Files
OpenRA/OpenRa.FileFormats/Format40.cs
chrisf b77a116f60 MOAR PERF
git-svn-id: svn://svn.ijw.co.nz/svn/OpenRa@1956 993157c7-ee19-0410-b2c4-bb4e9862e678
2008-03-25 02:07:15 +00:00

74 lines
1.7 KiB
C#

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
namespace OpenRa.FileFormats
{
public static class Format40
{
public static int DecodeInto( byte[] src, byte[] dest )
{
var ctx = new FastByteReader(src);
int destIndex = 0;
while( true )
{
byte i = ctx.ReadByte();
if( ( i & 0x80 ) == 0 )
{
int count = i & 0x7F;
if( count == 0 )
{
// case 6
count = ctx.ReadByte();
byte value = ctx.ReadByte();
for( int end = destIndex + count ; destIndex < end ; destIndex++ )
dest[ destIndex ] ^= value;
}
else
{
// case 5
for( int end = destIndex + count ; destIndex < end ; destIndex++ )
dest[destIndex] ^= ctx.ReadByte();
}
}
else
{
int count = i & 0x7F;
if( count == 0 )
{
count = ctx.ReadWord();
if( count == 0 )
return destIndex;
if( ( count & 0x8000 ) == 0 )
{
// case 2
destIndex += ( count & 0x7FFF );
}
else if( ( count & 0x4000 ) == 0 )
{
// case 3
for( int end = destIndex + ( count & 0x3FFF ) ; destIndex < end ; destIndex++ )
dest[destIndex] ^= ctx.ReadByte();
}
else
{
// case 4
byte value = ctx.ReadByte();
for( int end = destIndex + ( count & 0x3FFF ) ; destIndex < end ; destIndex++ )
dest[ destIndex ] ^= value;
}
}
else
{
// case 1
destIndex += count;
}
}
}
}
}
}