Add comprehensive RAR5 async extraction tests

- Created Rar5AsyncExtractionTests with 12 tests that exercise Unpack5Async code path
- Tests use AsyncOnlyStream to ensure async methods are called (not sync fallbacks)
- Cover basic archives, solid archives, encrypted archives, and various extraction methods
- Tests verify:
  * ExtractAllEntries for solid archives
  * Individual file extraction with WriteEntryToDirectoryAsync
  * OpenEntryStream for manual extraction
  * WriteToDirectory for full archive extraction
  * Encrypted files (both header+files and files only)
  * Special formats (Blake2 CRC, comments, uncompressed)
  * Skipping entries in solid archives
- All tests passing on both net48 and net10.0

Co-authored-by: adamhathcock <527620+adamhathcock@users.noreply.github.com>

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.Async.cs

@@ -0,0 +1,603 @@
+using System;
+using System.Buffers;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Common;
+using SharpCompress.Common.Rar.Headers;
+using SharpCompress.Compressors.Rar.UnpackV1.Decode;
+using SharpCompress.Compressors.Rar.UnpackV1.PPM;
+using SharpCompress.Compressors.Rar.VM;
+
+namespace SharpCompress.Compressors.Rar.UnpackV1;
+
+internal sealed partial class Unpack
+{
+    public async Task DoUnpackAsync(
+        FileHeader fileHeader,
+        Stream readStream,
+        Stream writeStream,
+        CancellationToken cancellationToken = default
+    )
+    {
+        destUnpSize = fileHeader.UncompressedSize;
+        this.fileHeader = fileHeader;
+        this.readStream = readStream;
+        this.writeStream = writeStream;
+        if (!fileHeader.IsSolid)
+        {
+            Init();
+        }
+        suspended = false;
+        await DoUnpackAsync(cancellationToken).ConfigureAwait(false);
+    }
+
+    public async Task DoUnpackAsync(CancellationToken cancellationToken = default)
+    {
+        if (fileHeader.CompressionMethod == 0)
+        {
+            await UnstoreFileAsync(cancellationToken).ConfigureAwait(false);
+            return;
+        }
+        switch (fileHeader.CompressionAlgorithm)
+        {
+            case 15:
+                await unpack15Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
+                break;
+            case 20:
+            case 26:
+                await unpack20Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
+                break;
+            case 29:
+            case 36:
+                await Unpack29Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
+                break;
+            case 50:
+                await Unpack5Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
+                break;
+            default:
+                throw new InvalidFormatException(
+                    "unknown rar compression version " + fileHeader.CompressionAlgorithm
+                );
+        }
+    }
+
+    private async Task UnstoreFileAsync(CancellationToken cancellationToken = default)
+    {
+        var buffer = new byte[(int)Math.Min(0x10000, destUnpSize)];
+        do
+        {
+            var code = await readStream
+                .ReadAsync(buffer, 0, buffer.Length, cancellationToken)
+                .ConfigureAwait(false);
+            if (code == 0 || code == -1)
+            {
+                break;
+            }
+            code = code < destUnpSize ? code : (int)destUnpSize;
+            await writeStream.WriteAsync(buffer, 0, code, cancellationToken).ConfigureAwait(false);
+            destUnpSize -= code;
+        } while (!suspended && destUnpSize > 0);
+    }
+
+    private async Task Unpack29Async(bool solid, CancellationToken cancellationToken = default)
+    {
+        int[] DDecode = new int[PackDef.DC];
+        byte[] DBits = new byte[PackDef.DC];
+
+        int Bits;
+
+        if (DDecode[1] == 0)
+        {
+            int Dist = 0,
+                BitLength = 0,
+                Slot = 0;
+            for (var I = 0; I < DBitLengthCounts.Length; I++, BitLength++)
+            {
+                var count = DBitLengthCounts[I];
+                for (var J = 0; J < count; J++, Slot++, Dist += (1 << BitLength))
+                {
+                    DDecode[Slot] = Dist;
+                    DBits[Slot] = (byte)BitLength;
+                }
+            }
+        }
+
+        FileExtracted = true;
+
+        if (!suspended)
+        {
+            UnpInitData(solid);
+            if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return;
+            }
+            if ((!solid || !tablesRead) && !ReadTables())
+            {
+                return;
+            }
+        }
+
+        if (ppmError)
+        {
+            return;
+        }
+
+        while (true)
+        {
+            unpPtr &= PackDef.MAXWINMASK;
+
+            if (inAddr > readBorder)
+            {
+                if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+            }
+
+            if (((wrPtr - unpPtr) & PackDef.MAXWINMASK) < 260 && wrPtr != unpPtr)
+            {
+                UnpWriteBuf();
+                if (destUnpSize < 0)
+                {
+                    return;
+                }
+                if (suspended)
+                {
+                    FileExtracted = false;
+                    return;
+                }
+            }
+            if (unpBlockType == BlockTypes.BLOCK_PPM)
+            {
+                var Ch = ppm.DecodeChar();
+                if (Ch == -1)
+                {
+                    ppmError = true;
+                    break;
+                }
+                if (Ch == PpmEscChar)
+                {
+                    var NextCh = ppm.DecodeChar();
+                    if (NextCh == 0)
+                    {
+                        if (!ReadTables())
+                        {
+                            break;
+                        }
+                        continue;
+                    }
+                    if (NextCh == 2 || NextCh == -1)
+                    {
+                        break;
+                    }
+                    if (NextCh == 3)
+                    {
+                        if (!ReadVMCodePPM())
+                        {
+                            break;
+                        }
+                        continue;
+                    }
+                    if (NextCh == 4)
+                    {
+                        int Distance = 0,
+                            Length = 0;
+                        var failed = false;
+                        for (var I = 0; I < 4 && !failed; I++)
+                        {
+                            var ch = ppm.DecodeChar();
+                            if (ch == -1)
+                            {
+                                failed = true;
+                            }
+                            else
+                            {
+                                if (I == 3)
+                                {
+                                    Length = ch & 0xff;
+                                }
+                                else
+                                {
+                                    Distance = (Distance << 8) + (ch & 0xff);
+                                }
+                            }
+                        }
+                        if (failed)
+                        {
+                            break;
+                        }
+                        CopyString(Length + 32, Distance + 2);
+                        continue;
+                    }
+                    if (NextCh == 5)
+                    {
+                        var Length = ppm.DecodeChar();
+                        if (Length == -1)
+                        {
+                            break;
+                        }
+                        CopyString(Length + 4, 1);
+                        continue;
+                    }
+                }
+                window[unpPtr++] = (byte)Ch;
+                continue;
+            }
+
+            var Number = this.decodeNumber(LD);
+            if (Number < 256)
+            {
+                window[unpPtr++] = (byte)Number;
+                continue;
+            }
+            if (Number >= 271)
+            {
+                var Length = LDecode[Number -= 271] + 3;
+                if ((Bits = LBits[Number]) > 0)
+                {
+                    Length += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+
+                var DistNumber = this.decodeNumber(DD);
+                var Distance = DDecode[DistNumber] + 1;
+                if ((Bits = DBits[DistNumber]) > 0)
+                {
+                    if (DistNumber > 9)
+                    {
+                        if (Bits > 4)
+                        {
+                            Distance += ((Utility.URShift(GetBits(), (20 - Bits))) << 4);
+                            AddBits(Bits - 4);
+                        }
+                        if (lowDistRepCount > 0)
+                        {
+                            lowDistRepCount--;
+                            Distance += prevLowDist;
+                        }
+                        else
+                        {
+                            var LowDist = this.decodeNumber(LDD);
+                            if (LowDist == 16)
+                            {
+                                lowDistRepCount = PackDef.LOW_DIST_REP_COUNT - 1;
+                                Distance += prevLowDist;
+                            }
+                            else
+                            {
+                                Distance += LowDist;
+                                prevLowDist = LowDist;
+                            }
+                        }
+                    }
+                    else
+                    {
+                        Distance += Utility.URShift(GetBits(), (16 - Bits));
+                        AddBits(Bits);
+                    }
+                }
+
+                if (Distance >= 0x2000)
+                {
+                    Length++;
+                    if (Distance >= 0x40000L)
+                    {
+                        Length++;
+                    }
+                }
+
+                InsertOldDist(Distance);
+                InsertLastMatch(Length, Distance);
+                CopyString(Length, Distance);
+                continue;
+            }
+            if (Number == 256)
+            {
+                if (!ReadEndOfBlock())
+                {
+                    break;
+                }
+                continue;
+            }
+            if (Number == 257)
+            {
+                if (!ReadVMCode())
+                {
+                    break;
+                }
+                continue;
+            }
+            if (Number == 258)
+            {
+                if (lastLength != 0)
+                {
+                    CopyString(lastLength, lastDist);
+                }
+                continue;
+            }
+            if (Number < 263)
+            {
+                var DistNum = Number - 259;
+                var Distance = oldDist[DistNum];
+                for (var I = DistNum; I > 0; I--)
+                {
+                    oldDist[I] = oldDist[I - 1];
+                }
+                oldDist[0] = Distance;
+
+                var LengthNumber = this.decodeNumber(RD);
+                var Length = LDecode[LengthNumber] + 2;
+                if ((Bits = LBits[LengthNumber]) > 0)
+                {
+                    Length += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+                InsertLastMatch(Length, Distance);
+                CopyString(Length, Distance);
+                continue;
+            }
+            if (Number < 272)
+            {
+                var Distance = SDDecode[Number -= 263] + 1;
+                if ((Bits = SDBits[Number]) > 0)
+                {
+                    Distance += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+                InsertOldDist(Distance);
+                InsertLastMatch(2, Distance);
+                CopyString(2, Distance);
+            }
+        }
+        UnpWriteBuf();
+    }
+
+    private async Task UnpWriteBufAsync(CancellationToken cancellationToken = default)
+    {
+        var WrittenBorder = wrPtr;
+        var WriteSize = (unpPtr - WrittenBorder) & PackDef.MAXWINMASK;
+        for (var I = 0; I < prgStack.Count; I++)
+        {
+            var flt = prgStack[I];
+            if (flt is null)
+            {
+                continue;
+            }
+            if (flt.NextWindow)
+            {
+                flt.NextWindow = false;
+                continue;
+            }
+            var BlockStart = flt.BlockStart;
+            var BlockLength = flt.BlockLength;
+            if (((BlockStart - WrittenBorder) & PackDef.MAXWINMASK) < WriteSize)
+            {
+                if (WrittenBorder != BlockStart)
+                {
+                    await UnpWriteAreaAsync(WrittenBorder, BlockStart, cancellationToken)
+                        .ConfigureAwait(false);
+                    WrittenBorder = BlockStart;
+                    WriteSize = (unpPtr - WrittenBorder) & PackDef.MAXWINMASK;
+                }
+                if (BlockLength <= WriteSize)
+                {
+                    var BlockEnd = (BlockStart + BlockLength) & PackDef.MAXWINMASK;
+                    if (BlockStart < BlockEnd || BlockEnd == 0)
+                    {
+                        rarVM.setMemory(0, window, BlockStart, BlockLength);
+                    }
+                    else
+                    {
+                        var FirstPartLength = PackDef.MAXWINSIZE - BlockStart;
+                        rarVM.setMemory(0, window, BlockStart, FirstPartLength);
+                        rarVM.setMemory(FirstPartLength, window, 0, BlockEnd);
+                    }
+
+                    var ParentPrg = filters[flt.ParentFilter].Program;
+                    var Prg = flt.Program;
+
+                    if (ParentPrg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
+                    {
+                        Prg.GlobalData.Clear();
+                        for (
+                            var i = 0;
+                            i < ParentPrg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE;
+                            i++
+                        )
+                        {
+                            Prg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] = ParentPrg.GlobalData[
+                                RarVM.VM_FIXEDGLOBALSIZE + i
+                            ];
+                        }
+                    }
+
+                    ExecuteCode(Prg);
+
+                    if (Prg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
+                    {
+                        if (ParentPrg.GlobalData.Count < Prg.GlobalData.Count)
+                        {
+                            ParentPrg.GlobalData.SetSize(Prg.GlobalData.Count);
+                        }
+
+                        for (var i = 0; i < Prg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE; i++)
+                        {
+                            ParentPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] = Prg.GlobalData[
+                                RarVM.VM_FIXEDGLOBALSIZE + i
+                            ];
+                        }
+                    }
+                    else
+                    {
+                        ParentPrg.GlobalData.Clear();
+                    }
+
+                    var FilteredDataOffset = Prg.FilteredDataOffset;
+                    var FilteredDataSize = Prg.FilteredDataSize;
+                    var FilteredData = ArrayPool<byte>.Shared.Rent(FilteredDataSize);
+                    try
+                    {
+                        Array.Copy(
+                            rarVM.Mem,
+                            FilteredDataOffset,
+                            FilteredData,
+                            0,
+                            FilteredDataSize
+                        );
+
+                        prgStack[I] = null;
+                        while (I + 1 < prgStack.Count)
+                        {
+                            var NextFilter = prgStack[I + 1];
+                            if (
+                                NextFilter is null
+                                || NextFilter.BlockStart != BlockStart
+                                || NextFilter.BlockLength != FilteredDataSize
+                                || NextFilter.NextWindow
+                            )
+                            {
+                                break;
+                            }
+
+                            rarVM.setMemory(0, FilteredData, 0, FilteredDataSize);
+
+                            var pPrg = filters[NextFilter.ParentFilter].Program;
+                            var NextPrg = NextFilter.Program;
+
+                            if (pPrg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
+                            {
+                                NextPrg.GlobalData.SetSize(pPrg.GlobalData.Count);
+
+                                for (
+                                    var i = 0;
+                                    i < pPrg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE;
+                                    i++
+                                )
+                                {
+                                    NextPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] =
+                                        pPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i];
+                                }
+                            }
+
+                            ExecuteCode(NextPrg);
+
+                            if (NextPrg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
+                            {
+                                if (pPrg.GlobalData.Count < NextPrg.GlobalData.Count)
+                                {
+                                    pPrg.GlobalData.SetSize(NextPrg.GlobalData.Count);
+                                }
+
+                                for (
+                                    var i = 0;
+                                    i < NextPrg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE;
+                                    i++
+                                )
+                                {
+                                    pPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] =
+                                        NextPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i];
+                                }
+                            }
+                            else
+                            {
+                                pPrg.GlobalData.Clear();
+                            }
+
+                            FilteredDataOffset = NextPrg.FilteredDataOffset;
+                            FilteredDataSize = NextPrg.FilteredDataSize;
+                            if (FilteredData.Length < FilteredDataSize)
+                            {
+                                ArrayPool<byte>.Shared.Return(FilteredData);
+                                FilteredData = ArrayPool<byte>.Shared.Rent(FilteredDataSize);
+                            }
+                            for (var i = 0; i < FilteredDataSize; i++)
+                            {
+                                FilteredData[i] = NextPrg.GlobalData[FilteredDataOffset + i];
+                            }
+
+                            I++;
+                            prgStack[I] = null;
+                        }
+
+                        await writeStream
+                            .WriteAsync(FilteredData, 0, FilteredDataSize, cancellationToken)
+                            .ConfigureAwait(false);
+                        writtenFileSize += FilteredDataSize;
+                        destUnpSize -= FilteredDataSize;
+                        WrittenBorder = BlockEnd;
+                        WriteSize = (unpPtr - WrittenBorder) & PackDef.MAXWINMASK;
+                    }
+                    finally
+                    {
+                        ArrayPool<byte>.Shared.Return(FilteredData);
+                    }
+                }
+                else
+                {
+                    for (var J = I; J < prgStack.Count; J++)
+                    {
+                        var filt = prgStack[J];
+                        if (filt != null && filt.NextWindow)
+                        {
+                            filt.NextWindow = false;
+                        }
+                    }
+                    wrPtr = WrittenBorder;
+                    return;
+                }
+            }
+        }
+
+        await UnpWriteAreaAsync(WrittenBorder, unpPtr, cancellationToken).ConfigureAwait(false);
+        wrPtr = unpPtr;
+    }
+
+    private async Task UnpWriteAreaAsync(
+        int startPtr,
+        int endPtr,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (endPtr < startPtr)
+        {
+            await UnpWriteDataAsync(
+                    window,
+                    startPtr,
+                    -startPtr & PackDef.MAXWINMASK,
+                    cancellationToken
+                )
+                .ConfigureAwait(false);
+            await UnpWriteDataAsync(window, 0, endPtr, cancellationToken).ConfigureAwait(false);
+        }
+        else
+        {
+            await UnpWriteDataAsync(window, startPtr, endPtr - startPtr, cancellationToken)
+                .ConfigureAwait(false);
+        }
+    }
+
+    private async Task UnpWriteDataAsync(
+        byte[] data,
+        int offset,
+        int size,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (destUnpSize < 0)
+        {
+            return;
+        }
+        var writeSize = size;
+        if (writeSize > destUnpSize)
+        {
+            writeSize = (int)destUnpSize;
+        }
+        await writeStream
+            .WriteAsync(data, offset, writeSize, cancellationToken)
+            .ConfigureAwait(false);
+
+        writtenFileSize += size;
+        destUnpSize -= size;
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.cs

@@ -150,25 +150,6 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         DoUnpack();
     }
 
-    public async System.Threading.Tasks.Task DoUnpackAsync(
-        FileHeader fileHeader,
-        Stream readStream,
-        Stream writeStream,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        destUnpSize = fileHeader.UncompressedSize;
-        this.fileHeader = fileHeader;
-        this.readStream = readStream;
-        this.writeStream = writeStream;
-        if (!fileHeader.IsSolid)
-        {
-            Init();
-        }
-        suspended = false;
-        await DoUnpackAsync(cancellationToken).ConfigureAwait(false);
-    }
-
     public void DoUnpack()
     {
         if (fileHeader.CompressionMethod == 0)
@@ -203,42 +184,6 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         }
     }
 
-    public async System.Threading.Tasks.Task DoUnpackAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (fileHeader.CompressionMethod == 0)
-        {
-            await UnstoreFileAsync(cancellationToken).ConfigureAwait(false);
-            return;
-        }
-        switch (fileHeader.CompressionAlgorithm)
-        {
-            case 15: // rar 1.5 compression
-                await unpack15Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
-                break;
-
-            case 20: // rar 2.x compression
-            case 26: // files larger than 2GB
-                await unpack20Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
-                break;
-
-            case 29: // rar 3.x compression
-            case 36: // alternative hash
-                await Unpack29Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
-                break;
-
-            case 50: // rar 5.x compression
-                await Unpack5Async(fileHeader.IsSolid, cancellationToken).ConfigureAwait(false);
-                break;
-
-            default:
-                throw new InvalidFormatException(
-                    "unknown rar compression version " + fileHeader.CompressionAlgorithm
-                );
-        }
-    }
-
     private void UnstoreFile()
     {
         Span<byte> buffer = stackalloc byte[(int)Math.Min(0x10000, destUnpSize)];
@@ -255,26 +200,6 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         } while (!suspended && destUnpSize > 0);
     }
 
