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-/* Lzlib - A compression library for lzip files
- Copyright (C) 2009, 2010, 2011 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 library. 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.
-*/
-
-namespace Lzlib {
-
-enum { max_num_trials = 1 << 12,
- price_shift = 6 };
-
-class Dis_slots
- {
- unsigned char data[1<<12];
-
-public:
- Dis_slots()
- {
- for( int slot = 0; slot < 4; ++slot ) data[slot] = slot;
- for( int i = 4, size = 2, slot = 4; slot < 24; slot += 2 )
- {
- std::memset( &data[i], slot, size );
- std::memset( &data[i+size], slot + 1, size );
- size <<= 1;
- i += size;
- }
- }
-
- 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];
- if( dis < (1 << 23) ) return data[dis>>11] + 22;
- return data[dis>>22] + 44;
- }
- };
-
-extern const Dis_slots dis_slots;
-
-
-class Prob_prices
- {
- int data[bit_model_total >> 2];
-
-public:
- Prob_prices()
- {
- const int num_bits = ( bit_model_total_bits - 2 );
- int j = 1, end = 2;
- data[0] = bit_model_total_bits << price_shift;
- for( int i = num_bits - 1; i >= 0; --i, end <<= 1 )
- {
- for( ; j < end; ++j )
- data[j] = ( i << price_shift ) +
- ( ( (end - j) << price_shift ) >> ( num_bits - i - 1 ) );
- }
- }
-
- int operator[]( const int probability ) const throw()
- { return data[probability >> 2]; }
- };
-
-extern const Prob_prices prob_prices;
-
-
-inline int price0( const Bit_model & bm ) throw()
- { return prob_prices[bm.probability]; }
-
-inline int price1( const Bit_model & bm ) throw()
- { return prob_prices[bit_model_total-bm.probability]; }
-
-inline int price_bit( const Bit_model & bm, const int bit ) throw()
- { if( bit ) return price1( bm ); else return price0( bm ); }
-
-
-inline int price_symbol( const Bit_model bm[], int symbol, const int num_bits ) throw()
- {
- int price = 0;
- symbol |= ( 1 << num_bits );
- while( symbol > 1 )
- {
- const int bit = symbol & 1;
- symbol >>= 1;
- price += price_bit( bm[symbol], bit );
- }
- return price;
- }
-
-
-inline int price_symbol_reversed( const Bit_model bm[], int symbol,
- const int num_bits ) throw()
- {
- int price = 0;
- int model = 1;
- for( int i = num_bits; i > 0; --i )
- {
- const int bit = symbol & 1;
- symbol >>= 1;
- price += price_bit( bm[model], bit );
- model = ( model << 1 ) | bit;
- }
- return price;
- }
-
-
-inline int price_matched( const Bit_model bm[], const int symbol,
- const int match_byte ) throw()
- {
- int price = 0;
- int model = 1;
-
- for( int i = 7; i >= 0; --i )
- {
- const int match_bit = ( match_byte >> i ) & 1;
- int bit = ( symbol >> i ) & 1;
- price += price_bit( bm[(match_bit<<8)+model+0x100], bit );
- model = ( model << 1 ) | bit;
- if( match_bit != bit )
- {
- while( --i >= 0 )
- {
- bit = ( symbol >> i ) & 1;
- price += price_bit( bm[model], bit );
- model = ( model << 1 ) | bit;
- }
- break;
- }
- }
- return price;
- }
-
-
-class Matchfinder
- {
- enum { // bytes to keep in buffer before dictionary
- before_size = max_num_trials + 1,
- // bytes to keep in buffer after pos
- after_size = max_num_trials + max_match_len,
- num_prev_positions4 = 1 << 20,
- num_prev_positions3 = 1 << 18,
- num_prev_positions2 = 1 << 16,
- num_prev_positions = num_prev_positions4 + num_prev_positions3 +
- num_prev_positions2 };
-
- long long partial_data_pos;
- const int dictionary_size_; // bytes to keep in buffer before pos
- const int buffer_size;
- uint8_t * const buffer; // input buffer
- int32_t * const prev_positions; // last seen position of key
- int32_t * const prev_pos_tree;
- int pos; // current pos in buffer
- int cyclic_pos; // current pos in dictionary
- int stream_pos; // first byte not yet read from file
- const int pos_limit; // when reached, a new block must be read
- const int match_len_limit_;
- const int cycles;
- bool at_stream_end_; // stream_pos shows real end of file
- bool been_flushed;
-
-public:
