationToken)
+        public void Normalize()
         {
             while (_range < K_TOP_VALUE)
             {
-                _code = (_code << 8) | await _stream.ReadByteAsync(cancellationToken);
+                _code = (_code << 8) | (byte)_stream.ReadByte();
                 _range <<= 8;
                 _total++;
             }
         }
-        
+
+        public void Normalize2()
+        {
+            if (_range < K_TOP_VALUE)
+            {
+                _code = (_code << 8) | (byte)_stream.ReadByte();
+                _range <<= 8;
+                _total++;
+            }
+        }
+
         public uint GetThreshold(uint total)
         {
             return _code / (_range /= total);
         }
 
-        public async ValueTask DecodeAsync(uint start, uint size, CancellationToken cancellationToken)
+        public void Decode(uint start, uint size)
         {
             _code -= start * _range;
             _range *= size;
-            await NormalizeAsync(cancellationToken);
+            Normalize();
         }
 
-        public async ValueTask<uint> DecodeDirectBitsAsync(int numTotalBits, CancellationToken cancellationToken)
+        public uint DecodeDirectBits(int numTotalBits)
         {
             uint range = _range;
             uint code = _code;
@@ -214,7 +218,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
 
                 if (range < K_TOP_VALUE)
                 {
-                    code = (code << 8) | await _stream.ReadByteAsync(cancellationToken);
+                    code = (code << 8) | (byte)_stream.ReadByte();
                     range <<= 8;
                     _total++;
                 }
@@ -224,7 +228,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             return result;
         }
 
-        public async ValueTask<uint> DecodeBitAsync(uint size0, int numTotalBits, CancellationToken cancellationToken)
+        public uint DecodeBit(uint size0, int numTotalBits)
         {
             uint newBound = (_range >> numTotalBits) * size0;
             uint symbol;
@@ -239,7 +243,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
                 _code -= newBound;
                 _range -= newBound;
             }
-            await NormalizeAsync(cancellationToken);
+            Normalize();
             return symbol;
         }
 

src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoderBit.cs

@@ -1,7 +1,4 @@
 using System;
-using System.Buffers;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.LZMA.RangeCoder
 {
@@ -32,7 +29,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             }
         }
 
-        public async ValueTask EncodeAsync(Encoder encoder, uint symbol)
+        public void Encode(Encoder encoder, uint symbol)
         {
             // encoder.EncodeBit(Prob, kNumBitModelTotalBits, symbol);
             // UpdateModel(symbol);
@@ -51,7 +48,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             if (encoder._range < Encoder.K_TOP_VALUE)
             {
                 encoder._range <<= 8;
-                await encoder.ShiftLowAsync();
+                encoder.ShiftLow();
             }
         }
 
@@ -113,7 +110,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             _prob = K_BIT_MODEL_TOTAL >> 1;
         }
 
-        public async ValueTask<uint> DecodeAsync(Decoder rangeDecoder, CancellationToken cancellationToken)
+        public uint Decode(Decoder rangeDecoder)
         {
             uint newBound = (rangeDecoder._range >> K_NUM_BIT_MODEL_TOTAL_BITS) * _prob;
             if (rangeDecoder._code < newBound)
@@ -122,7 +119,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
                 _prob += (K_BIT_MODEL_TOTAL - _prob) >> K_NUM_MOVE_BITS;
                 if (rangeDecoder._range < Decoder.K_TOP_VALUE)
                 {
-                    rangeDecoder._code = (rangeDecoder._code << 8) | await rangeDecoder._stream.ReadByteAsync(cancellationToken);
+                    rangeDecoder._code = (rangeDecoder._code << 8) | (byte)rangeDecoder._stream.ReadByte();
                     rangeDecoder._range <<= 8;
                     rangeDecoder._total++;
                 }
@@ -133,7 +130,7 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             _prob -= (_prob) >> K_NUM_MOVE_BITS;
             if (rangeDecoder._range < Decoder.K_TOP_VALUE)
             {
-                rangeDecoder._code = (rangeDecoder._code << 8) | await rangeDecoder._stream.ReadByteAsync(cancellationToken);
+                rangeDecoder._code = (rangeDecoder._code << 8) | (byte)rangeDecoder._stream.ReadByte();
                 rangeDecoder._range <<= 8;
                 rangeDecoder._total++;
             }

src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoderBitTree.cs

@@ -1,6 +1,4 @@
 using System;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.LZMA.RangeCoder
 {
@@ -23,25 +21,25 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             }
         }
 
-        public async ValueTask EncodeAsync(Encoder rangeEncoder, UInt32 symbol)
+        public void Encode(Encoder rangeEncoder, UInt32 symbol)
         {
             UInt32 m = 1;
             for (int bitIndex = _numBitLevels; bitIndex > 0;)
             {
                 bitIndex--;
                 UInt32 bit = (symbol >> bitIndex) & 1;
-                await _models[m].EncodeAsync(rangeEncoder, bit);
+                _models[m].Encode(rangeEncoder, bit);
                 m = (m << 1) | bit;
             }
         }
 
-        public async ValueTask ReverseEncodeAsync(Encoder rangeEncoder, UInt32 symbol)
+        public void ReverseEncode(Encoder rangeEncoder, UInt32 symbol)
         {
             UInt32 m = 1;
             for (UInt32 i = 0; i < _numBitLevels; i++)
             {
                 UInt32 bit = symbol & 1;
-                await _models[m].EncodeAsync(rangeEncoder, bit);
+                _models[m].Encode(rangeEncoder, bit);
                 m = (m << 1) | bit;
                 symbol >>= 1;
             }
@@ -90,14 +88,14 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             return price;
         }
 
-        public static async ValueTask ReverseEncodeAsync(BitEncoder[] models, UInt32 startIndex,
+        public static void ReverseEncode(BitEncoder[] models, UInt32 startIndex,
                                          Encoder rangeEncoder, int numBitLevels, UInt32 symbol)
         {
             UInt32 m = 1;
             for (int i = 0; i < numBitLevels; i++)
             {
                 UInt32 bit = symbol & 1;
-                await models[startIndex + m].EncodeAsync(rangeEncoder, bit);
+                models[startIndex + m].Encode(rangeEncoder, bit);
                 m = (m << 1) | bit;
                 symbol >>= 1;
             }
@@ -123,23 +121,23 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             }
         }
 
-        public async ValueTask<uint> DecodeAsync(Decoder rangeDecoder, CancellationToken cancellationToken)
+        public uint Decode(Decoder rangeDecoder)
         {
             uint m = 1;
             for (int bitIndex = _numBitLevels; bitIndex > 0; bitIndex--)
             {
-                m = (m << 1) + await _models[m].DecodeAsync(rangeDecoder, cancellationToken);
+                m = (m << 1) + _models[m].Decode(rangeDecoder);
             }
             return m - ((uint)1 << _numBitLevels);
         }
 
-        public async ValueTask<uint> ReverseDecode(Decoder rangeDecoder, CancellationToken cancellationToken)
+        public uint ReverseDecode(Decoder rangeDecoder)
         {
             uint m = 1;
             uint symbol = 0;
             for (int bitIndex = 0; bitIndex < _numBitLevels; bitIndex++)
             {
-                uint bit = await _models[m].DecodeAsync(rangeDecoder, cancellationToken);
+                uint bit = _models[m].Decode(rangeDecoder);
                 m <<= 1;
                 m += bit;
                 symbol |= (bit << bitIndex);
@@ -147,14 +145,14 @@ namespace SharpCompress.Compressors.LZMA.RangeCoder
             return symbol;
         }
 