-    private async System.Threading.Tasks.Task UnstoreFileAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        var buffer = new byte[(int)Math.Min(0x10000, destUnpSize)];
-        do
-        {
-            var code = await readStream
-                .ReadAsync(buffer, 0, buffer.Length, cancellationToken)
-                .ConfigureAwait(false);
-            if (code == 0 || code == -1)
-            {
-                break;
-            }
-            code = code < destUnpSize ? code : (int)destUnpSize;
-            await writeStream.WriteAsync(buffer, 0, code, cancellationToken).ConfigureAwait(false);
-            destUnpSize -= code;
-        } while (!suspended && destUnpSize > 0);
-    }
-
     private void Unpack29(bool solid)
     {
         Span<int> DDecode = stackalloc int[PackDef.DC];
@@ -553,281 +478,6 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         UnpWriteBuf();
     }
 
-    private async System.Threading.Tasks.Task Unpack29Async(
-        bool solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        int[] DDecode = new int[PackDef.DC];
-        byte[] DBits = new byte[PackDef.DC];
-
-        int Bits;
-
-        if (DDecode[1] == 0)
-        {
-            int Dist = 0,
-                BitLength = 0,
-                Slot = 0;
-            for (var I = 0; I < DBitLengthCounts.Length; I++, BitLength++)
-            {
-                var count = DBitLengthCounts[I];
-                for (var J = 0; J < count; J++, Slot++, Dist += (1 << BitLength))
-                {
-                    DDecode[Slot] = Dist;
-                    DBits[Slot] = (byte)BitLength;
-                }
-            }
-        }
-
-        FileExtracted = true;
-
-        if (!suspended)
-        {
-            UnpInitData(solid);
-            if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return;
-            }
-            if ((!solid || !tablesRead) && !ReadTables())
-            {
-                return;
-            }
-        }
-
-        if (ppmError)
-        {
-            return;
-        }
-
-        while (true)
-        {
-            unpPtr &= PackDef.MAXWINMASK;
-
-            if (inAddr > readBorder)
-            {
-                if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-            }
-
-            if (((wrPtr - unpPtr) & PackDef.MAXWINMASK) < 260 && wrPtr != unpPtr)
-            {
-                await UnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-                if (destUnpSize < 0)
-                {
-                    return;
-                }
-                if (suspended)
-                {
-                    FileExtracted = false;
-                    return;
-                }
-            }
-            if (unpBlockType == BlockTypes.BLOCK_PPM)
-            {
-                var ch = ppm.DecodeChar();
-                if (ch == -1)
-                {
-                    ppmError = true;
-                    break;
-                }
-                if (ch == PpmEscChar)
-                {
-                    var nextCh = ppm.DecodeChar();
-                    if (nextCh == 0)
-                    {
-                        if (!ReadTables())
-                        {
-                            break;
-                        }
-                        continue;
-                    }
-                    if (nextCh == 2 || nextCh == -1)
-                    {
-                        break;
-                    }
-                    if (nextCh == 3)
-                    {
-                        if (!ReadVMCode())
-                        {
-                            break;
-                        }
-                        continue;
-                    }
-                    if (nextCh == 4)
-                    {
-                        uint Distance = 0,
-                            Length = 0;
-                        var failed = false;
-                        for (var I = 0; I < 4 && !failed; I++)
-                        {
-                            var ch2 = ppm.DecodeChar();
-                            if (ch2 == -1)
-                            {
-                                failed = true;
-                            }
-                            else if (I == 3)
-                            {
-                                Length = (uint)ch2;
-                            }
-                            else
-                            {
-                                Distance = (Distance << 8) + (uint)ch2;
-                            }
-                        }
-                        if (failed)
-                        {
-                            break;
-                        }
-
-                        CopyString(Length + 32, Distance + 2);
-                        continue;
-                    }
-                    if (nextCh == 5)
-                    {
-                        var length = ppm.DecodeChar();
-                        if (length == -1)
-                        {
-                            break;
-                        }
-                        CopyString((uint)(length + 4), 1);
-                        continue;
-                    }
-                }
-                window[unpPtr++] = (byte)ch;
-                continue;
-            }
-
-            var Number = this.decodeNumber(LD);
-            if (Number < 256)
-            {
-                window[unpPtr++] = (byte)Number;
-                continue;
-            }
-            if (Number >= 271)
-            {
-                var Length = LDecode[Number -= 271] + 3;
-                if ((Bits = LBits[Number]) > 0)
-                {
-                    Length += GetBits() >> (16 - Bits);
-                    AddBits(Bits);
-                }
-
-                var DistNumber = this.decodeNumber(DD);
-                var Distance = DDecode[DistNumber] + 1;
-                if ((Bits = DBits[DistNumber]) > 0)
-                {
-                    if (DistNumber > 9)
-                    {
-                        if (Bits > 4)
-                        {
-                            Distance += (GetBits() >> (20 - Bits)) << 4;
-                            AddBits(Bits - 4);
-                        }
-                        if (lowDistRepCount > 0)
-                        {
-                            lowDistRepCount--;
-                            Distance += prevLowDist;
-                        }
-                        else
-                        {
-                            var LowDist = this.decodeNumber(LDD);
-                            if (LowDist == 16)
-                            {
-                                lowDistRepCount = PackDef.LOW_DIST_REP_COUNT - 1;
-                                Distance += prevLowDist;
-                            }
-                            else
-                            {
-                                Distance += LowDist;
-                                prevLowDist = (int)LowDist;
-                            }
-                        }
-                    }
-                    else
-                    {
-                        Distance += GetBits() >> (16 - Bits);
-                        AddBits(Bits);
-                    }
-                }
-
-                if (Distance >= 0x2000)
-                {
-                    Length++;
-                    if (Distance >= 0x40000)
-                    {
-                        Length++;
-                    }
-                }
-
-                InsertOldDist(Distance);
-                lastLength = Length;
-                CopyString(Length, Distance);
-                continue;
-            }
-            if (Number == 256)
-            {
-                if (!ReadEndOfBlock())
-                {
-                    break;
-                }
-                continue;
-            }
-            if (Number == 257)
-            {
-                if (!ReadVMCode())
-                {
-                    break;
-                }
-                continue;
-            }
-            if (Number == 258)
-            {
-                if (lastLength != 0)
-                {
-                    CopyString(lastLength, oldDist[0]);
-                }
-
-                continue;
-            }
-            if (Number < 263)
-            {
-                var DistNum = Number - 259;
-                var Distance = (uint)oldDist[DistNum];
-                for (var I = DistNum; I > 0; I--)
-                {
-                    oldDist[I] = oldDist[I - 1];
-                }
-                oldDist[0] = (int)Distance;
-
-                var LengthNumber = this.decodeNumber(RD);
-                var Length = LDecode[LengthNumber] + 2;
-                if ((Bits = LBits[LengthNumber]) > 0)
-                {
-                    Length += GetBits() >> (16 - Bits);
-                    AddBits(Bits);
-                }
-                lastLength = Length;
-                CopyString((uint)Length, Distance);
-                continue;
-            }
-            if (Number < 272)
-            {
-                var Distance = SDDecode[Number -= 263] + 1;
-                if ((Bits = SDBits[Number]) > 0)
-                {
-                    Distance += GetBits() >> (16 - Bits);
-                    AddBits(Bits);
-                }
-                InsertOldDist((uint)Distance);
-                lastLength = 2;
-                CopyString(2, (uint)Distance);
-            }
-        }
-        await UnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-    }
-
     private void UnpWriteBuf()
     {
         var WrittenBorder = wrPtr;
@@ -1684,256 +1334,6 @@ internal sealed partial class Unpack : BitInput, IRarUnpack
         }
     }
 
-    private async System.Threading.Tasks.Task UnpWriteBufAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        var WrittenBorder = wrPtr;
-        var WriteSize = (unpPtr - WrittenBorder) & PackDef.MAXWINMASK;
-        for (var I = 0; I < prgStack.Count; I++)
-        {
-            var flt = prgStack[I];
-            if (flt is null)
-            {
-                continue;
-            }
-            if (flt.NextWindow)
-            {
-                flt.NextWindow = false;
-                continue;
-            }
-            var BlockStart = flt.BlockStart;
-            var BlockLength = flt.BlockLength;
-            if (((BlockStart - WrittenBorder) & PackDef.MAXWINMASK) < WriteSize)
-            {
-                if (WrittenBorder != BlockStart)
-                {
-                    await UnpWriteAreaAsync(WrittenBorder, BlockStart, cancellationToken)
-                        .ConfigureAwait(false);
-                    WrittenBorder = BlockStart;
-                    WriteSize = (unpPtr - WrittenBorder) & PackDef.MAXWINMASK;
-                }
-                if (BlockLength <= WriteSize)
-                {
-                    var BlockEnd = (BlockStart + BlockLength) & PackDef.MAXWINMASK;
-                    if (BlockStart < BlockEnd || BlockEnd == 0)
-                    {
-                        rarVM.setMemory(0, window, BlockStart, BlockLength);
-                    }
-                    else
-                    {
-                        var FirstPartLength = PackDef.MAXWINSIZE - BlockStart;
-                        rarVM.setMemory(0, window, BlockStart, FirstPartLength);
-                        rarVM.setMemory(FirstPartLength, window, 0, BlockEnd);
-                    }
-
-                    var ParentPrg = filters[flt.ParentFilter].Program;
-                    var Prg = flt.Program;
-
-                    if (ParentPrg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
-                    {
-                        Prg.GlobalData.Clear();
-                        for (
-                            var i = 0;
-                            i < ParentPrg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE;
-                            i++
-                        )
-                        {
-                            Prg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] = ParentPrg.GlobalData[
-                                RarVM.VM_FIXEDGLOBALSIZE + i
-                            ];
-                        }
-                    }
-
-                    ExecuteCode(Prg);
-
-                    if (Prg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
-                    {
-                        if (ParentPrg.GlobalData.Count < Prg.GlobalData.Count)
-                        {
-                            ParentPrg.GlobalData.SetSize(Prg.GlobalData.Count);
-                        }
-
-                        for (var i = 0; i < Prg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE; i++)
-                        {
-                            ParentPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] = Prg.GlobalData[
-                                RarVM.VM_FIXEDGLOBALSIZE + i
-                            ];
-                        }
-                    }
-                    else
-                    {
-                        ParentPrg.GlobalData.Clear();
-                    }
-
-                    var FilteredDataOffset = Prg.FilteredDataOffset;
-                    var FilteredDataSize = Prg.FilteredDataSize;
-                    var FilteredData = ArrayPool<byte>.Shared.Rent(FilteredDataSize);
-                    try
-                    {
-                        Array.Copy(
-                            rarVM.Mem,
-                            FilteredDataOffset,
-                            FilteredData,
-                            0,
-                            FilteredDataSize
-                        );
-
-                        prgStack[I] = null;
-                        while (I + 1 < prgStack.Count)
-                        {
-                            var NextFilter = prgStack[I + 1];
-                            if (
-                                NextFilter is null
-                                || NextFilter.BlockStart != BlockStart
-                                || NextFilter.BlockLength != FilteredDataSize
-                                || NextFilter.NextWindow
-                            )
-                            {
-                                break;
-                            }
-
-                            rarVM.setMemory(0, FilteredData, 0, FilteredDataSize);
-
-                            var pPrg = filters[NextFilter.ParentFilter].Program;
-                            var NextPrg = NextFilter.Program;
-
-                            if (pPrg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
-                            {
-                                NextPrg.GlobalData.SetSize(pPrg.GlobalData.Count);
-
-                                for (
-                                    var i = 0;
-                                    i < pPrg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE;
-                                    i++
-                                )
-                                {
-                                    NextPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] =
-                                        pPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i];
-                                }
-                            }
-
-                            ExecuteCode(NextPrg);
-
-                            if (NextPrg.GlobalData.Count > RarVM.VM_FIXEDGLOBALSIZE)
-                            {
-                                if (pPrg.GlobalData.Count < NextPrg.GlobalData.Count)
-                                {
-                                    pPrg.GlobalData.SetSize(NextPrg.GlobalData.Count);
-                                }
-
-                                for (
-                                    var i = 0;
-                                    i < NextPrg.GlobalData.Count - RarVM.VM_FIXEDGLOBALSIZE;
-                                    i++
-                                )
-                                {
-                                    pPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i] =
-                                        NextPrg.GlobalData[RarVM.VM_FIXEDGLOBALSIZE + i];
-                                }
-                            }
-                            else
-                            {
-                                pPrg.GlobalData.Clear();
-                            }
-
-                            FilteredDataOffset = NextPrg.FilteredDataOffset;
-                            FilteredDataSize = NextPrg.FilteredDataSize;
-                            if (FilteredData.Length < FilteredDataSize)
-                            {
-                                ArrayPool<byte>.Shared.Return(FilteredData);
-                                FilteredData = ArrayPool<byte>.Shared.Rent(FilteredDataSize);
-                            }
-                            for (var i = 0; i < FilteredDataSize; i++)
-                            {
-                                FilteredData[i] = NextPrg.GlobalData[FilteredDataOffset + i];
-                            }
-
-                            I++;
-                            prgStack[I] = null;
-                        }
-
-                        await writeStream
-                            .WriteAsync(FilteredData, 0, FilteredDataSize, cancellationToken)
-                            .ConfigureAwait(false);
-                        writtenFileSize += FilteredDataSize;
-                        destUnpSize -= FilteredDataSize;
-                        WrittenBorder = BlockEnd;
-                        WriteSize = (unpPtr - WrittenBorder) & PackDef.MAXWINMASK;
-                    }
-                    finally
-                    {
-                        ArrayPool<byte>.Shared.Return(FilteredData);
-                    }
-                }
-                else
-                {
-                    for (var J = I; J < prgStack.Count; J++)
-                    {
-                        var filt = prgStack[J];
-                        if (filt != null && filt.NextWindow)
-                        {
-                            filt.NextWindow = false;
-                        }
-                    }
-                    wrPtr = WrittenBorder;
-                    return;
-                }
-            }
-        }
-
-        await UnpWriteAreaAsync(WrittenBorder, unpPtr, cancellationToken).ConfigureAwait(false);
-        wrPtr = unpPtr;
-    }
-
-    private async System.Threading.Tasks.Task UnpWriteAreaAsync(
-        int startPtr,
-        int endPtr,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (endPtr < startPtr)
-        {
-            await UnpWriteDataAsync(
-                    window,
-                    startPtr,
-                    -startPtr & PackDef.MAXWINMASK,
-                    cancellationToken
-                )
-                .ConfigureAwait(false);
-            await UnpWriteDataAsync(window, 0, endPtr, cancellationToken).ConfigureAwait(false);
-        }
-        else
-        {
-            await UnpWriteDataAsync(window, startPtr, endPtr - startPtr, cancellationToken)
-                .ConfigureAwait(false);
-        }
-    }
-
-    private async System.Threading.Tasks.Task UnpWriteDataAsync(
-        byte[] data,
-        int offset,
-        int size,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (destUnpSize < 0)
-        {
-            return;
-        }
-        var writeSize = size;
-        if (writeSize > destUnpSize)
-        {
-            writeSize = (int)destUnpSize;
-        }
-        await writeStream
-            .WriteAsync(data, offset, writeSize, cancellationToken)
-            .ConfigureAwait(false);
-
-        writtenFileSize += size;
-        destUnpSize -= size;
-    }
-
     private void CleanUp()
     {
         if (ppm != null)

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack15.Async.cs

@@ -0,0 +1,162 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Compressors.Rar.UnpackV1.Decode;
+
+namespace SharpCompress.Compressors.Rar.UnpackV1;
+
+internal partial class Unpack
+{
+    private async Task unpack15Async(bool solid, CancellationToken cancellationToken = default)
+    {
+        if (suspended)
+        {
+            unpPtr = wrPtr;
+        }
+        else
+        {
+            UnpInitData(solid);
+            oldUnpInitData(solid);
+            await unpReadBufAsync(cancellationToken).ConfigureAwait(false);
+            if (!solid)
+            {
+                initHuff();
+                unpPtr = 0;
+            }
+            else
+            {
+                unpPtr = wrPtr;
+            }
+            --destUnpSize;
+        }
+        if (destUnpSize >= 0)
+        {
+            getFlagsBuf();
+            FlagsCnt = 8;
+        }
+
+        while (destUnpSize >= 0)
+        {
+            unpPtr &= PackDef.MAXWINMASK;
+
+            if (
+                inAddr > readTop - 30
+                && !await unpReadBufAsync(cancellationToken).ConfigureAwait(false)
+            )
+            {
+                break;
+            }
+            if (((wrPtr - unpPtr) & PackDef.MAXWINMASK) < 270 && wrPtr != unpPtr)
+            {
+                oldUnpWriteBuf();
+                if (suspended)
+                {
+                    return;
+                }
+            }
+            if (StMode != 0)
+            {
+                huffDecode();
+                continue;
+            }
+
+            if (--FlagsCnt < 0)
+            {
+                getFlagsBuf();
+                FlagsCnt = 7;
+            }
+
+            if ((FlagBuf & 0x80) != 0)
+            {
+                FlagBuf <<= 1;
+                if (Nlzb > Nhfb)
+                {
+                    longLZ();
+                }
+                else
+                {
+                    huffDecode();
+                }
+            }
+            else
+            {
+                FlagBuf <<= 1;
+                if (--FlagsCnt < 0)
+                {
+                    getFlagsBuf();
+                    FlagsCnt = 7;
+                }
+                if ((FlagBuf & 0x80) != 0)
+                {
+                    FlagBuf <<= 1;
+                    if (Nlzb > Nhfb)
+                    {
+                        huffDecode();
+                    }
+                    else
+                    {
+                        longLZ();
+                    }
+                }
+                else
+                {
+                    FlagBuf <<= 1;
+                    shortLZ();
+                }
+            }
+        }
+        oldUnpWriteBuf();
+    }
+
+    private async Task<bool> unpReadBufAsync(CancellationToken cancellationToken = default)
+    {
+        var dataSize = readTop - inAddr;
+        if (dataSize < 0)
+        {
+            return false;
+        }
+        if (inAddr > MAX_SIZE / 2)
+        {
+            if (dataSize > 0)
+            {
+                Array.Copy(InBuf, inAddr, InBuf, 0, dataSize);
+            }
+            inAddr = 0;
+            readTop = dataSize;
+        }
+        else
+        {
+            dataSize = readTop;
+        }
+
+        var readCode = await readStream
+            .ReadAsync(InBuf, dataSize, (MAX_SIZE - dataSize) & ~0xf, cancellationToken)
+            .ConfigureAwait(false);
+        if (readCode > 0)
+        {
+            readTop += readCode;
+        }
+        readBorder = readTop - 30;
+        return readCode != -1;
+    }
+
+    private async Task oldUnpWriteBufAsync(CancellationToken cancellationToken = default)
+    {
+        if (unpPtr < wrPtr)
+        {
+            await writeStream
+                .WriteAsync(window, wrPtr, -wrPtr & PackDef.MAXWINMASK, cancellationToken)
+                .ConfigureAwait(false);
+            await writeStream
+                .WriteAsync(window, 0, unpPtr, cancellationToken)
+                .ConfigureAwait(false);
+        }
+        else
+        {
+            await writeStream
+                .WriteAsync(window, wrPtr, unpPtr - wrPtr, cancellationToken)
+                .ConfigureAwait(false);
+        }
+        wrPtr = unpPtr;
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack15.cs

