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/* Lzip - Data compressor based on the LZMA algorithm
Copyright (C) 2008, 2009, 2010, 2011 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
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define _FILE_OFFSET_BITS 64
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <unistd.h>
#include "lzip.h"
#include "decoder.h"
const CRC32 crc32;
// Returns the number of bytes really read.
// If (returned value < size) and (errno == 0), means EOF was reached.
//
int readblock( const int fd, uint8_t * const buf, const int size )
{
int rest = size;
errno = 0;
while( rest > 0 )
{
errno = 0;
const int n = read( fd, buf + size - rest, rest );
if( n > 0 ) rest -= n;
else if( n == 0 ) break;
else if( errno != EINTR && errno != EAGAIN ) break;
}
return ( rest > 0 ) ? size - rest : size;
}
// Returns the number of bytes really written.
// If (returned value < size), it is always an error.
//
int writeblock( const int fd, const uint8_t * const buf, const int size )
{
int rest = size;
errno = 0;
while( rest > 0 )
{
errno = 0;
const int n = write( fd, buf + size - rest, rest );
if( n > 0 ) rest -= n;
else if( errno && errno != EINTR && errno != EAGAIN ) break;
}
return ( rest > 0 ) ? size - rest : size;
}
bool Range_decoder::read_block()
{
if( !at_stream_end )
{
stream_pos = readblock( infd, buffer, buffer_size );
if( stream_pos != buffer_size && errno ) exit(-1);
at_stream_end = ( stream_pos < buffer_size );
partial_member_pos += pos;
pos = 0;
}
return pos < stream_pos;
}
void LZ_decoder::flush_data()
{
const int size = pos - stream_pos;
if( size > 0 )
{
crc32.update( crc_, buffer + stream_pos, size );
if( outfd >= 0 &&
writeblock( outfd, buffer + stream_pos, size ) != size )
exit(-1);
if( pos >= buffer_size ) { partial_data_pos += pos; pos = 0; }
stream_pos = pos;
}
}
bool LZ_decoder::verify_trailer() const
{
File_trailer trailer;
const int trailer_size = File_trailer::size( member_version );
const long long member_size = range_decoder.member_position() + trailer_size;
bool error = false;
for( int i = 0; i < trailer_size && !error; ++i )
{
if( !range_decoder.finished() )
trailer.data[i] = range_decoder.get_byte();
else
{
error = true;
for( ; i < trailer_size; ++i ) trailer.data[i] = 0;
}
}
if( member_version == 0 ) trailer.member_size( member_size );
if( !range_decoder.code_is_zero() )
{
error = true;
pp( "Range decoder final code is not zero" );
}
if( trailer.data_crc() != crc() )
{
error = true;
}
if( trailer.data_size() != data_position() )
{
error = true;
}
if( trailer.member_size() != member_size )
{
error = true;
}
return !error;
}
// Return value: 0 = OK, 1 = decoder error, 2 = unexpected EOF,
// 3 = trailer error, 4 = unknown marker found.
int LZ_decoder::decode_member()
{
Bit_model bm_match[State::states][pos_states];
Bit_model bm_rep[State::states];
Bit_model bm_rep0[State::states];
Bit_model bm_rep1[State::states];
Bit_model bm_rep2[State::states];
Bit_model bm_len[State::states][pos_states];
Bit_model bm_dis_slot[max_dis_states][1<<dis_slot_bits];
Bit_model bm_dis[modeled_distances-end_dis_model+1];
Bit_model bm_align[dis_align_size];
unsigned int rep0 = 0; // rep[0-3] latest four distances
unsigned int rep1 = 0; // used for efficient coding of
unsigned int rep2 = 0; // repeated distances
unsigned int rep3 = 0;
Len_decoder len_decoder;
Len_decoder rep_match_len_decoder;
Literal_decoder literal_decoder;
State state;
range_decoder.load();
while( true )
{
if( range_decoder.finished() ) { flush_data(); return 2; }
const int pos_state = data_position() & pos_state_mask;
if( range_decoder.decode_bit( bm_match[state()][pos_state] ) == 0 )
{
const uint8_t prev_byte = get_prev_byte();
if( state.is_char() )
put_byte( literal_decoder.decode( range_decoder, prev_byte ) );
else
put_byte( literal_decoder.decode_matched( range_decoder, prev_byte,
get_byte( rep0 ) ) );
state.set_char();
}
else
{
int len;
if( range_decoder.decode_bit( bm_rep[state()] ) == 1 )
{
len = 0;
if( range_decoder.decode_bit( bm_rep0[state()] ) == 1 )
{
unsigned int distance;
if( range_decoder.decode_bit( bm_rep1[state()] ) == 0 )
distance = rep1;
else
{
if( range_decoder.decode_bit( bm_rep2[state()] ) == 0 )
distance = rep2;
else { distance = rep3; rep3 = rep2; }
rep2 = rep1;
}
rep1 = rep0;
rep0 = distance;
}
else
{
if( range_decoder.decode_bit( bm_len[state()][pos_state] ) == 0 )
{ state.set_short_rep(); len = 1; }
}
if( len == 0 )
{
state.set_rep();
len = min_match_len + rep_match_len_decoder.decode( range_decoder, pos_state );
}
}
else
{
const unsigned int rep0_saved = rep0;
len = min_match_len + len_decoder.decode( range_decoder, pos_state );
const int dis_slot = range_decoder.decode_tree( bm_dis_slot[get_dis_state(len)], dis_slot_bits );
if( dis_slot < start_dis_model ) rep0 = dis_slot;
else
{
const int direct_bits = ( dis_slot >> 1 ) - 1;
rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
if( dis_slot < end_dis_model )
rep0 += range_decoder.decode_tree_reversed( bm_dis + rep0 - dis_slot, direct_bits );
else
{
rep0 += range_decoder.decode( direct_bits - dis_align_bits ) << dis_align_bits;
rep0 += range_decoder.decode_tree_reversed( bm_align, dis_align_bits );
if( rep0 == 0xFFFFFFFFU ) // Marker found
{
rep0 = rep0_saved;
range_decoder.normalize();
flush_data();
if( len == min_match_len ) // End Of Stream marker
{
if( verify_trailer() ) return 0; else return 3;
}
if( len == min_match_len + 1 ) // Sync Flush marker
{
range_decoder.load(); continue;
}
return 4;
}
}
}
rep3 = rep2; rep2 = rep1; rep1 = rep0_saved;
state.set_match();
if( rep0 >= (unsigned int)dictionary_size ||
( rep0 >= (unsigned int)pos && !partial_data_pos ) )
{ flush_data(); return 1; }
}
copy_block( rep0, len );
}
}
}
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