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Fix synchronous reads called in async RAR unpacker paths #1305

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Fix synchronous reads called in async RAR unpacker paths #1305

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Copilot Apr 28, 2026
0e4cfef
Fix sync methods called in async RAR unpacker paths (Unpack29Async, U…
Copilot Apr 28, 2026
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201 changes: 197 additions & 4 deletions src/SharpCompress/Compressors/Rar/UnpackV1/Unpack.Async.cs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
using System;
using System.Buffers;
using System.Collections.Generic;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
Expand Down Expand Up @@ -112,7 +113,10 @@ private async Task Unpack29Async(bool solid, CancellationToken cancellationToken
{
return;
}
if ((!solid || !tablesRead) && !ReadTables())
if (
(!solid || !tablesRead)
&& !await ReadTablesAsync(cancellationToken).ConfigureAwait(false)
)
{
return;
}
Expand Down Expand Up @@ -161,7 +165,7 @@ private async Task Unpack29Async(bool solid, CancellationToken cancellationToken
var NextCh = ppm.DecodeChar();
if (NextCh == 0)
{
if (!ReadTables())
if (!await ReadTablesAsync(cancellationToken).ConfigureAwait(false))
{
break;
}
Expand Down Expand Up @@ -294,15 +298,15 @@ private async Task Unpack29Async(bool solid, CancellationToken cancellationToken
}
if (Number == 256)
{
if (!ReadEndOfBlock())
if (!await ReadEndOfBlockAsync(cancellationToken).ConfigureAwait(false))
{
break;
}
continue;
}
if (Number == 257)
{
if (!ReadVMCode())
if (!await ReadVMCodeAsync(cancellationToken).ConfigureAwait(false))
{
break;
}
Expand Down Expand Up @@ -600,4 +604,193 @@ await writeStream
writtenFileSize += size;
destUnpSize -= size;
}

private async Task<bool> ReadTablesAsync(CancellationToken cancellationToken = default)
{
var bitLength = new byte[PackDef.BC];
var table = new byte[PackDef.HUFF_TABLE_SIZE];

if (inAddr > readTop - 25)
{
if (!await unpReadBufAsync(cancellationToken).ConfigureAwait(false))
{
return false;
}
}
AddBits((8 - inBit) & 7);
long bitField = GetBits() & unchecked((int)0xffFFffFF);
if ((bitField & 0x8000) != 0)
{
unpBlockType = BlockTypes.BLOCK_PPM;
return ppm.DecodeInit(this, PpmEscChar);
}
unpBlockType = BlockTypes.BLOCK_LZ;

prevLowDist = 0;
lowDistRepCount = 0;

if ((bitField & 0x4000) == 0)
{
new Span<byte>(unpOldTable).Clear();
}
AddBits(2);

for (var i = 0; i < PackDef.BC; i++)
{
var length = (Utility.URShift(GetBits(), 12)) & 0xFF;
AddBits(4);
if (length == 15)
{
var zeroCount = (Utility.URShift(GetBits(), 12)) & 0xFF;
AddBits(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;
}
}

UnpackUtility.makeDecodeTables(bitLength, 0, BD, PackDef.BC);

var TableSize = PackDef.HUFF_TABLE_SIZE;

for (var i = 0; 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 + unpOldTable[i]) & 0xf);
i++;
}
else if (Number < 18)
{
int N;
if (Number == 16)
{
N = (Utility.URShift(GetBits(), 13)) + 3;
AddBits(3);
}
else
{
N = (Utility.URShift(GetBits(), 9)) + 11;
AddBits(7);
}
while (N-- > 0 && i < TableSize)
{
table[i] = table[i - 1];
i++;
}
}
else
{
int N;
if (Number == 18)
{
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;
}
}
}
tablesRead = true;
if (inAddr > readTop)
{
return false;
}
UnpackUtility.makeDecodeTables(table, 0, LD, PackDef.NC);
UnpackUtility.makeDecodeTables(table, PackDef.NC, DD, PackDef.DC);
UnpackUtility.makeDecodeTables(table, PackDef.NC + PackDef.DC, LDD, PackDef.LDC);
UnpackUtility.makeDecodeTables(
table,
PackDef.NC + PackDef.DC + PackDef.LDC,
RD,
PackDef.RC
);

