diff --git a/src/SharpCompress/Algorithms/Alder32.cs b/src/SharpCompress/Algorithms/Alder32.cs
new file mode 100644
index 00000000..d0b3279f
--- /dev/null
+++ b/src/SharpCompress/Algorithms/Alder32.cs
@@ -0,0 +1,285 @@
+// 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 NETCOREAPP3_1
+using System.Runtime.Intrinsics;
+using System.Runtime.Intrinsics.X86;
+#endif
+
+namespace SharpCompress.Algorithms
+{
+ ///
+ /// Calculates the 32 bit Adler checksum of a given buffer according to
+ /// RFC 1950. ZLIB Compressed Data Format Specification version 3.3)
+ ///
+ internal static class Adler32
+ {
+ ///
+ /// The default initial seed value of a Adler32 checksum calculation.
+ ///
+ public const uint SeedValue = 1U;
+
+#if NETCOREAPP3_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;
+
+ ///
+ /// Calculates the Adler32 checksum with the bytes taken from the span.
+ ///
+ /// The readonly span of bytes.
+ /// The .
+ [MethodImpl(MethodImplOptions.AggressiveInlining)]
+ public static uint Calculate(ReadOnlySpan buffer)
+ {
+ return Calculate(SeedValue, buffer);
+ }
+
+ ///
+ /// Calculates the Adler32 checksum with the bytes taken from the span and seed.
+ ///
+ /// The input Adler32 value.
+ /// The readonly span of bytes.
+ /// The .
+ public static uint Calculate(uint adler, ReadOnlySpan buffer)
+ {
+ if (buffer.IsEmpty)
+ {
+ return SeedValue;
+ }
+
+#if NETCOREAPP3_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 NETCOREAPP3_1
+ private static unsafe uint CalculateSse(uint adler, ReadOnlySpan 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 zero = Vector128.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 v_ps = Vector128.CreateScalar(s1 * n).AsInt32();
+ Vector128 v_s2 = Vector128.CreateScalar(s2).AsInt32();
+ Vector128 v_s1 = Vector128.Zero;
+
+ do
+ {
+ // Load 32 input bytes.
+ Vector128 bytes1 = Sse3.LoadDquVector128(localBufferPtr);
+ Vector128 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 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 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 buffer)
+ {
+ uint s1 = adler & 0xFFFF;
+ uint s2 = (adler >> 16) & 0xFFFF;
+ uint k;
+
+ ref byte bufferRef = ref MemoryMarshal.GetReference(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;
+ }
+ }
+}
\ No newline at end of file
diff --git a/src/SharpCompress/Compressors/Deflate/DeflateManager.cs b/src/SharpCompress/Compressors/Deflate/DeflateManager.cs
index c182d5e7..0abc4564 100644
--- a/src/SharpCompress/Compressors/Deflate/DeflateManager.cs
+++ b/src/SharpCompress/Compressors/Deflate/DeflateManager.cs
@@ -70,6 +70,8 @@
using System;
+using SharpCompress.Algorithms;
+
namespace SharpCompress.Compressors.Deflate
{
internal sealed partial class DeflateManager
@@ -1685,7 +1687,7 @@ namespace SharpCompress.Compressors.Deflate
Rfc1950BytesEmitted = false;
status = (WantRfc1950HeaderBytes) ? INIT_STATE : BUSY_STATE;
- _codec._Adler32 = Adler.Adler32(0, null, 0, 0);
+ _codec._adler32 = 1;
last_flush = (int)FlushType.None;
@@ -1763,7 +1765,7 @@ namespace SharpCompress.Compressors.Deflate
throw new ZlibException("Stream error.");
}