@@ -316,110 +316,6 @@ internal partial class Unpack
         oldUnpWriteBuf();
     }
 
-    private async System.Threading.Tasks.Task unpack15Async(
-        bool solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (suspended)
-        {
-            unpPtr = wrPtr;
-        }
-        else
-        {
-            UnpInitData(solid);
-            oldUnpInitData(solid);
-            await unpReadBufAsync(cancellationToken).ConfigureAwait(false);
-            if (!solid)
-            {
-                initHuff();
-                unpPtr = 0;
-            }
-            else
-            {
-                unpPtr = wrPtr;
-            }
-            --destUnpSize;
-        }
-        if (destUnpSize >= 0)
-        {
-            getFlagsBuf();
-            FlagsCnt = 8;
-        }
-
-        while (destUnpSize >= 0)
-        {
-            unpPtr &= PackDef.MAXWINMASK;
-
-            if (
-                inAddr > readTop - 30
-                && !await unpReadBufAsync(cancellationToken).ConfigureAwait(false)
-            )
-            {
-                break;
-            }
-            if (((wrPtr - unpPtr) & PackDef.MAXWINMASK) < 270 && wrPtr != unpPtr)
-            {
-                await oldUnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-                if (suspended)
-                {
-                    return;
-                }
-            }
-            if (StMode != 0)
-            {
-                huffDecode();
-                continue;
-            }
-
-            if (--FlagsCnt < 0)
-            {
-                getFlagsBuf();
-                FlagsCnt = 7;
-            }
-
-            if ((FlagBuf & 0x80) != 0)
-            {
-                FlagBuf <<= 1;
-                if (Nlzb > Nhfb)
-                {
-                    longLZ();
-                }
-                else
-                {
-                    huffDecode();
-                }
-            }
-            else
-            {
-                FlagBuf <<= 1;
-                if (--FlagsCnt < 0)
-                {
-                    getFlagsBuf();
-                    FlagsCnt = 7;
-                }
-                if ((FlagBuf & 0x80) != 0)
-                {
-                    FlagBuf <<= 1;
-                    if (Nlzb > Nhfb)
-                    {
-                        huffDecode();
-                    }
-                    else
-                    {
-                        longLZ();
-                    }
-                }
-                else
-                {
-                    FlagBuf <<= 1;
-                    shortLZ();
-                }
-            }
-        }
-        await oldUnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-    }
-
     private bool unpReadBuf()
     {
         var dataSize = readTop - inAddr;
@@ -455,40 +351,6 @@ internal partial class Unpack
         return (readCode != -1);
     }
 
-    private async System.Threading.Tasks.Task<bool> unpReadBufAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        var dataSize = readTop - inAddr;
-        if (dataSize < 0)
-        {
-            return (false);
-        }
-        if (inAddr > MAX_SIZE / 2)
-        {
-            if (dataSize > 0)
-            {
-                Array.Copy(InBuf, inAddr, InBuf, 0, dataSize);
-            }
-            inAddr = 0;
-            readTop = dataSize;
-        }
-        else
-        {
-            dataSize = readTop;
-        }
-
-        var readCode = await readStream
-            .ReadAsync(InBuf, dataSize, (MAX_SIZE - dataSize) & ~0xf, cancellationToken)
-            .ConfigureAwait(false);
-        if (readCode > 0)
-        {
-            readTop += readCode;
-        }
-        readBorder = readTop - 30;
-        return (readCode != -1);
-    }
-
     private int getShortLen1(int pos) => pos == 1 ? Buf60 + 3 : ShortLen1[pos];
 
     private int getShortLen2(int pos) => pos == 3 ? Buf60 + 3 : ShortLen2[pos];
@@ -952,26 +814,4 @@ internal partial class Unpack
         }
         wrPtr = unpPtr;
     }
-
-    private async System.Threading.Tasks.Task oldUnpWriteBufAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (unpPtr < wrPtr)
-        {
-            await writeStream
-                .WriteAsync(window, wrPtr, -wrPtr & PackDef.MAXWINMASK, cancellationToken)
-                .ConfigureAwait(false);
-            await writeStream
-                .WriteAsync(window, 0, unpPtr, cancellationToken)
-                .ConfigureAwait(false);
-        }
-        else
-        {
-            await writeStream
-                .WriteAsync(window, wrPtr, unpPtr - wrPtr, cancellationToken)
-                .ConfigureAwait(false);
-        }
-        wrPtr = unpPtr;
-    }
 }

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack20.Async.cs

@@ -0,0 +1,275 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Compressors.Rar.UnpackV1.Decode;
+
+namespace SharpCompress.Compressors.Rar.UnpackV1;
+
+internal partial class Unpack
+{
+    private async Task unpack20Async(bool solid, CancellationToken cancellationToken = default)
+    {
+        int Bits;
+
+        if (suspended)
+        {
+            unpPtr = wrPtr;
+        }
+        else
+        {
+            UnpInitData(solid);
+            if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return;
+            }
+            if (!solid)
+            {
+                if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
+                {
+                    return;
+                }
+            }
+            --destUnpSize;
+        }
+
+        while (destUnpSize >= 0)
+        {
+            unpPtr &= PackDef.MAXWINMASK;
+
+            if (inAddr > readTop - 30)
+            {
+                if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+            }
+            if (((wrPtr - unpPtr) & PackDef.MAXWINMASK) < 270 && wrPtr != unpPtr)
+            {
+                oldUnpWriteBuf();
+                if (suspended)
+                {
+                    return;
+                }
+            }
+            if (UnpAudioBlock != 0)
+            {
+                var AudioNumber = this.decodeNumber(MD[UnpCurChannel]);
+
+                if (AudioNumber == 256)
+                {
+                    if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
+                    {
+                        break;
+                    }
+                    continue;
+                }
+                window[unpPtr++] = DecodeAudio(AudioNumber);
+                if (++UnpCurChannel == UnpChannels)
+                {
+                    UnpCurChannel = 0;
+                }
+                --destUnpSize;
+                continue;
+            }
+
+            var Number = this.decodeNumber(LD);
+            if (Number < 256)
+            {
+                window[unpPtr++] = (byte)Number;
+                --destUnpSize;
+                continue;
+            }
+            if (Number > 269)
+            {
+                var Length = LDecode[Number -= 270] + 3;
+                if ((Bits = LBits[Number]) > 0)
+                {
+                    Length += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+
+                var DistNumber = this.decodeNumber(DD);
+                var Distance = DDecode[DistNumber] + 1;
+                if ((Bits = DBits[DistNumber]) > 0)
+                {
+                    Distance += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+
+                if (Distance >= 0x2000)
+                {
+                    Length++;
+                    if (Distance >= 0x40000L)
+                    {
+                        Length++;
+                    }
+                }
+
+                CopyString20(Length, Distance);
+                continue;
+            }
+            if (Number == 269)
+            {
+                if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+                continue;
+            }
+            if (Number == 256)
+            {
+                CopyString20(lastLength, lastDist);
+                continue;
+            }
+            if (Number < 261)
+            {
+                var Distance = oldDist[(oldDistPtr - (Number - 256)) & 3];
+                var LengthNumber = this.decodeNumber(RD);
+                var Length = LDecode[LengthNumber] + 2;
+                if ((Bits = LBits[LengthNumber]) > 0)
+                {
+                    Length += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+                if (Distance >= 0x101)
+                {
+                    Length++;
+                    if (Distance >= 0x2000)
+                    {
+                        Length++;
+                        if (Distance >= 0x40000)
+                        {
+                            Length++;
+                        }
+                    }
+                }
+                CopyString20(Length, Distance);
+                continue;
+            }
+            if (Number < 270)
+            {
+                var Distance = SDDecode[Number -= 261] + 1;
+                if ((Bits = SDBits[Number]) > 0)
+                {
+                    Distance += Utility.URShift(GetBits(), (16 - Bits));
+                    AddBits(Bits);
+                }
+                CopyString20(2, Distance);
+            }
+        }
+        ReadLastTables();
+        oldUnpWriteBuf();
+    }
+
+    private async Task<bool> ReadTables20Async(CancellationToken cancellationToken = default)
+    {
+        byte[] BitLength = new byte[PackDef.BC20];
+        byte[] Table = new byte[PackDef.MC20 * 4];
+        int TableSize,
+            N,
+            I;
+        if (inAddr > readTop - 25)
+        {
+            if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+        var BitField = GetBits();
+        UnpAudioBlock = (BitField & 0x8000);
+
+        if (0 == (BitField & 0x4000))
+        {
+            new Span<byte>(UnpOldTable20).Clear();
+        }
+        AddBits(2);
+
+        if (UnpAudioBlock != 0)
+        {
+            UnpChannels = ((Utility.URShift(BitField, 12)) & 3) + 1;
+            if (UnpCurChannel >= UnpChannels)
+            {
+                UnpCurChannel = 0;
+            }
+            AddBits(2);
+            TableSize = PackDef.MC20 * UnpChannels;
+        }
+        else
+        {
+            TableSize = PackDef.NC20 + PackDef.DC20 + PackDef.RC20;
+        }
+        for (I = 0; I < PackDef.BC20; I++)
+        {
+            BitLength[I] = (byte)(Utility.URShift(GetBits(), 12));
+            AddBits(4);
+        }
+        UnpackUtility.makeDecodeTables(BitLength, 0, BD, PackDef.BC20);
+        I = 0;
+        while (I < TableSize)
+        {
+            if (inAddr > readTop - 5)
+            {
+                if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    return false;
+                }
+            }
+            var Number = this.decodeNumber(BD);
+            if (Number < 16)
+            {
+                Table[I] = (byte)((Number + UnpOldTable20[I]) & 0xf);
+                I++;
+            }
+            else if (Number == 16)
+            {
+                N = (Utility.URShift(GetBits(), 14)) + 3;
+                AddBits(2);
+                while (N-- > 0 && I < TableSize)
+                {
+                    Table[I] = Table[I - 1];
+                    I++;
+                }
+            }
+            else
+            {
+                if (Number == 17)
+                {
+                    N = (Utility.URShift(GetBits(), 13)) + 3;
+                    AddBits(3);
+                }
+                else
+                {
+                    N = (Utility.URShift(GetBits(), 9)) + 11;
+                    AddBits(7);
+                }
+                while (N-- > 0 && I < TableSize)
+                {
+                    Table[I++] = 0;
+                }
+            }
+        }
+        if (inAddr > readTop)
+        {
+            return true;
+        }
+        if (UnpAudioBlock != 0)
+        {
+            for (I = 0; I < UnpChannels; I++)
+            {
+                UnpackUtility.makeDecodeTables(Table, I * PackDef.MC20, MD[I], PackDef.MC20);
+            }
+        }
+        else
+        {
+            UnpackUtility.makeDecodeTables(Table, 0, LD, PackDef.NC20);
+            UnpackUtility.makeDecodeTables(Table, PackDef.NC20, DD, PackDef.DC20);
+            UnpackUtility.makeDecodeTables(Table, PackDef.NC20 + PackDef.DC20, RD, PackDef.RC20);
+        }
+
+        for (var i = 0; i < UnpOldTable20.Length; i++)
+        {
+            UnpOldTable20[i] = Table[i];
+        }
+        return true;
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack20.cs

@@ -368,163 +368,6 @@ internal partial class Unpack
         oldUnpWriteBuf();
     }
 
-    private async System.Threading.Tasks.Task unpack20Async(
-        bool solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        int Bits;
-
-        if (suspended)
-        {
-            unpPtr = wrPtr;
-        }
-        else
-        {
-            UnpInitData(solid);
-            if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return;
-            }
-            if (!solid)
-            {
-                if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
-                {
-                    return;
-                }
-            }
-            --destUnpSize;
-        }
-
-        while (destUnpSize >= 0)
-        {
-            unpPtr &= PackDef.MAXWINMASK;
-
-            if (inAddr > readTop - 30)
-            {
-                if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-            }
-            if (((wrPtr - unpPtr) & PackDef.MAXWINMASK) < 270 && wrPtr != unpPtr)
-            {
-                await oldUnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-                if (suspended)
-                {
-                    return;
-                }
-            }
-            if (UnpAudioBlock != 0)
-            {
-                var AudioNumber = this.decodeNumber(MD[UnpCurChannel]);
-
-                if (AudioNumber == 256)
-                {
-                    if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
-                    {
-                        break;
-                    }
-                    continue;
-                }
-                window[unpPtr++] = DecodeAudio(AudioNumber);
-                if (++UnpCurChannel == UnpChannels)
-                {
-                    UnpCurChannel = 0;
-                }
-                --destUnpSize;
-                continue;
-            }
-
-            var Number = this.decodeNumber(LD);
-            if (Number < 256)
-            {
-                window[unpPtr++] = (byte)Number;
-                --destUnpSize;
-                continue;
-            }
-            if (Number > 269)
-            {
-                var Length = LDecode[Number -= 270] + 3;
-                if ((Bits = LBits[Number]) > 0)
-                {
-                    Length += Utility.URShift(GetBits(), (16 - Bits));
-                    AddBits(Bits);
-                }
-
-                var DistNumber = this.decodeNumber(DD);
-                var Distance = DDecode[DistNumber] + 1;
-                if ((Bits = DBits[DistNumber]) > 0)
-                {
-                    Distance += Utility.URShift(GetBits(), (16 - Bits));
-                    AddBits(Bits);
-                }
-
-                if (Distance >= 0x2000)
-                {
-                    Length++;
-                    if (Distance >= 0x40000L)
-                    {
-                        Length++;
-                    }
-                }
-
-                CopyString20(Length, Distance);
-                continue;
-            }
-            if (Number == 269)
-            {
-                if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-                continue;
-            }
-            if (Number == 256)
-            {
-                CopyString20(lastLength, lastDist);
-                continue;
-            }
-            if (Number < 261)
-            {
-                var Distance = oldDist[(oldDistPtr - (Number - 256)) & 3];
-                var LengthNumber = this.decodeNumber(RD);
-                var Length = LDecode[LengthNumber] + 2;
-                if ((Bits = LBits[LengthNumber]) > 0)
-                {
-                    Length += Utility.URShift(GetBits(), (16 - Bits));
-                    AddBits(Bits);
-                }
-                if (Distance >= 0x101)
-                {
-                    Length++;
-                    if (Distance >= 0x2000)
-                    {
-                        Length++;
-                        if (Distance >= 0x40000)
-                        {
-                            Length++;
-                        }
-                    }
-                }
-                CopyString20(Length, Distance);
-                continue;
-            }
-            if (Number < 270)
-            {
-                var Distance = SDDecode[Number -= 261] + 1;
-                if ((Bits = SDBits[Number]) > 0)
-                {
-                    Distance += Utility.URShift(GetBits(), (16 - Bits));
-                    AddBits(Bits);
-                }
-                CopyString20(2, Distance);
-            }
-        }
-        ReadLastTables();
-        await oldUnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-    }
-
     private void CopyString20(int Length, int Distance)
     {
         lastDist = oldDist[oldDistPtr++ & 3] = Distance;
@@ -691,120 +534,6 @@ internal partial class Unpack
         return (true);
     }
 
-    private async System.Threading.Tasks.Task<bool> ReadTables20Async(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        byte[] BitLength = new byte[PackDef.BC20];
-        byte[] Table = new byte[PackDef.MC20 * 4];
-        int TableSize,
-            N,
-            I;
-        if (inAddr > readTop - 25)
-        {
-            if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return (false);
-            }
-        }
-        var BitField = GetBits();
-        UnpAudioBlock = (BitField & 0x8000);
-
-        if (0 == (BitField & 0x4000))
-        {
-            new Span<byte>(UnpOldTable20).Clear();
-        }
-        AddBits(2);
-
-        if (UnpAudioBlock != 0)
-        {
-            UnpChannels = ((Utility.URShift(BitField, 12)) & 3) + 1;
-            if (UnpCurChannel >= UnpChannels)
-            {
-                UnpCurChannel = 0;
-            }
-            AddBits(2);
-            TableSize = PackDef.MC20 * UnpChannels;
-        }
-        else
-        {
-            TableSize = PackDef.NC20 + PackDef.DC20 + PackDef.RC20;
-        }
-        for (I = 0; I < PackDef.BC20; I++)
-        {
-            BitLength[I] = (byte)(Utility.URShift(GetBits(), 12));
-            AddBits(4);
-        }
-        UnpackUtility.makeDecodeTables(BitLength, 0, BD, PackDef.BC20);
-        I = 0;
-        while (I < TableSize)
-        {
-            if (inAddr > readTop - 5)
-            {
-                if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    return (false);
-                }
-            }
-            var Number = this.decodeNumber(BD);
-            if (Number < 16)
-            {
-                Table[I] = (byte)((Number + UnpOldTable20[I]) & 0xf);
-                I++;
-            }
-            else if (Number == 16)
-            {
-                N = (Utility.URShift(GetBits(), 14)) + 3;
-                AddBits(2);
-                while (N-- > 0 && I < TableSize)
-                {
-                    Table[I] = Table[I - 1];
-                    I++;
-                }
-            }
-            else
-            {
-                if (Number == 17)
-                {
-                    N = (Utility.URShift(GetBits(), 13)) + 3;
-                    AddBits(3);
-                }
-                else
-                {
-                    N = (Utility.URShift(GetBits(), 9)) + 11;
-                    AddBits(7);
-                }
-                while (N-- > 0 && I < TableSize)
-                {
-                    Table[I++] = 0;
-                }
-            }
-        }
-        if (inAddr > readTop)
-        {
-            return (true);
-        }
-        if (UnpAudioBlock != 0)
-        {
-            for (I = 0; I < UnpChannels; I++)
-            {
-                UnpackUtility.makeDecodeTables(Table, I * PackDef.MC20, MD[I], PackDef.MC20);
-            }
-        }
-        else
-        {
-            UnpackUtility.makeDecodeTables(Table, 0, LD, PackDef.NC20);
-            UnpackUtility.makeDecodeTables(Table, PackDef.NC20, DD, PackDef.DC20);
-            UnpackUtility.makeDecodeTables(Table, PackDef.NC20 + PackDef.DC20, RD, PackDef.RC20);
-        }
-
-        for (var i = 0; i < UnpOldTable20.Length; i++)
-        {
-            UnpOldTable20[i] = Table[i];
-        }
-        return (true);
-    }
-
     private void unpInitData20(bool Solid)
     {
         if (!Solid)

