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| -rw-r--r-- | encoder.cc | 573 |
1 files changed, 573 insertions, 0 deletions
diff --git a/encoder.cc b/encoder.cc new file mode 100644 index 0000000..3bc855b --- /dev/null +++ b/encoder.cc @@ -0,0 +1,573 @@ +/* Lzlib - A compression library for lzip files + Copyright (C) 2009 Antonio Diaz Diaz. + + This library 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 library 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/>. + + As a special exception, you may use this file as part of a free + software library without restriction. Specifically, if other files + instantiate templates or use macros or inline functions from this + file, or you compile this file and link it with other files to + produce an executable, this file does not by itself cause the + resulting executable to be covered by the GNU General Public + License. This exception does not however invalidate any other + reasons why the executable file might be covered by the GNU General + Public License. +*/ + +#define _FILE_OFFSET_BITS 64 + +#include <algorithm> +#include <cerrno> +#include <cstdlib> +#include <cstring> +#include <string> +#include <vector> +#include <stdint.h> + +#include "lzlib.h" +#include "lzip.h" +#include "encoder.h" + + +const Dis_slots dis_slots; +const Prob_prices prob_prices; + + +int Matchfinder::write_data( uint8_t * const in_buffer, const int in_size ) throw() + { + if( at_stream_end_ ) return 0; + if( pos >= pos_limit ) + { + const int offset = pos - dictionary_size_ - max_num_trials; + const int size = stream_pos - offset; +// std::fprintf( stderr, "%6d offset, %5d size, %4d margin.\n", +// offset, size, after_size - ( pos - pos_limit ) ); + 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 < 2 * dictionary_size_; ++i ) + if( prev_pos_tree[i] >= 0 ) prev_pos_tree[i] -= offset; + } + const int size = std::min( buffer_size - stream_pos, in_size ); + if( size > 0 ) + { + std::memmove( buffer + stream_pos, in_buffer, size ); + stream_pos += size; + } + return size; + } + + +bool Matchfinder::reset() throw() + { + const int size = stream_pos - pos; + std::memmove( buffer, buffer + pos, size ); + partial_data_pos = 0; + stream_pos -= pos; + pos = 0; + cyclic_pos = 0; + for( int i = 0; i < num_prev_positions; ++i ) prev_positions[i] = -1; + return true; + } + + +bool Matchfinder::move_pos() throw() + { + if( ++cyclic_pos >= dictionary_size_ ) cyclic_pos = 0; + if( ++pos > stream_pos ) { pos = stream_pos; return false; } + return true; + } + + +int Matchfinder::longest_match_len( int * const distances ) 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; + const int key2 = num_prev_positions4 + num_prev_positions3 + + ( ( (int)data[0] << 8 ) | data[1] ); + const int tmp = crc32[data[0]] ^ data[1] ^ ( (int)data[2] << 8 ); + const int key3 = num_prev_positions4 + ( tmp & ( num_prev_positions3 - 1 ) ); + const int key4 = ( tmp ^ ( crc32[data[3]] << 5 ) ) & + ( num_prev_positions4 - 1 ); + + if( distances ) + { + int np = prev_positions[key2]; + if( np >= min_pos ) + { distances[2] = pos - np - 1; maxlen = 2; } + else distances[2] = 0x7FFFFFFF; + np = prev_positions[key3]; + if( np >= min_pos && buffer[np] == data[0] ) + { distances[3] = pos - np - 1; maxlen = 3; } + else distances[3] = 0x7FFFFFFF; + distances[4] = 0x7FFFFFFF; + } + + prev_positions[key2] = pos; + prev_positions[key3] = pos; + int newpos = prev_positions[key4]; + prev_positions[key4] = pos; + + int idx0 = cyclic_pos << 1; + int idx1 = idx0 + 1; + int len0 = 0, len1 = 0; + + for( int count = 16 + ( match_len_limit_ / 2 ); ; ) + { + if( newpos < min_pos || --count < 0 ) + { prev_pos_tree[idx0] = prev_pos_tree[idx1] = -1; break; } + const uint8_t * const newdata = buffer + newpos; + int len = std::min( len0, len1 ); + while( len < len_limit && newdata[len] == data[len] ) ++len; + + const int delta = pos - newpos; + if( distances ) while( maxlen < len ) distances[++maxlen] = delta - 1; + + const int newidx = ( cyclic_pos - delta + + ( ( cyclic_pos >= delta ) ? 