- Matchfinder( const int dict_size, const int len_limit );
-
- ~Matchfinder()
- { delete[] prev_pos_tree; delete[] prev_positions; delete[] buffer; }
-
- uint8_t operator[]( const int i ) const throw() { return buffer[pos+i]; }
- bool at_stream_end() const throw() { return at_stream_end_; }
- int available_bytes() const throw() { return stream_pos - pos; }
- long long data_position() const throw() { return partial_data_pos + pos; }
- int dictionary_size() const throw() { return dictionary_size_; }
- bool finished() const throw() { return at_stream_end_ && pos >= stream_pos; }
- void flushing( const bool b ) throw() { at_stream_end_ = b; }
- int free_bytes() const throw()
- { if( at_stream_end_ ) return 0; return buffer_size - stream_pos; }
- int match_len_limit() const throw() { return match_len_limit_; }
- const uint8_t * ptr_to_current_pos() const throw() { return buffer + pos; }
-
- bool dec_pos( const int ahead ) throw()
- {
- if( ahead < 0 || pos < ahead ) return false;
- pos -= ahead;
- cyclic_pos -= ahead;
- if( cyclic_pos < 0 ) cyclic_pos += dictionary_size_;
- return true;
- }
-
- bool enough_available_bytes() const throw()
- {
- return ( stream_pos > pos &&
- ( at_stream_end_ || stream_pos - pos >= after_size ) );
- }
-
- int true_match_len( const int index, const int distance, int len_limit ) const throw()
- {
- if( index + len_limit > available_bytes() )
- len_limit = available_bytes() - index;
- const uint8_t * const data = buffer + pos + index - distance;
- int i = 0;
- while( i < len_limit && data[i] == data[i+distance] ) ++i;
- return i;
- }
-
- int write_data( const uint8_t * const in_buffer, const int in_size ) throw();
- void reset() throw();
- bool move_pos() throw();
- int longest_match_len( int * const distances = 0 ) throw();
- };
-
-
-class Range_encoder : public Circular_buffer
- {
- enum { min_free_bytes = 2 * max_num_trials };
- uint64_t low;
- long long partial_member_pos;
- uint32_t range;
- int ff_count;
- uint8_t cache;
-
- void shift_low()
- {
- const uint32_t carry = low >> 32;
- if( low < 0xFF000000U || carry == 1 )
- {
- put_byte( cache + carry );
- for( ; ff_count > 0; --ff_count ) put_byte( 0xFF + carry );
- cache = low >> 24;
- }
- else ++ff_count;
- low = ( low & 0x00FFFFFFU ) << 8;
- }
-
-public:
- Range_encoder()
- :
- Circular_buffer( 65536 + min_free_bytes ),
- low( 0 ),
- partial_member_pos( 0 ),
- range( 0xFFFFFFFFU ),
- ff_count( 0 ),
- cache( 0 ) {}
-
- long long member_position() const throw()
- { return partial_member_pos + used_bytes() + ff_count; }
-
- bool enough_free_bytes() const throw()
- { return free_bytes() >= min_free_bytes; }
-
- int read_data( uint8_t * const out_buffer, const int out_size ) throw()
- {
- const int size = Circular_buffer::read_data( out_buffer, out_size );
- if( size > 0 ) partial_member_pos += size;
- return size;
- }
-
- void flush()
- {
- for( int i = 0; i < 5; ++i ) shift_low();
- low = 0;
- range = 0xFFFFFFFFU;
- ff_count = 0;
- cache = 0;
- }
-
- void encode( const int symbol, const int num_bits )
- {
- for( int i = num_bits - 1; i >= 0; --i )
- {
- range >>= 1;
- if( (symbol >> i) & 1 ) low += range;
- if( range <= 0x00FFFFFFU ) { range <<= 8; shift_low(); }
- }
- }
-
- void encode_bit( Bit_model & bm, const int bit )
- {
- const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability;
- if( !bit )
- {
- range = bound;
- bm.probability += (bit_model_total - bm.probability) >> bit_model_move_bits;
- }
- else
- {
- low += bound;
- range -= bound;
- bm.probability -= bm.probability >> bit_model_move_bits;
- }
- if( range <= 0x00FFFFFFU ) { range <<= 8; shift_low(); }
- }
-
- void encode_tree( Bit_model bm[], const int symbol, const int num_bits )
- {
- int mask = ( 1 << ( num_bits - 1 ) );
- int model = 1;
- for( int i = num_bits; i > 0; --i, mask >>= 1 )
- {
- const int bit = ( symbol & mask );
- encode_bit( bm[model], bit );
- model <<= 1;
- if( bit ) model |= 1;
- }
- }
-