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack50.Async.cs

@@ -0,0 +1,321 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using SharpCompress.Compressors.Rar.UnpackV1.Decode;
+
+namespace SharpCompress.Compressors.Rar.UnpackV1;
+
+internal partial class Unpack
+{
+    private async Task<bool> UnpReadBufAsync(CancellationToken cancellationToken = default)
+    {
+        var DataSize = ReadTop - Inp.InAddr; // Data left to process.
+        if (DataSize < 0)
+        {
+            return false;
+        }
+
+        BlockHeader.BlockSize -= Inp.InAddr - BlockHeader.BlockStart;
+        if (Inp.InAddr > MAX_SIZE / 2)
+        {
+            if (DataSize > 0)
+            {
+                Array.Copy(InBuf, inAddr, InBuf, 0, DataSize);
+            }
+
+            Inp.InAddr = 0;
+            ReadTop = DataSize;
+        }
+        else
+        {
+            DataSize = ReadTop;
+        }
+
+        var ReadCode = 0;
+        if (MAX_SIZE != DataSize)
+        {
+            ReadCode = await readStream
+                .ReadAsync(InBuf, DataSize, MAX_SIZE - DataSize, cancellationToken)
+                .ConfigureAwait(false);
+        }
+
+        if (ReadCode > 0) // Can be also -1.
+        {
+            ReadTop += ReadCode;
+        }
+
+        ReadBorder = ReadTop - 30;
+        BlockHeader.BlockStart = Inp.InAddr;
+        if (BlockHeader.BlockSize != -1) // '-1' means not defined yet.
+        {
+            ReadBorder = Math.Min(ReadBorder, BlockHeader.BlockStart + BlockHeader.BlockSize - 1);
+        }
+        return ReadCode != -1;
+    }
+
+    public async Task Unpack5Async(bool Solid, CancellationToken cancellationToken = default)
+    {
+        FileExtracted = true;
+
+        if (!Suspended)
+        {
+            UnpInitData(Solid);
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return;
+            }
+
+            // Check TablesRead5 to be sure that we read tables at least once
+            // regardless of current block header TablePresent flag.
+            // So we can safefly use these tables below.
+            if (
+                !await ReadBlockHeaderAsync(cancellationToken).ConfigureAwait(false)
+                || !ReadTables()
+                || !TablesRead5
+            )
+            {
+                return;
+            }
+        }
+
+        while (true)
+        {
+            UnpPtr &= MaxWinMask;
+
+            if (Inp.InAddr >= ReadBorder)
+            {
+                var FileDone = false;
+
+                // We use 'while', because for empty block containing only Huffman table,
+                // we'll be on the block border once again just after reading the table.
+                while (
+                    Inp.InAddr > BlockHeader.BlockStart + BlockHeader.BlockSize - 1
+                    || Inp.InAddr == BlockHeader.BlockStart + BlockHeader.BlockSize - 1
+                        && Inp.InBit >= BlockHeader.BlockBitSize
+                )
+                {
+                    if (BlockHeader.LastBlockInFile)
+                    {
+                        FileDone = true;
+                        break;
+                    }
+                    if (
+                        !await ReadBlockHeaderAsync(cancellationToken).ConfigureAwait(false)
+                        || !ReadTables()
+                    )
+                    {
+                        return;
+                    }
+                }
+                if (FileDone || !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+            }
+
+            if (
+                ((WriteBorder - UnpPtr) & MaxWinMask) < PackDef.MAX_LZ_MATCH + 3
+                && WriteBorder != UnpPtr
+            )
+            {
+                UnpWriteBuf();
+                if (WrittenFileSize > DestUnpSize)
+                {
+                    return;
+                }
+
+                if (Suspended)
+                {
+                    FileExtracted = false;
+                    return;
+                }
+            }
+
+            var MainSlot = this.DecodeNumber(LD);
+            if (MainSlot < 256)
+            {
+                Window[UnpPtr++] = (byte)MainSlot;
+                continue;
+            }
+            if (MainSlot >= 262)
+            {
+                var Length = SlotToLength(MainSlot - 262);
+
+                int DBits;
+                uint Distance = 1,
+                    DistSlot = this.DecodeNumber(DD);
+                if (DistSlot < 4)
+                {
+                    DBits = 0;
+                    Distance += DistSlot;
+                }
+                else
+                {
+                    DBits = (int)((DistSlot / 2) - 1);
+                    Distance += (2 | (DistSlot & 1)) << DBits;
+                }
+
+                if (DBits > 0)
+                {
+                    if (DBits >= 4)
+                    {
+                        if (DBits > 4)
+                        {
+                            Distance += ((Inp.getbits() >> (36 - DBits)) << 4);
+                            Inp.AddBits(DBits - 4);
+                        }
+                        var LowDist = this.DecodeNumber(LDD);
+                        Distance += LowDist;
+                    }
+                    else
+                    {
+                        Distance += Inp.getbits() >> (32 - DBits);
+                        Inp.AddBits(DBits);
+                    }
+                }
+
+                if (Distance > 0x100)
+                {
+                    Length++;
+                    if (Distance > 0x2000)
+                    {
+                        Length++;
+                        if (Distance > 0x40000)
+                        {
+                            Length++;
+                        }
+                    }
+                }
+
+                InsertOldDist(Distance);
+                LastLength = Length;
+                CopyString(Length, Distance);
+                continue;
+            }
+            if (MainSlot == 256)
+            {
+                var Filter = new UnpackFilter();
+                if (
+                    !await ReadFilterAsync(Filter, cancellationToken).ConfigureAwait(false)
+                    || !AddFilter(Filter)
+                )
+                {
+                    break;
+                }
+
+                continue;
+            }
+            if (MainSlot == 257)
+            {
+                if (LastLength != 0)
+                {
+                    CopyString(LastLength, OldDistN(0));
+                }
+
+                continue;
+            }
+            if (MainSlot < 262)
+            {
+                var DistNum = (int)(MainSlot - 258);
+                var Distance = OldDistN(DistNum);
+                for (var I = DistNum; I > 0; I--)
+                {
+                    SetOldDistN(I, OldDistN(I - 1));
+                }
+
+                SetOldDistN(0, Distance);
+
+                var LengthSlot = this.DecodeNumber(RD);
+                var Length = SlotToLength(LengthSlot);
+                LastLength = Length;
+                CopyString(Length, Distance);
+                continue;
+            }
+        }
+        UnpWriteBuf();
+    }
+
+    private async Task<bool> ReadBlockHeaderAsync(CancellationToken cancellationToken = default)
+    {
+        Header.HeaderSize = 0;
+
+        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 7)
+        {
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+
+        Inp.faddbits((uint)((8 - Inp.InBit) & 7));
+
+        var BlockFlags = (byte)(Inp.fgetbits() >> 8);
+        Inp.faddbits(8);
+        var ByteCount = (uint)(((BlockFlags >> 3) & 3) + 1);
+
+        if (ByteCount == 4)
+        {
+            return false;
+        }
+
+        Header.HeaderSize = (int)(2 + ByteCount);
+
+        Header.BlockBitSize = (BlockFlags & 7) + 1;
+
+        var SavedCheckSum = (byte)(Inp.fgetbits() >> 8);
+        Inp.faddbits(8);
+
+        var BlockSize = 0;
+        for (var I = 0; I < ByteCount; I++)
+        {
+            BlockSize += (int)(Inp.fgetbits() >> 8) << (I * 8);
+            Inp.AddBits(8);
+        }
+
+        Header.BlockSize = BlockSize;
+        var CheckSum = (byte)(0x5a ^ BlockFlags ^ BlockSize ^ (BlockSize >> 8) ^ (BlockSize >> 16));
+        if (CheckSum != SavedCheckSum)
+        {
+            return false;
+        }
+
+        Header.BlockStart = Inp.InAddr;
+        ReadBorder = Math.Min(ReadBorder, Header.BlockStart + Header.BlockSize - 1);
+
+        Header.LastBlockInFile = (BlockFlags & 0x40) != 0;
+        Header.TablePresent = (BlockFlags & 0x80) != 0;
+        return true;
+    }
+
+    private async Task<bool> ReadFilterAsync(
+        UnpackFilter Filter,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 16)
+        {
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+
+        Filter.uBlockStart = ReadFilterData();
+        Filter.uBlockLength = ReadFilterData();
+        if (Filter.BlockLength > MAX_FILTER_BLOCK_SIZE)
+        {
+            Filter.BlockLength = 0;
+        }
+
+        Filter.Type = (byte)(Inp.fgetbits() >> 13);
+        Inp.faddbits(3);
+
+        if (Filter.Type == (byte)FilterType.FILTER_DELTA)
+        {
+            Filter.Channels = (byte)((Inp.fgetbits() >> 11) + 1);
+            Inp.faddbits(5);
+        }
+
+        return true;
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV1/Unpack50.cs

@@ -479,354 +479,6 @@ internal partial class Unpack
         return ReadCode != -1;
     }
 
-    private async System.Threading.Tasks.Task<bool> UnpReadBufAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        var DataSize = ReadTop - Inp.InAddr; // Data left to process.
-        if (DataSize < 0)
-        {
-            return false;
-        }
-
-        BlockHeader.BlockSize -= Inp.InAddr - BlockHeader.BlockStart;
-        if (Inp.InAddr > MAX_SIZE / 2)
-        {
-            if (DataSize > 0)
-            {
-                Array.Copy(InBuf, inAddr, InBuf, 0, DataSize);
-            }
-
-            Inp.InAddr = 0;
-            ReadTop = DataSize;
-        }
-        else
-        {
-            DataSize = ReadTop;
-        }
-
-        var ReadCode = 0;
-        if (MAX_SIZE != DataSize)
-        {
-            ReadCode = await readStream
-                .ReadAsync(InBuf, DataSize, MAX_SIZE - DataSize, cancellationToken)
-                .ConfigureAwait(false);
-        }
-
-        if (ReadCode > 0) // Can be also -1.
-        {
-            ReadTop += ReadCode;
-        }
-
-        ReadBorder = ReadTop - 30;
-        BlockHeader.BlockStart = Inp.InAddr;
-        if (BlockHeader.BlockSize != -1) // '-1' means not defined yet.
-        {
-            ReadBorder = Math.Min(ReadBorder, BlockHeader.BlockStart + BlockHeader.BlockSize - 1);
-        }
-        return ReadCode != -1;
-    }
-
-    public async System.Threading.Tasks.Task Unpack5Async(
-        bool Solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        FileExtracted = true;
-
-        if (!Suspended)
-        {
-            UnpInitData(Solid);
-            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return;
-            }
-
-            // Check TablesRead5 to be sure that we read tables at least once
-            // regardless of current block header TablePresent flag.
-            // So we can safefly use these tables below.
-            if (
-                !await ReadBlockHeaderAsync(cancellationToken).ConfigureAwait(false)
-                || !ReadTables()
-                || !TablesRead5
-            )
-            {
-                return;
-            }
-        }
-
-        while (true)
-        {
-            UnpPtr &= MaxWinMask;
-
-            if (Inp.InAddr >= ReadBorder)
-            {
-                var FileDone = false;
-
-                // We use 'while', because for empty block containing only Huffman table,
-                // we'll be on the block border once again just after reading the table.
-                while (
-                    Inp.InAddr > BlockHeader.BlockStart + BlockHeader.BlockSize - 1
-                    || Inp.InAddr == BlockHeader.BlockStart + BlockHeader.BlockSize - 1
-                        && Inp.InBit >= BlockHeader.BlockBitSize
-                )
-                {
-                    if (BlockHeader.LastBlockInFile)
-                    {
-                        FileDone = true;
-                        break;
-                    }
-                    if (
-                        !await ReadBlockHeaderAsync(cancellationToken).ConfigureAwait(false)
-                        || !ReadTables()
-                    )
-                    {
-                        return;
-                    }
-                }
-                if (FileDone || !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-            }
-
-            if (
-                ((WriteBorder - UnpPtr) & MaxWinMask) < PackDef.MAX_LZ_MATCH + 3
-                && WriteBorder != UnpPtr
-            )
-            {
-                UnpWriteBuf();
-                if (WrittenFileSize > DestUnpSize)
-                {
-                    return;
-                }
-
-                if (Suspended)
-                {
-                    FileExtracted = false;
-                    return;
-                }
-            }
-
-            //uint MainSlot=DecodeNumber(Inp,LD);
-            var MainSlot = this.DecodeNumber(LD);
-            if (MainSlot < 256)
-            {
-                //              if (Fragmented)
-                //                FragWindow[UnpPtr++]=(byte)MainSlot;
-                //              else
-                Window[UnpPtr++] = (byte)MainSlot;
-                continue;
-            }
-            if (MainSlot >= 262)
-            {
-                var Length = SlotToLength(MainSlot - 262);
-
-                //uint DBits,Distance=1,DistSlot=DecodeNumber(Inp,&BlockTables.DD);
-                int DBits;
-                uint Distance = 1,
-                    DistSlot = this.DecodeNumber(DD);
-                if (DistSlot < 4)
-                {
-                    DBits = 0;
-                    Distance += DistSlot;
-                }
-                else
-                {
-                    //DBits=DistSlot/2 - 1;
-                    DBits = (int)((DistSlot / 2) - 1);
-                    Distance += (2 | (DistSlot & 1)) << DBits;
-                }
-
-                if (DBits > 0)
-                {
-                    if (DBits >= 4)
-                    {
-                        if (DBits > 4)
-                        {
-                            Distance += ((Inp.getbits() >> (36 - DBits)) << 4);
-                            Inp.AddBits(DBits - 4);
-                        }
-                        //uint LowDist=DecodeNumber(Inp,&BlockTables.LDD);
-                        var LowDist = this.DecodeNumber(LDD);
-                        Distance += LowDist;
-                    }
-                    else
-                    {
-                        Distance += Inp.getbits() >> (32 - DBits);
-                        Inp.AddBits(DBits);
-                    }
-                }
-
-                if (Distance > 0x100)
-                {
-                    Length++;
-                    if (Distance > 0x2000)
-                    {
-                        Length++;
-                        if (Distance > 0x40000)
-                        {
-                            Length++;
-                        }
-                    }
-                }
-
-                InsertOldDist(Distance);
-                LastLength = Length;
-                //              if (Fragmented)
-                //                FragWindow.CopyString(Length,Distance,UnpPtr,MaxWinMask);
-                //              else
-                CopyString(Length, Distance);
-                continue;
-            }
-            if (MainSlot == 256)
-            {
-                var Filter = new UnpackFilter();
-                if (
-                    !await ReadFilterAsync(Filter, cancellationToken).ConfigureAwait(false)
-                    || !AddFilter(Filter)
-                )
-                {
-                    break;
-                }
-
-                continue;
-            }
-            if (MainSlot == 257)
-            {
-                if (LastLength != 0)
-                //                if (Fragmented)
-                //                  FragWindow.CopyString(LastLength,OldDist[0],UnpPtr,MaxWinMask);
-                //                else
-                //CopyString(LastLength,OldDist[0]);
-                {
-                    CopyString(LastLength, OldDistN(0));
-                }
-
-                continue;
-            }
-            if (MainSlot < 262)
-            {
-                //uint DistNum=MainSlot-258;
-                var DistNum = (int)(MainSlot - 258);
-                //uint Distance=OldDist[DistNum];
-                var Distance = OldDistN(DistNum);
-                //for (uint I=DistNum;I>0;I--)
-                for (var I = DistNum; I > 0; I--)
-                //OldDistN[I]=OldDistN(I-1);
-                {
-                    SetOldDistN(I, OldDistN(I - 1));
-                }
-
-                //OldDistN[0]=Distance;
-                SetOldDistN(0, Distance);
-
-                var LengthSlot = this.DecodeNumber(RD);
-                var Length = SlotToLength(LengthSlot);
-                LastLength = Length;
-                //              if (Fragmented)
-                //                FragWindow.CopyString(Length,Distance,UnpPtr,MaxWinMask);
-                //              else
-                CopyString(Length, Distance);
-                continue;
-            }
-        }
-        UnpWriteBuf();
-    }
-
-    private async System.Threading.Tasks.Task<bool> ReadBlockHeaderAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        Header.HeaderSize = 0;
-
-        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 7)
-        {
-            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return false;
-            }
-        }
-
-        //Inp.faddbits((8-Inp.InBit)&7);
-        Inp.faddbits((uint)((8 - Inp.InBit) & 7));
-
-        var BlockFlags = (byte)(Inp.fgetbits() >> 8);
-        Inp.faddbits(8);
-        //uint ByteCount=((BlockFlags>>3)&3)+1; // Block size byte count.
-        var ByteCount = (uint)(((BlockFlags >> 3) & 3) + 1); // Block size byte count.
-
-        if (ByteCount == 4)
-        {
-            return false;
-        }
-
-        //Header.HeaderSize=2+ByteCount;
-        Header.HeaderSize = (int)(2 + ByteCount);
-
-        Header.BlockBitSize = (BlockFlags & 7) + 1;
-
-        var SavedCheckSum = (byte)(Inp.fgetbits() >> 8);
-        Inp.faddbits(8);
-
-        var BlockSize = 0;
-        //for (uint I=0;I<ByteCount;I++)
-        for (var I = 0; I < ByteCount; I++)
-        {
-            //BlockSize+=(Inp.fgetbits()>>8)<<(I*8);
-            BlockSize += (int)(Inp.fgetbits() >> 8) << (I * 8);
-            Inp.AddBits(8);
-        }
-
-        Header.BlockSize = BlockSize;
-        var CheckSum = (byte)(0x5a ^ BlockFlags ^ BlockSize ^ (BlockSize >> 8) ^ (BlockSize >> 16));
-        if (CheckSum != SavedCheckSum)
-        {
-            return false;
-        }
-
-        Header.BlockStart = Inp.InAddr;
-        ReadBorder = Math.Min(ReadBorder, Header.BlockStart + Header.BlockSize - 1);
-
-        Header.LastBlockInFile = (BlockFlags & 0x40) != 0;
-        Header.TablePresent = (BlockFlags & 0x80) != 0;
-        return true;
-    }
-
-    private async System.Threading.Tasks.Task<bool> ReadFilterAsync(
-        UnpackFilter Filter,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 16)
-        {
-            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return false;
-            }
-        }
-
-        Filter.uBlockStart = ReadFilterData();
-        Filter.uBlockLength = ReadFilterData();
-        if (Filter.BlockLength > MAX_FILTER_BLOCK_SIZE)
-        {
-            Filter.BlockLength = 0;
-        }
-
-        //Filter.Type=Inp.fgetbits()>>13;
-        Filter.Type = (byte)(Inp.fgetbits() >> 13);
-        Inp.faddbits(3);
-
-        if (Filter.Type == (byte)FilterType.FILTER_DELTA)
-        {
-            //Filter.Channels=(Inp.fgetbits()>>11)+1;
-            Filter.Channels = (byte)((Inp.fgetbits() >> 11) + 1);
-            Inp.faddbits(5);
-        }
-
-        return true;
-    }
-
     //?
     //        void UnpWriteBuf()
     //        {

