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-rw-r--r--decoder.h46
1 files changed, 27 insertions, 19 deletions
diff --git a/decoder.h b/decoder.h
index 6944dd1..2825604 100644
--- a/decoder.h
+++ b/decoder.h
@@ -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; }