- _codec._Adler32 = Adler.Adler32(_codec._Adler32, dictionary, 0, dictionary.Length);
+ _codec._adler32 = Adler32.Calculate(_codec._adler32, dictionary);
if (length < MIN_MATCH)
{
@@ -1850,12 +1852,12 @@ namespace SharpCompress.Compressors.Deflate
////putShortMSB((int)(SharedUtils.URShift(_codec._Adler32, 16)));
//putShortMSB((int)((UInt64)_codec._Adler32 >> 16));
//putShortMSB((int)(_codec._Adler32 & 0xffff));
- pending[pendingCount++] = (byte)((_codec._Adler32 & 0xFF000000) >> 24);
- pending[pendingCount++] = (byte)((_codec._Adler32 & 0x00FF0000) >> 16);
- pending[pendingCount++] = (byte)((_codec._Adler32 & 0x0000FF00) >> 8);
- pending[pendingCount++] = (byte)(_codec._Adler32 & 0x000000FF);
+ pending[pendingCount++] = (byte)((_codec._adler32 & 0xFF000000) >> 24);
+ pending[pendingCount++] = (byte)((_codec._adler32 & 0x00FF0000) >> 16);
+ pending[pendingCount++] = (byte)((_codec._adler32 & 0x0000FF00) >> 8);
+ pending[pendingCount++] = (byte)(_codec._adler32 & 0x000000FF);
}
- _codec._Adler32 = Adler.Adler32(0, null, 0, 0);
+ _codec._adler32 = 1;
}
// Flush as much pending output as possible
@@ -1968,10 +1970,10 @@ namespace SharpCompress.Compressors.Deflate
}
// Write the zlib trailer (adler32)
- pending[pendingCount++] = (byte)((_codec._Adler32 & 0xFF000000) >> 24);
- pending[pendingCount++] = (byte)((_codec._Adler32 & 0x00FF0000) >> 16);
- pending[pendingCount++] = (byte)((_codec._Adler32 & 0x0000FF00) >> 8);
- pending[pendingCount++] = (byte)(_codec._Adler32 & 0x000000FF);
+ pending[pendingCount++] = (byte)((_codec._adler32 & 0xFF000000) >> 24);
+ pending[pendingCount++] = (byte)((_codec._adler32 & 0x00FF0000) >> 16);
+ pending[pendingCount++] = (byte)((_codec._adler32 & 0x0000FF00) >> 8);
+ pending[pendingCount++] = (byte)(_codec._adler32 & 0x000000FF);
//putShortMSB((int)(SharedUtils.URShift(_codec._Adler32, 16)));
//putShortMSB((int)(_codec._Adler32 & 0xffff));
diff --git a/src/SharpCompress/Compressors/Deflate/Inflate.cs b/src/SharpCompress/Compressors/Deflate/Inflate.cs
index f9b66c0c..863f999f 100644
--- a/src/SharpCompress/Compressors/Deflate/Inflate.cs
+++ b/src/SharpCompress/Compressors/Deflate/Inflate.cs
@@ -65,6 +65,8 @@
using System;
+using SharpCompress.Algorithms;
+
namespace SharpCompress.Compressors.Deflate
{
internal sealed class InflateBlocks
@@ -118,7 +120,7 @@ namespace SharpCompress.Compressors.Deflate
if (checkfn != null)
{
- _codec._Adler32 = check = Adler.Adler32(0, null, 0, 0);
+ _codec._adler32 = check = 1;
}
return oldCheck;
}
@@ -739,7 +741,7 @@ namespace SharpCompress.Compressors.Deflate
// update check information
if (checkfn != null)
{
- _codec._Adler32 = check = Adler.Adler32(check, window, readAt, nBytes);
+ _codec._adler32 = check = Adler32.Calculate(check, window.AsSpan(readAt, nBytes));
}
// copy as far as end of window
@@ -1764,7 +1766,7 @@ namespace SharpCompress.Compressors.Deflate
_codec.AvailableBytesIn--;
_codec.TotalBytesIn++;
expectedCheck += (uint)(_codec.InputBuffer[_codec.NextIn++] & 0x000000ff);
- _codec._Adler32 = expectedCheck;
+ _codec._adler32 = expectedCheck;
mode = InflateManagerMode.DICT0;
return ZlibConstants.Z_NEED_DICT;
