diff options
Diffstat (limited to 'decoder.h')
| -rw-r--r-- | decoder.h | 46 |
1 files changed, 27 insertions, 19 deletions
@@ -1,5 +1,6 @@ /* Lzip - LZMA lossless data compressor - Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013 Antonio Diaz Diaz. + Copyright (C) 2008, 2009, 2010, 2011, 2012, 2013, 2014 + Antonio Diaz Diaz. This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -76,6 +77,7 @@ public: code = 0; for( int i = 0; i < 5; ++i ) code = (code << 8) | get_byte(); range = 0xFFFFFFFFU; + code &= range; // make sure that first byte is discarded } void normalize() @@ -120,12 +122,13 @@ public: } } - int decode_tree( Bit_model bm[], const int num_bits ) + int decode_tree3( Bit_model bm[] ) { int symbol = 1; - for( int i = num_bits; i > 0; --i ) - symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); - return symbol - (1 << num_bits); + symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); + symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); + symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); + return symbol & 7; } int decode_tree6( Bit_model bm[] ) @@ -137,7 +140,15 @@ public: symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); - return symbol - (1 << 6); + return symbol & 0x3F; + } + + int decode_tree8( Bit_model bm[] ) + { + int symbol = 1; + while( symbol < 0x100 ) + symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); + return symbol & 0xFF; } int decode_tree_reversed( Bit_model bm[], const int num_bits ) @@ -156,10 +167,9 @@ public: int decode_tree_reversed4( Bit_model bm[] ) { int model = 1; - int symbol = 0; + int symbol = decode_bit( bm[model] ); + model = (model << 1) + symbol; int bit = decode_bit( bm[model] ); - model = (model << 1) + bit; symbol |= bit; - bit = decode_bit( bm[model] ); model = (model << 1) + bit; symbol |= (bit << 1); bit = decode_bit( bm[model] ); model = (model << 1) + bit; symbol |= (bit << 2); @@ -171,7 +181,7 @@ public: { Bit_model * const bm1 = bm + 0x100; int symbol = 1; - for( int i = 7; i >= 0; --i ) + while( symbol < 0x100 ) { match_byte <<= 1; const int match_bit = match_byte & 0x100; @@ -184,18 +194,16 @@ public: break; } } - return symbol - 0x100; + return symbol & 0xFF; } int decode_len( Len_model & lm, const int pos_state ) { if( decode_bit( lm.choice1 ) == 0 ) - return decode_tree( lm.bm_low[pos_state], len_low_bits ); + return decode_tree3( lm.bm_low[pos_state] ); if( decode_bit( lm.choice2 ) == 0 ) - return len_low_symbols + - decode_tree( lm.bm_mid[pos_state], len_mid_bits ); - return len_low_symbols + len_mid_symbols + - decode_tree( lm.bm_high, len_high_bits ); + return len_low_symbols + decode_tree3( lm.bm_mid[pos_state] ); + return len_low_symbols + len_mid_symbols + decode_tree8( lm.bm_high ); } }; @@ -204,7 +212,7 @@ class LZ_decoder { unsigned long long partial_data_pos; Range_decoder & rdec; - const int dictionary_size; + const unsigned dictionary_size; const int buffer_size; uint8_t * const buffer; // output buffer int pos; // current pos in buffer @@ -261,14 +269,14 @@ public: partial_data_pos( 0 ), rdec( rde ), dictionary_size( header.dictionary_size() ), - buffer_size( std::max( 65536, dictionary_size ) ), + buffer_size( std::max( 65536U, dictionary_size ) ), buffer( new uint8_t[buffer_size] ), pos( 0 ), stream_pos( 0 ), crc_( 0xFFFFFFFFU ), outfd( ofd ), member_version( header.version() ) - { buffer[buffer_size-1] = 0; } // prev_byte of first_byte + { buffer[buffer_size-1] = 0; } // prev_byte of first_byte ~LZ_decoder() { delete[] buffer; } |