git-svn-id: svn://svn.ijw.co.nz/svn/OpenRa@1061 993157c7-ee19-0410-b2c4-bb4e9862e678

OpenRa.FileFormats/Format40.cs

@@ -0,0 +1,86 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.IO;
+
+namespace OpenRa.FileFormats
+{
+	public static class Format40
+	{
+		static byte ReadByte( MemoryStream input )
+		{
+			int inp = input.ReadByte();
+			if( inp == -1 )
+				throw new InvalidDataException();
+
+			return (byte)inp;
+		}
+
+		static int ReadWord( MemoryStream input )
+		{
+			int inp = ReadByte( input );
+			return inp + ( ReadByte( input ) << 8 );
+		}
+
+		public static int DecodeInto( MemoryStream input, byte[] dest )
+		{
+			int destIndex = 0;
+			while( true )
+			{
+				byte i = ReadByte( input );
+				if( ( i & 0x80 ) == 0 )
+				{
+					int count = i & 0x7F;
+					if( count == 0 )
+					{
+						// case 6
+						count = ReadByte( input );
+						byte value = ReadByte( input );
+						for( int end = destIndex + count ; destIndex < end ; destIndex++ )
+							dest[ destIndex ] ^= value;
+					}
+					else
+					{
+						// case 5
+						for( int end = destIndex + count ; destIndex < end ; destIndex++ )
+							dest[ destIndex ] ^= ReadByte( input );
+					}
+				}
+				else
+				{
+					int count = i & 0x7F;
+					if( count == 0 )
+					{
+						count = ReadWord( input );
+						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 ] ^= ReadByte( input );
+						}
+						else
+						{
+							// case 4
+							byte value = ReadByte( input );
+							for( int end = destIndex + ( count & 0x3FFF ) ; destIndex < end ; destIndex++ )
+								dest[ destIndex ] ^= value;
+						}
+					}
+					else
+					{
+						// case 1
+						destIndex += count;
+					}
+				}
+			}
+		}
+	}
+}