0 : dictionary_size_ ) ) << 1; + + if( len < len_limit ) + { + if( newdata[len] < data[len] ) + { + prev_pos_tree[idx0] = newpos; + idx0 = newidx + 1; + newpos = prev_pos_tree[idx0]; + len0 = len; + } + else + { + prev_pos_tree[idx1] = newpos; + idx1 = newidx; + newpos = prev_pos_tree[idx1]; + len1 = len; + } + } + else + { + prev_pos_tree[idx0] = prev_pos_tree[newidx]; + prev_pos_tree[idx1] = prev_pos_tree[newidx+1]; + break; + } + } + if( distances ) + { + if( distances[3] > distances[4] ) distances[3] = distances[4]; + if( distances[2] > distances[3] ) distances[2] = distances[3]; + } + return maxlen; + } + + +void Len_encoder::encode( Range_encoder & range_encoder, int symbol, + const int pos_state ) + { + symbol -= min_match_len; + if( symbol < len_low_symbols ) + { + range_encoder.encode_bit( choice1, 0 ); + range_encoder.encode_tree( bm_low[pos_state], symbol, len_low_bits ); + } + else + { + range_encoder.encode_bit( choice1, 1 ); + if( symbol < len_low_symbols + len_mid_symbols ) + { + range_encoder.encode_bit( choice2, 0 ); + range_encoder.encode_tree( bm_mid[pos_state], symbol - len_low_symbols, len_mid_bits ); + } + else + { + range_encoder.encode_bit( choice2, 1 ); + range_encoder.encode_tree( bm_high, symbol - len_low_symbols - len_mid_symbols, len_high_bits ); + } + } + if( --counters[pos_state] <= 0 ) update_prices( pos_state ); + } + + +void LZ_encoder::fill_align_prices() throw() + { + for( int i = 0; i < dis_align_size; ++i ) + align_prices[i] = price_symbol_reversed( bm_align, i, dis_align_bits ); + align_price_count = dis_align_size; + } + + +void LZ_encoder::fill_distance_prices() throw() + { + for( int dis_state = 0; dis_state < max_dis_states; ++dis_state ) + { + int * dsp = dis_slot_prices[dis_state]; + const Bit_model * bmds = bm_dis_slot[dis_state]; + int slot = 0; + for( ; slot < end_dis_model && slot < num_dis_slots; ++slot ) + dsp[slot] = price_symbol( bmds, slot, dis_slot_bits ); + for( ; slot < num_dis_slots; ++slot ) + dsp[slot] = price_symbol( bmds, slot, dis_slot_bits ) + + (((( slot >> 1 ) - 1 ) - dis_align_bits ) << price_shift ); + + int * dp = dis_prices[dis_state]; + int dis = 0; + for( ; dis < start_dis_model; ++dis ) + dp[dis] = dsp[dis]; + for( ; dis < modeled_distances; ++dis ) + { + const int dis_slot = dis_slots[dis]; + const int direct_bits = ( dis_slot >> 1 ) - 1; + const int base = ( 2 | ( dis_slot & 1 ) ) << direct_bits; + dp[dis] = dsp[dis_slot] + + price_symbol_reversed( bm_dis + base - dis_slot, dis - base, direct_bits ); + } + } + } + + +// Return value: ( dis == -1 ) && ( len == 1 ) means literal +int LZ_encoder::best_pair_sequence( const int reps[num_rep_distances], + const State & state ) + { + int main_len; + if( longest_match_found > 0 ) // from previous call + { + main_len = longest_match_found; + longest_match_found = 0; + } + else main_len = read_match_distances(); + + int replens[num_rep_distances]; + int rep_index = 0; + for( int i = 0; i < num_rep_distances; ++i ) + { + replens[i] = matchfinder.true_match_len( 0, reps[i] + 1, max_match_len ); + if( replens[i] > replens[rep_index] ) rep_index = i; + } + if( replens[rep_index] >= matchfinder.match_len_limit() ) + { + trials[0].dis = rep_index; + trials[0].price = replens[rep_index]; + if( !move_pos( replens[rep_index], true ) ) return 0; + return replens[rep_index]; + } + + if( main_len >= matchfinder.match_len_limit() ) + { + trials[0].dis = match_distances[matchfinder.match_len_limit()] + + num_rep_distances; + trials[0].price = main_len; + if( !move_pos( main_len, true ) ) return 0; + return main_len; + } + + trials[0].state = state; + for( int i = 0; i < num_rep_distances; ++i ) trials[0].reps[i] = reps[i]; + + const uint8_t cur_byte = matchfinder[0]; + const uint8_t match_byte = matchfinder[-reps[0]-1]; + unsigned int position = matchfinder.data_position(); + const int pos_state = position & pos_state_mask; + + trials[1].dis = -1; + trials[1].prev_index = 0; + trials[1].price = price0( bm_match[state()][pos_state] ); + if( state.is_char() ) + trials[1].price += literal_encoder.price_symbol( matchfinder[-1], cur_byte ); + else + trials[1].price += literal_encoder.price_matched( matchfinder[-1], cur_byte, match_byte ); + + const int match_price = price1( bm_match[state()][pos_state] ); + const int rep_match_price = match_price + price1( bm_rep[state()] ); + + if( match_byte == cur_byte ) + trials[1].update( 0, 0, rep_match_price + price_rep_len1( state, pos_state ) ); + + if( main_len < min_match_len ) + { + trials[0].dis = trials[1].dis; + trials[0].price = 1; + if( !matchfinder.move_pos() ) return 0; + return 1; + } + + { + const int normal_match_price = match_price + price0( bm_rep[state()] ); + int len = min_match_len; + if( main_len <= replens[rep_index] ) + { + main_len = replens[rep_index]; + for( ; len <= main_len; ++len ) trials[len].price = infinite_price; + } + else for( ; len <= main_len; ++len ) + { + trials[len].dis = match_distances[len] + num_rep_distances; + trials[len].prev_index = 0; + trials[len].price = normal_match_price + + price_pair( match_distances[len], len, pos_state ); + } + } + + for( int rep = 0; rep < num_rep_distances; ++rep ) + for( int len = min_match_len; len <= replens[rep]; ++len ) + trials[len].update( rep, 0, rep_match_price + + price_rep( rep, len, state, pos_state ) ); + + int cur = 0; + int num_trials = main_len; + if( !matchfinder.move_pos() ) return 0; + + while( true ) + { + if( ++cur >= num_trials ) + { + backward( cur ); + return cur; + } + const int newlen = read_match_distances(); + if( newlen >= matchfinder.match_len_limit() ) + { + longest_match_found = newlen; + backward( cur ); + return cur; + } + + Trial & cur_trial = trials[cur]; + const int prev_index = cur_trial.prev_index; + + cur_trial.state = trials[prev_index].state; + + for( int i = 0; i < num_rep_distances; ++i ) + cur_trial.reps[i] = trials[prev_index].reps[i]; + if( prev_index == cur - 1 ) + { + if( cur_trial.dis == 0 ) cur_trial.state.set_short_rep(); + else cur_trial.state.set_char(); + } + else + { + if( cur_trial.dis < num_rep_distances ) cur_trial.state.set_rep(); + else cur_trial.state.set_match(); + mtf_reps( cur_trial.dis, cur_trial.reps ); + } + + const uint8_t cur_byte = matchfinder[0]; + const uint8_t match_byte = matchfinder[-cur_trial.reps[0]-1]; + const int pos_state = ++position & pos_state_mask; + int next_price = cur_trial.price + price0( bm_match[cur_trial.state()][pos_state] ); + if( cur_trial.state.is_char() ) + next_price += literal_encoder.price_symbol( matchfinder[-1], cur_byte ); + else + next_price += literal_encoder.price_matched( matchfinder[-1], cur_byte, match_byte ); + if( !matchfinder.move_pos() ) return 0; + + Trial & next_trial = trials[cur+1]; + + next_trial.update( -1, cur, next_price ); + + const int match_price = cur_trial.price + price1( bm_match[cur_trial.state()][pos_state] ); + const int rep_match_price = match_price + price1( bm_rep[cur_trial.state()] ); + + if( match_byte == cur_byte && next_trial.dis != 0 ) + next_trial.update( 0, cur, rep_match_price + + price_rep_len1( cur_trial.state, pos_state ) ); + + const int len_limit = std::min( std::min( max_num_trials - 1 - cur, + matchfinder.available_bytes() ), matchfinder.match_len_limit() ); + if( len_limit < min_match_len ) continue; + + for( int rep = 0; rep < num_rep_distances; ++rep ) + { + const int dis = cur_trial.reps[rep] + 1; + int len = 0; + const uint8_t * const data = matchfinder.ptr_to_current_pos() - 1; + while( len < len_limit && data[len] == data[len-dis] ) ++len; + if( len >= min_match_len ) + { + while( num_trials < cur + len ) + trials[++num_trials].price = infinite_price; + for( ; len >= min_match_len; --len ) + trials[cur+len].update( rep, cur, rep_match_price + + price_rep( rep, len, cur_trial.state, pos_state ) ); + } + } + + if( newlen <= len_limit && + ( newlen > min_match_len || + ( newlen == min_match_len && + match_distances[newlen] < modeled_distances ) ) ) + { + const int normal_match_price = match_price + + price0( bm_rep[cur_trial.state()] ); + while( num_trials < cur + newlen ) + trials[++num_trials].price = infinite_price; + + for( int len = newlen; len >= min_match_len; --len ) + trials[cur+len].update( match_distances[len] + num_rep_distances, cur, + normal_match_price + + price_pair( match_distances[len], len, pos_state ) ); + } + } + } + + + // End Of Stream mark => (dis == 0xFFFFFFFF, len == min_match_len) +void LZ_encoder::flush( const State & state ) + { + const int pos_state = ( matchfinder.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( 0xFFFFFFFF, min_match_len, pos_state ); + range_encoder.flush(); + File_trailer trailer; + trailer.data_crc( crc() ); + trailer.data_size( matchfinder.data_position() ); + trailer.member_size( range_encoder.member_position() + sizeof trailer ); + for( unsigned int i = 0; i < sizeof trailer; ++i ) + range_encoder.put_byte( (( uint8_t *)&trailer)[i] ); + } + + +LZ_encoder::LZ_encoder( Matchfinder & mf, const File_header & header, + const long long member_size ) + : + member_size_limit( member_size - sizeof( File_trailer ) - 15 ), + longest_match_found( 0 ), + crc_( 0xFFFFFFFF ), + matchfinder( mf ), + range_encoder(), + len_encoder( matchfinder.match_len_limit() ), + rep_match_len_encoder( matchfinder.match_len_limit() ), + literal_encoder(), + num_dis_slots( 2 * File_header::real_bits( matchfinder.dictionary_size() - 1 ) ), + fill_counter( 0 ), + prev_byte( 0 ), + member_finished_( false ) + { + for( int i = 0; i < num_rep_distances; ++i ) rep_distances[i] = 0; + fill_align_prices(); + + for( unsigned int i = 0; i < sizeof header; ++i ) + range_encoder.put_byte( (( uint8_t *)&header)[i] ); + } + + +bool LZ_encoder::encode_member() + { + if( member_finished_ ) return true; + if( !matchfinder.finished() && !matchfinder.available_bytes() ) + return true; // need at least 1 byte + + if( range_encoder.member_position() == sizeof( File_header ) && + !matchfinder.finished() ) // copy first byte + { + range_encoder.encode_bit( bm_match[state()][0], 0 ); + const uint8_t cur_byte = matchfinder[0]; + literal_encoder.encode( range_encoder, prev_byte, cur_byte ); + prev_byte = cur_byte; + crc32.update( crc_, cur_byte ); + if( !move_pos( 1 ) ) return false; + } + + while( true ) + { + if( matchfinder.finished() ) + { flush( state ); member_finished_ = true; return true; } + if( !matchfinder.available_bytes() || + ( !matchfinder.at_stream_end() && + matchfinder.available_bytes() < max_num_trials + max_match_len ) ) + return true; // need more data + if( range_encoder.free_bytes() < 2 * max_num_trials ) return true; + if( fill_counter <= 0 ) { fill_distance_prices(); fill_counter = 512; } + + int ahead = best_pair_sequence( rep_distances, state ); + if( ahead <= 0 ) return false; + fill_counter -= ahead; + + for( int i = 0; ; ) + { + const int pos_state = ( matchfinder.data_position() - ahead ) & pos_state_mask; + int dis = trials[i].dis; + const int len = trials[i].price; + + bool bit = ( dis < 0 && len == 1 ); + range_encoder.encode_bit( bm_match[state()][pos_state], !bit ); + if( bit ) + { + const uint8_t cur_byte = matchfinder[-ahead]; + if( state.is_char() ) + literal_encoder.encode( range_encoder, prev_byte, cur_byte ); + else + { + const uint8_t match_byte = matchfinder[-rep_distances[0]-1-ahead]; + literal_encoder.encode_matched( range_encoder, prev_byte, match_byte, cur_byte ); + } + state.set_char(); + prev_byte = cur_byte; + } + else + { + 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(); + } + prev_byte = matchfinder[len-1-ahead]; + } + for( int j = 0; j < len; ++j ) + crc32.update( crc_, matchfinder[j-ahead] ); + ahead -= len; i += len; + if( range_encoder.member_position() >= member_size_limit ) + { + if( !matchfinder.dec_pos( ahead ) ) return false; + flush( state ); + member_finished_ = true; + return true; + } + if( ahead <= 0 ) break; + } + } + } |