/* Lzip - LZMA lossless data compressor
Copyright (C) 2008-2021 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 2 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 .
*/
class FLZ_encoder : public LZ_encoder_base
{
unsigned key4; // key made from latest 4 bytes
void reset_key4()
{
key4 = 0;
for( int i = 0; i < 3 && i < available_bytes(); ++i )
key4 = ( key4 << 4 ) ^ buffer[i];
}
int longest_match_len( int * const distance );
void update_and_move( int n )
{
while( --n >= 0 )
{
if( available_bytes() >= 4 )
{
key4 = ( ( key4 << 4 ) ^ buffer[pos+3] ) & key4_mask;
pos_array[cyclic_pos] = prev_positions[key4];
prev_positions[key4] = pos + 1;
}
move_pos();
}
}
enum { before_size = 0,
dict_size = 65536,
// bytes to keep in buffer after pos
after_size = max_match_len,
dict_factor = 16,
num_prev_positions23 = 0,
pos_array_factor = 1 };
public:
FLZ_encoder( const int ifd, const int outfd )
:
LZ_encoder_base( before_size, dict_size, after_size, dict_factor,
num_prev_positions23, pos_array_factor, ifd, outfd )
{}
bool encode_member( const unsigned long long member_size );
};