#region Copyright & License Information
/*
 * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
 * This file is part of OpenRA.
 * 
 *  OpenRA is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 * 
 *  OpenRA is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

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;
					}
				}
			}
		}
	}
}
