ryujinx/Ryujinx.HLE/Loaders/Compression/BackwardsLz.cs
gdkchan 22bacc6188
Improve kernel IPC implementation (#550)
* Implement some IPC related kernel SVCs properly

* Fix BLZ decompression when the segment also has a uncompressed chunck

* Set default cpu core on process start from ProgramLoader, remove debug message

* Load process capabilities properly on KIPs

* Fix a copy/paste error in UnmapPhysicalMemory64

* Implement smarter switching between old and new IPC system to support the old HLE services implementation without the manual switch

* Implement RegisterService on sm and AcceptSession (partial)

* Misc fixes and improvements on new IPC methods

* Move IPC related SVCs into a separate file, and logging on RegisterService (sm)

* Some small fixes related to receive list buffers and error cases

* Load NSOs using the correct pool partition

* Fix corner case on GetMaskFromMinMax where range is 64, doesn't happen in pratice however

* Fix send static buffer copy

* Session release, implement closing requests on client disconnect

* Implement ConnectToPort SVC

* KLightSession init
2019-01-18 20:26:39 -02:00

107 lines
2.9 KiB
C#

using System;
namespace Ryujinx.HLE.Loaders.Compression
{
static class BackwardsLz
{
private class BackwardsReader
{
private byte[] _data;
private int _position;
public int Position => _position;
public BackwardsReader(byte[] data, int end)
{
_data = data;
_position = end;
}
public void SeekCurrent(int offset)
{
_position += offset;
}
public byte ReadByte()
{
return _data[--_position];
}
public short ReadInt16()
{
return (short)((ReadByte() << 8) | (ReadByte() << 0));
}
public int ReadInt32()
{
return ((ReadByte() << 24) |
(ReadByte() << 16) |
(ReadByte() << 8) |
(ReadByte() << 0));
}
}
public static void DecompressInPlace(byte[] buffer, int headerEnd)
{
BackwardsReader reader = new BackwardsReader(buffer, headerEnd);
int additionalDecLength = reader.ReadInt32();
int startOffset = reader.ReadInt32();
int compressedLength = reader.ReadInt32();
reader.SeekCurrent(12 - startOffset);
int decBase = headerEnd - compressedLength;
int decPos = compressedLength + additionalDecLength;
byte mask = 0;
byte header = 0;
while (decPos > 0)
{
if ((mask >>= 1) == 0)
{
header = reader.ReadByte();
mask = 0x80;
}
if ((header & mask) == 0)
{
buffer[decBase + --decPos] = reader.ReadByte();
}
else
{
ushort pair = (ushort)reader.ReadInt16();
int length = (pair >> 12) + 3;
int position = (pair & 0xfff) + 3;
if (length > decPos)
{
length = decPos;
}
decPos -= length;
int dstPos = decBase + decPos;
if (length <= position)
{
int srcPos = dstPos + position;
Buffer.BlockCopy(buffer, srcPos, buffer, dstPos, length);
}
else
{
for (int offset = 0; offset < length; offset++)
{
buffer[dstPos + offset] = buffer[dstPos + position + offset];
}
}
}
}
}
}
}