ryujinx/Ryujinx.HLE/Loaders/Compression/Lz4.cs
Alex Barney b2b736abc2 Misc cleanup (#708)
* Fix typos

* Remove unneeded using statements

* Enforce var style more

* Remove redundant qualifiers

* Fix some indentation

* Disable naming warnings on files with external enum names

* Fix build

* Mass find & replace for comments with no spacing

* Standardize todo capitalization and for/if spacing
2019-07-02 04:39:22 +02:00

78 lines
1.9 KiB
C#

using System;
namespace Ryujinx.HLE.Loaders.Compression
{
static class Lz4
{
public static byte[] Decompress(byte[] cmp, int decLength)
{
byte[] dec = new byte[decLength];
int cmpPos = 0;
int decPos = 0;
int GetLength(int length)
{
byte sum;
if (length == 0xf)
{
do
{
length += (sum = cmp[cmpPos++]);
}
while (sum == 0xff);
}
return length;
}
do
{
byte token = cmp[cmpPos++];
int encCount = (token >> 0) & 0xf;
int litCount = (token >> 4) & 0xf;
// Copy literal chunk
litCount = GetLength(litCount);
Buffer.BlockCopy(cmp, cmpPos, dec, decPos, litCount);
cmpPos += litCount;
decPos += litCount;
if (cmpPos >= cmp.Length)
{
break;
}
// Copy compressed chunk
int back = cmp[cmpPos++] << 0 |
cmp[cmpPos++] << 8;
encCount = GetLength(encCount) + 4;
int encPos = decPos - back;
if (encCount <= back)
{
Buffer.BlockCopy(dec, encPos, dec, decPos, encCount);
decPos += encCount;
}
else
{
while (encCount-- > 0)
{
dec[decPos++] = dec[encPos++];
}
}
}
while (cmpPos < cmp.Length &&
decPos < dec.Length);
return dec;
}
}
}