-        public static async ValueTask<uint> ReverseDecode(BitDecoder[] models, UInt32 startIndex,
-                                                          Decoder rangeDecoder, int numBitLevels, CancellationToken cancellationToken)
+        public static uint ReverseDecode(BitDecoder[] models, UInt32 startIndex,
+                                         Decoder rangeDecoder, int numBitLevels)
         {
             uint m = 1;
             uint symbol = 0;
             for (int bitIndex = 0; bitIndex < numBitLevels; bitIndex++)
             {
-                uint bit = await models[startIndex + m].DecodeAsync(rangeDecoder, cancellationToken);
+                uint bit = models[startIndex + m].Decode(rangeDecoder);
                 m <<= 1;
                 m += bit;
                 symbol |= (bit << bitIndex);

src/SharpCompress/Compressors/LZMA/Registry.cs

@@ -1,14 +1,12 @@
 using System;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common.SevenZip;
 using SharpCompress.Compressors.BZip2;
 using SharpCompress.Compressors.Deflate;
 using SharpCompress.Compressors.Filters;
 using SharpCompress.Compressors.LZMA.Utilites;
-//using SharpCompress.Compressors.PPMd;
+using SharpCompress.Compressors.PPMd;
 
 namespace SharpCompress.Compressors.LZMA
 {
@@ -24,10 +22,9 @@ namespace SharpCompress.Compressors.LZMA
         private const uint K_DEFLATE = 0x040108;
         private const uint K_B_ZIP2 = 0x040202;
 
-        internal static async ValueTask<Stream> CreateDecoderStream(CMethodId id, Stream[] inStreams, byte[] info, IPasswordProvider pass,
-                                                                    long limit, CancellationToken cancellationToken)
+        internal static Stream CreateDecoderStream(CMethodId id, Stream[] inStreams, byte[] info, IPasswordProvider pass,
+                                                   long limit)
         {
-            await Task.CompletedTask;
             switch (id._id)
             {
                 case K_COPY:
@@ -38,17 +35,17 @@ namespace SharpCompress.Compressors.LZMA
                     return inStreams.Single();
                 case K_LZMA:
                 case K_LZMA2:
-                    return await LzmaStream.CreateAsync(info, inStreams.Single(), -1, limit, cancellationToken: cancellationToken);
+                    return new LzmaStream(info, inStreams.Single(), -1, limit);
                 case CMethodId.K_AES_ID:
                     return new AesDecoderStream(inStreams.Single(), info, pass, limit);
                 case K_BCJ:
                     return new BCJFilter(false, inStreams.Single());
                 case K_BCJ2:
                     return new Bcj2DecoderStream(inStreams, info, limit);
-                /* case K_B_ZIP2:
-                     return await BZip2Stream.CreateAsync(inStreams.Single(), CompressionMode.Decompress, true, cancellationToken);
-                 case K_PPMD:
-                     return new PpmdStream(new PpmdProperties(info), inStreams.Single(), false);*/
+                case K_B_ZIP2:
+                    return new BZip2Stream(inStreams.Single(), CompressionMode.Decompress, true);
+                case K_PPMD:
+                    return new PpmdStream(new PpmdProperties(info), inStreams.Single(), false);
                 case K_DEFLATE:
                     return new DeflateStream(inStreams.Single(), CompressionMode.Decompress);
                 default:

src/SharpCompress/Compressors/Rar/MultiVolumeReadOnlyStream.cs

@@ -3,8 +3,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 using SharpCompress.Common.Rar;
 
@@ -15,7 +13,7 @@ namespace SharpCompress.Compressors.Rar
         private long currentPosition;
         private long maxPosition;
 
-        private IAsyncEnumerator<RarFilePart> filePartEnumerator;
+        private IEnumerator<RarFilePart> filePartEnumerator;
         private Stream currentStream;
 
         private readonly IExtractionListener streamListener;
@@ -23,33 +21,34 @@ namespace SharpCompress.Compressors.Rar
         private long currentPartTotalReadBytes;
         private long currentEntryTotalReadBytes;
 
-        internal MultiVolumeReadOnlyStream(IExtractionListener streamListener)
+        internal MultiVolumeReadOnlyStream(IEnumerable<RarFilePart> parts, IExtractionListener streamListener)
         {
             this.streamListener = streamListener;
+
+            filePartEnumerator = parts.GetEnumerator();
+            filePartEnumerator.MoveNext();
+            InitializeNextFilePart();
         }
 
-        internal async ValueTask Initialize(IAsyncEnumerable<RarFilePart> parts, CancellationToken cancellationToken)
+        protected override void Dispose(bool disposing)
         {
-            filePartEnumerator = parts.GetAsyncEnumerator(cancellationToken);
-            await filePartEnumerator.MoveNextAsync(cancellationToken);
-            await InitializeNextFilePartAsync(cancellationToken);
-        }
-
-        public override async ValueTask DisposeAsync()
-        {
-            if (filePartEnumerator != null)
+            base.Dispose(disposing);
+            if (disposing)
             {
-                await filePartEnumerator.DisposeAsync();
-                filePartEnumerator = null;
+                if (filePartEnumerator != null)
+                {
+                    filePartEnumerator.Dispose();
+                    filePartEnumerator = null;
+                }
+                currentStream = null;
             }
-            currentStream = null;
         }
 
-        private async ValueTask InitializeNextFilePartAsync(CancellationToken cancellationToken)
+        private void InitializeNextFilePart()
         {
             maxPosition = filePartEnumerator.Current.FileHeader.CompressedSize;
             currentPosition = 0;
-            currentStream = await filePartEnumerator.Current.GetCompressedStreamAsync(cancellationToken);
+            currentStream = filePartEnumerator.Current.GetCompressedStream();
 
             currentPartTotalReadBytes = 0;
 
@@ -61,15 +60,10 @@ namespace SharpCompress.Compressors.Rar
         }
 
         public override int Read(byte[] buffer, int offset, int count)
-        {
-            throw new NotImplementedException();
-        }
-
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken)
         {
             int totalRead = 0;
-            int currentOffset = 0;
-            int currentCount = buffer.Length;
+            int currentOffset = offset;
+            int currentCount = count;
             while (currentCount > 0)
             {
                 int readSize = currentCount;
@@ -78,7 +72,7 @@ namespace SharpCompress.Compressors.Rar
                     readSize = (int)(maxPosition - currentPosition);
                 }
 
-                int read = await currentStream.ReadAsync(buffer.Slice(currentOffset, readSize), cancellationToken);
+                int read = currentStream.Read(buffer, currentOffset, readSize);
                 if (read < 0)
                 {
                     throw new EndOfStreamException();
@@ -96,12 +90,12 @@ namespace SharpCompress.Compressors.Rar
                         throw new InvalidFormatException("Sharpcompress currently does not support multi-volume decryption.");
                     }
                     string fileName = filePartEnumerator.Current.FileHeader.FileName;
-                    if (!await filePartEnumerator.MoveNextAsync(cancellationToken))
+                    if (!filePartEnumerator.MoveNext())
                     {
                         throw new InvalidFormatException(
                                                          "Multi-part rar file is incomplete.  Entry expects a new volume: " + fileName);
                     }
-                    await InitializeNextFilePartAsync(cancellationToken);
+                    InitializeNextFilePart();
                 }
                 else
                 {

src/SharpCompress/Compressors/Xz/BinaryUtils.cs

@@ -1,9 +1,6 @@
 using System;
 using System.Buffers.Binary;
-using System.Buffers;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.Xz
 {
@@ -19,21 +16,20 @@ namespace SharpCompress.Compressors.Xz
         {
             return unchecked((uint)ReadLittleEndianInt32(reader));
         }
-        public static async ValueTask<int> ReadLittleEndianInt32(this Stream stream, CancellationToken cancellationToken)
+        public static int ReadLittleEndianInt32(this Stream stream)
         {
-            using var buffer = MemoryPool<byte>.Shared.Rent(4);
-            var slice = buffer.Memory.Slice(0, 4);
-            var read = await stream.ReadAsync(slice, cancellationToken);
-            if (read != 4)
+            Span<byte> bytes = stackalloc byte[4];
+            var read = stream.ReadFully(bytes);
+            if (!read)
             {
                 throw new EndOfStreamException();
             }
-            return BinaryPrimitives.ReadInt32LittleEndian(slice.Span);
+            return BinaryPrimitives.ReadInt32LittleEndian(bytes);
         }
 