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.cs

@@ -1,5 +1,7 @@
 using System;
 using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
 using SharpCompress.Common.Rar.Headers;
 using size_t = System.UInt32;
 
@@ -23,11 +25,11 @@ internal partial class Unpack : IRarUnpack
         // NOTE: caller has logic to check for -1 for error we throw instead.
         readStream.Read(buf, offset, count);
 
-    private async System.Threading.Tasks.Task<int> UnpIO_UnpReadAsync(
+    private async Task<int> UnpIO_UnpReadAsync(
         byte[] buf,
         int offset,
         int count,
-        System.Threading.CancellationToken cancellationToken = default
+        CancellationToken cancellationToken = default
     ) =>
         // NOTE: caller has logic to check for -1 for error we throw instead.
         await readStream.ReadAsync(buf, offset, count, cancellationToken).ConfigureAwait(false);
@@ -35,11 +37,11 @@ internal partial class Unpack : IRarUnpack
     private void UnpIO_UnpWrite(byte[] buf, size_t offset, uint count) =>
         writeStream.Write(buf, checked((int)offset), checked((int)count));
 
-    private async System.Threading.Tasks.Task UnpIO_UnpWriteAsync(
+    private async Task UnpIO_UnpWriteAsync(
         byte[] buf,
         size_t offset,
         uint count,
-        System.Threading.CancellationToken cancellationToken = default
+        CancellationToken cancellationToken = default
     ) =>
         await writeStream
             .WriteAsync(buf, checked((int)offset), checked((int)count), cancellationToken)
@@ -66,11 +68,11 @@ internal partial class Unpack : IRarUnpack
         DoUnpack();
     }
 
-    public async System.Threading.Tasks.Task DoUnpackAsync(
+    public async Task DoUnpackAsync(
         FileHeader fileHeader,
         Stream readStream,
         Stream writeStream,
-        System.Threading.CancellationToken cancellationToken = default
+        CancellationToken cancellationToken = default
     )
     {
         DestUnpSize = fileHeader.UncompressedSize;
@@ -97,9 +99,7 @@ internal partial class Unpack : IRarUnpack
         }
     }
 
-    public async System.Threading.Tasks.Task DoUnpackAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
+    public async Task DoUnpackAsync(CancellationToken cancellationToken = default)
     {
         if (fileHeader.IsStored)
         {
@@ -133,9 +133,7 @@ internal partial class Unpack : IRarUnpack
         } while (!Suspended);
     }
 
-    private async System.Threading.Tasks.Task UnstoreFileAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
+    private async Task UnstoreFileAsync(CancellationToken cancellationToken = default)
     {
         var buffer = new byte[(int)Math.Min(0x10000, DestUnpSize)];
         do

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack15_async.cs

@@ -0,0 +1,100 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace SharpCompress.Compressors.Rar.UnpackV2017;
+
+internal partial class Unpack
+{
+    private async Task Unpack15Async(bool Solid, CancellationToken cancellationToken = default)
+    {
+        UnpInitData(Solid);
+        UnpInitData15(Solid);
+        await UnpReadBufAsync(cancellationToken).ConfigureAwait(false);
+        if (!Solid)
+        {
+            InitHuff();
+            UnpPtr = 0;
+        }
+        else
+        {
+            UnpPtr = WrPtr;
+        }
+
+        --DestUnpSize;
+        if (DestUnpSize >= 0)
+        {
+            GetFlagsBuf();
+            FlagsCnt = 8;
+        }
+
+        while (DestUnpSize >= 0)
+        {
+            UnpPtr &= MaxWinMask;
+
+            if (
+                Inp.InAddr > ReadTop - 30
+                && !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false)
+            )
+            {
+                break;
+            }
+
+            if (((WrPtr - UnpPtr) & MaxWinMask) < 270 && WrPtr != UnpPtr)
+            {
+                UnpWriteBuf20();
+            }
+
+            if (StMode != 0)
+            {
+                HuffDecode();
+                continue;
+            }
+
+            if (--FlagsCnt < 0)
+            {
+                GetFlagsBuf();
+                FlagsCnt = 7;
+            }
+
+            if ((FlagBuf & 0x80) != 0)
+            {
+                FlagBuf <<= 1;
+                if (Nlzb > Nhfb)
+                {
+                    LongLZ();
+                }
+                else
+                {
+                    HuffDecode();
+                }
+            }
+            else
+            {
+                FlagBuf <<= 1;
+                if (--FlagsCnt < 0)
+                {
+                    GetFlagsBuf();
+                    FlagsCnt = 7;
+                }
+                if ((FlagBuf & 0x80) != 0)
+                {
+                    FlagBuf <<= 1;
+                    if (Nlzb > Nhfb)
+                    {
+                        HuffDecode();
+                    }
+                    else
+                    {
+                        LongLZ();
+                    }
+                }
+                else
+                {
+                    FlagBuf <<= 1;
+                    ShortLZ();
+                }
+            }
+        }
+        UnpWriteBuf20();
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack15_cpp.cs

@@ -200,102 +200,6 @@ internal partial class Unpack
         UnpWriteBuf20();
     }
 
-    private async System.Threading.Tasks.Task Unpack15Async(
-        bool Solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        UnpInitData(Solid);
-        UnpInitData15(Solid);
-        await UnpReadBufAsync(cancellationToken).ConfigureAwait(false);
-        if (!Solid)
-        {
-            InitHuff();
-            UnpPtr = 0;
-        }
-        else
-        {
-            UnpPtr = WrPtr;
-        }
-
-        --DestUnpSize;
-        if (DestUnpSize >= 0)
-        {
-            GetFlagsBuf();
-            FlagsCnt = 8;
-        }
-
-        while (DestUnpSize >= 0)
-        {
-            UnpPtr &= MaxWinMask;
-
-            if (
-                Inp.InAddr > ReadTop - 30
-                && !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false)
-            )
-            {
-                break;
-            }
-
-            if (((WrPtr - UnpPtr) & MaxWinMask) < 270 && WrPtr != UnpPtr)
-            {
-                await UnpWriteBuf20Async(cancellationToken).ConfigureAwait(false);
-            }
-
-            if (StMode != 0)
-            {
-                HuffDecode();
-                continue;
-            }
-
-            if (--FlagsCnt < 0)
-            {
-                GetFlagsBuf();
-                FlagsCnt = 7;
-            }
-
-            if ((FlagBuf & 0x80) != 0)
-            {
-                FlagBuf <<= 1;
-                if (Nlzb > Nhfb)
-                {
-                    LongLZ();
-                }
-                else
-                {
-                    HuffDecode();
-                }
-            }
-            else
-            {
-                FlagBuf <<= 1;
-                if (--FlagsCnt < 0)
-                {
-                    GetFlagsBuf();
-                    FlagsCnt = 7;
-                }
-                if ((FlagBuf & 0x80) != 0)
-                {
-                    FlagBuf <<= 1;
-                    if (Nlzb > Nhfb)
-                    {
-                        HuffDecode();
-                    }
-                    else
-                    {
-                        LongLZ();
-                    }
-                }
-                else
-                {
-                    FlagBuf <<= 1;
-                    ShortLZ();
-                }
-            }
-        }
-        await UnpWriteBuf20Async(cancellationToken).ConfigureAwait(false);
-    }
-
     //#define GetShortLen1(pos) ((pos)==1 ? Buf60+3:ShortLen1[pos])
     private uint GetShortLen1(uint pos) => ((pos) == 1 ? (uint)(Buf60 + 3) : ShortLen1[pos]);
 

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack20_async.cs

@@ -0,0 +1,319 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using static SharpCompress.Compressors.Rar.UnpackV2017.PackDef;
+using static SharpCompress.Compressors.Rar.UnpackV2017.Unpack.Unpack20Local;
+
+namespace SharpCompress.Compressors.Rar.UnpackV2017;
+
+internal partial class Unpack
+{
+    private async Task Unpack20Async(bool Solid, CancellationToken cancellationToken = default)
+    {
+        uint Bits;
+
+        if (Suspended)
+        {
+            UnpPtr = WrPtr;
+        }
+        else
+        {
+            UnpInitData(Solid);
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return;
+            }
+
+            if (
+                (!Solid || !TablesRead2)
+                && !await ReadTables20Async(cancellationToken).ConfigureAwait(false)
+            )
+            {
+                return;
+            }
+
+            --DestUnpSize;
+        }
+
+        while (DestUnpSize >= 0)
+        {
+            UnpPtr &= MaxWinMask;
+
+            if (Inp.InAddr > ReadTop - 30)
+            {
+                if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+            }
+
+            if (((WrPtr - UnpPtr) & MaxWinMask) < 270 && WrPtr != UnpPtr)
+            {
+                UnpWriteBuf20();
+                if (Suspended)
+                {
+                    return;
+                }
+            }
+            if (UnpAudioBlock)
+            {
+                var AudioNumber = DecodeNumber(Inp, MD[UnpCurChannel]);
+
+                if (AudioNumber == 256)
+                {
+                    if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
+                    {
+                        break;
+                    }
+
+                    continue;
+                }
+                Window[UnpPtr++] = DecodeAudio((int)AudioNumber);
+                if (++UnpCurChannel == UnpChannels)
+                {
+                    UnpCurChannel = 0;
+                }
+
+                --DestUnpSize;
+                continue;
+            }
+
+            var Number = DecodeNumber(Inp, BlockTables.LD);
+            if (Number < 256)
+            {
+                Window[UnpPtr++] = (byte)Number;
+                --DestUnpSize;
+                continue;
+            }
+            if (Number > 269)
+            {
+                var Length = (uint)(LDecode[Number -= 270] + 3);
+                if ((Bits = LBits[Number]) > 0)
+                {
+                    Length += Inp.getbits() >> (int)(16 - Bits);
+                    Inp.addbits(Bits);
+                }
+
+                var DistNumber = DecodeNumber(Inp, BlockTables.DD);
+                var Distance = DDecode[DistNumber] + 1;
+                if ((Bits = DBits[DistNumber]) > 0)
+                {
+                    Distance += Inp.getbits() >> (int)(16 - Bits);
+                    Inp.addbits(Bits);
+                }
+
+                if (Distance >= 0x2000)
+                {
+                    Length++;
+                    if (Distance >= 0x40000L)
+                    {
+                        Length++;
+                    }
+                }
+
+                CopyString20(Length, Distance);
+                continue;
+            }
+            if (Number == 269)
+            {
+                if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+
+                continue;
+            }
+            if (Number == 256)
+            {
+                CopyString20(LastLength, LastDist);
+                continue;
+            }
+            if (Number < 261)
+            {
+                var Distance = OldDist[(OldDistPtr - (Number - 256)) & 3];
+                var LengthNumber = DecodeNumber(Inp, BlockTables.RD);
+                var Length = (uint)(LDecode[LengthNumber] + 2);
+                if ((Bits = LBits[LengthNumber]) > 0)
+                {
+                    Length += Inp.getbits() >> (int)(16 - Bits);
+                    Inp.addbits(Bits);
+                }
+                if (Distance >= 0x101)
+                {
+                    Length++;
+                    if (Distance >= 0x2000)
+                    {
+                        Length++;
+                        if (Distance >= 0x40000)
+                        {
+                            Length++;
+                        }
+                    }
+                }
+                CopyString20(Length, Distance);
+                continue;
+            }
+            if (Number < 270)
+            {
+                var Distance = (uint)(SDDecode[Number -= 261] + 1);
+                if ((Bits = SDBits[Number]) > 0)
+                {
+                    Distance += Inp.getbits() >> (int)(16 - Bits);
+                    Inp.addbits(Bits);
+                }
+                CopyString20(2, Distance);
+                continue;
+            }
+        }
+        ReadLastTables();
+        UnpWriteBuf20();
+    }
+
+    private async Task UnpWriteBuf20Async(CancellationToken cancellationToken = default)
+    {
+        if (UnpPtr != WrPtr)
+        {
+            UnpSomeRead = true;
+        }
+
+        if (UnpPtr < WrPtr)
+        {
+            await UnpIO_UnpWriteAsync(
+                    Window,
+                    WrPtr,
+                    (uint)(-(int)WrPtr & MaxWinMask),
+                    cancellationToken
+                )
+                .ConfigureAwait(false);
+            await UnpIO_UnpWriteAsync(Window, 0, UnpPtr, cancellationToken).ConfigureAwait(false);
+            UnpAllBuf = true;
+        }
+        else
+        {
+            await UnpIO_UnpWriteAsync(Window, WrPtr, UnpPtr - WrPtr, cancellationToken)
+                .ConfigureAwait(false);
+        }
+
+        WrPtr = UnpPtr;
+    }
+
+    private async Task<bool> ReadTables20Async(CancellationToken cancellationToken = default)
+    {
+        byte[] BitLength = new byte[checked((int)BC20)];
+        byte[] Table = new byte[checked((int)MC20 * 4)];
+        if (Inp.InAddr > ReadTop - 25)
+        {
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+
+        var BitField = Inp.getbits();
+        UnpAudioBlock = (BitField & 0x8000) != 0;
+
+        if ((BitField & 0x4000) != 0)
+        {
+            Array.Clear(UnpOldTable20, 0, UnpOldTable20.Length);
+        }
+
+        Inp.addbits(2);
+
+        uint TableSize;
+        if (UnpAudioBlock)
+        {
+            UnpChannels = ((BitField >> 12) & 3) + 1;
+            if (UnpCurChannel >= UnpChannels)
+            {
+                UnpCurChannel = 0;
+            }
+
+            Inp.addbits(2);
+            TableSize = MC20 * UnpChannels;
+        }
+        else
+        {
+            TableSize = NC20 + DC20 + RC20;
+        }
+
+        for (int I = 0; I < checked((int)BC20); I++)
+        {
+            BitLength[I] = (byte)(Inp.getbits() >> 12);
+            Inp.addbits(4);
+        }
+        MakeDecodeTables(BitLength, 0, BlockTables.BD, BC20);
+        for (int I = 0; I < checked((int)TableSize); )
+        {
+            if (Inp.InAddr > ReadTop - 5)
+            {
+                if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    return false;
+                }
+            }
+
+            var Number = DecodeNumber(Inp, BlockTables.BD);
+            if (Number < 16)
+            {
+                Table[I] = (byte)((Number + UnpOldTable20[I]) & 0xf);
+                I++;
+            }
+            else if (Number == 16)
+            {
+                var N = (Inp.getbits() >> 14) + 3;
+                Inp.addbits(2);
+                if (I == 0)
+                {
+                    return false; // We cannot have "repeat previous" code at the first position.
+                }
+                else
+                {
+                    while (N-- > 0 && I < TableSize)
+                    {
+                        Table[I] = Table[I - 1];
+                        I++;
+                    }
+                }
+            }
+            else
+            {
+                uint N;
+                if (Number == 17)
+                {
+                    N = (Inp.getbits() >> 13) + 3;
+                    Inp.addbits(3);
+                }
+                else
+                {
+                    N = (Inp.getbits() >> 9) + 11;
+                    Inp.addbits(7);
+                }
+                while (N-- > 0 && I < TableSize)
+                {
+                    Table[I++] = 0;
+                }
+            }
+        }
+        TablesRead2 = true;
+        if (Inp.InAddr > ReadTop)
+        {
+            return true;
+        }
+
+        if (UnpAudioBlock)
+        {
+            for (int I = 0; I < UnpChannels; I++)
+            {
+                MakeDecodeTables(Table, (int)(I * MC20), MD[I], MC20);
+            }
+        }
+        else
+        {
+            MakeDecodeTables(Table, 0, BlockTables.LD, NC20);
+            MakeDecodeTables(Table, (int)NC20, BlockTables.DD, DC20);
+            MakeDecodeTables(Table, (int)(NC20 + DC20), BlockTables.RD, RC20);
+        }
+        Array.Copy(Table, 0, this.UnpOldTable20, 0, UnpOldTable20.Length);
+        return true;
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack20_cpp.cs

@@ -342,170 +342,6 @@ internal partial class Unpack
         UnpWriteBuf20();
     }
 
