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lzip/fast_encoder.cc
Daniel Baumann b18962ac2a
Merging upstream version 1.11. 
Signed-off-by: Daniel Baumann <daniel@debian.org>
2025-02-20 22:37:22 +01:00

378 lines
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/* Lzip - Data compressor based on the LZMA algorithm
Copyright (C) 2008, 2009, 2010 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 <algorithm>
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <stdint.h>
#include "lzip.h"
#include "encoder.h"
#include "fast_encoder.h"
bool Fmatchfinder::read_block()
{
if( !at_stream_end && stream_pos < buffer_size )
{
const int size = buffer_size - stream_pos;
const int rd = readblock( infd, buffer + stream_pos, size );
stream_pos += rd;
if( rd != size && errno ) throw Error( "Read error" );
at_stream_end = ( rd < size );
}
return pos < stream_pos;
}
Fmatchfinder::Fmatchfinder( const int ifd )
:
partial_data_pos( 0 ),
prev_positions( new int32_t[num_prev_positions] ),
pos( 0 ),
cyclic_pos( 0 ),
key4( 0 ),
stream_pos( 0 ),
match_len_limit_( 16 ),
infd( ifd ),
at_stream_end( false )
{
const int dict_size = 65536;
const int buffer_size_limit = ( 16 * dict_size ) + before_size + after_size;
buffer_size = dict_size;
buffer = (uint8_t *)std::malloc( buffer_size );
if( !buffer ) throw std::bad_alloc();
if( read_block() && !at_stream_end && buffer_size < buffer_size_limit )
{
buffer_size = buffer_size_limit;
buffer = (uint8_t *)std::realloc( buffer, buffer_size );
if( !buffer ) throw std::bad_alloc();
read_block();
}
if( at_stream_end && stream_pos < dict_size )
dictionary_size_ = std::max( (int)min_dictionary_size, stream_pos );
else dictionary_size_ = dict_size;
pos_limit = buffer_size;
if( !at_stream_end ) pos_limit -= after_size;
prev_pos_chain = new int32_t[dictionary_size_];
for( int i = 0; i < num_prev_positions; ++i ) prev_positions[i] = -1;
}
void Fmatchfinder::reset()
{
const int size = stream_pos - pos;
if( size > 0 ) std::memmove( buffer, buffer + pos, size );
partial_data_pos = 0;
stream_pos -= pos;
pos = 0;
cyclic_pos = 0;
key4 = 0;
for( int i = 0; i < num_prev_positions; ++i ) prev_positions[i] = -1;
read_block();
}
void Fmatchfinder::move_pos()
{
if( ++cyclic_pos >= dictionary_size_ ) cyclic_pos = 0;
if( ++pos >= pos_limit )
{
if( pos > stream_pos )
internal_error( "pos > stream_pos in Fmatchfinder::move_pos" );
if( !at_stream_end )
{
const int offset = pos - dictionary_size_ - before_size;
const int size = stream_pos - offset;
std::memmove( buffer, buffer + offset, size );
partial_data_pos += offset;
pos -= offset;
stream_pos -= offset;
for( int i = 0; i < num_prev_positions; ++i )
if( prev_positions[i] >= 0 ) prev_positions[i] -= offset;
for( int i = 0; i < dictionary_size_; ++i )
if( prev_pos_chain[i] >= 0 ) prev_pos_chain[i] -= offset;
read_block();
}
}
}
int Fmatchfinder::longest_match_len( int * const distance ) throw()
{
int len_limit = match_len_limit_;
if( len_limit > available_bytes() )
{
len_limit = available_bytes();
if( len_limit < 4 ) return 0;
}
int maxlen = min_match_len - 1;
const int min_pos = (pos >= dictionary_size_) ?
