diff options
Diffstat (limited to 'fast_encoder.c')
| -rw-r--r-- | fast_encoder.c | 84 |
1 files changed, 33 insertions, 51 deletions
diff --git a/fast_encoder.c b/fast_encoder.c index 03697cc..af81137 100644 --- a/fast_encoder.c +++ b/fast_encoder.c @@ -1,28 +1,20 @@ /* Lzlib - Compression library for the lzip format - Copyright (C) 2009-2016 Antonio Diaz Diaz. + Copyright (C) 2009-2017 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 2 of the License, or - (at your option) any later version. + This library is free software. Redistribution and use in source and + binary forms, with or without modification, are permitted provided + that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. 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. + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. */ int FLZe_longest_match_len( struct FLZ_encoder * const fe, int * const distance ) @@ -30,21 +22,22 @@ int FLZe_longest_match_len( struct FLZ_encoder * const fe, int * const distance enum { len_limit = 16 }; const uint8_t * const data = Mb_ptr_to_current_pos( &fe->eb.mb ); int32_t * ptr0 = fe->eb.mb.pos_array + fe->eb.mb.cyclic_pos; - int32_t * newptr; const int pos1 = fe->eb.mb.pos + 1; - int maxlen = 0; - int count, delta, newpos; - if( len_limit > Mb_available_bytes( &fe->eb.mb ) ) { *ptr0 = 0; return 0; } + int maxlen = 0, newpos1, count; + const int available = min( Mb_available_bytes( &fe->eb.mb ), max_match_len ); + if( available < len_limit ) { *ptr0 = 0; return 0; } fe->key4 = ( ( fe->key4 << 4 ) ^ data[3] ) & fe->eb.mb.key4_mask; - newpos = fe->eb.mb.prev_positions[fe->key4]; + newpos1 = fe->eb.mb.prev_positions[fe->key4]; fe->eb.mb.prev_positions[fe->key4] = pos1; for( count = 4; ; ) { - if( --count < 0 || newpos <= 0 ) { *ptr0 = 0; break; } - delta = pos1 - newpos; - if( delta > fe->eb.mb.dictionary_size ) { *ptr0 = 0; break; } + int32_t * newptr; + int delta; + if( newpos1 <= 0 || --count < 0 || + ( delta = pos1 - newpos1 ) > fe->eb.mb.dictionary_size ) + { *ptr0 = 0; break; } newptr = fe->eb.mb.pos_array + ( fe->eb.mb.cyclic_pos - delta + ( ( fe->eb.mb.cyclic_pos >= delta ) ? 0 : fe->eb.mb.dictionary_size + 1 ) ); @@ -52,23 +45,15 @@ int FLZe_longest_match_len( struct FLZ_encoder * const fe, int * const distance if( data[maxlen-delta] == data[maxlen] ) { int len = 0; - while( len < len_limit && data[len-delta] == data[len] ) ++len; - if( maxlen < len ) { maxlen = len; *distance = delta - 1; } + while( len < available && data[len-delta] == data[len] ) ++len; + if( maxlen < len ) + { maxlen = len; *distance = delta - 1; + if( maxlen >= len_limit ) { *ptr0 = *newptr; break; } } } - if( maxlen < len_limit ) - { - *ptr0 = newpos; - ptr0 = newptr; - newpos = *ptr0; - } - else - { - *ptr0 = *newptr; - maxlen += Mb_true_match_len( &fe->eb.mb, maxlen, *distance + 1, - max_match_len - maxlen ); - break; - } + *ptr0 = newpos1; + ptr0 = newptr; + newpos1 = *ptr0; } return maxlen; } @@ -81,10 +66,7 @@ bool FLZe_encode_member( struct FLZ_encoder * const fe ) if( fe->eb.member_finished ) return true; if( Re_member_position( &fe->eb.renc ) >= fe->eb.member_size_limit ) - { - if( LZeb_full_flush( &fe->eb ) ) fe->eb.member_finished = true; - return true; - } + { LZeb_try_full_flush( &fe->eb ); return true; } if( Mb_data_position( &fe->eb.mb ) == 0 && !Mb_data_finished( &fe->eb.mb ) ) /* encode first byte */ @@ -105,7 +87,8 @@ bool FLZe_encode_member( struct FLZ_encoder * const fe ) Re_member_position( &fe->eb.renc ) < fe->eb.member_size_limit ) { int match_distance; - int main_len, pos_state, len = 0; + int main_len, pos_state; + int len = 0; if( !Mb_enough_available_bytes( &fe->eb.mb ) || !Re_enough_free_bytes( &fe->eb.renc ) ) return true; main_len = FLZe_longest_match_len( fe, &match_distance ); @@ -113,8 +96,7 @@ bool FLZe_encode_member( struct FLZ_encoder * const fe ) for( i = 0; i < num_rep_distances; ++i ) { - const int tlen = Mb_true_match_len( &fe->eb.mb, 0, - fe->eb.reps[i] + 1, max_match_len ); + const int tlen = Mb_true_match_len( &fe->eb.mb, 0, fe->eb.reps[i] + 1 ); if( tlen > len ) { len = tlen; rep = i; } } if( len > min_match_len && len + 3 > main_len ) @@ -195,6 +177,6 @@ bool FLZe_encode_member( struct FLZ_encoder * const fe ) } } - if( LZeb_full_flush( &fe->eb ) ) fe->eb.member_finished = true; + LZeb_try_full_flush( &fe->eb ); return true; } |