-    private async System.Threading.Tasks.Task Unpack20Async(
-        bool Solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        uint Bits;
-
-        if (Suspended)
-        {
-            UnpPtr = WrPtr;
-        }
-        else
-        {
-            UnpInitData(Solid);
-            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return;
-            }
-
-            if (
-                (!Solid || !TablesRead2)
-                && !await ReadTables20Async(cancellationToken).ConfigureAwait(false)
-            )
-            {
-                return;
-            }
-
-            --DestUnpSize;
-        }
-
-        while (DestUnpSize >= 0)
-        {
-            UnpPtr &= MaxWinMask;
-
-            if (Inp.InAddr > ReadTop - 30)
-            {
-                if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-            }
-
-            if (((WrPtr - UnpPtr) & MaxWinMask) < 270 && WrPtr != UnpPtr)
-            {
-                await UnpWriteBuf20Async(cancellationToken).ConfigureAwait(false);
-                if (Suspended)
-                {
-                    return;
-                }
-            }
-            if (UnpAudioBlock)
-            {
-                var AudioNumber = DecodeNumber(Inp, MD[UnpCurChannel]);
-
-                if (AudioNumber == 256)
-                {
-                    if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
-                    {
-                        break;
-                    }
-
-                    continue;
-                }
-                Window[UnpPtr++] = DecodeAudio((int)AudioNumber);
-                if (++UnpCurChannel == UnpChannels)
-                {
-                    UnpCurChannel = 0;
-                }
-
-                --DestUnpSize;
-                continue;
-            }
-
-            var Number = DecodeNumber(Inp, BlockTables.LD);
-            if (Number < 256)
-            {
-                Window[UnpPtr++] = (byte)Number;
-                --DestUnpSize;
-                continue;
-            }
-            if (Number > 269)
-            {
-                var Length = (uint)(LDecode[Number -= 270] + 3);
-                if ((Bits = LBits[Number]) > 0)
-                {
-                    Length += Inp.getbits() >> (int)(16 - Bits);
-                    Inp.addbits(Bits);
-                }
-
-                var DistNumber = DecodeNumber(Inp, BlockTables.DD);
-                var Distance = DDecode[DistNumber] + 1;
-                if ((Bits = DBits[DistNumber]) > 0)
-                {
-                    Distance += Inp.getbits() >> (int)(16 - Bits);
-                    Inp.addbits(Bits);
-                }
-
-                if (Distance >= 0x2000)
-                {
-                    Length++;
-                    if (Distance >= 0x40000L)
-                    {
-                        Length++;
-                    }
-                }
-
-                CopyString20(Length, Distance);
-                continue;
-            }
-            if (Number == 269)
-            {
-                if (!await ReadTables20Async(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-
-                continue;
-            }
-            if (Number == 256)
-            {
-                CopyString20(LastLength, LastDist);
-                continue;
-            }
-            if (Number < 261)
-            {
-                var Distance = OldDist[(OldDistPtr - (Number - 256)) & 3];
-                var LengthNumber = DecodeNumber(Inp, BlockTables.RD);
-                var Length = (uint)(LDecode[LengthNumber] + 2);
-                if ((Bits = LBits[LengthNumber]) > 0)
-                {
-                    Length += Inp.getbits() >> (int)(16 - Bits);
-                    Inp.addbits(Bits);
-                }
-                if (Distance >= 0x101)
-                {
-                    Length++;
-                    if (Distance >= 0x2000)
-                    {
-                        Length++;
-                        if (Distance >= 0x40000)
-                        {
-                            Length++;
-                        }
-                    }
-                }
-                CopyString20(Length, Distance);
-                continue;
-            }
-            if (Number < 270)
-            {
-                var Distance = (uint)(SDDecode[Number -= 261] + 1);
-                if ((Bits = SDBits[Number]) > 0)
-                {
-                    Distance += Inp.getbits() >> (int)(16 - Bits);
-                    Inp.addbits(Bits);
-                }
-                CopyString20(2, Distance);
-                continue;
-            }
-        }
-        ReadLastTables();
-        await UnpWriteBuf20Async(cancellationToken).ConfigureAwait(false);
-    }
-
     private void UnpWriteBuf20()
     {
         if (UnpPtr != WrPtr)
@@ -527,36 +363,6 @@ internal partial class Unpack
         WrPtr = UnpPtr;
     }
 
-    private async System.Threading.Tasks.Task UnpWriteBuf20Async(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (UnpPtr != WrPtr)
-        {
-            UnpSomeRead = true;
-        }
-
-        if (UnpPtr < WrPtr)
-        {
-            await UnpIO_UnpWriteAsync(
-                    Window,
-                    WrPtr,
-                    (uint)(-(int)WrPtr & MaxWinMask),
-                    cancellationToken
-                )
-                .ConfigureAwait(false);
-            await UnpIO_UnpWriteAsync(Window, 0, UnpPtr, cancellationToken).ConfigureAwait(false);
-            UnpAllBuf = true;
-        }
-        else
-        {
-            await UnpIO_UnpWriteAsync(Window, WrPtr, UnpPtr - WrPtr, cancellationToken)
-                .ConfigureAwait(false);
-        }
-
-        WrPtr = UnpPtr;
-    }
-
     private bool ReadTables20()
     {
         Span<byte> BitLength = stackalloc byte[checked((int)BC20)];
@@ -677,130 +483,6 @@ internal partial class Unpack
         return true;
     }
 
-    private async System.Threading.Tasks.Task<bool> ReadTables20Async(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        byte[] BitLength = new byte[checked((int)BC20)];
-        byte[] Table = new byte[checked((int)MC20 * 4)];
-        if (Inp.InAddr > ReadTop - 25)
-        {
-            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return false;
-            }
-        }
-
-        var BitField = Inp.getbits();
-        UnpAudioBlock = (BitField & 0x8000) != 0;
-
-        if ((BitField & 0x4000) != 0)
-        {
-            Array.Clear(UnpOldTable20, 0, UnpOldTable20.Length);
-        }
-
-        Inp.addbits(2);
-
-        uint TableSize;
-        if (UnpAudioBlock)
-        {
-            UnpChannels = ((BitField >> 12) & 3) + 1;
-            if (UnpCurChannel >= UnpChannels)
-            {
-                UnpCurChannel = 0;
-            }
-
-            Inp.addbits(2);
-            TableSize = MC20 * UnpChannels;
-        }
-        else
-        {
-            TableSize = NC20 + DC20 + RC20;
-        }
-
-        for (int I = 0; I < checked((int)BC20); I++)
-        {
-            BitLength[I] = (byte)(Inp.getbits() >> 12);
-            Inp.addbits(4);
-        }
-        MakeDecodeTables(BitLength, 0, BlockTables.BD, BC20);
-        for (int I = 0; I < checked((int)TableSize); )
-        {
-            if (Inp.InAddr > ReadTop - 5)
-            {
-                if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    return false;
-                }
-            }
-
-            var Number = DecodeNumber(Inp, BlockTables.BD);
-            if (Number < 16)
-            {
-                Table[I] = (byte)((Number + UnpOldTable20[I]) & 0xF);
-                I++;
-            }
-            else if (Number < 18)
-            {
-                uint N;
-                if (Number == 16)
-                {
-                    N = (Inp.getbits() >> 14) + 3;
-                    Inp.addbits(2);
-                }
-                else
-                {
-                    N = (Inp.getbits() >> 13) + 11;
-                    Inp.addbits(3);
-                }
-                if (I == 0)
-                {
-                    return false;
-                }
-
-                while (N-- > 0 && I < checked((int)TableSize))
-                {
-                    Table[I] = Table[I - 1];
-                    I++;
-                }
-            }
-            else
-            {
-                uint N;
-                if (Number == 18)
-                {
-                    N = (Inp.getbits() >> 13) + 3;
-                    Inp.addbits(3);
-                }
-                else
-                {
-                    N = (Inp.getbits() >> 9) + 11;
-                    Inp.addbits(7);
-                }
-
-                while (N-- > 0 && I < checked((int)TableSize))
-                {
-                    Table[I++] = 0;
-                }
-            }
-        }
-        if (UnpAudioBlock)
-        {
-            for (int I = 0; I < UnpChannels; I++)
-            {
-                MakeDecodeTables(Table, (int)(I * MC20), MD[I], MC20);
-            }
-        }
-        else
-        {
-            MakeDecodeTables(Table, 0, BlockTables.LD, NC20);
-            MakeDecodeTables(Table, (int)NC20, BlockTables.DD, DC20);
-            MakeDecodeTables(Table, (int)(NC20 + DC20), BlockTables.RD, RC20);
-        }
-        Array.Copy(Table, 0, this.UnpOldTable20, 0, UnpOldTable20.Length);
-        return true;
-    }
-
     private void ReadLastTables()
     {
         if (ReadTop >= Inp.InAddr + 5)