-        internal static async ValueTask<uint> ReadLittleEndianUInt32(this Stream stream, CancellationToken cancellationToken)
+        internal static uint ReadLittleEndianUInt32(this Stream stream)
         {
-            return unchecked((uint)await ReadLittleEndianInt32(stream, cancellationToken));
+            return unchecked((uint)ReadLittleEndianInt32(stream));
         }
 
         internal static byte[] ToBigEndianBytes(this uint uint32)

src/SharpCompress/Compressors/Xz/Crc32.cs

@@ -11,19 +11,19 @@ namespace SharpCompress.Compressors.Xz
 
         private static UInt32[] defaultTable;
 
-        public static UInt32 Compute(ReadOnlyMemory<byte> buffer)
+        public static UInt32 Compute(byte[] buffer)
         {
             return Compute(DefaultSeed, buffer);
         }
 
-        public static UInt32 Compute(UInt32 seed, ReadOnlyMemory<byte> buffer)
+        public static UInt32 Compute(UInt32 seed, byte[] buffer)
         {
             return Compute(DefaultPolynomial, seed, buffer);
         }
 
-        public static UInt32 Compute(UInt32 polynomial, UInt32 seed, ReadOnlyMemory<byte> buffer)
+        public static UInt32 Compute(UInt32 polynomial, UInt32 seed, byte[] buffer)
         {
-            return ~CalculateHash(InitializeTable(polynomial), seed, buffer.Span);
+            return ~CalculateHash(InitializeTable(polynomial), seed, buffer);
         }
 
         private static UInt32[] InitializeTable(UInt32 polynomial)

src/SharpCompress/Compressors/Xz/Filters/BlockFilter.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.Xz.Filters
 {
@@ -53,6 +52,6 @@ namespace SharpCompress.Compressors.Xz.Filters
             return filter;
         }
 
-        public abstract ValueTask SetBaseStreamAsync(Stream stream);
+        public abstract void SetBaseStream(Stream stream);
     }
 }

src/SharpCompress/Compressors/Xz/Filters/Lzma2Filter.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Compressors.LZMA;
 
 namespace SharpCompress.Compressors.Xz.Filters
@@ -51,14 +49,19 @@ namespace SharpCompress.Compressors.Xz.Filters
         {
         }
 
-        public override async ValueTask SetBaseStreamAsync(Stream stream)
+        public override void SetBaseStream(Stream stream)
         {
-            BaseStream = await LzmaStream.CreateAsync(new[] { _dictionarySize }, stream);
+            BaseStream = new LzmaStream(new[] { _dictionarySize }, stream);
         }
 
-        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
-            return BaseStream.ReadAsync(buffer, offset, count, cancellationToken);
+            return BaseStream.Read(buffer, offset, count);
+        }
+
+        public override int ReadByte()
+        {
+            return BaseStream.ReadByte();
         }
     }
 }

src/SharpCompress/Compressors/Xz/ReadOnlyStream.cs

@@ -2,13 +2,10 @@
 
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
-using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.Xz
 {
-    public abstract class ReadOnlyStream : AsyncStream
+    public abstract class ReadOnlyStream : Stream
     {
         public Stream BaseStream { get; protected set; }
 
@@ -26,6 +23,11 @@ namespace SharpCompress.Compressors.Xz
             set => throw new NotSupportedException();
         }
 
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
         public override long Seek(long offset, SeekOrigin origin)
         {
             throw new NotSupportedException();
@@ -36,12 +38,7 @@ namespace SharpCompress.Compressors.Xz
             throw new NotSupportedException();
         }
 
-        public override ValueTask DisposeAsync()
-        {
-            return new();
-        }
-
-        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
             throw new NotSupportedException();
         }

src/SharpCompress/Compressors/Xz/XZBlock.cs

@@ -1,10 +1,8 @@
-using System;
-using System.Buffers;
+#nullable disable
+
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Compressors.Xz.Filters;
 
 namespace SharpCompress.Compressors.Xz
@@ -21,7 +19,7 @@ namespace SharpCompress.Compressors.Xz
         private bool _streamConnected;
         private int _numFilters;
         private byte _blockHeaderSizeByte;
-        private Stream? _decomStream;
+        private Stream _decomStream;
         private bool _endOfStream;
         private bool _paddingSkipped;
         private bool _crcChecked;
@@ -34,25 +32,25 @@ namespace SharpCompress.Compressors.Xz
             _checkSize = checkSize;
         }
 
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             int bytesRead = 0;
             if (!HeaderIsLoaded)
             {
-                await LoadHeader(cancellationToken);
+                LoadHeader();
             }
 
             if (!_streamConnected)
             {
-                await ConnectStreamAsync();
+                ConnectStream();
             }
 
-            if (!_endOfStream && _decomStream is not null)
+            if (!_endOfStream)
             {
-                bytesRead = await _decomStream.ReadAsync(buffer, cancellationToken);
+                bytesRead = _decomStream.Read(buffer, offset, count);
             }
 
-            if (bytesRead != buffer.Length)
+            if (bytesRead != count)
             {
                 _endOfStream = true;
             }
@@ -95,27 +93,24 @@ namespace SharpCompress.Compressors.Xz
             _crcChecked = true;
         }
 
-        private async ValueTask ConnectStreamAsync()
+        private void ConnectStream()
         {
             _decomStream = BaseStream;
             while (Filters.Any())
             {
                 BlockFilter filter = Filters.Pop();
-                await filter.SetBaseStreamAsync(_decomStream);
+                filter.SetBaseStream(_decomStream);
                 _decomStream = filter;
             }
             _streamConnected = true;
         }
 
-        private async ValueTask LoadHeader(CancellationToken cancellationToken)
+        private void LoadHeader()
         {
-            await ReadHeaderSize(cancellationToken);
-            using var blockHeaderWithoutCrc = MemoryPool<byte>.Shared.Rent(BlockHeaderSize - 4);
-            var headerCache = blockHeaderWithoutCrc.Memory.Slice(0, BlockHeaderSize - 4);
-            await CacheHeader(headerCache, cancellationToken);
+            ReadHeaderSize();
+            byte[] headerCache = CacheHeader();
 
-            //TODO: memory-size this
-            await using (var cache = new MemoryStream(headerCache.ToArray()))
+            using (var cache = new MemoryStream(headerCache))
             using (var cachedReader = new BinaryReader(cache))
             {
                 cachedReader.BaseStream.Position = 1; // skip the header size byte
@@ -125,30 +120,33 @@ namespace SharpCompress.Compressors.Xz
             HeaderIsLoaded = true;
         }
 
-        private async ValueTask ReadHeaderSize(CancellationToken cancellationToken)
+        private void ReadHeaderSize()
         {
-            _blockHeaderSizeByte = await BaseStream.ReadByteAsync(cancellationToken);
+            _blockHeaderSizeByte = (byte)BaseStream.ReadByte();
             if (_blockHeaderSizeByte == 0)
             {
                 throw new XZIndexMarkerReachedException();
             }
         }
 
-        private async ValueTask CacheHeader(Memory<byte> blockHeaderWithoutCrc, CancellationToken cancellationToken)
+        private byte[] CacheHeader()
         {
-            blockHeaderWithoutCrc.Span[0] = _blockHeaderSizeByte;
-            var read = await BaseStream.ReadAsync(blockHeaderWithoutCrc.Slice( 1, BlockHeaderSize - 5), cancellationToken);
+            byte[] blockHeaderWithoutCrc = new byte[BlockHeaderSize - 4];
+            blockHeaderWithoutCrc[0] = _blockHeaderSizeByte;
+            var read = BaseStream.Read(blockHeaderWithoutCrc, 1, BlockHeaderSize - 5);
             if (read != BlockHeaderSize - 5)
             {
-                throw new EndOfStreamException("Reached end of stream unexpectedly");
+                throw new EndOfStreamException("Reached end of stream unexectedly");
             }
 