(pos - dictionary_size_ + 1) : 0;
const uint8_t * const data = buffer + pos;
key4 = ( ( key4 << 4 ) ^ data[3] ) & ( num_prev_positions - 1 );
int newpos = prev_positions[key4];
prev_positions[key4] = pos;
int32_t * ptr0 = prev_pos_chain + cyclic_pos;
for( int count = 4; ; )
{
if( newpos < min_pos || --count < 0 ) { *ptr0 = -1; break; }
const uint8_t * const newdata = buffer + newpos;
int len = 0;
while( len < len_limit && newdata[len] == data[len] ) ++len;
const int delta = pos - newpos;
if( maxlen < len ) { maxlen = len; *distance = delta - 1; }
int32_t * const newptr = prev_pos_chain +
( cyclic_pos - delta +
( ( cyclic_pos >= delta ) ? 0 : dictionary_size_ ) );
if( len < len_limit )
{
*ptr0 = newpos;
ptr0 = newptr;
newpos = *ptr0;
}
else
{
*ptr0 = *newptr;
break;
}
}
return maxlen;
}
void Fmatchfinder::longest_match_len() throw()
{
int len_limit = match_len_limit_;
if( len_limit > available_bytes() )
{
len_limit = available_bytes();
if( len_limit < 4 ) return;
}
const int min_pos = (pos >= dictionary_size_) ?
(pos - dictionary_size_ + 1) : 0;
const uint8_t * const data = buffer + pos;
key4 = ( ( key4 << 4 ) ^ data[3] ) & ( num_prev_positions - 1 );
const int newpos = prev_positions[key4];
prev_positions[key4] = pos;
int32_t * const ptr0 = prev_pos_chain + cyclic_pos;
if( newpos < min_pos ) *ptr0 = -1;
else
{
const uint8_t * const newdata = buffer + newpos;
if( newdata[len_limit-1] != data[len_limit-1] ||
std::memcmp( newdata, data, len_limit - 1 ) ) *ptr0 = newpos;
else
{
const int delta = pos - newpos;
int idx = cyclic_pos - delta;
if( idx < 0 ) idx += dictionary_size_;
*ptr0 = prev_pos_chain[idx];
}
}
}
// Return value == number of bytes advanced (len).
// *disp returns the distance to encode.
// ( *disp == -1 && len == 1 ) means literal.
int FLZ_encoder::sequence_optimizer( const int reps[num_rep_distances],
int * const disp, const State & state )
{
const int main_len = read_match_distances();
int replen = 0;
int rep_index = 0;
for( int i = 0; i < num_rep_distances; ++i )
{
const int len = fmatchfinder.true_match_len( 0, reps[i] + 1, max_match_len );
if( len > replen ) { replen = len; rep_index = i; }
}
if( replen > min_match_len )
{
*disp = rep_index;
move_pos( replen, true );
return replen;
}
if( main_len > min_match_len ||
( main_len == min_match_len && match_distance < modeled_distances ) )
{
*disp = num_rep_distances + match_distance;
move_pos( main_len, true );
return main_len;
}
const uint8_t cur_byte = fmatchfinder[0];
const uint8_t match_byte = fmatchfinder[-reps[0]-1];
*disp = -1;
if( match_byte == cur_byte )
{
const uint8_t prev_byte = fmatchfinder[-1];
const int pos_state = fmatchfinder.data_position() & pos_state_mask;
int price = price0( bm_match[state()][pos_state] );
if( state.is_char() )
price += literal_encoder.price_symbol( prev_byte, cur_byte );
else
price += literal_encoder.price_matched( prev_byte, cur_byte, match_byte );
const int short_rep_price = price1( bm_match[state()][pos_state] ) +
price1( bm_rep[state()] ) +
price_rep_len1( state, pos_state );
if( short_rep_price < price ) *disp = 0;
}
fmatchfinder.move_pos();
return 1;
}
// End Of Stream mark => (dis == 0xFFFFFFFFU, len == min_match_len)
void FLZ_encoder::full_flush( const State & state )
{
const int pos_state = fmatchfinder.data_position() & pos_state_mask;
