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+/* Lzip - A data compressor based on the LZMA algorithm
+ Copyright (C) 2008, 2009 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/>.
+*/
+
+const int max_num_trials = 1 << 12;
+const int price_shift = 6;
+
+class Dis_slots
+ {
+ unsigned char data[1<<12];
+
+public:
+ void init() throw()
+ {
+ 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;
+ }
+ }
+
+ 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 Dis_slots dis_slots;
+
+class Prob_prices
+ {
+ int data[bit_model_total >> 2];
+
+public:
+ void init() throw()
+ {
+ const int num_bits = ( bit_model_total_bits - 2 );
+ for( int i = num_bits - 1; i >= 0; --i )
+ {
+ 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) );
+ }
+ }
+
+ int operator[]( const int symbol ) const throw()
+ { return data[symbol >> 2]; }
+ };
+
+extern 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()
+ {
+ symbol |= ( 1 << num_bits );
+ int price = 0;
+ while( symbol > 1 )
+ {
+ const int bit = symbol & 1;
+ symbol >>= 1;
+ price += price_bit( bm[symbol-1], 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-1], 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;
+ const int bit = ( symbol >> i ) & 1;
+ price += price_bit( bm[(match_bit<<8)+model+0xFF], bit );
+ model = ( model << 1 ) | bit;
+ if( match_bit != bit )
+ {
+ while( --i >= 0 )
+ {
+ const int bit = ( symbol >> i ) & 1;
+ price += price_bit( bm[model-1], bit );
+ model = ( model << 1 ) | bit;
+ }
+ break;
+ }
+ }
+ return price;
+ }
+
+
+class Matchfinder
+ {
+ enum { 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;
+ int dictionary_size_; // bytes to keep in buffer before pos
+ const int after_size; // bytes to keep in buffer after pos
+ const int buffer_size;
+ uint8_t * const buffer;
+ int pos;
+ int cyclic_pos;
+ int stream_pos; // first byte not yet read from file
+ const int pos_limit; // when reached, a new block must be read
+ const int ides_;
+ const int match_len_limit_;
+ int32_t * const prev_positions; // last seen position of key
+ int32_t * prev_pos_tree;
+ bool at_stream_end; // stream_pos shows real end of file
+
+ bool read_block() throw();
+
+public:
+ Matchfinder( const int dict_size, const int len_limit, const int ides )
+ :
+ partial_data_pos( 0 ),
+ dictionary_size_( dict_size ),
+ after_size( max_match_len ),
+ buffer_size( ( 2 * std::max( 65536, dictionary_size_ ) ) +
+ max_num_trials + after_size ),
+ buffer( new uint8_t[buffer_size] ),
+ pos( 0 ),
+ cyclic_pos( 0 ),
+ stream_pos( 0 ),
+ pos_limit( buffer_size - after_size ),
+ ides_( ides ),
+ match_len_limit_( len_limit ),
+ prev_positions( new int32_t[num_prev_positions] ),
+ at_stream_end( false )
+ {
+ if( !read_block() ) throw Error( "read error" );
+ if( at_stream_end && stream_pos < dictionary_size_ )
+ dictionary_size_ = std::max( min_dictionary_size, stream_pos );
+ prev_pos_tree = new int32_t[2*dictionary_size_];
+ for( int i = 0; i < num_prev_positions; ++i ) prev_positions[i] = -1;
+ }
+
+ ~Matchfinder()
+ { delete[] prev_pos_tree; delete[] prev_positions; delete[] buffer; }
+
+ uint8_t operator[]( const int i ) const throw() { return buffer[pos+i]; }
+ 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; }
+ 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;
+ }
+
+ 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;
+ }
+
+ bool reset() throw();
+ bool move_pos() throw();
+ int longest_match_len( int * const distances = 0 ) throw();
+ };
+
+
+class Range_encoder
+ {
+ enum { buffer_size = 65536 };
+
+ uint64_t low;
+ long long partial_member_pos;
+ uint8_t * const buffer;
+ int pos;
+ uint32_t range;
+ int ff_count;
+ const int odes_;
+ uint8_t cache;
+
+ void shift_low()
+ {
+ const uint32_t carry = low >> 32;
+ if( low < 0xFF000000 || carry == 1 )
+ {
+ put_byte( cache + carry );
+ for( ; ff_count > 0; --ff_count ) put_byte( 0xFF + carry );
+ cache = low >> 24;
+ }
+ else ++ff_count;
+ low = ( low & 0x00FFFFFF ) << 8;
+ }
+
+public:
+ Range_encoder( const int odes )
+ :
+ low( 0 ),
+ partial_member_pos( 0 ),
