diff options
Diffstat (limited to 'encoder.h')
| -rw-r--r-- | encoder.h | 101 |
1 files changed, 48 insertions, 53 deletions
@@ -1,4 +1,4 @@ -/* Lzip - A data compressor based on the LZMA algorithm +/* 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 @@ -15,8 +15,8 @@ along with this program. If not, see <http://www.gnu.org/licenses/>. */ -const int max_num_trials = 1 << 12; -const int price_shift = 6; +enum { max_num_trials = 1 << 12, + price_shift = 6 }; class Dis_slots { @@ -35,6 +35,8 @@ public: } } + unsigned char table( const int dis ) const throw() { return data[dis]; } + int operator[]( const uint32_t dis ) const throw() { if( dis < (1 << 12) ) return data[dis]; @@ -54,13 +56,13 @@ public: void init() throw() { const int num_bits = ( bit_model_total_bits - 2 ); - for( int i = num_bits - 1; i >= 0; --i ) + int j = 1, end = 2; + data[0] = bit_model_total_bits << price_shift; + for( int i = num_bits - 1; i >= 0; --i, end <<= 1 ) { - int start = 1 << ( num_bits - i - 1 ); - int end = 1 << ( num_bits - i); - for( int j = start; j < end; ++j ) - data[j] = (i << price_shift) + - ( ((end - j) << price_shift) >> (num_bits - i - 1) ); + for( ; j < end; ++j ) + data[j] = ( i << price_shift ) + + ( ( (end - j) << price_shift ) >> ( num_bits - i - 1 ) ); } } @@ -83,8 +85,8 @@ inline int price_bit( const Bit_model & bm, const int bit ) throw() inline int price_symbol( const Bit_model bm[], int symbol, const int num_bits ) throw() { - symbol |= ( 1 << num_bits ); int price = 0; + symbol |= ( 1 << num_bits ); while( symbol > 1 ) { const int bit = symbol & 1; @@ -151,23 +153,24 @@ class Matchfinder num_prev_positions2 }; long long partial_data_pos; + uint8_t * buffer; // input buffer + int32_t * const prev_positions; // last seen position of key + int32_t * prev_pos_tree; int dictionary_size_; // bytes to keep in buffer before pos int buffer_size; - uint8_t * buffer; - int pos; - int cyclic_pos; + int pos; // current pos in buffer + int cyclic_pos; // current pos in dictionary int stream_pos; // first byte not yet read from file int pos_limit; // when reached, a new block must be read - const int infd_; // input file descriptor const int match_len_limit_; - int32_t * const prev_positions; // last seen position of key - int32_t * prev_pos_tree; + const int cycles; + const int infd; // input file descriptor bool at_stream_end; // stream_pos shows real end of file - bool read_block() throw(); + bool read_block(); public: - Matchfinder( const int dict_size, const int len_limit, const int infd ); + Matchfinder( const int dict_size, const int len_limit, const int ifd ); ~Matchfinder() { delete[] prev_pos_tree; delete[] prev_positions; std::free( buffer ); } @@ -199,8 +202,8 @@ public: return i; } - bool reset() throw(); - bool move_pos() throw(); + void reset(); + void move_pos(); int longest_match_len( int * const distances = 0 ) throw(); }; @@ -210,11 +213,11 @@ class Range_encoder enum { buffer_size = 65536 }; uint64_t low; long long partial_member_pos; - uint8_t * const buffer; - int pos; + uint8_t * const buffer; // output buffer + int pos; // current pos in buffer uint32_t range; int ff_count; - const int outfd_; // output file descriptor + const int outfd; // output file descriptor uint8_t cache; void shift_low() @@ -231,7 +234,7 @@ class Range_encoder } public: - Range_encoder( const int outfd ) + Range_encoder( const int ofd ) : low( 0 ), partial_member_pos( 0 ), @@ -239,26 +242,13 @@ public: pos( 0 ), range( 0xFFFFFFFFU ), ff_count( 0 ), - outfd_( outfd ), + outfd( ofd ), cache( 0 ) {} ~Range_encoder() { delete[] buffer; } - void flush_data() - { - if( pos > 0 ) - { - if( outfd_ >= 0 ) - { - const int wr = writeblock( outfd_, buffer, pos ); - if( wr != pos ) throw Error( "write error" ); - } - partial_member_pos += pos; - pos = 0; - } - } - void flush() { for( int i = 0; i < 5; ++i ) shift_low(); } + void flush_data(); long long member_position() const throw() { return partial_member_pos + pos + ff_count; } @@ -397,24 +387,28 @@ class Literal_encoder { return ( prev_byte >> ( 8 - literal_context_bits ) ); } public: - void encode( Range_encoder & range_encoder, uint8_t prev_byte, uint8_t symbol ) + void encode( Range_encoder & range_encoder, + uint8_t prev_byte, uint8_t symbol ) { range_encoder.encode_tree( bm_literal[lstate(prev_byte)], symbol, 8 ); } - void encode_matched( Range_encoder & range_encoder, uint8_t prev_byte, uint8_t match_byte, uint8_t symbol ) - { range_encoder.encode_matched( bm_literal[lstate(prev_byte)], symbol, match_byte ); } - - int price_matched( uint8_t prev_byte, uint8_t symbol, uint8_t match_byte ) const throw() - { return ::price_matched( bm_literal[lstate(prev_byte)], symbol, match_byte ); } + void encode_matched( Range_encoder & range_encoder, + uint8_t prev_byte, uint8_t symbol, uint8_t match_byte ) + { range_encoder.encode_matched( bm_literal[lstate(prev_byte)], + symbol, match_byte ); } int price_symbol( uint8_t prev_byte, uint8_t symbol ) const throw() { return ::price_symbol( bm_literal[lstate(prev_byte)], symbol, 8 ); } + + int price_matched( uint8_t prev_byte, uint8_t symbol, + uint8_t match_byte ) const throw() + { return ::price_matched( bm_literal[lstate(prev_byte)], + symbol, match_byte ); } }; class LZ_encoder { - enum { dis_align_mask = dis_align_size - 1, - infinite_price = 0x0FFFFFFF, + enum { infinite_price = 0x0FFFFFFF, max_marker_size = 16, num_rep_distances = 4 }; // must be 4 @@ -426,7 +420,9 @@ class LZ_encoder int price; // dual use var; cumulative price, match length int reps[num_rep_distances]; void update( const int d, const int p_i, const int pr ) throw() - { if( pr < price ) { dis = d; prev_index = p_i; price = pr; } } + { + if( pr < price ) { dis = d; prev_index = p_i; price = pr; } + } }; int longest_match_found; @@ -439,7 +435,7 @@ class LZ_encoder Bit_model bm_rep2[State::states]; Bit_model bm_len[State::states][pos_states]; Bit_model bm_dis_slot[max_dis_states][1<<dis_slot_bits]; - Bit_model bm_dis[modeled_distances-end_dis_model]; + Bit_model bm_dis[modeled_distances-end_dis_model+1]; Bit_model bm_align[dis_align_size]; Matchfinder & matchfinder; @@ -509,7 +505,7 @@ class LZ_encoder price += dis_prices[dis_state][dis]; else price += dis_slot_prices[dis_state][dis_slots[dis]] + - align_prices[dis & dis_align_mask]; + align_prices[dis & (dis_align_size - 1)]; return price; } @@ -545,15 +541,14 @@ class LZ_encoder return len; } - bool move_pos( int n, bool skip = false ) throw() + void move_pos( int n, bool skip = false ) { while( --n >= 0 ) { if( skip ) skip = false; else matchfinder.longest_match_len(); - if( !matchfinder.move_pos() ) return false; + matchfinder.move_pos(); } - return true; } void backward( int cur ) |