- void encode_tree_reversed( Bit_model bm[], int symbol, const int num_bits )
- {
- int model = 1;
- for( int i = num_bits; i > 0; --i )
- {
- const int bit = symbol & 1;
- encode_bit( bm[model], bit );
- model = ( model << 1 ) | bit;
- symbol >>= 1;
- }
- }
-
- void encode_matched( Bit_model bm[], int symbol, int match_byte )
- {
- int model = 1;
- for( int i = 7; i >= 0; --i )
- {
- const int match_bit = ( match_byte >> i ) & 1;
- int bit = ( symbol >> i ) & 1;
- encode_bit( bm[(match_bit<<8)+model+0x100], bit );
- model = ( model << 1 ) | bit;
- if( match_bit != bit )
- {
- while( --i >= 0 )
- {
- bit = ( symbol >> i ) & 1;
- encode_bit( bm[model], bit );
- model = ( model << 1 ) | bit;
- }
- break;
- }
- }
- }
- };
-
-
-class Len_encoder
- {
- Bit_model choice1;
- Bit_model choice2;
- Bit_model bm_low[pos_states][len_low_symbols];
- Bit_model bm_mid[pos_states][len_mid_symbols];
- Bit_model bm_high[len_high_symbols];
- int prices[pos_states][max_len_symbols];
- const int len_symbols;
- int counters[pos_states];
-
- void update_prices( const int pos_state ) throw()
- {
- int * const pps = prices[pos_state];
- int tmp = price0( choice1 );
- int len = 0;
- for( ; len < len_low_symbols && len < len_symbols; ++len )
- pps[len] = tmp +
- price_symbol( bm_low[pos_state], len, len_low_bits );
- tmp = price1( choice1 );
- for( ; len < len_low_symbols + len_mid_symbols && len < len_symbols; ++len )
- pps[len] = tmp + price0( choice2 ) +
- price_symbol( bm_mid[pos_state], len - len_low_symbols, len_mid_bits );
- for( ; len < len_symbols; ++len )
- // using 4 slots per value makes "price" faster
- prices[3][len] = prices[2][len] = prices[1][len] = prices[0][len] =
- tmp + price1( choice2 ) +
- price_symbol( bm_high, len - len_low_symbols - len_mid_symbols, len_high_bits );
- counters[pos_state] = len_symbols;
- }
-
-public:
- Len_encoder( const int len_limit )
- : len_symbols( len_limit + 1 - min_match_len )
- {
- for( int i = 0; i < pos_states; ++i ) update_prices( i );
- }
-
- void encode( Range_encoder & range_encoder, int symbol,
- const int pos_state );
-
- int price( const int symbol, const int pos_state ) const throw()
- { return prices[pos_state][symbol - min_match_len]; }
- };
-
-
-class Literal_encoder
- {
- Bit_model bm_literal[1<<literal_context_bits][0x300];
-
- int lstate( const uint8_t prev_byte ) const throw()
- { return ( prev_byte >> ( 8 - literal_context_bits ) ); }
-
-public:
- 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 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 Lzlib::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 Lzlib::price_matched( bm_literal[lstate(prev_byte)],
- symbol, match_byte ); }
- };
-
-
-class LZ_encoder
- {
- enum { infinite_price = 0x0FFFFFFF,
- max_marker_size = 16,
- num_rep_distances = 4 }; // must be 4
-
- struct Trial
- {
- State state;
- int dis;
- int prev_index; // index of prev trial in trials[]
- 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; } }
- };
-
- const long long member_size_limit;
- int longest_match_found;
- uint32_t crc_;
-
- Bit_model bm_match[State::states][pos_states];
- Bit_model bm_rep[State::states];
- Bit_model bm_rep0[State::states];
- Bit_model bm_rep1[State::states];
- 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+1];
- Bit_model bm_align[dis_align_size];
-
- Matchfinder & matchfinder;
- Range_encoder range_encoder;
- Len_encoder len_encoder;
- Len_encoder rep_match_len_encoder;
- Literal_encoder literal_encoder;
-
- const int num_dis_slots;
- int rep_distances[num_rep_distances];
- int match_distances[max_match_len+1];
- Trial trials[max_num_trials];
-
- int dis_slot_prices[max_dis_states][2*max_dictionary_bits];
- int dis_prices[max_dis_states][modeled_distances];
- int align_prices[dis_align_size];
- int align_price_count;
- int fill_counter;
- State main_state;
- bool member_finished_;
-
- void fill_align_prices() throw();
- void fill_distance_prices() throw();