-            uint crc = await BaseStream.ReadLittleEndianUInt32(cancellationToken);
+            uint crc = BaseStream.ReadLittleEndianUInt32();
             uint calcCrc = Crc32.Compute(blockHeaderWithoutCrc);
             if (crc != calcCrc)
             {
                 throw new InvalidDataException("Block header corrupt");
             }
+
+            return blockHeaderWithoutCrc;
         }
 
         private void ReadBlockFlags(BinaryReader reader)

src/SharpCompress/Compressors/Xz/XZHeader.cs

@@ -1,65 +1,58 @@
 using System;
-using System.Buffers;
 using System.IO;
 using System.Linq;
 using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.IO;
 
 namespace SharpCompress.Compressors.Xz
 {
     public class XZHeader
     {
-        private readonly Stream _stream;
-        private static readonly ReadOnlyMemory<byte> MagicHeader = new(new byte[]{ 0xFD, 0x37, 0x7A, 0x58, 0x5a, 0x00 });
+        private readonly BinaryReader _reader;
+        private readonly byte[] MagicHeader = { 0xFD, 0x37, 0x7A, 0x58, 0x5a, 0x00 };
 
         public CheckType BlockCheckType { get; private set; }
         public int BlockCheckSize => ((((int)BlockCheckType) + 2) / 3) * 4;
 
-        public XZHeader(Stream reader)
+        public XZHeader(BinaryReader reader)
         {
-            _stream = reader;
+            _reader = reader;
         }
 
-        public static async ValueTask<XZHeader> FromStream(Stream stream, CancellationToken cancellationToken = default)
+        public static XZHeader FromStream(Stream stream)
         {
-            var header = new XZHeader(new NonDisposingStream(stream));
-            await header.Process(cancellationToken);
+            var header = new XZHeader(new BinaryReader(new NonDisposingStream(stream), Encoding.UTF8));
+            header.Process();
             return header;
         }
 
-        public async ValueTask Process(CancellationToken cancellationToken = default)
+        public void Process()
         {
-            using var header = MemoryPool<byte>.Shared.Rent(6);
-            await _stream.ReadAsync(header.Memory.Slice(0, 6), cancellationToken);
-            CheckMagicBytes(header.Memory.Slice(0, 6));
-            await ProcessStreamFlags(cancellationToken);
+            CheckMagicBytes(_reader.ReadBytes(6));
+            ProcessStreamFlags();
         }
 
-        private async ValueTask ProcessStreamFlags(CancellationToken cancellationToken)
+        private void ProcessStreamFlags()
         {
-            using var header = MemoryPool<byte>.Shared.Rent(6);
-            await _stream.ReadAsync(header.Memory.Slice(0, 2), cancellationToken);
-
-            BlockCheckType = (CheckType)(header.Memory.Span[1] & 0x0F);
-            byte futureUse = (byte)(header.Memory.Span[1] & 0xF0);
-            if (futureUse != 0 || header.Memory.Span[0] != 0)
-            {
-                throw new InvalidDataException("Unknown XZ Stream Version");
-            }
-            
-            UInt32 crc = await _stream.ReadLittleEndianUInt32(cancellationToken);
-            UInt32 calcCrc = Crc32.Compute(header.Memory.Slice(0, 2));
+            byte[] streamFlags = _reader.ReadBytes(2);
+            UInt32 crc = _reader.ReadLittleEndianUInt32();
+            UInt32 calcCrc = Crc32.Compute(streamFlags);
             if (crc != calcCrc)
             {
                 throw new InvalidDataException("Stream header corrupt");
             }
+
+            BlockCheckType = (CheckType)(streamFlags[1] & 0x0F);
+            byte futureUse = (byte)(streamFlags[1] & 0xF0);
+            if (futureUse != 0 || streamFlags[0] != 0)
+            {
+                throw new InvalidDataException("Unknown XZ Stream Version");
+            }
         }
 
-        private void CheckMagicBytes(ReadOnlyMemory<byte> header)
+        private void CheckMagicBytes(byte[] header)
         {
-            if (!header.Equals(MagicHeader))
+            if (!header.SequenceEqual(MagicHeader))
             {
                 throw new InvalidDataException("Invalid XZ Stream");
             }

src/SharpCompress/Compressors/Xz/XZStream.cs

@@ -1,18 +1,18 @@
-using System;
+#nullable disable
+
+using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Compressors.Xz
 {
     [CLSCompliant(false)]
     public sealed class XZStream : XZReadOnlyStream
     {
-        public static async ValueTask<bool> IsXZStreamAsync(Stream stream, CancellationToken cancellationToken = default)
+        public static bool IsXZStream(Stream stream)
         {
             try
             {
-                return null != await XZHeader.FromStream(stream, cancellationToken);
+                return null != XZHeader.FromStream(stream);
             }
             catch (Exception)
             {
@@ -22,7 +22,7 @@ namespace SharpCompress.Compressors.Xz
 
         private void AssertBlockCheckTypeIsSupported()
         {
-            switch (Header?.BlockCheckType)
+            switch (Header.BlockCheckType)
             {
                 case CheckType.NONE:
                     break;
@@ -36,11 +36,11 @@ namespace SharpCompress.Compressors.Xz
                     throw new NotSupportedException("Check Type unknown to this version of decoder.");
             }
         }
-        public XZHeader? Header { get; private set; }
-        public XZIndex? Index { get; private set; }
-        public XZFooter? Footer { get; private set; }
+        public XZHeader Header { get; private set; }
+        public XZIndex Index { get; private set; }
+        public XZFooter Footer { get; private set; }
         public bool HeaderIsRead { get; private set; }
-        private XZBlock? _currentBlock;
+        private XZBlock _currentBlock;
 
         private bool _endOfStream;
 
@@ -48,12 +48,7 @@ namespace SharpCompress.Compressors.Xz
         {
         }
 
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            return await ReadAsync(new Memory<byte>(buffer, offset, count), cancellationToken);
-        }
-
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             int bytesRead = 0;
             if (_endOfStream)
@@ -63,11 +58,11 @@ namespace SharpCompress.Compressors.Xz
 
             if (!HeaderIsRead)
             {
-                await ReadHeader();
+                ReadHeader();
             }
 
-            bytesRead = await ReadBlocks(buffer, cancellationToken);
-            if (bytesRead < buffer.Length)
+            bytesRead = ReadBlocks(buffer, offset, count);
+            if (bytesRead < count)
             {
                 _endOfStream = true;
                 ReadIndex();
@@ -76,9 +71,9 @@ namespace SharpCompress.Compressors.Xz
             return bytesRead;
         }
 
-        private async ValueTask ReadHeader()
+        private void ReadHeader()
         {
-            Header = await XZHeader.FromStream(BaseStream);
+            Header = XZHeader.FromStream(BaseStream);
             AssertBlockCheckTypeIsSupported();
             HeaderIsRead = true;
         }
@@ -95,29 +90,29 @@ namespace SharpCompress.Compressors.Xz
             // TODO verify footer
         }
 
-        private async ValueTask<int> ReadBlocks(Memory<byte> buffer, CancellationToken cancellationToken)
+        private int ReadBlocks(byte[] buffer, int offset, int count)
         {
             int bytesRead = 0;
             if (_currentBlock is null)
             {
-                _currentBlock = NextBlock();
+                NextBlock();
             }
 
             for (; ; )
             {
                 try
                 {
-                    if (bytesRead >= buffer.Length)
+                    if (bytesRead >= count)
                     {
                         break;
                     }
 
-                    int remaining = buffer.Length - bytesRead;
-                    int newOffset = bytesRead;
-                    int justRead = await _currentBlock.ReadAsync(buffer.Slice(newOffset, remaining), cancellationToken);
+                    int remaining = count - bytesRead;
+                    int newOffset = offset + bytesRead;
+                    int justRead = _currentBlock.Read(buffer, newOffset, remaining);
                     if (justRead < remaining)
                     {
-                        _currentBlock = NextBlock();
+                        NextBlock();
                     }
 
                     bytesRead += justRead;
@@ -130,9 +125,9 @@ namespace SharpCompress.Compressors.Xz
             return bytesRead;
         }
 
-        private XZBlock NextBlock()
+        private void NextBlock()
         {
-            return new XZBlock(BaseStream, Header!.BlockCheckType, Header!.BlockCheckSize);
+            _currentBlock = new XZBlock(BaseStream, Header.BlockCheckType, Header.BlockCheckSize);
         }
     }
 }

src/SharpCompress/Crypto/Crc32Stream.cs

@@ -2,8 +2,6 @@
 
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.Crypto
 {
@@ -44,7 +42,7 @@ namespace SharpCompress.Crypto
 
         public override void SetLength(long value) => throw new NotSupportedException();
 