range_encoder.encode_bit( bm_match[state()][pos_state], 1 );
range_encoder.encode_bit( bm_rep[state()], 0 );
encode_pair( 0xFFFFFFFFU, min_match_len, pos_state );
range_encoder.flush();
File_trailer trailer;
trailer.data_crc( crc() );
trailer.data_size( fmatchfinder.data_position() );
trailer.member_size( range_encoder.member_position() + File_trailer::size() );
for( int i = 0; i < File_trailer::size(); ++i )
range_encoder.put_byte( trailer.data[i] );
range_encoder.flush_data();
}
FLZ_encoder::FLZ_encoder( Fmatchfinder & mf, const File_header & header,
const int outfd )
:
crc_( 0xFFFFFFFFU ),
fmatchfinder( mf ),
range_encoder( outfd ),
len_encoder( fmatchfinder.match_len_limit() ),
rep_match_len_encoder( fmatchfinder.match_len_limit() ),
num_dis_slots( 2 * real_bits( fmatchfinder.dictionary_size() - 1 ) )
{
for( int i = 0; i < File_header::size; ++i )
range_encoder.put_byte( header.data[i] );
}
bool FLZ_encoder::encode_member( const long long member_size )
{
const long long member_size_limit =
member_size - File_trailer::size() - max_marker_size;
int rep_distances[num_rep_distances];
State state;
for( int i = 0; i < num_rep_distances; ++i ) rep_distances[i] = 0;
if( fmatchfinder.data_position() != 0 ||
range_encoder.member_position() != File_header::size )
return false; // can be called only once
if( !fmatchfinder.finished() ) // encode first byte
{
const uint8_t prev_byte = 0;
const uint8_t cur_byte = fmatchfinder[0];
range_encoder.encode_bit( bm_match[state()][0], 0 );
literal_encoder.encode( range_encoder, prev_byte, cur_byte );
crc32.update( crc_, cur_byte );
move_pos( 1 );
}
while( true )
{
if( fmatchfinder.finished() ) { full_flush( state ); return true; }
const int pos_state = fmatchfinder.data_position() & pos_state_mask;
int dis;
const int len = sequence_optimizer( rep_distances, &dis, state );
if( len <= 0 ) return false;
bool bit = ( dis < 0 && len == 1 );
range_encoder.encode_bit( bm_match[state()][pos_state], !bit );
if( bit ) // literal byte
{
const uint8_t prev_byte = fmatchfinder[-len-1];
const uint8_t cur_byte = fmatchfinder[-len];
crc32.update( crc_, cur_byte );
if( state.is_char() )
literal_encoder.encode( range_encoder, prev_byte, cur_byte );
else
{
const uint8_t match_byte = fmatchfinder[-len-rep_distances[0]-1];
literal_encoder.encode_matched( range_encoder,
prev_byte, cur_byte, match_byte );
}
state.set_char();
}
else // match or repeated match
{
crc32.update( crc_, fmatchfinder.ptr_to_current_pos() - len, len );
mtf_reps( dis, rep_distances );
bit = ( dis < num_rep_distances );
range_encoder.encode_bit( bm_rep[state()], bit );
if( bit )
{
bit = ( dis == 0 );
range_encoder.encode_bit( bm_rep0[state()], !bit );
if( bit )
range_encoder.encode_bit( bm_len[state()][pos_state], len > 1 );
else
{
range_encoder.encode_bit( bm_rep1[state()], dis > 1 );
if( dis > 1 )
range_encoder.encode_bit( bm_rep2[state()], dis > 2 );
}
if( len == 1 ) state.set_short_rep();
else
{
rep_match_len_encoder.encode( range_encoder, len, pos_state );
state.set_rep();
}
}
else
{
encode_pair( dis - num_rep_distances, len, pos_state );
state.set_match();
}
}
if( range_encoder.member_position() >= member_size_limit )
{
full_flush( state );
return true;
}
}
}
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