105 lines
2.7 KiB
C#
105 lines
2.7 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Text;
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using System.IO;
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namespace OpenRa.FileFormats
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{
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public static class Format80
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{
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static byte ReadByte( MemoryStream input )
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{
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int inp = input.ReadByte();
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if( inp == -1 )
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throw new InvalidDataException();
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return (byte)inp;
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}
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static int ReadWord( MemoryStream input )
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{
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int inp = ReadByte( input );
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return inp + ( ReadByte( input ) << 8 );
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}
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static void ReplicatePrevious( byte[] dest, int destIndex, int srcIndex, int count )
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{
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if( srcIndex >= destIndex )
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throw new NotImplementedException( string.Format( "srcIndex >= destIndex {0} {1}", srcIndex, destIndex ) );
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for( int i = 0 ; i < Math.Min( count, destIndex - srcIndex ) ; i++ )
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dest[ destIndex + i ] = dest[ srcIndex + i ];
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if( srcIndex + count <= destIndex )
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return;
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for( int i = destIndex + destIndex - srcIndex ; i < destIndex + count ; i++ )
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dest[ i ] = dest[ destIndex - 1 ];
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}
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public static int DecodeInto( MemoryStream input, byte[] dest )
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{
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int destIndex = 0;
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while( true )
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{
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byte i = ReadByte( input );
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if( ( i & 0x80 ) == 0 )
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{
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// case 2
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byte secondByte = ReadByte( input );
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int count = ( ( i & 0x70 ) >> 4 ) + 3;
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int rpos = ( ( i & 0xf ) << 8 ) + secondByte;
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ReplicatePrevious( dest, destIndex, destIndex - rpos, count );
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destIndex += count;
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}
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else if( ( i & 0x40 ) == 0 )
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{
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// case 1
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int count = i & 0x3F;
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if( count == 0 )
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return destIndex;
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input.Read( dest, destIndex, count );
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destIndex += count;
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}
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else
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{
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int count3 = i & 0x3F;
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if( count3 == 0x3E )
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{
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// case 4
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int count = ReadWord( input );
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byte color = ReadByte( input );
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for( int end = destIndex + count ; destIndex < end ; destIndex++ )
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dest[ destIndex ] = color;
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}
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else if( count3 == 0x3F )
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{
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// case 5
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int count = ReadWord( input );
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int srcIndex = ReadWord( input );
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if( srcIndex >= destIndex )
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throw new NotImplementedException( string.Format( "srcIndex >= destIndex {0} {1}", srcIndex, destIndex ) );
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for( int end = destIndex + count ; destIndex < end ; destIndex++ )
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dest[ destIndex ] = dest[ srcIndex++ ];
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}
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else
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{
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// case 3
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int count = count3 + 3;
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int srcIndex = ReadWord( input );
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if( srcIndex >= destIndex )
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throw new NotImplementedException( string.Format( "srcIndex >= destIndex {0} {1}", srcIndex, destIndex ) );
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for( int end = destIndex + count ; destIndex < end ; destIndex++ )
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dest[ destIndex ] = dest[ srcIndex++ ];
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}
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}
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}
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}
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}
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}
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