+ buffer( new uint8_t[buffer_size] ),
+ pos( 0 ),
+ range( 0xFFFFFFFF ),
+ ff_count( 0 ),
+ odes_( odes ),
+ cache( 0 ) {}
+
+ ~Range_encoder() { delete[] buffer; }
+
+ void flush_data()
+ {
+ if( pos > 0 )
+ {
+ if( odes_ >= 0 )
+ {
+ const int wr = writeblock( odes_, (char *)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(); }
+
+ long long member_position() const throw()
+ { return partial_member_pos + pos + ff_count; }
+
+ void put_byte( const uint8_t b )
+ {
+ buffer[pos] = b;
+ if( ++pos >= buffer_size ) flush_data();
+ }
+
+ 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 <= 0x00FFFFFF ) { 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 <= 0x00FFFFFF ) { 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-1], 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-1], 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 bit = ( symbol >> i ) & 1;
+ const int match_bit = ( match_byte >> i ) & 1;
+ encode_bit( bm[(match_bit<<8)+model+0xFF], bit );
+ model = ( model << 1 ) | bit;
+ if( match_bit != bit )
+ {
+ while( --i >= 0 )
+ {
+ const int bit = ( symbol >> i ) & 1;
+ encode_bit( bm[model-1], 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 price = price0( choice1 );
+ int len = 0;
+ for( ; len < len_low_symbols && len < len_symbols; ++len )
+ pps[len] = price +
+ price_symbol( bm_low[pos_state], len, len_low_bits );
+ price = price1( choice1 );
+ for( ; len < len_low_symbols + len_mid_symbols && len < len_symbols; ++len )
+ pps[len] = price + price0( choice2 ) +
+ price_symbol( bm_mid[pos_state], len - len_low_symbols, len_mid_bits );
+ for( ; len < len_symbols; ++len )
+ pps[len] = price + 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 state( const int 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[state(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[state(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[state(prev_byte)], symbol, match_byte ); }
+
+ int price_symbol( uint8_t prev_byte, uint8_t symbol ) const throw()
+ { return ::price_symbol( bm_literal[state(prev_byte)], symbol, 8 ); }
+ };
+
+
+class LZ_encoder
+ {
+ enum { dis_align_mask = dis_align_size - 1,
+ infinite_price = 0x0FFFFFFF,
+ num_rep_distances = 4 }; // must be 4
+
+ struct Trial
+ {
+ State state;
+ int dis;
+ int prev_index;
+ 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; } }
+ };
+
+ 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];
+ 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 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;
+
+ void fill_align_prices() throw();
+ void fill_distance_prices() throw();
+
+ uint32_t crc() const throw() { return crc_ ^ 0xFFFFFFFF; }
+
+ 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 int len, const State & state,
+ const int pos_state ) const throw()
+ {
+ int price = rep_match_len_encoder.price( len, pos_state );
+ if( rep == 0 )
+ {
+ price += price0( bm_rep0[state()] );
+ price += price1( bm_len[state()][pos_state] );
+ }
+ else
+ {
+ 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_pair( const int dis, const int len, const int pos_state ) const throw()
+ {
+ if( len <= min_match_len && dis >= modeled_distances )
+ return infinite_price;
+ int price = len_encoder.price( len, pos_state );
+ const int dis_state = get_dis_state( len );
+ if( dis < modeled_distances )
+ price += dis_prices[dis_state][dis];
+ else
+ price += dis_slot_prices[dis_state][dis_slots[dis]] +
+ align_prices[dis & dis_align_mask];
+ return price;
+ }
+
+ 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];
+ std::swap( dis, prev_trial.dis );
+ prev_trial.price = cur - prev_index; // len
+ cur = prev_index;
+ }
+ }
+
+ int best_pair_sequence( const int reps[num_rep_distances],
+ const State & state );
+
+ void flush( const State & state );
+
+public:
+ LZ_encoder( Matchfinder & mf, const File_header & header, const int odes );
+
+ bool encode_member( const long long member_size );
+
+ long long member_position() const throw()
+ { return range_encoder.member_position(); }
+ };
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