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/* Clzip - LZMA lossless data compressor
Copyright (C) 2010-2025 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 <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "lzip.h"
#include "encoder_base.h"
#include "fast_encoder.h"
int FLZe_longest_match_len( FLZ_encoder * const fe, int * const distance )
{
enum { len_limit = 16 };
const int available = min( Mb_available_bytes( &fe->eb.mb ), max_match_len );
if( available < len_limit ) return 0;
const uint8_t * const data = Mb_ptr_to_current_pos( &fe->eb.mb );
fe->key4 = ( ( fe->key4 << 4 ) ^ data[3] ) & fe->eb.mb.key4_mask;
const int pos1 = fe->eb.mb.pos + 1;
int newpos1 = fe->eb.mb.prev_positions[fe->key4];
fe->eb.mb.prev_positions[fe->key4] = pos1;
int32_t * ptr0 = fe->eb.mb.pos_array + fe->eb.mb.cyclic_pos;
int maxlen = 0, count;
for( count = 4; ; )
{
int delta;
if( newpos1 <= 0 || --count < 0 ||
( delta = pos1 - newpos1 ) > fe->eb.mb.dictionary_size )
{ *ptr0 = 0; break; }
int32_t * const newptr = fe->eb.mb.pos_array +
( fe->eb.mb.cyclic_pos - delta +
( ( fe->eb.mb.cyclic_pos >= delta ) ? 0 : fe->eb.mb.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 FLZe_encode_member( FLZ_encoder * const fe,
const unsigned long long member_size )
{
const unsigned long long member_size_limit =
member_size - Lt_size - max_marker_size;
int rep = 0, i;
int reps[num_rep_distances];
State state = 0;
for( i = 0; i < num_rep_distances; ++i ) reps[i] = 0;
if( Mb_data_position( &fe->eb.mb ) != 0 ||
Re_member_position( &fe->eb.renc ) != Lh_size )
return false; /* can be called only once */
if( !Mb_data_finished( &fe->eb.mb ) ) /* encode first byte */
{
const uint8_t prev_byte = 0;
const uint8_t cur_byte = Mb_peek( &fe->eb.mb, 0 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][0], 0 );
LZeb_encode_literal( &fe->eb, prev_byte, cur_byte );
CRC32_update_byte( &fe->eb.crc, cur_byte );
FLZe_reset_key4( fe );
FLZe_update_and_move( fe, 1 );
}
while( !Mb_data_finished( &fe->eb.mb ) &&
Re_member_position( &fe->eb.renc ) < member_size_limit )
{
int match_distance;
const int main_len = FLZe_longest_match_len( fe, &match_distance );
const int pos_state = Mb_data_position( &fe->eb.mb ) & pos_state_mask;
int len = 0;
for( i = 0; i < num_rep_distances; ++i )
{
const int tlen = Mb_true_match_len( &fe->eb.mb, 0, reps[i] + 1 );
if( tlen > len ) { len = tlen; rep = i; }
}
if( len > min_match_len && len + 3 > main_len )
{
CRC32_update_buf( &fe->eb.crc, Mb_ptr_to_current_pos( &fe->eb.mb ), len );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep0[state], rep != 0 );
if( rep == 0 )
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_len[state][pos_state], 1 );
else
{
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep1[state], rep > 1 );
if( rep > 1 )
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep2[state], rep > 2 );
const int distance = reps[rep];
for( i = rep; i > 0; --i ) reps[i] = reps[i-1];
reps[0] = distance;
}
state = St_set_rep( state );
Re_encode_len( &fe->eb.renc, &fe->eb.rep_len_model, len, pos_state );
Mb_move_pos( &fe->eb.mb );
FLZe_update_and_move( fe, len - 1 );
continue;
}
if( main_len > min_match_len )
{
CRC32_update_buf( &fe->eb.crc, Mb_ptr_to_current_pos( &fe->eb.mb ), main_len );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[state], 0 );
state = St_set_match( state );
for( i = num_rep_distances - 1; i > 0; --i ) reps[i] = reps[i-1];
reps[0] = match_distance;
LZeb_encode_pair( &fe->eb, match_distance, main_len, pos_state );
Mb_move_pos( &fe->eb.mb );
FLZe_update_and_move( fe, main_len - 1 );
continue;
}
const uint8_t prev_byte = Mb_peek( &fe->eb.mb, 1 );
const uint8_t cur_byte = Mb_peek( &fe->eb.mb, 0 );
const uint8_t match_byte = Mb_peek( &fe->eb.mb, reps[0] + 1 );
Mb_move_pos( &fe->eb.mb );
CRC32_update_byte( &fe->eb.crc, cur_byte );
if( match_byte == cur_byte )
{
const int shortrep_price = price1( fe->eb.bm_match[state][pos_state] ) +
price1( fe->eb.bm_rep[state] ) +
price0( fe->eb.bm_rep0[state] ) +
price0( fe->eb.bm_len[state][pos_state] );
int price = price0( fe->eb.bm_match[state][pos_state] );
if( St_is_char( state ) )
price += LZeb_price_literal( &fe->eb, prev_byte, cur_byte );
else
price += LZeb_price_matched( &fe->eb, prev_byte, cur_byte, match_byte );
if( shortrep_price < price )
{
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep[state], 1 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_rep0[state], 0 );
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_len[state][pos_state], 0 );
state = St_set_shortrep( state );
continue;
}
}
/* literal byte */
Re_encode_bit( &fe->eb.renc, &fe->eb.bm_match[state][pos_state], 0 );
if( ( state = St_set_char( state ) ) < 4 )
LZeb_encode_literal( &fe->eb, prev_byte, cur_byte );
else
LZeb_encode_matched( &fe->eb, prev_byte, cur_byte, match_byte );
}
LZeb_full_flush( &fe->eb, state );
return true;
}
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