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack50_async.cs

@@ -0,0 +1,709 @@
+#nullable disable
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using static SharpCompress.Compressors.Rar.UnpackV2017.PackDef;
+using static SharpCompress.Compressors.Rar.UnpackV2017.UnpackGlobal;
+using size_t = System.UInt32;
+
+namespace SharpCompress.Compressors.Rar.UnpackV2017;
+
+internal partial class Unpack
+{
+    private async Task Unpack5Async(bool Solid, CancellationToken cancellationToken = default)
+    {
+        FileExtracted = true;
+
+        if (!Suspended)
+        {
+            UnpInitData(Solid);
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return;
+            }
+
+            // Check TablesRead5 to be sure that we read tables at least once
+            // regardless of current block header TablePresent flag.
+            // So we can safefly use these tables below.
+            if (
+                !await ReadBlockHeaderAsync(Inp, cancellationToken).ConfigureAwait(false)
+                || !await ReadTablesAsync(Inp, cancellationToken).ConfigureAwait(false)
+                || !TablesRead5
+            )
+            {
+                return;
+            }
+        }
+
+        while (true)
+        {
+            UnpPtr &= MaxWinMask;
+
+            if (Inp.InAddr >= ReadBorder)
+            {
+                var FileDone = false;
+
+                // We use 'while', because for empty block containing only Huffman table,
+                // we'll be on the block border once again just after reading the table.
+                while (
+                    Inp.InAddr > BlockHeader.BlockStart + BlockHeader.BlockSize - 1
+                    || Inp.InAddr == BlockHeader.BlockStart + BlockHeader.BlockSize - 1
+                        && Inp.InBit >= BlockHeader.BlockBitSize
+                )
+                {
+                    if (BlockHeader.LastBlockInFile)
+                    {
+                        FileDone = true;
+                        break;
+                    }
+                    if (
+                        !await ReadBlockHeaderAsync(Inp, cancellationToken).ConfigureAwait(false)
+                        || !await ReadTablesAsync(Inp, cancellationToken).ConfigureAwait(false)
+                    )
+                    {
+                        return;
+                    }
+                }
+                if (FileDone || !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    break;
+                }
+            }
+
+            if (((WriteBorder - UnpPtr) & MaxWinMask) < MAX_LZ_MATCH + 3 && WriteBorder != UnpPtr)
+            {
+                await UnpWriteBufAsync(cancellationToken);
+                if (WrittenFileSize > DestUnpSize)
+                {
+                    return;
+                }
+
+                if (Suspended)
+                {
+                    FileExtracted = false;
+                    return;
+                }
+            }
+
+            var MainSlot = DecodeNumber(Inp, BlockTables.LD);
+            if (MainSlot < 256)
+            {
+                if (Fragmented)
+                {
+                    FragWindow[UnpPtr++] = (byte)MainSlot;
+                }
+                else
+                {
+                    Window[UnpPtr++] = (byte)MainSlot;
+                }
+                continue;
+            }
+            if (MainSlot >= 262)
+            {
+                var Length = SlotToLength(Inp, MainSlot - 262);
+
+                uint DBits,
+                    Distance = 1,
+                    DistSlot = DecodeNumber(Inp, BlockTables.DD);
+                if (DistSlot < 4)
+                {
+                    DBits = 0;
+                    Distance += DistSlot;
+                }
+                else
+                {
+                    DBits = (DistSlot / 2) - 1;
+                    Distance += (2 | (DistSlot & 1)) << (int)DBits;
+                }
+
+                if (DBits > 0)
+                {
+                    if (DBits >= 4)
+                    {
+                        if (DBits > 4)
+                        {
+                            Distance += ((Inp.getbits32() >> (int)(36 - DBits)) << 4);
+                            Inp.addbits(DBits - 4);
+                        }
+
+                        var LowDist = DecodeNumber(Inp, BlockTables.LDD);
+                        Distance += LowDist;
+                    }
+                    else
+                    {
+                        Distance += Inp.getbits32() >> (int)(32 - DBits);
+                        Inp.addbits(DBits);
+                    }
+                }
+
+                if (Distance > 0x100)
+                {
+                    Length++;
+                    if (Distance > 0x2000)
+                    {
+                        Length++;
+                        if (Distance > 0x40000)
+                        {
+                            Length++;
+                        }
+                    }
+                }
+
+                InsertOldDist(Distance);
+                LastLength = Length;
+                if (Fragmented)
+                {
+                    FragWindow.CopyString(Length, Distance, ref UnpPtr, MaxWinMask);
+                }
+                else
+                {
+                    CopyString(Length, Distance);
+                }
+                continue;
+            }
+            if (MainSlot == 256)
+            {
+                var Filter = new UnpackFilter();
+                if (
+                    !await ReadFilterAsync(Inp, Filter, cancellationToken).ConfigureAwait(false)
+                    || !AddFilter(Filter)
+                )
+                {
+                    break;
+                }
+                continue;
+            }
+            if (MainSlot == 257)
+            {
+                if (LastLength != 0)
+                {
+                    if (Fragmented)
+                    {
+                        FragWindow.CopyString(LastLength, OldDist[0], ref UnpPtr, MaxWinMask);
+                    }
+                    else
+                    {
+                        CopyString(LastLength, OldDist[0]);
+                    }
+                }
+                continue;
+            }
+            if (MainSlot < 262)
+            {
+                var DistNum = MainSlot - 258;
+                var Distance = OldDist[DistNum];
+                for (var I = DistNum; I > 0; I--)
+                {
+                    OldDist[I] = OldDist[I - 1];
+                }
+
+                OldDist[0] = Distance;
+
+                var LengthSlot = DecodeNumber(Inp, BlockTables.RD);
+                var Length = SlotToLength(Inp, LengthSlot);
+                LastLength = Length;
+                if (Fragmented)
+                {
+                    FragWindow.CopyString(Length, Distance, ref UnpPtr, MaxWinMask);
+                }
+                else
+                {
+                    CopyString(Length, Distance);
+                }
+
+                continue;
+            }
+        }
+        await UnpWriteBufAsync(cancellationToken);
+    }
+
+    private async Task<bool> ReadFilterAsync(
+        BitInput Inp,
+        UnpackFilter Filter,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 16)
+        {
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+
+        Filter.BlockStart = ReadFilterData(Inp);
+        Filter.BlockLength = ReadFilterData(Inp);
+        if (Filter.BlockLength > MAX_FILTER_BLOCK_SIZE)
+        {
+            Filter.BlockLength = 0;
+        }
+
+        Filter.Type = (byte)(Inp.fgetbits() >> 13);
+        Inp.faddbits(3);
+
+        if (Filter.Type == FILTER_DELTA)
+        {
+            Filter.Channels = (byte)((Inp.fgetbits() >> 11) + 1);
+            Inp.faddbits(5);
+        }
+
+        return true;
+    }
+
+    private async Task<bool> UnpReadBufAsync(CancellationToken cancellationToken = default)
+    {
+        var DataSize = ReadTop - Inp.InAddr; // Data left to process.
+        if (DataSize < 0)
+        {
+            return false;
+        }
+
+        BlockHeader.BlockSize -= Inp.InAddr - BlockHeader.BlockStart;
+        if (Inp.InAddr > MAX_SIZE / 2)
+        {
+            if (DataSize > 0)
+            {
+                Buffer.BlockCopy(Inp.InBuf, Inp.InAddr, Inp.InBuf, 0, DataSize);
+            }
+
+            Inp.InAddr = 0;
+            ReadTop = DataSize;
+        }
+        else
+        {
+            DataSize = ReadTop;
+        }
+
+        var ReadCode = 0;
+        if (MAX_SIZE != DataSize)
+        {
+            ReadCode = await UnpIO_UnpReadAsync(
+                    Inp.InBuf,
+                    DataSize,
+                    MAX_SIZE - DataSize,
+                    cancellationToken
+                )
+                .ConfigureAwait(false);
+        }
+
+        if (ReadCode > 0) // Can be also -1.
+        {
+            ReadTop += ReadCode;
+        }
+
+        ReadBorder = ReadTop - 30;
+        BlockHeader.BlockStart = Inp.InAddr;
+        if (BlockHeader.BlockSize != -1) // '-1' means not defined yet.
+        {
+            ReadBorder = Math.Min(ReadBorder, BlockHeader.BlockStart + BlockHeader.BlockSize - 1);
+        }
+        return ReadCode != -1;
+    }
+
+    private async Task UnpWriteBufAsync(CancellationToken cancellationToken = default)
+    {
+        var WrittenBorder = WrPtr;
+        var FullWriteSize = (UnpPtr - WrittenBorder) & MaxWinMask;
+        var WriteSizeLeft = FullWriteSize;
+        var NotAllFiltersProcessed = false;
+
+        for (var I = 0; I < Filters.Count; I++)
+        {
+            var flt = Filters[I];
+            if (flt.Type == FILTER_NONE)
+            {
+                continue;
+            }
+
+            if (flt.NextWindow)
+            {
+                if (((flt.BlockStart - WrPtr) & MaxWinMask) <= FullWriteSize)
+                {
+                    flt.NextWindow = false;
+                }
+                continue;
+            }
+
+            var BlockStart = flt.BlockStart;
+            var BlockLength = flt.BlockLength;
+            if (((BlockStart - WrittenBorder) & MaxWinMask) < WriteSizeLeft)
+            {
+                if (WrittenBorder != BlockStart)
+                {
+                    await UnpWriteAreaAsync(WrittenBorder, BlockStart, cancellationToken)
+                        .ConfigureAwait(false);
+                    WrittenBorder = BlockStart;
+                    WriteSizeLeft = (UnpPtr - WrittenBorder) & MaxWinMask;
+                }
+                if (BlockLength <= WriteSizeLeft)
+                {
+                    if (BlockLength > 0)
+                    {
+                        var BlockEnd = (BlockStart + BlockLength) & MaxWinMask;
+
+                        FilterSrcMemory = EnsureCapacity(
+                            FilterSrcMemory,
+                            checked((int)BlockLength)
+                        );
+                        var Mem = FilterSrcMemory;
+                        if (BlockStart < BlockEnd || BlockEnd == 0)
+                        {
+                            if (Fragmented)
+                            {
+                                FragWindow.CopyData(Mem, 0, BlockStart, BlockLength);
+                            }
+                            else
+                            {
+                                Buffer.BlockCopy(Window, (int)BlockStart, Mem, 0, (int)BlockLength);
+                            }
+                        }
+                        else
+                        {
+                            var FirstPartLength = MaxWinSize - BlockStart;
+                            if (Fragmented)
+                            {
+                                FragWindow.CopyData(Mem, 0, BlockStart, FirstPartLength);
+                                FragWindow.CopyData(Mem, FirstPartLength, 0, BlockEnd);
+                            }
+                            else
+                            {
+                                Buffer.BlockCopy(
+                                    Window,
+                                    (int)BlockStart,
+                                    Mem,
+                                    0,
+                                    (int)FirstPartLength
+                                );
+                                Buffer.BlockCopy(
+                                    Window,
+                                    0,
+                                    Mem,
+                                    (int)FirstPartLength,
+                                    (int)BlockEnd
+                                );
+                            }
+                        }
+
+                        var OutMem = ApplyFilter(Mem, BlockLength, flt);
+
+                        Filters[I].Type = FILTER_NONE;
+
+                        if (OutMem != null)
+                        {
+                            await UnpIO_UnpWriteAsync(OutMem, 0, BlockLength, cancellationToken)
+                                .ConfigureAwait(false);
+                            WrittenFileSize += BlockLength;
+                        }
+
+                        WrittenBorder = BlockEnd;
+                        WriteSizeLeft = (UnpPtr - WrittenBorder) & MaxWinMask;
+                    }
+                }
+                else
+                {
+                    NotAllFiltersProcessed = true;
+                    for (var J = I; J < Filters.Count; J++)
+                    {
+                        var fltj = Filters[J];
+                        if (
+                            fltj.Type != FILTER_NONE
+                            && fltj.NextWindow == false
+                            && ((fltj.BlockStart - WrPtr) & MaxWinMask) < FullWriteSize
+                        )
+                        {
+                            fltj.NextWindow = true;
+                        }
+                    }
+                    break;
+                }
+            }
+        }
+
+        var EmptyCount = 0;
+        for (var I = 0; I < Filters.Count; I++)
+        {
+            if (EmptyCount > 0)
+            {
+                Filters[I - EmptyCount] = Filters[I];
+            }
+
+            if (Filters[I].Type == FILTER_NONE)
+            {
+                EmptyCount++;
+            }
+        }
+        if (EmptyCount > 0)
+        {
+            Filters.RemoveRange(Filters.Count - EmptyCount, EmptyCount);
+        }
+
+        if (!NotAllFiltersProcessed)
+        {
+            await UnpWriteAreaAsync(WrittenBorder, UnpPtr, cancellationToken).ConfigureAwait(false);
+            WrPtr = UnpPtr;
+        }
+
+        WriteBorder = (UnpPtr + Math.Min(MaxWinSize, UNPACK_MAX_WRITE)) & MaxWinMask;
+
+        if (
+            WriteBorder == UnpPtr
+            || WrPtr != UnpPtr
+                && ((WrPtr - UnpPtr) & MaxWinMask) < ((WriteBorder - UnpPtr) & MaxWinMask)
+        )
+        {
+            WriteBorder = WrPtr;
+        }
+    }
+
+    private async Task UnpWriteAreaAsync(
+        size_t StartPtr,
+        size_t EndPtr,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (EndPtr != StartPtr)
+        {
+            UnpSomeRead = true;
+        }
+
+        if (EndPtr < StartPtr)
+        {
+            UnpAllBuf = true;
+        }
+
+        if (Fragmented)
+        {
+            var SizeToWrite = (EndPtr - StartPtr) & MaxWinMask;
+            while (SizeToWrite > 0)
+            {
+                var BlockSize = FragWindow.GetBlockSize(StartPtr, SizeToWrite);
+                FragWindow.GetBuffer(StartPtr, out var __buffer, out var __offset);
+                await UnpWriteDataAsync(__buffer, __offset, BlockSize, cancellationToken)
+                    .ConfigureAwait(false);
+                SizeToWrite -= BlockSize;
+                StartPtr = (StartPtr + BlockSize) & MaxWinMask;
+            }
+        }
+        else if (EndPtr < StartPtr)
+        {
+            await UnpWriteDataAsync(Window, StartPtr, MaxWinSize - StartPtr, cancellationToken)
+                .ConfigureAwait(false);
+            await UnpWriteDataAsync(Window, 0, EndPtr, cancellationToken).ConfigureAwait(false);
+        }
+        else
+        {
+            await UnpWriteDataAsync(Window, StartPtr, EndPtr - StartPtr, cancellationToken)
+                .ConfigureAwait(false);
+        }
+    }
+
+    private async Task UnpWriteDataAsync(
+        byte[] Data,
+        size_t offset,
+        size_t Size,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (WrittenFileSize >= DestUnpSize)
+        {
+            return;
+        }
+
+        var WriteSize = Size;
+        var LeftToWrite = DestUnpSize - WrittenFileSize;
+        if (WriteSize > LeftToWrite)
+        {
+            WriteSize = (size_t)LeftToWrite;
+        }
+
+        await UnpIO_UnpWriteAsync(Data, offset, WriteSize, cancellationToken).ConfigureAwait(false);
+        WrittenFileSize += Size;
+    }
+
+    private async Task<bool> ReadBlockHeaderAsync(
+        BitInput Inp,
+        CancellationToken cancellationToken = default
+    )
+    {
+        BlockHeader.HeaderSize = 0;
+
+        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 7)
+        {
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+
+        Inp.faddbits((uint)((8 - Inp.InBit) & 7));
+
+        var BlockFlags = (byte)(Inp.fgetbits() >> 8);
+        Inp.faddbits(8);
+        var ByteCount = (uint)(((BlockFlags >> 3) & 3) + 1); // Block size byte count.
+
+        if (ByteCount == 4)
+        {
+            return false;
+        }
+
+        BlockHeader.HeaderSize = (int)(2 + ByteCount);
+
+        BlockHeader.BlockBitSize = (BlockFlags & 7) + 1;
+
+        var SavedCheckSum = (byte)(Inp.fgetbits() >> 8);
+        Inp.faddbits(8);
+
+        var BlockSize = 0;
+        for (uint I = 0; I < ByteCount; I++)
+        {
+            BlockSize += (int)((Inp.fgetbits() >> 8) << (int)(I * 8));
+            Inp.addbits(8);
+        }
+
+        BlockHeader.BlockSize = BlockSize;
+        var CheckSum = (byte)(0x5a ^ BlockFlags ^ BlockSize ^ (BlockSize >> 8) ^ (BlockSize >> 16));
+        if (CheckSum != SavedCheckSum)
+        {
+            return false;
+        }
+
+        BlockHeader.BlockStart = Inp.InAddr;
+        ReadBorder = Math.Min(ReadBorder, BlockHeader.BlockStart + BlockHeader.BlockSize - 1);
+
+        BlockHeader.LastBlockInFile = (BlockFlags & 0x40) != 0;
+        BlockHeader.TablePresent = (BlockFlags & 0x80) != 0;
+        return true;
+    }
+
+    private async Task<bool> ReadTablesAsync(
+        BitInput Inp,
+        CancellationToken cancellationToken = default
+    )
+    {
+        if (!BlockHeader.TablePresent)
+        {
+            return true;
+        }
+
+        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 25)
+        {
+            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+            {
+                return false;
+            }
+        }
+
+        var BitLength = new byte[checked((int)BC)];
+        for (int I = 0; I < BC; I++)
+        {
+            uint Length = (byte)(Inp.fgetbits() >> 12);
+            Inp.faddbits(4);
+            if (Length == 15)
+            {
+                uint ZeroCount = (byte)(Inp.fgetbits() >> 12);
+                Inp.faddbits(4);
+                if (ZeroCount == 0)
+                {
+                    BitLength[I] = 15;
+                }
+                else
+                {
+                    ZeroCount += 2;
+                    while (ZeroCount-- > 0 && I < BitLength.Length)
+                    {
+                        BitLength[I++] = 0;
+                    }
+
+                    I--;
+                }
+            }
+            else
+            {
+                BitLength[I] = (byte)Length;
+            }
+        }
+
+        MakeDecodeTables(BitLength, 0, BlockTables.BD, BC);
+
+        var Table = new byte[checked((int)HUFF_TABLE_SIZE)];
+        const int TableSize = checked((int)HUFF_TABLE_SIZE);
+        for (int I = 0; I < TableSize; )
+        {
+            if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 5)
+            {
+                if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
+                {
+                    return false;
+                }
+            }
+
+            var Number = DecodeNumber(Inp, BlockTables.BD);
+            if (Number < 16)
+            {
+                Table[I] = (byte)Number;
+                I++;
+            }
+            else if (Number < 18)
+            {
+                uint N;
+                if (Number == 16)
+                {
+                    N = (Inp.fgetbits() >> 13) + 3;
+                    Inp.faddbits(3);
+                }
+                else
+                {
+                    N = (Inp.fgetbits() >> 9) + 11;
+                    Inp.faddbits(7);
+                }
+                if (I == 0)
+                {
+                    // We cannot have "repeat previous" code at the first position.
+                    // Multiple such codes would shift Inp position without changing I,
+                    // which can lead to reading beyond of Inp boundary in mutithreading
+                    // mode, where Inp.ExternalBuffer disables bounds check and we just
+                    // reserve a lot of buffer space to not need such check normally.
+                    return false;
+                }
+                else
+                {
+                    while (N-- > 0 && I < TableSize)
+                    {
+                        Table[I] = Table[I - 1];
+                        I++;
+                    }
+                }
+            }
+            else
+            {
+                uint N;
+                if (Number == 18)
+                {
+                    N = (Inp.fgetbits() >> 13) + 3;
+                    Inp.faddbits(3);
+                }
+                else
+                {
+                    N = (Inp.fgetbits() >> 9) + 11;
+                    Inp.faddbits(7);
+                }
+                while (N-- > 0 && I < TableSize)
+                {
+                    Table[I++] = 0;
+                }
+            }
+        }
+        TablesRead5 = true;
+        if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop)
+        {
+            return false;
+        }
+
+        MakeDecodeTables(Table, 0, BlockTables.LD, NC);
+        MakeDecodeTables(Table, (int)NC, BlockTables.DD, DC);
+        MakeDecodeTables(Table, (int)(NC + DC), BlockTables.LDD, LDC);
+        MakeDecodeTables(Table, (int)(NC + DC + LDC), BlockTables.RD, RC);
+        return true;
+    }
+}

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack50_cpp.cs

@@ -24,11 +24,7 @@ internal partial class Unpack
             // Check TablesRead5 to be sure that we read tables at least once
             // regardless of current block header TablePresent flag.
             // So we can safefly use these tables below.
-            if (
-                !ReadBlockHeader(Inp, ref BlockHeader)
-                || !ReadTables(Inp, ref BlockHeader, ref BlockTables)
-                || !TablesRead5
-            )
+            if (!ReadBlockHeader(Inp) || !ReadTables(Inp) || !TablesRead5)
             {
                 return;
             }
@@ -55,10 +51,7 @@ internal partial class Unpack
                         FileDone = true;
                         break;
                     }
-                    if (
-                        !ReadBlockHeader(Inp, ref BlockHeader)
-                        || !ReadTables(Inp, ref BlockHeader, ref BlockTables)
-                    )
+                    if (!ReadBlockHeader(Inp) || !ReadTables(Inp))
                     {
                         return;
                     }
@@ -216,180 +209,6 @@ internal partial class Unpack
         UnpWriteBuf();
     }
 
-    private async System.Threading.Tasks.Task Unpack5Async(
-        bool Solid,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        FileExtracted = true;
-
-        if (!Suspended)
-        {
-            UnpInitData(Solid);
-            if (!await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-            {
-                return;
-            }
-
-            if (
-                !ReadBlockHeader(Inp, ref BlockHeader)
-                || !ReadTables(Inp, ref BlockHeader, ref BlockTables)
-                || !TablesRead5
-            )
-            {
-                return;
-            }
-        }
-
-        while (true)
-        {
-            UnpPtr &= MaxWinMask;
-
-            if (Inp.InAddr >= ReadBorder)
-            {
-                var FileDone = false;
-
-                while (
-                    Inp.InAddr > BlockHeader.BlockStart + BlockHeader.BlockSize - 1
-                    || Inp.InAddr == BlockHeader.BlockStart + BlockHeader.BlockSize - 1
-                        && Inp.InBit >= BlockHeader.BlockBitSize
-                )
-                {
-                    if (BlockHeader.LastBlockInFile)
-                    {
-                        FileDone = true;
-                        break;
-                    }
-                    if (
-                        !ReadBlockHeader(Inp, ref BlockHeader)
-                        || !ReadTables(Inp, ref BlockHeader, ref BlockTables)
-                    )
-                    {
-                        return;
-                    }
-                }
-                if (FileDone || !await UnpReadBufAsync(cancellationToken).ConfigureAwait(false))
-                {
-                    break;
-                }
-            }
-
-            if (((WriteBorder - UnpPtr) & MaxWinMask) < MAX_LZ_MATCH + 3 && WriteBorder != UnpPtr)
-            {
-                await UnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-                if (WrittenFileSize > DestUnpSize)
-                {
-                    return;
-                }
-            }
-
-            uint MainSlot = DecodeNumber(Inp, BlockTables.LD);
-            if (MainSlot < 256)
-            {
-                if (Fragmented)
-                {
-                    FragWindow[UnpPtr++] = (byte)MainSlot;
-                }
-                else
-                {
-                    Window[UnpPtr++] = (byte)MainSlot;
-                }
-                continue;
-            }
-            if (MainSlot >= 262)
-            {
-                uint Length = SlotToLength(Inp, MainSlot - 262);
-
-                uint DBits,
-                    Distance = 1,
-                    DistSlot = DecodeNumber(Inp, BlockTables.DD);
-                if (DistSlot < 4)
-                {
-                    DBits = 0;
-                    Distance += DistSlot;
-                }
-                else
-                {
-                    DBits = (DistSlot / 2) - 1;
-                    Distance += (2 | (DistSlot & 1)) << (int)DBits;
-                }
-
-                if (DBits > 0)
-                {
-                    if (DBits >= 4)
-                    {
-                        if (DBits > 4)
-                        {
-                            Distance += ((Inp.getbits() >> (int)(20 - DBits)) << 4);
-                            Inp.addbits(DBits - 4);
-                        }
-
-                        uint LowDist = DecodeNumber(Inp, BlockTables.LDD);
-                        Distance += LowDist;
-                    }
-                    else
-                    {
-                        Distance += Inp.getbits() >> (int)(16 - DBits);
-                        Inp.addbits(DBits);
-                    }
-                }
-
-                if (Distance > 0x100)
-                {
-                    Length++;
-                    if (Distance > 0x2000)
-                    {
-                        Length++;
-                        if (Distance > 0x40000)
-                        {
-                            Length++;
-                        }
-                    }
-                }
-
-                InsertOldDist(Distance);
-                LastLength = Length;
-                CopyString(Length, Distance);
-                continue;
-            }
-            if (MainSlot == 256)
-            {
-                var Filter = new UnpackFilter();
-                if (!ReadFilter(Inp, Filter) || !AddFilter(Filter))
-                {
-                    break;
-                }
-                continue;
-            }
-            if (MainSlot == 257)
-            {
-                if (LastLength != 0)
-                {
-                    CopyString((uint)LastLength, (uint)OldDist[0]);
-                }
-                continue;
-            }
-            if (MainSlot < 262)
-            {
-                uint DistNum = MainSlot - 258;
-                uint Distance = (uint)OldDist[(int)DistNum];
-                for (var I = (int)DistNum; I > 0; I--)
-                {
-                    OldDist[I] = OldDist[I - 1];
-                }
-                OldDist[0] = Distance;
-
-                uint LengthSlot = DecodeNumber(Inp, BlockTables.RD);
-                uint Length = SlotToLength(Inp, LengthSlot);
-                LastLength = Length;
-                CopyString(Length, Distance);
-
-                continue;
-            }
-        }
-        await UnpWriteBufAsync(cancellationToken).ConfigureAwait(false);
-    }
-
     private uint ReadFilterData(BitInput Inp)
     {
         var ByteCount = (Inp.fgetbits() >> 14) + 1;
@@ -507,58 +326,6 @@ internal partial class Unpack
         return ReadCode != -1;
     }
 
-    private async System.Threading.Tasks.Task<bool> UnpReadBufAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        var DataSize = ReadTop - Inp.InAddr; // Data left to process.
-        if (DataSize < 0)
-        {
-            return false;
-        }
-
-        BlockHeader.BlockSize -= Inp.InAddr - BlockHeader.BlockStart;
-        if (Inp.InAddr > MAX_SIZE / 2)
-        {
-            if (DataSize > 0)
-            {
-                Buffer.BlockCopy(Inp.InBuf, Inp.InAddr, Inp.InBuf, 0, DataSize);
-            }
-
-            Inp.InAddr = 0;
-            ReadTop = DataSize;
-        }
-        else
-        {
-            DataSize = ReadTop;
-        }
-
-        var ReadCode = 0;
-        if (MAX_SIZE != DataSize)
-        {
-            ReadCode = await UnpIO_UnpReadAsync(
-                    Inp.InBuf,
-                    DataSize,
-                    MAX_SIZE - DataSize,
-                    cancellationToken
-                )
-                .ConfigureAwait(false);
-        }
-
-        if (ReadCode > 0) // Can be also -1.
-        {
-            ReadTop += ReadCode;
-        }
-
-        ReadBorder = ReadTop - 30;
-        BlockHeader.BlockStart = Inp.InAddr;
-        if (BlockHeader.BlockSize != -1) // '-1' means not defined yet.
-        {
-            ReadBorder = Math.Min(ReadBorder, BlockHeader.BlockStart + BlockHeader.BlockSize - 1);
-        }
-        return ReadCode != -1;
-    }
-
     private void UnpWriteBuf()
     {
         var WrittenBorder = WrPtr;
@@ -753,163 +520,6 @@ internal partial class Unpack
         }
     }
 
