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Rar2 v20,v26 Multimedia (Audio) decoder fix #896

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Merged
adamhathcock merged 2 commits into from
Feb 12, 2025
Merged

Rar2 v20,v26 Multimedia (Audio) decoder fix #896

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c41888b
Rar2 v20,v26 Multimedia (Audio) decoder fix
Nanook Feb 11, 2025
6bc690b
Seriously?
Nanook Feb 11, 2025
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38 changes: 34 additions & 4 deletions src/SharpCompress/Compressors/Rar/UnpackV1/Unpack20.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,13 @@ namespace SharpCompress.Compressors.Rar.UnpackV1;

internal partial class Unpack
{
private readonly MultDecode[] MD = new MultDecode[4];
private readonly MultDecode[] MD = new[]
{
new MultDecode(),
new MultDecode(),
new MultDecode(),
new MultDecode(),
};

private readonly byte[] UnpOldTable20 = new byte[PackDef.MC20 * 4];

Expand Down Expand Up @@ -475,6 +481,31 @@ private bool ReadTables20()
{
Table[I++] = 0;
}
// Nanook. Working port from Rar C code. Added when working on Audio Decode Fix. Seems equal to above, so commented it
//byte v;
//if (Number == 16)
//{
// N = (Utility.URShift(GetBits(), 14)) + 3;
// AddBits(2);
// v = Table[I - 1];
//}
//else
//{
// N = (Number - 17) * 4;
// int bits = 3 + N;
// N += N + 3 + (Utility.URShift(GetBits(), 16 - bits));
// AddBits(bits);
// v = 0;
//}
//N += I;
//if (N > TableSize)
//{
// N = TableSize; // original unRAR
//}
//do
//{
// Table[I++] = v;
//} while (I < N);
}
}
if (inAddr > readTop)
Expand Down Expand Up @@ -559,8 +590,7 @@ private byte DecodeAudio(int Delta)
PCh = (Utility.URShift(PCh, 3)) & 0xFF;

var Ch = PCh - Delta;

var D = ((byte)Delta) << 3;
var D = ((sbyte)Delta) << 3;

v.Dif[0] += Math.Abs(D); // V->Dif[0]+=abs(D);
v.Dif[1] += Math.Abs(D - v.D1); // V->Dif[1]+=abs(D-V->D1);
Expand All @@ -574,7 +604,7 @@ private byte DecodeAudio(int Delta)
v.Dif[9] += Math.Abs(D - UnpChannelDelta); // V->Dif[9]+=abs(D-UnpChannelDelta);
v.Dif[10] += Math.Abs(D + UnpChannelDelta); // V->Dif[10]+=abs(D+UnpChannelDelta);

v.LastDelta = (byte)(Ch - v.LastChar);
v.LastDelta = (sbyte)(Ch - v.LastChar);
UnpChannelDelta = v.LastDelta;
v.LastChar = Ch; // V->LastChar=Ch;

Expand Down