diff options
Diffstat (limited to '')
| -rw-r--r-- | encoder.h | 62 |
1 files changed, 30 insertions, 32 deletions
@@ -1,5 +1,5 @@ /* Lzip - LZMA lossless data compressor - Copyright (C) 2008-2016 Antonio Diaz Diaz. + Copyright (C) 2008-2017 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 @@ -21,11 +21,10 @@ class Len_prices const int len_symbols; const int count; int prices[pos_states][max_len_symbols]; - int counters[pos_states]; + int counters[pos_states]; // may decrement below 0 void update_low_mid_prices( const int pos_state ) { - counters[pos_state] = count; int * const pps = prices[pos_state]; int tmp = price0( lm.choice1 ); int len = 0; @@ -64,13 +63,14 @@ public: bool high_pending = false; for( int pos_state = 0; pos_state < pos_states; ++pos_state ) if( counters[pos_state] <= 0 ) - { update_low_mid_prices( pos_state ); high_pending = true; } + { counters[pos_state] = count; + update_low_mid_prices( pos_state ); high_pending = true; } if( high_pending && len_symbols > len_low_symbols + len_mid_symbols ) update_high_prices(); } - int price( const int symbol, const int pos_state ) const - { return prices[pos_state][symbol - min_match_len]; } + int price( const int len, const int pos_state ) const + { return prices[pos_state][len - min_match_len]; } }; @@ -91,32 +91,33 @@ class LZ_encoder : public LZ_encoder_base { State state; int price; // dual use var; cumulative price, match length - int dis; // rep index or match distance. (-1 for literal) + int dis4; // -1 for literal, or rep, or match distance + 4 int prev_index; // index of prev trial in trials[] int prev_index2; // -2 trial is single step // -1 literal + rep0 // >= 0 ( rep or match ) + literal + rep0 int reps[num_rep_distances]; - void update( const int pr, const int distance, const int p_i ) + void update( const int pr, const int distance4, const int p_i ) { if( pr < price ) - { price = pr; dis = distance; prev_index = p_i; + { price = pr; dis4 = distance4; prev_index = p_i; prev_index2 = single_step_trial; } } void update2( const int pr, const int p_i ) { if( pr < price ) - { price = pr; dis = 0; prev_index = p_i; + { price = pr; dis4 = 0; prev_index = p_i; prev_index2 = dual_step_trial; } } - void update3( const int pr, const int distance, const int p_i, + void update3( const int pr, const int distance4, const int p_i, const int p_i2 ) { if( pr < price ) - { price = pr; dis = distance; prev_index = p_i; prev_index2 = p_i2; } + { price = pr; dis4 = distance4; prev_index = p_i; + prev_index2 = p_i2; } } }; @@ -137,26 +138,26 @@ class LZ_encoder : public LZ_encoder_base { if( ahead < 0 || pos < ahead ) return false; pos -= ahead; + if( cyclic_pos < ahead ) cyclic_pos += dictionary_size + 1; cyclic_pos -= ahead; - if( cyclic_pos < 0 ) cyclic_pos += dictionary_size + 1; return true; } int get_match_pairs( Pair * pairs = 0 ); void update_distance_prices(); - // move-to-front dis in/into reps if( dis > 0 ) - static void mtf_reps( const int dis, int reps[num_rep_distances] ) + // move-to-front dis in/into reps; do nothing if( dis4 <= 0 ) + static void mtf_reps( const int dis4, int reps[num_rep_distances] ) { - if( dis >= num_rep_distances ) + if( dis4 >= num_rep_distances ) // match { - for( int i = num_rep_distances - 1; i > 0; --i ) reps[i] = reps[i-1]; - reps[0] = dis - num_rep_distances; + reps[3] = reps[2]; reps[2] = reps[1]; reps[1] = reps[0]; + reps[0] = dis4 - num_rep_distances; } - else if( dis > 0 ) + else if( dis4 > 0 ) // repeated match { - const int distance = reps[dis]; - for( int i = dis; i > 0; --i ) reps[i] = reps[i-1]; + const int distance = reps[dis4]; + for( int i = dis4; i > 0; --i ) reps[i] = reps[i-1]; reps[0] = distance; } } @@ -203,13 +204,10 @@ class LZ_encoder : public LZ_encoder_base const int num_pairs = get_match_pairs( pairs ); if( num_pairs > 0 ) { - int len = pairs[num_pairs-1].len; + const int len = pairs[num_pairs-1].len; if( len == match_len_limit && len < max_match_len ) - { - len += true_match_len( len, pairs[num_pairs-1].dis + 1, - max_match_len - len ); - pairs[num_pairs-1].len = len; - } + pairs[num_pairs-1].len = + true_match_len( len, pairs[num_pairs-1].dis + 1 ); } return num_pairs; } @@ -226,7 +224,7 @@ class LZ_encoder : public LZ_encoder_base void backward( int cur ) { - int & dis = trials[cur].dis; + int dis4 = trials[cur].dis4; while( cur > 0 ) { const int prev_index = trials[cur].prev_index; @@ -234,19 +232,19 @@ class LZ_encoder : public LZ_encoder_base if( trials[cur].prev_index2 != single_step_trial ) { - prev_trial.dis = -1; + prev_trial.dis4 = -1; // literal prev_trial.prev_index = prev_index - 1; prev_trial.prev_index2 = single_step_trial; if( trials[cur].prev_index2 >= 0 ) { Trial & prev_trial2 = trials[prev_index-1]; - prev_trial2.dis = dis; dis = 0; + prev_trial2.dis4 = dis4; dis4 = 0; // rep0 prev_trial2.prev_index = trials[cur].prev_index2; prev_trial2.prev_index2 = single_step_trial; } } prev_trial.price = cur - prev_index; // len - cur = dis; dis = prev_trial.dis; prev_trial.dis = cur; + cur = dis4; dis4 = prev_trial.dis4; prev_trial.dis4 = cur; cur = prev_index; } } @@ -254,7 +252,7 @@ class LZ_encoder : public LZ_encoder_base int sequence_optimizer( const int reps[num_rep_distances], const State state ); - enum { before = max_num_trials + 1, + enum { before = max_num_trials, // bytes to keep in buffer after pos after_size = ( 2 * max_match_len ) + 1, dict_factor = 2, |