diff options
Diffstat (limited to 'fast_encoder.h')
-rw-r--r-- | fast_encoder.h | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/fast_encoder.h b/fast_encoder.h new file mode 100644 index 0000000..b9421f4 --- /dev/null +++ b/fast_encoder.h @@ -0,0 +1,70 @@ +/* Lzlib - Compression library for the lzip format + Copyright (C) 2009-2024 Antonio Diaz Diaz. + + 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. +*/ + +struct FLZ_encoder + { + struct LZ_encoder_base eb; + unsigned key4; /* key made from latest 4 bytes */ + }; + +static inline void FLZe_reset_key4( struct FLZ_encoder * const fe ) + { + int i; + fe->key4 = 0; + for( i = 0; i < 3 && i < Mb_available_bytes( &fe->eb.mb ); ++i ) + fe->key4 = ( fe->key4 << 4 ) ^ fe->eb.mb.buffer[i]; + } + +static inline bool FLZe_update_and_move( struct FLZ_encoder * const fe, int n ) + { + struct Matchfinder_base * const mb = &fe->eb.mb; + while( --n >= 0 ) + { + if( Mb_available_bytes( mb ) >= 4 ) + { + fe->key4 = ( ( fe->key4 << 4 ) ^ mb->buffer[mb->pos+3] ) & mb->key4_mask; + mb->pos_array[mb->cyclic_pos] = mb->prev_positions[fe->key4]; + mb->prev_positions[fe->key4] = mb->pos + 1; + } + else mb->pos_array[mb->cyclic_pos] = 0; + if( !Mb_move_pos( mb ) ) return false; + } + return true; + } + +static inline bool FLZe_init( struct FLZ_encoder * const fe, + const unsigned long long member_size ) + { + enum { before_size = 0, + dict_size = 65536, + /* bytes to keep in buffer after pos */ + after_size = max_match_len, + dict_factor = 16, + min_free_bytes = max_marker_size, + num_prev_positions23 = 0, + pos_array_factor = 1 }; + + return LZeb_init( &fe->eb, before_size, dict_size, after_size, dict_factor, + num_prev_positions23, pos_array_factor, min_free_bytes, + member_size ); + } + +static inline void FLZe_reset( struct FLZ_encoder * const fe, + const unsigned long long member_size ) + { LZeb_reset( &fe->eb, member_size ); } |