new Span<byte>(table).CopyTo(unpOldTable);
return true;
}

private async Task<bool> ReadEndOfBlockAsync(CancellationToken cancellationToken = default)
{
var BitField = GetBits();
bool NewTable,
NewFile = false;
if ((BitField & 0x8000) != 0)
{
NewTable = true;
AddBits(1);
}
else
{
NewFile = true;
NewTable = (BitField & 0x4000) != 0;
AddBits(2);
}
tablesRead = !NewTable;
return !(
NewFile || NewTable && !await ReadTablesAsync(cancellationToken).ConfigureAwait(false)
);
}

private async Task<bool> ReadVMCodeAsync(CancellationToken cancellationToken = default)
{
var FirstByte = GetBits() >> 8;
AddBits(8);
var Length = (FirstByte & 7) + 1;
if (Length == 7)
{
Length = (GetBits() >> 8) + 7;
AddBits(8);
}
else if (Length == 8)
{
Length = GetBits();
AddBits(16);
}

var vmCode = new List<byte>();
for (var I = 0; I < Length; I++)
{
if (
inAddr >= readTop - 1
&& !await unpReadBufAsync(cancellationToken).ConfigureAwait(false)
&& I < Length - 1
)
{
return false;
}
vmCode.Add((byte)(GetBits() >> 8));
AddBits(8);
}
return AddVMCode(FirstByte, vmCode);
}
}
4 changes: 2 additions & 2 deletions src/SharpCompress/Compressors/Rar/UnpackV1/Unpack50.Async.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -70,7 +70,7 @@ public async Task Unpack5Async(bool Solid, CancellationToken cancellationToken =
// So we can safefly use these tables below.
if (
!await ReadBlockHeaderAsync(cancellationToken).ConfigureAwait(false)
|| !ReadTables()
|| !await ReadTablesAsync(cancellationToken).ConfigureAwait(false)
|| !TablesRead5
)
{
Expand Down Expand Up @@ -101,7 +101,7 @@ public async Task Unpack5Async(bool Solid, CancellationToken cancellationToken =
}
if (
!await ReadBlockHeaderAsync(cancellationToken).ConfigureAwait(false)
|| !ReadTables()
|| !await ReadTablesAsync(cancellationToken).ConfigureAwait(false)
)
{
return;
Expand Down
12 changes: 6 additions & 6 deletions src/SharpCompress/packages.lock.json
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Original file line number Diff line number Diff line change
Expand Up @@ -268,9 +268,9 @@
"net10.0": {
"Microsoft.NET.ILLink.Tasks": {
"type": "Direct",
"requested": "[10.0.5, )",
"resolved": "10.0.5",
"contentHash": "A+5ZuQ0f449tM+MQrhf6R9ZX7lYpjk/ODEwLYKrnF6111rtARx8fVsm4YznUnQiKnnXfaXNBqgxmil6RW3L3SA=="
"requested": "[10.0.0, )",
"resolved": "10.0.0",
"contentHash": "kICGrGYEzCNI3wPzfEXcwNHgTvlvVn9yJDhSdRK+oZQy4jvYH529u7O0xf5ocQKzOMjfS07+3z9PKRIjrFMJDA=="
},
"Microsoft.NETFramework.ReferenceAssemblies": {
"type": "Direct",
Expand Down Expand Up @@ -400,9 +400,9 @@
"net8.0": {
"Microsoft.NET.ILLink.Tasks": {
"type": "Direct",
"requested": "[8.0.25, )",
"resolved": "8.0.25",
"contentHash": "sqX4nmBft05ivqKvUT4nxaN8rT3apCLt9SWFkfRrQPwra1zPwFknQAw1lleuMCKOCLvVmOWwrC2iPSm9RiXZUg=="
"requested": "[8.0.22, )",
"resolved": "8.0.22",
"contentHash": "MhcMithKEiyyNkD2ZfbDZPmcOdi0GheGfg8saEIIEfD/fol3iHmcV8TsZkD4ZYz5gdUuoX4YtlVySUU7Sxl9SQ=="
},
"Microsoft.NETFramework.ReferenceAssemblies": {
"type": "Direct",
Expand Down
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