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/* Lzip - LZMA lossless data compressor
Copyright (C) 2008-2018 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 2 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 <algorithm>
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include "lzip.h"
#include "encoder_base.h"
#include "fast_encoder.h"
int FLZ_encoder::longest_match_len( int * const distance )
{
enum { len_limit = 16 };
const int available = std::min( available_bytes(), (int)max_match_len );
if( available < len_limit ) return 0;
const uint8_t * const data = ptr_to_current_pos();
key4 = ( ( key4 << 4 ) ^ data[3] ) & key4_mask;
const int pos1 = pos + 1;
int newpos1 = prev_positions[key4];
prev_positions[key4] = pos1;
int32_t * ptr0 = pos_array + cyclic_pos;
int maxlen = 0;
for( int count = 4; ; )
{
int delta;
if( newpos1 <= 0 || --count < 0 ||
( delta = pos1 - newpos1 ) > dictionary_size ) { *ptr0 = 0; break; }
int32_t * const newptr = pos_array +
( cyclic_pos - delta +
( ( cyclic_pos >= delta ) ? 0 : dictionary_size + 1 ) );
if( data[maxlen-delta] == data[maxlen] )
{
int len = 0;
while( len < available && data[len-delta] == data[len] ) ++len;
if( maxlen < len )
{ maxlen = len; *distance = delta - 1;
if( maxlen >= len_limit ) { *ptr0 = *newptr; break; } }
}
*ptr0 = newpos1;
ptr0 = newptr;
newpos1 = *ptr0;
}
return maxlen;
}
bool FLZ_encoder::encode_member( const unsigned long long member_size )
{
const unsigned long long member_size_limit =
member_size - File_trailer::size - max_marker_size;
int rep = 0;
int reps[num_rep_distances];
State state;
for( int i = 0; i < num_rep_distances; ++i ) reps[i] = 0;
if( data_position() != 0 || renc.member_position() != File_header::size )
return false; // can be called only once
if( !data_finished() ) // encode first byte
{
const uint8_t prev_byte = 0;
const uint8_t cur_byte = peek( 0 );
renc.encode_bit( bm_match[state()][0], 0 );
encode_literal( prev_byte, cur_byte );
crc32.update_byte( crc_, cur_byte );
reset_key4();
update_and_move( 1 );
}
while( !data_finished() && renc.member_position() < member_size_limit )
{
int match_distance;
const int main_len = longest_match_len( &match_distance );
const int pos_state = data_position() & pos_state_mask;
int len = 0;
for( int i = 0; i < num_rep_distances; ++i )
{
const int tlen = true_match_len( 0, reps[i] + 1 );
if( tlen > len ) { len = tlen; rep = i; }
}
if( len > min_match_len && len + 3 > main_len )
{
crc32.update_buf( crc_, ptr_to_current_pos(), len );
renc.encode_bit( bm_match[state()][pos_state], 1 );
renc.encode_bit( bm_rep[state()], 1 );
renc.encode_bit( bm_rep0[state()], rep != 0 );
if( rep == 0 )
renc.encode_bit( bm_len[state()][pos_state], 1 );
else
{
renc.encode_bit( bm_rep1[state()], rep > 1 );
if( rep > 1 )
renc.encode_bit( bm_rep2[state()], rep > 2 );
const int distance = reps[rep];
for( int i = rep; i > 0; --i ) reps[i] = reps[i-1];
reps[0] = distance;
}
state.set_rep();
renc.encode_len( rep_len_model, len, pos_state );
move_pos();
update_and_move( len - 1 );
continue;
}
if( main_len > min_match_len )
{
crc32.update_buf( crc_, ptr_to_current_pos(), main_len );
renc.encode_bit( bm_match[state()][pos_state], 1 );
renc.encode_bit( bm_rep[state()], 0 );
state.set_match();
for( int i = num_rep_distances - 1; i > 0; --i ) reps[i] = reps[i-1];
reps[0] = match_distance;
encode_pair( match_distance, main_len, pos_state );
move_pos();
update_and_move( main_len - 1 );
continue;
}
const uint8_t prev_byte = peek( 1 );
const uint8_t cur_byte = peek( 0 );
const uint8_t match_byte = peek( reps[0] + 1 );
move_pos();
crc32.update_byte( crc_, cur_byte );
if( match_byte == cur_byte )
{
const int short_rep_price = price1( bm_match[state()][pos_state] ) +
price1( bm_rep[state()] ) +
price0( bm_rep0[state()] ) +
price0( bm_len[state()][pos_state] );
int price = price0( bm_match[state()][pos_state] );
if( state.is_char() )
price += price_literal( prev_byte, cur_byte );
else
price += price_matched( prev_byte, cur_byte, match_byte );
if( short_rep_price < price )
{
renc.encode_bit( bm_match[state()][pos_state], 1 );
renc.encode_bit( bm_rep[state()], 1 );
renc.encode_bit( bm_rep0[state()], 0 );
renc.encode_bit( bm_len[state()][pos_state], 0 );
state.set_short_rep();
continue;
}
}
// literal byte
renc.encode_bit( bm_match[state()][pos_state], 0 );
if( state.is_char_set_char() )
encode_literal( prev_byte, cur_byte );
else
encode_matched( prev_byte, cur_byte, match_byte );
}
full_flush( state );
return true;
}
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