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https://github.com/ryujinx-mirror/ryujinx.git
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78 lines
1.9 KiB
C#
78 lines
1.9 KiB
C#
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using System;
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namespace Ryujinx.Loaders.Compression
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{
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static class Lz4
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{
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public static byte[] Decompress(byte[] Cmp, int DecLength)
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{
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byte[] Dec = new byte[DecLength];
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int CmpPos = 0;
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int DecPos = 0;
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int GetLength(int Length)
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{
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byte Sum;
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if (Length == 0xf)
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{
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do
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{
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Length += (Sum = Cmp[CmpPos++]);
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}
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while (Sum == 0xff);
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}
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return Length;
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}
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do
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{
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byte Token = Cmp[CmpPos++];
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int EncCount = (Token >> 0) & 0xf;
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int LitCount = (Token >> 4) & 0xf;
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//Copy literal chunck
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LitCount = GetLength(LitCount);
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Buffer.BlockCopy(Cmp, CmpPos, Dec, DecPos, LitCount);
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CmpPos += LitCount;
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DecPos += LitCount;
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if (CmpPos >= Cmp.Length)
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{
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break;
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}
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//Copy compressed chunck
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int Back = Cmp[CmpPos++] << 0 |
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Cmp[CmpPos++] << 8;
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EncCount = GetLength(EncCount) + 4;
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int EncPos = DecPos - Back;
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if (EncCount <= Back)
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{
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Buffer.BlockCopy(Dec, EncPos, Dec, DecPos, EncCount);
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DecPos += EncCount;
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}
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else
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{
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while (EncCount-- > 0)
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{
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Dec[DecPos++] = Dec[EncPos++];
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}
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}
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}
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while (CmpPos < Cmp.Length &&
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DecPos < Dec.Length);
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return Dec;
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}
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}
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}
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