-    private async System.Threading.Tasks.Task UnpWriteBufAsync(
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        var WrittenBorder = WrPtr;
-        var FullWriteSize = (UnpPtr - WrittenBorder) & MaxWinMask;
-        var WriteSizeLeft = FullWriteSize;
-        var NotAllFiltersProcessed = false;
-
-        for (var I = 0; I < Filters.Count; I++)
-        {
-            var flt = Filters[I];
-            if (flt.Type == FILTER_NONE)
-            {
-                continue;
-            }
-
-            if (flt.NextWindow)
-            {
-                if (((flt.BlockStart - WrPtr) & MaxWinMask) <= FullWriteSize)
-                {
-                    flt.NextWindow = false;
-                }
-                continue;
-            }
-
-            var BlockStart = flt.BlockStart;
-            var BlockLength = flt.BlockLength;
-            if (((BlockStart - WrittenBorder) & MaxWinMask) < WriteSizeLeft)
-            {
-                if (WrittenBorder != BlockStart)
-                {
-                    await UnpWriteAreaAsync(WrittenBorder, BlockStart, cancellationToken)
-                        .ConfigureAwait(false);
-                    WrittenBorder = BlockStart;
-                    WriteSizeLeft = (UnpPtr - WrittenBorder) & MaxWinMask;
-                }
-                if (BlockLength <= WriteSizeLeft)
-                {
-                    if (BlockLength > 0)
-                    {
-                        var BlockEnd = (BlockStart + BlockLength) & MaxWinMask;
-
-                        FilterSrcMemory = EnsureCapacity(
-                            FilterSrcMemory,
-                            checked((int)BlockLength)
-                        );
-                        var Mem = FilterSrcMemory;
-                        if (BlockStart < BlockEnd || BlockEnd == 0)
-                        {
-                            if (Fragmented)
-                            {
-                                FragWindow.CopyData(Mem, 0, BlockStart, BlockLength);
-                            }
-                            else
-                            {
-                                Buffer.BlockCopy(Window, (int)BlockStart, Mem, 0, (int)BlockLength);
-                            }
-                        }
-                        else
-                        {
-                            var FirstPartLength = MaxWinSize - BlockStart;
-                            if (Fragmented)
-                            {
-                                FragWindow.CopyData(Mem, 0, BlockStart, FirstPartLength);
-                                FragWindow.CopyData(Mem, FirstPartLength, 0, BlockEnd);
-                            }
-                            else
-                            {
-                                Buffer.BlockCopy(
-                                    Window,
-                                    (int)BlockStart,
-                                    Mem,
-                                    0,
-                                    (int)FirstPartLength
-                                );
-                                Buffer.BlockCopy(
-                                    Window,
-                                    0,
-                                    Mem,
-                                    (int)FirstPartLength,
-                                    (int)BlockEnd
-                                );
-                            }
-                        }
-
-                        var OutMem = ApplyFilter(Mem, BlockLength, flt);
-
-                        Filters[I].Type = FILTER_NONE;
-
-                        if (OutMem != null)
-                        {
-                            await UnpIO_UnpWriteAsync(OutMem, 0, BlockLength, cancellationToken)
-                                .ConfigureAwait(false);
-                            WrittenFileSize += BlockLength;
-                        }
-
-                        WrittenBorder = BlockEnd;
-                        WriteSizeLeft = (UnpPtr - WrittenBorder) & MaxWinMask;
-                    }
-                }
-                else
-                {
-                    NotAllFiltersProcessed = true;
-                    for (var J = I; J < Filters.Count; J++)
-                    {
-                        var fltj = Filters[J];
-                        if (
-                            fltj.Type != FILTER_NONE
-                            && fltj.NextWindow == false
-                            && ((fltj.BlockStart - WrPtr) & MaxWinMask) < FullWriteSize
-                        )
-                        {
-                            fltj.NextWindow = true;
-                        }
-                    }
-                    break;
-                }
-            }
-        }
-
-        var EmptyCount = 0;
-        for (var I = 0; I < Filters.Count; I++)
-        {
-            if (EmptyCount > 0)
-            {
-                Filters[I - EmptyCount] = Filters[I];
-            }
-
-            if (Filters[I].Type == FILTER_NONE)
-            {
-                EmptyCount++;
-            }
-        }
-        if (EmptyCount > 0)
-        {
-            Filters.RemoveRange(Filters.Count - EmptyCount, EmptyCount);
-        }
-
-        if (!NotAllFiltersProcessed)
-        {
-            await UnpWriteAreaAsync(WrittenBorder, UnpPtr, cancellationToken).ConfigureAwait(false);
-            WrPtr = UnpPtr;
-        }
-
-        WriteBorder = (UnpPtr + Math.Min(MaxWinSize, UNPACK_MAX_WRITE)) & MaxWinMask;
-
-        if (
-            WriteBorder == UnpPtr
-            || WrPtr != UnpPtr
-                && ((WrPtr - UnpPtr) & MaxWinMask) < ((WriteBorder - UnpPtr) & MaxWinMask)
-        )
-        {
-            WriteBorder = WrPtr;
-        }
-    }
-
     private byte[] ApplyFilter(byte[] __d, uint DataSize, UnpackFilter Flt)
     {
         var Data = 0;
@@ -1041,48 +651,6 @@ internal partial class Unpack
         }
     }
 
-    private async System.Threading.Tasks.Task UnpWriteAreaAsync(
-        size_t StartPtr,
-        size_t EndPtr,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (EndPtr != StartPtr)
-        {
-            UnpSomeRead = true;
-        }
-
-        if (EndPtr < StartPtr)
-        {
-            UnpAllBuf = true;
-        }
-
-        if (Fragmented)
-        {
-            var SizeToWrite = (EndPtr - StartPtr) & MaxWinMask;
-            while (SizeToWrite > 0)
-            {
-                var BlockSize = FragWindow.GetBlockSize(StartPtr, SizeToWrite);
-                FragWindow.GetBuffer(StartPtr, out var __buffer, out var __offset);
-                await UnpWriteDataAsync(__buffer, __offset, BlockSize, cancellationToken)
-                    .ConfigureAwait(false);
-                SizeToWrite -= BlockSize;
-                StartPtr = (StartPtr + BlockSize) & MaxWinMask;
-            }
-        }
-        else if (EndPtr < StartPtr)
-        {
-            await UnpWriteDataAsync(Window, StartPtr, MaxWinSize - StartPtr, cancellationToken)
-                .ConfigureAwait(false);
-            await UnpWriteDataAsync(Window, 0, EndPtr, cancellationToken).ConfigureAwait(false);
-        }
-        else
-        {
-            await UnpWriteDataAsync(Window, StartPtr, EndPtr - StartPtr, cancellationToken)
-                .ConfigureAwait(false);
-        }
-    }
-
     private void UnpWriteData(byte[] Data, size_t offset, size_t Size)
     {
         if (WrittenFileSize >= DestUnpSize)
@@ -1101,29 +669,6 @@ internal partial class Unpack
         WrittenFileSize += Size;
     }
 
-    private async System.Threading.Tasks.Task UnpWriteDataAsync(
-        byte[] Data,
-        size_t offset,
-        size_t Size,
-        System.Threading.CancellationToken cancellationToken = default
-    )
-    {
-        if (WrittenFileSize >= DestUnpSize)
-        {
-            return;
-        }
-
-        var WriteSize = Size;
-        var LeftToWrite = DestUnpSize - WrittenFileSize;
-        if (WriteSize > LeftToWrite)
-        {
-            WriteSize = (size_t)LeftToWrite;
-        }
-
-        await UnpIO_UnpWriteAsync(Data, offset, WriteSize, cancellationToken).ConfigureAwait(false);
-        WrittenFileSize += Size;
-    }
-
     private void UnpInitData50(bool Solid)
     {
         if (!Solid)
@@ -1132,9 +677,9 @@ internal partial class Unpack
         }
     }
 
-    private bool ReadBlockHeader(BitInput Inp, ref UnpackBlockHeader Header)
+    private bool ReadBlockHeader(BitInput Inp)
     {
-        Header.HeaderSize = 0;
+        BlockHeader.HeaderSize = 0;
 
         if (!Inp.ExternalBuffer && Inp.InAddr > ReadTop - 7)
         {
@@ -1155,9 +700,9 @@ internal partial class Unpack
             return false;
         }
 
-        Header.HeaderSize = (int)(2 + ByteCount);
+        BlockHeader.HeaderSize = (int)(2 + ByteCount);
 
-        Header.BlockBitSize = (BlockFlags & 7) + 1;
+        BlockHeader.BlockBitSize = (BlockFlags & 7) + 1;
 
         var SavedCheckSum = (byte)(Inp.fgetbits() >> 8);
         Inp.faddbits(8);
@@ -1169,28 +714,24 @@ internal partial class Unpack
             Inp.addbits(8);
         }
 
-        Header.BlockSize = BlockSize;
+        BlockHeader.BlockSize = BlockSize;
         var CheckSum = (byte)(0x5a ^ BlockFlags ^ BlockSize ^ (BlockSize >> 8) ^ (BlockSize >> 16));
         if (CheckSum != SavedCheckSum)
         {
             return false;
         }
 
-        Header.BlockStart = Inp.InAddr;
-        ReadBorder = Math.Min(ReadBorder, Header.BlockStart + Header.BlockSize - 1);
+        BlockHeader.BlockStart = Inp.InAddr;
+        ReadBorder = Math.Min(ReadBorder, BlockHeader.BlockStart + BlockHeader.BlockSize - 1);
 
-        Header.LastBlockInFile = (BlockFlags & 0x40) != 0;
-        Header.TablePresent = (BlockFlags & 0x80) != 0;
+        BlockHeader.LastBlockInFile = (BlockFlags & 0x40) != 0;
+        BlockHeader.TablePresent = (BlockFlags & 0x80) != 0;
         return true;
     }
 
-    private bool ReadTables(
-        BitInput Inp,
-        ref UnpackBlockHeader Header,
-        ref UnpackBlockTables Tables
-    )
+    private bool ReadTables(BitInput Inp)
     {
-        if (!Header.TablePresent)
+        if (!BlockHeader.TablePresent)
         {
             return true;
         }
@@ -1233,7 +774,7 @@ internal partial class Unpack
             }
         }
 
-        MakeDecodeTables(BitLength, 0, Tables.BD, BC);
+        MakeDecodeTables(BitLength, 0, BlockTables.BD, BC);
 
         Span<byte> Table = stackalloc byte[checked((int)HUFF_TABLE_SIZE)];
         const int TableSize = checked((int)HUFF_TABLE_SIZE);
@@ -1247,7 +788,7 @@ internal partial class Unpack
                 }
             }
 
-            var Number = DecodeNumber(Inp, Tables.BD);
+            var Number = DecodeNumber(Inp, BlockTables.BD);
             if (Number < 16)
             {
                 Table[I] = (byte)Number;
@@ -1309,10 +850,10 @@ internal partial class Unpack
             return false;
         }
 
-        MakeDecodeTables(Table, 0, Tables.LD, NC);
-        MakeDecodeTables(Table, (int)NC, Tables.DD, DC);
-        MakeDecodeTables(Table, (int)(NC + DC), Tables.LDD, LDC);
-        MakeDecodeTables(Table, (int)(NC + DC + LDC), Tables.RD, RC);
+        MakeDecodeTables(Table, 0, BlockTables.LD, NC);
+        MakeDecodeTables(Table, (int)NC, BlockTables.DD, DC);
+        MakeDecodeTables(Table, (int)(NC + DC), BlockTables.LDD, LDC);
+        MakeDecodeTables(Table, (int)(NC + DC + LDC), BlockTables.RD, RC);
         return true;
     }
 

src/SharpCompress/Compressors/Rar/UnpackV2017/Unpack.unpack_cpp.cs

@@ -2,6 +2,8 @@
 
 using System;
 using System.Buffers;
+using System.Threading;
+using System.Threading.Tasks;
 using SharpCompress.Common;
 using static SharpCompress.Compressors.Rar.UnpackV2017.PackDef;
 using static SharpCompress.Compressors.Rar.UnpackV2017.UnpackGlobal;
@@ -196,10 +198,10 @@ internal sealed partial class Unpack : BitInput
         }
     }
 
-    private async System.Threading.Tasks.Task DoUnpackAsync(
+    private async Task DoUnpackAsync(
         uint Method,
         bool Solid,
-        System.Threading.CancellationToken cancellationToken = default
+        CancellationToken cancellationToken = default
     )
     {
         // Methods <50 will crash in Fragmented mode when accessing NULL Window.

src/SharpCompress/packages.lock.json

@@ -216,9 +216,9 @@
     "net10.0": {
       "Microsoft.NET.ILLink.Tasks": {
         "type": "Direct",
-        "requested": "[10.0.0, )",
-        "resolved": "10.0.0",
-        "contentHash": "kICGrGYEzCNI3wPzfEXcwNHgTvlvVn9yJDhSdRK+oZQy4jvYH529u7O0xf5ocQKzOMjfS07+3z9PKRIjrFMJDA=="
+        "requested": "[10.0.2, )",
+        "resolved": "10.0.2",
+        "contentHash": "sXdDtMf2qcnbygw9OdE535c2lxSxrZP8gO4UhDJ0xiJbl1wIqXS1OTcTDFTIJPOFd6Mhcm8gPEthqWGUxBsTqw=="
       },
       "Microsoft.NETFramework.ReferenceAssemblies": {
         "type": "Direct",
@@ -264,9 +264,9 @@
     "net8.0": {
       "Microsoft.NET.ILLink.Tasks": {
         "type": "Direct",
-        "requested": "[8.0.22, )",
-        "resolved": "8.0.22",
-        "contentHash": "MhcMithKEiyyNkD2ZfbDZPmcOdi0GheGfg8saEIIEfD/fol3iHmcV8TsZkD4ZYz5gdUuoX4YtlVySUU7Sxl9SQ=="
+        "requested": "[8.0.23, )",
+        "resolved": "8.0.23",
+        "contentHash": "GqHiB1HbbODWPbY/lc5xLQH8siEEhNA0ptpJCC6X6adtAYNEzu5ZlqV3YHA3Gh7fuEwgA8XqVwMtH2KNtuQM1Q=="
       },
       "Microsoft.NETFramework.ReferenceAssemblies": {
         "type": "Direct",

tests/SharpCompress.Test/Rar/Rar5AsyncExtractionTests.cs

@@ -0,0 +1,243 @@
+using System.IO;
+using System.Linq;
+using System.Threading.Tasks;
+using SharpCompress.Archives;
+using SharpCompress.Archives.Rar;
+using SharpCompress.Common;
+using SharpCompress.Readers;
+using SharpCompress.Test.Mocks;
+using Xunit;
+
+namespace SharpCompress.Test.Rar;
+
+/// <summary>
+/// Tests specifically designed to exercise the Unpack5Async code path for RAR5 archives.
+/// These tests use AsyncOnlyStream to ensure that async methods are actually being called.
+/// </summary>
+public class Rar5AsyncExtractionTests : ArchiveTests
+{
+    [Fact]
+    public async Task Rar5_Basic_Reader_ExtractAll_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_None_Reader_ExtractAll_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.none.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Solid_ExtractAllEntries_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.solid.rar"));
+        await using var archive = RarArchive.OpenAsyncArchive(new AsyncOnlyStream(stream));
+
+        Assert.True(await archive.IsSolidAsync());
+
+        await using var reader = await archive.ExtractAllEntriesAsync();
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Solid_Reader_ExtractAll_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.solid.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Reader_OpenEntryStream_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                var entryStream = await reader.OpenEntryStreamAsync();
+                try
+                {
+                    var file = Path.GetFileName(reader.Entry.Key).NotNull();
+                    var folder = Path.GetDirectoryName(reader.Entry.Key) ?? "";
+                    var destdir = Path.Combine(SCRATCH_FILES_PATH, folder);
+                    if (!Directory.Exists(destdir))
+                    {
+                        Directory.CreateDirectory(destdir);
+                    }
+                    var destinationFileName = Path.Combine(destdir, file);
+
+                    using var fs = File.OpenWrite(destinationFileName);
+                    await entryStream.CopyToAsync(fs);
+                }
+                finally
+                {
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
+                    await entryStream.DisposeAsync();
+#else
+                    entryStream.Dispose();
+#endif
+                }
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Encrypted_FilesOnly_Reader_Async()
+    {
+        using var stream = File.OpenRead(
+            Path.Combine(TEST_ARCHIVES_PATH, "Rar5.encrypted_filesOnly.rar")
+        );
+        await using var reader = await ReaderFactory.OpenAsyncReader(
+            new AsyncOnlyStream(stream),
+            new ReaderOptions { Password = "test" }
+        );
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Encrypted_FilesAndHeader_Reader_Async()
+    {
+        using var stream = File.OpenRead(
+            Path.Combine(TEST_ARCHIVES_PATH, "Rar5.encrypted_filesAndHeader.rar")
+        );
+        await using var reader = await ReaderFactory.OpenAsyncReader(
+            new AsyncOnlyStream(stream),
+            new ReaderOptions { Password = "test" }
+        );
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_CRC_Blake2_Reader_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.crc_blake2.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Comment_Reader_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.comment.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            if (!reader.Entry.IsDirectory)
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Solid_Skip_Some_Entries_Reader_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.solid.rar"));
+        await using var reader = await ReaderFactory.OpenAsyncReader(new AsyncOnlyStream(stream));
+
+        while (await reader.MoveToNextEntryAsync())
+        {
+            // Only extract jpg files to test skipping in solid archive
+            if (!reader.Entry.IsDirectory && reader.Entry.Key.NotNull().Contains("jpg"))
+            {
+                Assert.Equal(CompressionType.Rar, reader.Entry.CompressionType);
+                await reader.WriteEntryToDirectoryAsync(SCRATCH_FILES_PATH);
+            }
+        }
+    }
+
+    [Fact]
+    public async Task Rar5_WriteToDirectory_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.rar"));
+        await using var archive = RarArchive.OpenAsyncArchive(new AsyncOnlyStream(stream));
+
+        await archive.WriteToDirectoryAsync(SCRATCH_FILES_PATH);
+        VerifyFiles();
+    }
+
+    [Fact]
+    public async Task Rar5_Solid_WriteToDirectory_Async()
+    {
+        using var stream = File.OpenRead(Path.Combine(TEST_ARCHIVES_PATH, "Rar5.solid.rar"));
+        await using var archive = RarArchive.OpenAsyncArchive(new AsyncOnlyStream(stream));
+
+        Assert.True(await archive.IsSolidAsync());
+        await archive.WriteToDirectoryAsync(SCRATCH_FILES_PATH);
+        VerifyFiles();
+    }
+}