@@ -1879,12 +1881,12 @@ namespace SharpCompress.Compressors.Deflate
throw new ZlibException("Stream error.");
}
- if (Adler.Adler32(1, dictionary, 0, dictionary.Length) != _codec._Adler32)
+ if (Adler32.Calculate(1, dictionary) != _codec._adler32)
{
return ZlibConstants.Z_DATA_ERROR;
}
- _codec._Adler32 = Adler.Adler32(0, null, 0, 0);
+ _codec._adler32 = 1;
if (length >= (1 << wbits))
{
diff --git a/src/SharpCompress/Compressors/Deflate/Zlib.cs b/src/SharpCompress/Compressors/Deflate/Zlib.cs
index d33cbcc9..6133feb4 100644
--- a/src/SharpCompress/Compressors/Deflate/Zlib.cs
+++ b/src/SharpCompress/Compressors/Deflate/Zlib.cs
@@ -405,88 +405,4 @@ namespace SharpCompress.Compressors.Deflate
BitLengths = new StaticTree(null, extra_blbits, 0, InternalConstants.BL_CODES, InternalConstants.MAX_BL_BITS);
}
}
-
- ///
- /// Computes an Adler-32 checksum.
- ///
- ///
- /// The Adler checksum is similar to a CRC checksum, but faster to compute, though less
- /// reliable. It is used in producing RFC1950 compressed streams. The Adler checksum
- /// is a required part of the "ZLIB" standard. Applications will almost never need to
- /// use this class directly.
- ///
- internal sealed class Adler
- {
- // largest prime smaller than 65536
- private static readonly uint BASE = 65521U;
-
- // NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1
- private static readonly int NMAX = 5552;
-
- internal static uint Adler32(uint adler, byte[]? buf, int index, int len)
- {
- if (buf is null)
- {
- return 1;
- }
-
- uint s1 = adler & 0xffffU;
- uint s2 = (adler >> 16) & 0xffffU;
-
- while (len > 0)
- {
- int k = len < NMAX ? len : NMAX;
- len -= k;
- while (k >= 16)
- {
- //s1 += (buf[index++] & 0xff); s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- s1 += buf[index++];
- s2 += s1;
- k -= 16;
- }
- if (k != 0)
- {
- do
- {
- s1 += buf[index++];
- s2 += s1;
- }
- while (--k != 0);
- }
- s1 %= BASE;
- s2 %= BASE;
- }
- return (s2 << 16) | s1;
- }
- }
}
\ No newline at end of file
diff --git a/src/SharpCompress/Compressors/Deflate/ZlibCodec.cs b/src/SharpCompress/Compressors/Deflate/ZlibCodec.cs
index e7e2ecb9..8b995018 100644
--- a/src/SharpCompress/Compressors/Deflate/ZlibCodec.cs
+++ b/src/SharpCompress/Compressors/Deflate/ZlibCodec.cs
@@ -137,7 +137,7 @@ namespace SharpCompress.Compressors.Deflate
internal DeflateManager dstate;
internal InflateManager istate;
- internal uint _Adler32;
+ internal uint _adler32;
///
/// The compression level to use in this codec. Useful only in compression mode.
@@ -173,7 +173,7 @@ namespace SharpCompress.Compressors.Deflate
///
/// The Adler32 checksum on the data transferred through the codec so far. You probably don't need to look at this.
///
- public int Adler32 => (int)_Adler32;
+ public int Adler32 => (int)_adler32;
///
/// Create a ZlibCodec.
@@ -737,7 +737,7 @@ namespace SharpCompress.Compressors.Deflate
if (dstate.WantRfc1950HeaderBytes)
{
- _Adler32 = Adler.Adler32(_Adler32, InputBuffer, NextIn, len);
+ _adler32 = Algorithms.Adler32.Calculate(_adler32, InputBuffer.AsSpan(NextIn, len));
}
Array.Copy(InputBuffer, NextIn, buf, start, len);
NextIn += len;