-#if !NET461 && !NETSTANDARD2_0
+#if !NETFRAMEWORK && !NETSTANDARD2_0
 
         public override void Write(ReadOnlySpan<byte> buffer)
         {
@@ -54,20 +52,16 @@ namespace SharpCompress.Crypto
         }
 #endif
 
-        public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = new CancellationToken())
-        {
-            await stream.WriteAsync(buffer, cancellationToken);
-            hash = CalculateCrc(table, hash, buffer.Span);
-        }
-
         public override void Write(byte[] buffer, int offset, int count)
         {
-            throw new NotSupportedException();
+            stream.Write(buffer, offset, count);
+            hash = CalculateCrc(table, hash, buffer.AsSpan(offset, count));
         }
 
         public override void WriteByte(byte value)
         {
-            throw new NotSupportedException();
+            stream.WriteByte(value);
+            hash = CalculateCrc(table, hash, value);
         }
 
         public override bool CanRead => stream.CanRead;

src/SharpCompress/IO/AsyncStream.cs

@@ -1,76 +0,0 @@
-using System;
-using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace SharpCompress.IO
-{
-    public abstract class AsyncStream : Stream
-    {
-        protected sealed override void Dispose(bool disposing)
-        {
-            if (disposing)
-            {
-                throw new NotSupportedException();
-            }
-        }
-        
-        public sealed override void Flush()
-        {
-            throw new NotSupportedException();
-        }
-
-        public abstract override ValueTask DisposeAsync();
-
-        public sealed override int Read(byte[] buffer, int offset, int count)
-        {
-            throw new NotSupportedException();
-        }
-
-        public sealed override void Write(byte[] buffer, int offset, int count)
-        {
-            throw new NotSupportedException();
-        }
-        
-        public sealed override IAsyncResult BeginRead(byte[] buffer, int offset, int count, AsyncCallback? callback, object? state)
-        {
-            throw new NotSupportedException();
-        }
-
-        public sealed override int EndRead(IAsyncResult asyncResult)
-        {
-            throw new NotSupportedException();
-        }
-        
-        public sealed override int ReadByte()
-        {
-            throw new NotSupportedException();
-        }
-        
-        public sealed override void WriteByte(byte b)
-        {
-            throw new NotSupportedException();
-        }
-
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            return await ReadAsync(new Memory<byte>(buffer, offset, count), cancellationToken);
-        }
-
-        public abstract override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken);
-
-#if !NET461 && !NETSTANDARD2_0
-
-        public sealed override int Read(Span<byte> buffer)
-        {
-            throw new NotSupportedException();
-        }
-
-        public sealed override void Write(ReadOnlySpan<byte> buffer)
-        {
-            throw new NotSupportedException();
-        }
-
-#endif
-    }
-}

src/SharpCompress/IO/BufferedSubStream.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.IO
 {
@@ -27,11 +25,16 @@ namespace SharpCompress.IO
 
         public override bool CanWrite => false;
 
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
         public override long Length => BytesLeftToRead;
 
         public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
 
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
             if (count > BytesLeftToRead)
             {
@@ -44,7 +47,7 @@ namespace SharpCompress.IO
                 {
                     cacheOffset = 0;
                     Stream.Position = position;
-                    cacheLength = await Stream.ReadAsync(cache, 0, cache.Length, cancellationToken);
+                    cacheLength = Stream.Read(cache, 0, cache.Length);
                     position += cacheLength;
                 }
 
@@ -71,5 +74,10 @@ namespace SharpCompress.IO
         {
             throw new NotSupportedException();
         }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
     }
 }

src/SharpCompress/IO/CountingWritableSubStream.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.IO
 {
@@ -19,15 +17,20 @@ namespace SharpCompress.IO
 
         public override bool CanWrite => true;
 
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
-            return Stream.FlushAsync(cancellationToken);
+            Stream.Flush();
         }
 
         public override long Length => throw new NotSupportedException();
 
         public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
 
+        public override int Read(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
+
         public override long Seek(long offset, SeekOrigin origin)
         {
             throw new NotSupportedException();
@@ -38,16 +41,16 @@ namespace SharpCompress.IO
             throw new NotSupportedException();
         }
 
-        public override async Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
-            await Stream.WriteAsync(buffer, offset, count, cancellationToken);
+            Stream.Write(buffer, offset, count);
             Count += (uint)count;
         }
 
-        public override async ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
+        public override void WriteByte(byte value)
         {
-            await Stream.WriteAsync(buffer, cancellationToken);
-            Count += (uint)buffer.Length;
+            Stream.WriteByte(value);
+            ++Count;
         }
     }
 }

src/SharpCompress/IO/NonDisposingStream.cs

@@ -1,11 +1,9 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.IO
 {
-    public class NonDisposingStream : AsyncStream
+    public class NonDisposingStream : Stream
     {
         public NonDisposingStream(Stream stream, bool throwOnDispose = false)
         {
@@ -15,14 +13,12 @@ namespace SharpCompress.IO
 
         public bool ThrowOnDispose { get; set; }
 
-        public override ValueTask DisposeAsync()
+        protected override void Dispose(bool disposing)
         {
             if (ThrowOnDispose)
             {
                 throw new InvalidOperationException($"Attempt to dispose of a {nameof(NonDisposingStream)} when {nameof(ThrowOnDispose)} is {ThrowOnDispose}");
             }
-
-            return new ValueTask();
         }
 
         protected Stream Stream { get; }
@@ -33,23 +29,18 @@ namespace SharpCompress.IO
 
         public override bool CanWrite => Stream.CanWrite;
 
-        public override Task FlushAsync(CancellationToken cancellationToken)
+        public override void Flush()
         {
-            return Stream.FlushAsync(cancellationToken);
+            Stream.Flush();
         }
 
         public override long Length => Stream.Length;
 
         public override long Position { get => Stream.Position; set => Stream.Position = value; }
 
-        public override ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken)
+        public override int Read(byte[] buffer, int offset, int count)
         {
-            return Stream.ReadAsync(buffer, cancellationToken);
-        }
-
-        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            return Stream.ReadAsync(buffer, offset, count, cancellationToken);
+            return Stream.Read(buffer, offset, count);
         }
 
         public override long Seek(long offset, SeekOrigin origin)
@@ -62,14 +53,23 @@ namespace SharpCompress.IO
             Stream.SetLength(value);
         }
 
-        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
+        public override void Write(byte[] buffer, int offset, int count)
         {
-            return Stream.WriteAsync(buffer, offset, count, cancellationToken);
+            Stream.Write(buffer, offset, count);
         }
 
-        public override ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = new CancellationToken())
+#if !NETFRAMEWORK && !NETSTANDARD2_0
+
+        public override int Read(Span<byte> buffer)
         {
-            return Stream.WriteAsync(buffer, cancellationToken);
+            return Stream.Read(buffer);
         }
+
+        public override void Write(ReadOnlySpan<byte> buffer)
+        {
+            Stream.Write(buffer);
+        }
+
+#endif
     }
-}
+}

src/SharpCompress/IO/ReadOnlySubStream.cs

@@ -1,7 +1,5 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.IO
 {
@@ -30,47 +28,41 @@ namespace SharpCompress.IO
 
         public override bool CanWrite => false;
 
+        public override void Flush()
+        {
+            throw new NotSupportedException();
+        }
+
         public override long Length => throw new NotSupportedException();
 
         public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
 
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
+        public override int Read(byte[] buffer, int offset, int count)
         {
-            var count = buffer.Length;
             if (BytesLeftToRead < count)
             {
                 count = (int)BytesLeftToRead;
             }
-
-            if (count == 0)
-            {
-                return 0;
-            }
-            int read = await Stream.ReadAsync(buffer.Slice(0, count), cancellationToken);
+            int read = Stream.Read(buffer, offset, count);
             if (read > 0)
             {
                 BytesLeftToRead -= read;
             }
             return read;
         }
-        
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            if (BytesLeftToRead < count)
-            {
-                count = (int)BytesLeftToRead;
-            }
 
