mirror of
https://github.com/martravi/wiiqt.git
synced 2024-11-17 22:59:21 +01:00
394 lines
7.2 KiB
C++
394 lines
7.2 KiB
C++
#include "lz77.h"
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//most functions here are taken from wii.cs by leathl
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//they have just been tweeked slightly to work with Qt C++
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LZ77::LZ77()
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{
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match_position = 0;
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match_length = 0;
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textsize = 0;
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codesize = 0;
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}
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int LZ77::GetLz77Offset( const QByteArray &data )
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{
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QByteArray start = data.left( 5000 );
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return start.indexOf( "LZ77" );
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}
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void LZ77::InitTree()
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{
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int i;
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int N = 4096;
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for( i = N + 1; i <= N + 256; i++ )
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rson[ i ] = N;
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for( i = 0; i < N; i++ )
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dad[ i ] = N;
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}
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void LZ77::DeleteNode( int p )
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{
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int N = 4096;
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int q;
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if( dad[ p ] == N )
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return; /* not in tree */
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if( rson[ p ] == N )
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q = lson[ p ];
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else if( lson[ p ] == N )
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q = rson[ p ];
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else
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{
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q = lson[ p ];
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if( rson[ q ] != N )
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{
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do
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{
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q = rson[ q ];
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}
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while( rson[ q ] != N );
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rson[ dad[ q ] ] = lson[ q ];
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dad[ lson[ q ] ] = dad[ q ];
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lson[ q ] = lson[ p ];
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dad[ lson[ p ] ] = q;
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}
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rson[ q ] = rson[ p ];
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dad[ rson[ p ] ] = q;
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}
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dad[ q ] = dad[ p ];
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if( rson[ dad[ p ] ] == p )
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rson[ dad[ p ] ] = q;
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else
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lson[ dad[ p ] ] = q;
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dad[ p ] = N;
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}
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void LZ77::InsertNode( int r )
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{
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int i, p, cmp;
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int N = 4096;
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int F = 18;
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cmp = 1;
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p = N + 1 + ( text_buf[ r ] == ( quint16 )0xffff ? ( quint16 )0 : text_buf[ r ] );
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rson[ r ] = lson[ r ] = N;
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match_length = 0;
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for( ; ; )
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{
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if( cmp >= 0 )
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{
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if( rson[ p ] != N )
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p = rson[ p ];
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else
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{
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rson[ p ] = r;
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dad[ r ] = p;
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return;
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}
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}
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else
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{
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if ( lson[ p ] != N )
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p = lson[ p ];
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else
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{
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lson[ p ] = r;
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dad[ r ] = p;
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return;
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}
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}
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for( i = 1; i < F; i++ )
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if( ( cmp = text_buf[ r + i ] - text_buf[ p + i ] ) != 0 )
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break;
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if( i > match_length )
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{
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match_position = p;
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if( ( match_length = i ) >= F )
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break;
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}
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}
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dad[ r ] = dad[ p ];
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lson[ r ] = lson[ p ];
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rson[ r ] = rson[ p ];
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dad[ lson[ p ] ] = r;
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dad[ rson[ p ] ] = r;
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if( rson[ dad[ p ] ] == p )
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rson[ dad[ p ] ] = r;
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else
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lson[ dad[ p ] ] = r;
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dad[ p ] = N;
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}
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quint32 LZ77::GetDecompressedSize( const QByteArray &data )
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{
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int off = GetLz77Offset( data );
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if( off == -1 )
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{
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qWarning() << "LZ77::GetDecompressedSize -> no lz77 magic";
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return 0;
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}
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QByteArray ba = data;
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QBuffer buf( &ba );
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if( !buf.open( QBuffer::ReadOnly ) )
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{
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qWarning() << "LZ77::GetDecompressedSize -> Can't create buffer";
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return 0;
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}
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buf.seek( off + 4 );
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quint32 gbaheader;
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buf.seek( off + 4 );
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buf.read( (char*)&gbaheader, 4 );
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return ( gbaheader >> 8 );
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}
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QByteArray LZ77::Decompress( const QByteArray &compressed, int offset )
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{
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int N = 4096;
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int F = 18;
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int threshold = 2;
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int k, r, z, flags;
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quint16 i, j;
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char ch;
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quint32 decomp_size;
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quint32 cur_size = 0;
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QByteArray crap = compressed;
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QBuffer infile( &crap );
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if( !infile.open( QBuffer::ReadOnly ) )
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{
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qWarning() << "Can't create buffer 1";
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return QByteArray();
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}
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QByteArray ret;
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QBuffer outfile( &ret );
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if( !outfile.open( QBuffer::ReadWrite ) )
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{
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qWarning() << "Can't create buffer 2";
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return QByteArray();
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}
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quint32 gbaheader;
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infile.seek( offset + 4 );
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infile.read( (char*)&gbaheader, 4 );
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decomp_size = gbaheader >> 8;
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quint8 text_buf[ N + 17 ];
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for( i = 0; i < N - F; i++ )
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text_buf[ i ] = 0xdf;
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r = N - F;
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flags = 7;
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z = 7;
