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/* 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
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/>.
*/
class Fmatchfinder
{
enum { // bytes to keep in buffer before dictionary
before_size = max_match_len + 1,
// bytes to keep in buffer after pos
after_size = max_match_len,
num_prev_positions = 1 << 16 };
long long partial_data_pos;
uint8_t * buffer; // input buffer
int32_t * const prev_positions; // last seen position of key
int32_t * prev_pos_chain;
int dictionary_size_; // bytes to keep in buffer before pos
int buffer_size;
int pos; // current pos in buffer
int cyclic_pos; // current pos in dictionary
int key4; // key made from latest 4 bytes
int stream_pos; // first byte not yet read from file
int pos_limit; // when reached, a new block must be read
const int match_len_limit_;
const int infd; // input file descriptor
bool at_stream_end; // stream_pos shows real end of file
bool read_block();
public:
Fmatchfinder( const int ifd );
~Fmatchfinder()
{ delete[] prev_pos_chain; delete[] prev_positions; std::free( 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; }
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;
}
void reset();
void move_pos();
int longest_match_len( int * const distance ) throw();
void longest_match_len() throw();
};
class FLZ_encoder
{
enum { max_marker_size = 16,
num_rep_distances = 4 }; // must be 4
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];
Fmatchfinder & fmatchfinder;
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_distance;
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] );
}
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 );
}
}
}
int read_match_distances() throw()
{
int len = fmatchfinder.longest_match_len( &match_distance );
if( len == fmatchfinder.match_len_limit() )
len += fmatchfinder.true_match_len( len, match_distance + 1, max_match_len - len );
return len;
}
void move_pos( int n, bool skip = false )
{
while( --n >= 0 )
{
if( skip ) skip = false;
else fmatchfinder.longest_match_len();
fmatchfinder.move_pos();
}
}
int sequence_optimizer( const int reps[num_rep_distances],
int * const disp, const State & state );
void full_flush( const State & state );
public:
FLZ_encoder( Fmatchfinder & mf, const File_header & header, const int outfd );
bool encode_member( const long long member_size );
long long member_position() const throw()
{ return range_encoder.member_position(); }
};
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