-            if (count == 0)
+        public override int ReadByte()
+        {
+            if (BytesLeftToRead <= 0)
             {
-                return 0;
+                return -1;
             }
-            int read = await Stream.ReadAsync(buffer, offset, count, cancellationToken);
-            if (read > 0)
+            int value = Stream.ReadByte();
+            if (value != -1)
             {
-                BytesLeftToRead -= read;
+                --BytesLeftToRead;
             }
-            return read;
+            return value;
         }
 
         public override long Seek(long offset, SeekOrigin origin)
@@ -82,5 +74,10 @@ namespace SharpCompress.IO
         {
             throw new NotSupportedException();
         }
+
+        public override void Write(byte[] buffer, int offset, int count)
+        {
+            throw new NotSupportedException();
+        }
     }
 }

src/SharpCompress/IO/RewindableStream.cs

@@ -1,14 +1,12 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace SharpCompress.IO
 {
     internal class RewindableStream : Stream
     {
         private readonly Stream stream;
-        private MemoryStream bufferStream = new();
+        private MemoryStream bufferStream = new MemoryStream();
         private bool isRewound;
         private bool isDisposed;
 
@@ -111,11 +109,6 @@ namespace SharpCompress.IO
         }
 
         public override int Read(byte[] buffer, int offset, int count)
-        {
-            throw new NotImplementedException();
-        }
-
-        public override async Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
         {
             //don't actually read if we don't really want to read anything
             //currently a network stream bug on Windows for .NET Core
@@ -126,13 +119,13 @@ namespace SharpCompress.IO
             int read;
             if (isRewound && bufferStream.Position != bufferStream.Length)
             {
-                read = await bufferStream.ReadAsync(buffer, offset, count, cancellationToken);
+                read = bufferStream.Read(buffer, offset, count);
                 if (read < count)
                 {
-                    int tempRead = await stream.ReadAsync(buffer, read, count - read, cancellationToken);
+                    int tempRead = stream.Read(buffer, offset + read, count - read);
                     if (IsRecording)
                     {
-                        await bufferStream.WriteAsync(buffer, read, tempRead, cancellationToken);
+                        bufferStream.Write(buffer, offset + read, tempRead);
                     }
                     read += tempRead;
                 }
@@ -144,48 +137,10 @@ namespace SharpCompress.IO
                 return read;
             }
 
-            read = await stream.ReadAsync(buffer, cancellationToken);
+            read = stream.Read(buffer, offset, count);
             if (IsRecording)
             {
-                await bufferStream.WriteAsync(buffer, cancellationToken);
-            }
-            return read;
-        }
-
-        public override async ValueTask<int> ReadAsync(Memory<byte> buffer, CancellationToken cancellationToken = default)
-        {
-            var count = buffer.Length;
-            //don't actually read if we don't really want to read anything
-            //currently a network stream bug on Windows for .NET Core
-            if (count == 0)
-            {
-                return 0;
-            }
-            int read;
-            if (isRewound && bufferStream.Position != bufferStream.Length)
-            {
-                read = await bufferStream.ReadAsync(buffer, cancellationToken);
-                if (read < count)
-                {
-                    int tempRead = await stream.ReadAsync(buffer.Slice(read, count - read), cancellationToken);
-                    if (IsRecording)
-                    {
-                        await bufferStream.WriteAsync(buffer.Slice(read, tempRead), cancellationToken);
-                    }
-                    read += tempRead;
-                }
-                if (bufferStream.Position == bufferStream.Length && !IsRecording)
-                {
-                    isRewound = false;
-                    bufferStream.SetLength(0);
-                }
-                return read;
-            }
-
-            read = await stream.ReadAsync(buffer, cancellationToken);
-            if (IsRecording)
-            {
-                await bufferStream.WriteAsync(buffer, cancellationToken);
+                bufferStream.Write(buffer, offset, read);
             }
             return read;
         }

src/SharpCompress/LazyReadOnlyCollection.cs

@@ -1,31 +1,23 @@
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
+#nullable disable
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
 
 namespace SharpCompress
 {
-    internal sealed class LazyReadOnlyCollection<T> : IAsyncEnumerable<T>
+    internal sealed class LazyReadOnlyCollection<T> : ICollection<T>
     {
-        private readonly List<T> backing = new();
-        private IAsyncEnumerator<T>? enumerator;
-        private readonly IAsyncEnumerable<T> enumerable;
+        private readonly List<T> backing = new List<T>();
+        private readonly IEnumerator<T> source;
         private bool fullyLoaded;
 
-        public LazyReadOnlyCollection(IAsyncEnumerable<T> source)
+        public LazyReadOnlyCollection(IEnumerable<T> source)
         {
-            enumerable = source;
+            this.source = source.GetEnumerator();
         }
 
-        private IAsyncEnumerator<T> GetEnumerator()
-        {
-            if (enumerator is null)
-            {
-                enumerator = enumerable.GetAsyncEnumerator();
-            }
-            return enumerator;
-        }
-
-        private class LazyLoader : IAsyncEnumerator<T>
+        private class LazyLoader : IEnumerator<T>
         {
             private readonly LazyReadOnlyCollection<T> lazyReadOnlyCollection;
             private bool disposed;
@@ -36,43 +28,58 @@ namespace SharpCompress
                 this.lazyReadOnlyCollection = lazyReadOnlyCollection;
             }
 
+            #region IEnumerator<T> Members
+
             public T Current => lazyReadOnlyCollection.backing[index];
-            
-            public ValueTask DisposeAsync()
+
+            #endregion
+
+            #region IDisposable Members
+
+            public void Dispose()
             {
                 if (!disposed)
                 {
                     disposed = true;
                 }
-                return new ValueTask(Task.CompletedTask);
             }
 
+            #endregion
 
-            public async ValueTask<bool> MoveNextAsync()
+            #region IEnumerator Members
+
+            object IEnumerator.Current => Current;
+
+            public bool MoveNext()
             {
                 if (index + 1 < lazyReadOnlyCollection.backing.Count)
                 {
                     index++;
                     return true;
                 }
-                if (!lazyReadOnlyCollection.fullyLoaded && await lazyReadOnlyCollection.GetEnumerator().MoveNextAsync())
+                if (!lazyReadOnlyCollection.fullyLoaded && lazyReadOnlyCollection.source.MoveNext())
                 {
-                    lazyReadOnlyCollection.backing.Add(lazyReadOnlyCollection.GetEnumerator().Current);
+                    lazyReadOnlyCollection.backing.Add(lazyReadOnlyCollection.source.Current);
                     index++;
                     return true;
                 }
                 lazyReadOnlyCollection.fullyLoaded = true;
                 return false;
             }
+
+            public void Reset()
+            {
+                throw new NotSupportedException();
+            }
+
+            #endregion
         }
 
-        internal async ValueTask EnsureFullyLoaded()
+        internal void EnsureFullyLoaded()
         {
             if (!fullyLoaded)
             {
-                await foreach (var x in this)
-                {
-                }
+                this.ForEach(x => { });
                 fullyLoaded = true;
             }
         }
@@ -82,14 +89,65 @@ namespace SharpCompress
             return backing;
         }
 
+        #region ICollection<T> Members
+
+        public void Add(T item)
+        {
+            throw new NotSupportedException();
+        }
+
+        public void Clear()
+        {
+            throw new NotSupportedException();
+        }
+
+        public bool Contains(T item)
+        {
+            EnsureFullyLoaded();
+            return backing.Contains(item);
+        }
+
+        public void CopyTo(T[] array, int arrayIndex)
+        {
+            EnsureFullyLoaded();
+            backing.CopyTo(array, arrayIndex);
+        }
+
+        public int Count
+        {
+            get
+            {
+                EnsureFullyLoaded();
+                return backing.Count;
+            }
+        }
+
+        public bool IsReadOnly => true;
+
+        public bool Remove(T item)
+        {
+            throw new NotSupportedException();
+        }
+
+        #endregion
+
         #region IEnumerable<T> Members
 