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while( true )
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{
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flags <<= 1;
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z++;
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if( z == 8 )
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{
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if( !infile.getChar( &ch ) )
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break;
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flags = (quint8) ch;
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z = 0;
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}
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if( ( flags & 0x80 ) == 0 )
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{
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if( !infile.getChar( &ch ) )
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break;
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if( cur_size < decomp_size )
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outfile.putChar( ch );
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text_buf[ r++ ] = ch;
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r &= ( N - 1 );
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cur_size++;
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}
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else
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{
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if( !infile.getChar( &ch ) )
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break;
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i = (quint8)ch;
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if( !infile.getChar( &ch ) )
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break;
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j = (quint8)ch;
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j = j | ( (i << 8) & 0xf00 );
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i = ( ( i >> 4 ) & 0x0f ) + threshold;
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for( k = 0; k <= i; k++ )
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{
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ch = text_buf[ ( r - j - 1 ) & ( N - 1 ) ];
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if( cur_size < decomp_size )
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outfile.putChar( ch );
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text_buf[ r++ ] = ch;
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r &= ( N - 1 );
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cur_size++;
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}
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}
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}
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return ret;
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}
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QByteArray LZ77::Decompress( const QByteArray &compressed )
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{
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int off = GetLz77Offset( compressed );
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if( off < 0 )
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{
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qWarning() << "LZ77::Decompress -> data is not compressed";
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return compressed;
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}
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return Decompress( compressed, off );
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}
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QByteArray LZ77::Compress( const QByteArray &ba )
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{
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//testing 1, 2
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//return ba;
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LZ77 lz;
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QByteArray ret = lz.Compr( ba );
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return ret;
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}
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QByteArray LZ77::Compr( const QByteArray &ba )
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{
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int i, len, r, s, last_match_length, code_buf_ptr;
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char ch;
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int code_buf[ 17 ];
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int mask;
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int N = 4096;
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int F = 18;
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int threshold = 2;
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quint32 filesize = (ba.size() << 8) + 0x10;
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QByteArray crap = ba;
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QBuffer infile( &crap );
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if( !infile.open( QBuffer::ReadOnly ) )
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{
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qWarning() << "Can't create buffer 1";
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return QByteArray();
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}
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QByteArray ret;
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QBuffer output( &ret );
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if( !output.open( QBuffer::ReadWrite ) )
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{
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qWarning() << "Can't create buffer 2";
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return QByteArray();
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}
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output.putChar( 'L' );
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output.putChar( 'Z' );
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output.putChar( '7' );
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output.putChar( '7' );
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output.write( (const char*)&filesize, 4 );
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InitTree();
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code_buf[ 0 ] = 0;
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code_buf_ptr = 1;
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mask = 0x80;
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s = 0;
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r = N - F;
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for( i = s; i < r; i++ )
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text_buf[ i ] = 0xffff;
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for( len = 0; len < F && infile.getChar( &ch ); len++ )
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text_buf[ r + len ] = (quint8)ch;
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if( ( textsize = len ) == 0)
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return ba;
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for( i = 1; i <= F; i++ )
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InsertNode( r - i );
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InsertNode( r );
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do
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{
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if( match_length > len )
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match_length = len;
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if( match_length <= threshold )
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{
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match_length = 1;
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code_buf[ code_buf_ptr++ ] = text_buf[ r ];
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}
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else
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{
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code_buf[ 0 ] |= mask;
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code_buf[ code_buf_ptr++ ] = (quint8)
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( ( ( r - match_position - 1 ) >> 8) & 0x0f ) |
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( ( match_length - ( threshold + 1 ) ) << 4 );
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code_buf[ code_buf_ptr++ ] = (quint8)( ( r - match_position - 1 ) & 0xff );
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}
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if( ( mask >>= 1 ) == 0 )
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{
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for( i = 0; i < code_buf_ptr; i++ )
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output.putChar( (quint8)code_buf[ i ] );
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codesize += code_buf_ptr;
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code_buf[ 0 ] = 0; code_buf_ptr = 1;
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mask = 0x80;
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}
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last_match_length = match_length;
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for( i = 0; i < last_match_length && infile.getChar( &ch ); i++ )
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{
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DeleteNode( s );
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text_buf[ s ] = (quint8)ch;
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if( s < F - 1 )
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text_buf[ s + N ] = (quint8)ch;
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s = ( s + 1 ) & ( N - 1 );
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r = ( r + 1 ) & ( N - 1 );
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InsertNode( r );
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}
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while( i++ < last_match_length )
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{
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DeleteNode( s );
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s = ( s + 1 ) & ( N - 1 );
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r = ( r + 1 ) & ( N - 1 );
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if( --len != 0 )
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InsertNode( r );
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}
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}
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while( len > 0 );
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if( code_buf_ptr > 1 )
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{
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for( i = 0; i < code_buf_ptr; i++ )
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output.putChar( (quint8)code_buf[ i ] );
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codesize += code_buf_ptr;
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}
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int padding = codesize % 4;
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if( padding != 0 )
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output.write( QByteArray( 4 - padding, '\0' ) );
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infile.close();
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return ret;
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}
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