-
- uint32_t crc() const throw() { return crc_ ^ 0xFFFFFFFFU; }
-
- // move-to-front dis in/into reps
- void mtf_reps( const int dis, int reps[num_rep_distances] ) throw()
- {
- if( dis >= num_rep_distances )
- {
- for( int i = num_rep_distances - 1; i > 0; --i ) reps[i] = reps[i-1];
- reps[0] = dis - num_rep_distances;
- }
- else if( dis > 0 )
- {
- const int distance = reps[dis];
- for( int i = dis; i > 0; --i ) reps[i] = reps[i-1];
- reps[0] = distance;
- }
- }
-
- int price_rep_len1( const State & state, const int pos_state ) const throw()
- {
- return price0( bm_rep0[state()] ) + price0( bm_len[state()][pos_state] );
- }
-
- int price_rep( const int rep, const State & state,
- const int pos_state ) const throw()
- {
- if( rep == 0 ) return price0( bm_rep0[state()] ) +
- price1( bm_len[state()][pos_state] );
- int price = price1( bm_rep0[state()] );
- if( rep == 1 )
- price += price0( bm_rep1[state()] );
- else
- {
- price += price1( bm_rep1[state()] );
- price += price_bit( bm_rep2[state()], rep - 2 );
- }
- return price;
- }
-
- int price_dis( const int dis, const int dis_state ) const throw()
- {
- if( dis < modeled_distances )
- return dis_prices[dis_state][dis];
- else
- return dis_slot_prices[dis_state][dis_slots[dis]] +
- align_prices[dis & (dis_align_size - 1)];
- }
-
- int price_pair( const int dis, const int len, const int pos_state ) const throw()
- {
- if( len <= min_match_len && dis >= modeled_distances )
- return infinite_price;
- return len_encoder.price( len, pos_state ) +
- price_dis( dis, get_dis_state( len ) );
- }
-
- void encode_pair( const uint32_t dis, const int len, const int pos_state ) throw()
- {
- len_encoder.encode( range_encoder, len, pos_state );
- const int dis_slot = dis_slots[dis];
- range_encoder.encode_tree( bm_dis_slot[get_dis_state(len)], dis_slot, dis_slot_bits );
-
- if( dis_slot >= start_dis_model )
- {
- const int direct_bits = ( dis_slot >> 1 ) - 1;
- const uint32_t base = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
- const uint32_t direct_dis = dis - base;
-
- if( dis_slot < end_dis_model )
- range_encoder.encode_tree_reversed( bm_dis + base - dis_slot,
- direct_dis, direct_bits );
- else
- {
- range_encoder.encode( direct_dis >> dis_align_bits, direct_bits - dis_align_bits );
- range_encoder.encode_tree_reversed( bm_align, direct_dis, dis_align_bits );
- if( --align_price_count <= 0 ) fill_align_prices();
- }
- }
- }
-
- int read_match_distances() throw()
- {
- int len = matchfinder.longest_match_len( match_distances );
- if( len == matchfinder.match_len_limit() )
- len += matchfinder.true_match_len( len, match_distances[len] + 1, max_match_len - len );
- return len;
- }
-
- bool move_pos( int n, bool skip = false ) throw()
- {
- while( --n >= 0 )
- {
- if( skip ) skip = false;
- else matchfinder.longest_match_len();
- if( !matchfinder.move_pos() ) return false;
- }
- return true;
- }
-
- void backward( int cur )
- {
- int & dis = trials[cur].dis;
- while( cur > 0 )
- {
- const int prev_index = trials[cur].prev_index;
- Trial & prev_trial = trials[prev_index];
- prev_trial.price = cur - prev_index; // len
- cur = dis; dis = prev_trial.dis; prev_trial.dis = cur;
- cur = prev_index;
- }
- }
-
- int sequence_optimizer( const int reps[num_rep_distances],
- const State & state );
-
- bool full_flush( const State & state );
-
-public:
- LZ_encoder( Matchfinder & mf, const File_header & header,
- const long long member_size );
-
- bool encode_member( const bool finish );
- bool member_finished() const throw()
- { return member_finished_ && !range_encoder.used_bytes(); }
- int read_data( uint8_t * const buffer, const int size ) throw()
- { return range_encoder.read_data( buffer, size ); }
- bool sync_flush();
-
- long long member_position() const throw()
- { return range_encoder.member_position(); }
- };
-
-} // end namespace Lzlib
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