         //TODO check for concurrent access
-        public IAsyncEnumerator<T> GetAsyncEnumerator(CancellationToken cancellationToken)
+        public IEnumerator<T> GetEnumerator()
         {
             return new LazyLoader(this);
         }
 
         #endregion
+
+        #region IEnumerable Members
+
+        IEnumerator IEnumerable.GetEnumerator()
+        {
+            return GetEnumerator();
+        }
+
+        #endregion
     }
 }

src/SharpCompress/Polyfills/StreamExtensions.cs

@@ -1,18 +1,20 @@
-#if NET461 || NETSTANDARD2_0
+#if NETFRAMEWORK || NETSTANDARD2_0
 
+using System;
 using System.Buffers;
+using System.IO;
 
-namespace System.IO
+namespace SharpCompress
 {
-    public static class StreamExtensions
+    internal static class StreamExtensions
     {
-        public static int Read(this Stream stream, Span<byte> buffer)
+        internal static int Read(this Stream stream, Span<byte> buffer)
         {
             byte[] temp = ArrayPool<byte>.Shared.Rent(buffer.Length);
 
             try
             {
-                int read = stream.Read(buffer);
+                int read = stream.Read(temp, 0, buffer.Length);
 
                 temp.AsSpan(0, read).CopyTo(buffer);
 
@@ -24,7 +26,7 @@ namespace System.IO
             }
         }
 
-        public static void Write(this Stream stream, ReadOnlySpan<byte> buffer)
+        internal static void Write(this Stream stream, ReadOnlySpan<byte> buffer)
         {
             byte[] temp = ArrayPool<byte>.Shared.Rent(buffer.Length);
 

src/SharpCompress/Polyfills/StringExtensions.cs

@@ -1,15 +1,15 @@
-#if NET461 || NETSTANDARD2_0
+#if NETFRAMEWORK || NETSTANDARD2_0
 
-namespace System
+namespace SharpCompress
 {
-    public static class StringExtensions
+    internal static class StringExtensions
     {
-        public static bool EndsWith(this string text, char value)
+        internal static bool EndsWith(this string text, char value)
         {
             return text.Length > 0 && text[text.Length - 1] == value;
         }
 
-        public static bool Contains(this string text, char value)
+        internal static bool Contains(this string text, char value)
         {
             return text.IndexOf(value) > -1;
         }

src/SharpCompress/Readers/AbstractReader.cs

@@ -2,8 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 
 namespace SharpCompress.Readers
@@ -16,7 +14,7 @@ namespace SharpCompress.Readers
         where TVolume : Volume
     {
         private bool completed;
-        private IAsyncEnumerator<TEntry>? entriesForCurrentReadStream;
+        private IEnumerator<TEntry>? entriesForCurrentReadStream;
         private bool wroteCurrentEntry;
 
         public event EventHandler<ReaderExtractionEventArgs<IEntry>>? EntryExtractionProgress;
@@ -42,14 +40,14 @@ namespace SharpCompress.Readers
         /// <summary>
         /// Current file entry 
         /// </summary>
-        public TEntry? Entry => entriesForCurrentReadStream?.Current ?? default;
+        public TEntry Entry => entriesForCurrentReadStream!.Current;
 
         #region IDisposable Members
 
-        public async ValueTask DisposeAsync()
+        public void Dispose()
         {
-            await (entriesForCurrentReadStream?.DisposeAsync() ?? new ValueTask());
-            await Volume.DisposeAsync();
+            entriesForCurrentReadStream?.Dispose();
+            Volume?.Dispose();
         }
 
         #endregion
@@ -69,7 +67,7 @@ namespace SharpCompress.Readers
             }
         }
 
-        public async ValueTask<bool> MoveToNextEntryAsync(CancellationToken cancellationToken = default)
+        public bool MoveToNextEntry()
         {
             if (completed)
             {
@@ -81,21 +79,14 @@ namespace SharpCompress.Readers
             }
             if (entriesForCurrentReadStream is null)
             {
-                var stream = await RequestInitialStream(cancellationToken);
-                if (stream is null || !stream.CanRead)
-                {
-                    throw new MultipartStreamRequiredException("File is split into multiple archives: '"
-                                                               + (Entry?.Key ?? "unknown") +
-                                                               "'. A new readable stream is required.  Use Cancel if it was intended.");
-                }
-                entriesForCurrentReadStream = GetEntries(stream, cancellationToken).GetAsyncEnumerator(cancellationToken);
-            } 
-            else if (!wroteCurrentEntry)
+                return LoadStreamForReading(RequestInitialStream());
+            }
+            if (!wroteCurrentEntry)
             {
-                await SkipEntry(cancellationToken);
+                SkipEntry();
             }
             wroteCurrentEntry = false;
-            if (await entriesForCurrentReadStream.MoveNextAsync())
+            if (NextEntryForCurrentStream())
             {
                 return true;
             }
@@ -103,29 +94,43 @@ namespace SharpCompress.Readers
             return false;
         }
 
-        protected virtual ValueTask<Stream> RequestInitialStream(CancellationToken cancellationToken)
+        protected bool LoadStreamForReading(Stream stream)
         {
-            return new(Volume.Stream);
+            entriesForCurrentReadStream?.Dispose();
+            if ((stream is null) || (!stream.CanRead))
+            {
+                throw new MultipartStreamRequiredException("File is split into multiple archives: '"
+                                                           + Entry.Key +
+                                                           "'. A new readable stream is required.  Use Cancel if it was intended.");
+            }
+            entriesForCurrentReadStream = GetEntries(stream).GetEnumerator();
+            return entriesForCurrentReadStream.MoveNext();
         }
 
-        protected abstract IAsyncEnumerable<TEntry> GetEntries(Stream stream, CancellationToken cancellationToken);
+        protected virtual Stream RequestInitialStream()
+        {
+            return Volume.Stream;
+        }
+
+        internal virtual bool NextEntryForCurrentStream()
+        {
+            return entriesForCurrentReadStream!.MoveNext();
+        }
+
+        protected abstract IEnumerable<TEntry> GetEntries(Stream stream);
 
         #region Entry Skip/Write
 
-        private async ValueTask SkipEntry(CancellationToken cancellationToken)
+        private void SkipEntry()
         {
-            if (Entry?.IsDirectory != true)
+            if (!Entry.IsDirectory)
             {
-                await SkipAsync(cancellationToken);
+                Skip();
             }
         }
 
-        private async ValueTask SkipAsync(CancellationToken cancellationToken)
+        private void Skip()
         {
-            if (Entry is null)
-            {
-                return;
-            }
             if (ArchiveType != ArchiveType.Rar
                 && !Entry.IsSolid
                 && Entry.CompressedSize > 0)
@@ -137,17 +142,19 @@ namespace SharpCompress.Readers
                 if (rawStream != null)
                 {
                     var bytesToAdvance = Entry.CompressedSize;
-                    await rawStream.SkipAsync(bytesToAdvance, cancellationToken: cancellationToken);
+                    rawStream.Skip(bytesToAdvance);
                     part.Skipped = true;
                     return;
                 }
             }
             //don't know the size so we have to try to decompress to skip
-            await using var s = await OpenEntryStreamAsync(cancellationToken);
-            await s.SkipAsync(cancellationToken);
+            using (var s = OpenEntryStream())
+            {
+                s.Skip();
+            }
         }
 
-        public async ValueTask WriteEntryToAsync(Stream writableStream, CancellationToken cancellationToken = default)
+        public void WriteEntryTo(Stream writableStream)
         {
             if (wroteCurrentEntry)
             {
@@ -158,28 +165,26 @@ namespace SharpCompress.Readers
                 throw new ArgumentNullException("A writable Stream was required.  Use Cancel if that was intended.");
             }
 
-            await WriteAsync(writableStream, cancellationToken);
+            Write(writableStream);
             wroteCurrentEntry = true;
         }
 
-        private async ValueTask WriteAsync(Stream writeStream, CancellationToken cancellationToken)
+        internal void Write(Stream writeStream)
         {
-            if (Entry is null)
-            {
-                throw new ArgumentException("Entry is null");
-            }
             var streamListener = this as IReaderExtractionListener;
-            await using Stream s = await OpenEntryStreamAsync(cancellationToken);
-            await s.TransferToAsync(writeStream, Entry, streamListener, cancellationToken);
+            using (Stream s = OpenEntryStream())
+            {
+                s.TransferTo(writeStream, Entry, streamListener);
+            }
         }
 
-        public async ValueTask<EntryStream> OpenEntryStreamAsync(CancellationToken cancellationToken = default)
+        public EntryStream OpenEntryStream()
         {
             if (wroteCurrentEntry)
             {
                 throw new ArgumentException("WriteEntryTo or OpenEntryStream can only be called once.");
             }
-            var stream = await GetEntryStreamAsync(cancellationToken);
+            var stream = GetEntryStream();
             wroteCurrentEntry = true;
             return stream;
         }
@@ -189,21 +194,17 @@ namespace SharpCompress.Readers
         /// </summary>
         protected EntryStream CreateEntryStream(Stream decompressed)
         {
-            return new(this, decompressed);
+            return new EntryStream(this, decompressed);
         }
 
-        protected async ValueTask<EntryStream> GetEntryStreamAsync(CancellationToken cancellationToken)
+        protected virtual EntryStream GetEntryStream()
         {
-            if (Entry is null)
-            {
-                throw new ArgumentException("Entry is null");
-            }
-            return CreateEntryStream(await Entry.Parts.First().GetCompressedStreamAsync(cancellationToken));
+            return CreateEntryStream(Entry.Parts.First().GetCompressedStream());
         }
 
         #endregion
 
-        IEntry? IReader.Entry => Entry;
+        IEntry IReader.Entry => Entry;
 
         void IExtractionListener.FireCompressedBytesRead(long currentPartCompressedBytes, long compressedReadBytes)
         {

src/SharpCompress/Readers/GZip/GZipReader.cs

@@ -1,6 +1,5 @@
 using System.Collections.Generic;
 using System.IO;
-using System.Threading;
 using SharpCompress.Common;
 using SharpCompress.Common.GZip;
 
@@ -32,9 +31,9 @@ namespace SharpCompress.Readers.GZip
 
         #endregion Open
 
-        protected override IAsyncEnumerable<GZipEntry> GetEntries(Stream stream, CancellationToken cancellationToken)
+        protected override IEnumerable<GZipEntry> GetEntries(Stream stream)
         {
-            return GZipEntry.GetEntries(stream, Options, cancellationToken);
+            return GZipEntry.GetEntries(stream, Options);
         }
     }
 }

src/SharpCompress/Readers/IReader.cs

@@ -1,12 +1,10 @@
 using System;
 using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
 using SharpCompress.Common;
 
 namespace SharpCompress.Readers
 {
-    public interface IReader : IAsyncDisposable
+    public interface IReader : IDisposable
     {
         event EventHandler<ReaderExtractionEventArgs<IEntry>> EntryExtractionProgress;
 
@@ -15,13 +13,13 @@ namespace SharpCompress.Readers
 
         ArchiveType ArchiveType { get; }
 
-        IEntry? Entry { get; }
+        IEntry Entry { get; }
 
         /// <summary>
         /// Decompresses the current entry to the stream.  This cannot be called twice for the current entry.
         /// </summary>
         /// <param name="writableStream"></param>
-        ValueTask WriteEntryToAsync(Stream writableStream, CancellationToken cancellationToken = default);
+        void WriteEntryTo(Stream writableStream);
 
         bool Cancelled { get; }
         void Cancel();
@@ -30,12 +28,12 @@ namespace SharpCompress.Readers
         /// Moves to the next entry by reading more data from the underlying stream.  This skips if data has not been read.
         /// </summary>
         /// <returns></returns>
-        ValueTask<bool> MoveToNextEntryAsync(CancellationToken cancellationToken = default);
+        bool MoveToNextEntry();
 
         /// <summary>
         /// Opens the current entry as a stream that will decompress as it is read.
         /// Read the entire stream or use SkipEntry on EntryStream.
         /// </summary>
-        ValueTask<EntryStream> OpenEntryStreamAsync(CancellationToken cancellationToken = default);
+        EntryStream OpenEntryStream();
     }
 }

src/SharpCompress/Readers/IReaderExtensions.cs

@@ -1,73 +1,63 @@
-using System;
-using System.IO;
-using System.Threading;
-using System.Threading.Tasks;
+using System.IO;
 using SharpCompress.Common;
 
 namespace SharpCompress.Readers
 {
     public static class IReaderExtensions
     {
-        public static async ValueTask WriteEntryToAsync(this IReader reader, string filePath)
+        public static void WriteEntryTo(this IReader reader, string filePath)
         {
-            await using Stream stream = File.Open(filePath, FileMode.Create, FileAccess.Write);
-            await reader.WriteEntryToAsync(stream);
+            using (Stream stream = File.Open(filePath, FileMode.Create, FileAccess.Write))
+            {
+                reader.WriteEntryTo(stream);
+            }
         }
 
-        public static async ValueTask WriteEntryToAsync(this IReader reader, FileInfo filePath)
+        public static void WriteEntryTo(this IReader reader, FileInfo filePath)
         {
-            await using Stream stream = filePath.Open(FileMode.Create);
-            await reader.WriteEntryToAsync(stream);
+            using (Stream stream = filePath.Open(FileMode.Create))
+            {
+                reader.WriteEntryTo(stream);
+            }
         }
 
         /// <summary>
         /// Extract all remaining unread entries to specific directory, retaining filename
         /// </summary>
-        public static async ValueTask WriteAllToDirectoryAsync(this IReader reader, string destinationDirectory,
+        public static void WriteAllToDirectory(this IReader reader, string destinationDirectory,
                                                ExtractionOptions? options = null)
         {
-            while (await reader.MoveToNextEntryAsync())
+            while (reader.MoveToNextEntry())
             {
-               await reader.WriteEntryToDirectoryAsync(destinationDirectory, options);
+                reader.WriteEntryToDirectory(destinationDirectory, options);
             }
         }
 
         /// <summary>
         /// Extract to specific directory, retaining filename
         /// </summary>
-        public static ValueTask WriteEntryToDirectoryAsync(this IReader reader, string destinationDirectory,
-                                                      ExtractionOptions? options = null,
-                                                      CancellationToken cancellationToken = default)
+        public static void WriteEntryToDirectory(this IReader reader, string destinationDirectory,
+                                                 ExtractionOptions? options = null)
         {
-            if (reader.Entry is null)
-            {
-                throw new ArgumentException("Entry is null");
-            }
-            return ExtractionMethods.WriteEntryToDirectoryAsync(reader.Entry, destinationDirectory, options,
-                                                                async (x, o, ct) =>
-                                                                {
-                                                                    await reader.WriteEntryToFileAsync(x, o, ct);
-                                                                }, cancellationToken);
+            ExtractionMethods.WriteEntryToDirectory(reader.Entry, destinationDirectory, options,
+                                              reader.WriteEntryToFile);
         }
 
         /// <summary>
         /// Extract to specific file
         /// </summary>
-        public static async ValueTask WriteEntryToFileAsync(this IReader reader,
+        public static void WriteEntryToFile(this IReader reader,
                                             string destinationFileName,
-                                            ExtractionOptions? options = null,
-                                            CancellationToken cancellationToken = default)
+                                            ExtractionOptions? options = null)
         {
-            if (reader.Entry is null)
-            {
-                throw new ArgumentException("Entry is null");
-            }
-            await ExtractionMethods.WriteEntryToFileAsync(reader.Entry, destinationFileName, options,
-                                               async (x, fm, ct) =>
+            ExtractionMethods.WriteEntryToFile(reader.Entry, destinationFileName, options,
+                                               (x, fm) =>
                                                {
-                                                   await using FileStream fs = File.Open(x, fm);
-                                                   await reader.WriteEntryToAsync(fs, ct);
-                                               }, cancellationToken);
+                                                   using (FileStream fs = File.Open(destinationFileName, fm))
+                                                   {
+                                                       reader.WriteEntryTo(fs);
+                                                   }
+                                               });
         }
     }
 }