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Diffstat (limited to 'clzip.h')
| -rw-r--r-- | clzip.h | 232 |
1 files changed, 232 insertions, 0 deletions
@@ -0,0 +1,232 @@ +/* Lzlib - A compression library for lzip files + Copyright (C) 2009, 2010, 2011, 2012 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 3 of the License, or + (at your option) any later version. + + 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. +*/ + +#ifndef max + #define max(x,y) ((x) >= (y) ? (x) : (y)) +#endif +#ifndef min + #define min(x,y) ((x) <= (y) ? (x) : (y)) +#endif + +typedef uint8_t State; + +enum { states = 12 }; + +static inline bool St_is_char( const State st ) { return st < 7; } + +static inline void St_set_char( State * const st ) + { + static const uint8_t next[states] = + { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 }; + *st = next[*st]; + } + +static inline void St_set_match( State * const st ) + { + static const uint8_t next[states] = + { 7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10 }; + *st = next[*st]; + } + +static inline void St_set_rep( State * const st ) + { + static const uint8_t next[states] = + { 8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11 }; + *st = next[*st]; + } + +static inline void St_set_short_rep( State * const st ) + { + static const uint8_t next[states] = + { 9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11 }; + *st = next[*st]; + } + + +enum { + min_dictionary_bits = 12, + min_dictionary_size = 1 << min_dictionary_bits, + max_dictionary_bits = 29, + max_dictionary_size = 1 << max_dictionary_bits, + literal_context_bits = 3, + pos_state_bits = 2, + pos_states = 1 << pos_state_bits, + pos_state_mask = pos_states - 1, + + dis_slot_bits = 6, + start_dis_model = 4, + end_dis_model = 14, + modeled_distances = 1 << (end_dis_model / 2), + dis_align_bits = 4, + dis_align_size = 1 << dis_align_bits, + + len_low_bits = 3, + len_mid_bits = 3, + len_high_bits = 8, + len_low_symbols = 1 << len_low_bits, + len_mid_symbols = 1 << len_mid_bits, + len_high_symbols = 1 << len_high_bits, + max_len_symbols = len_low_symbols + len_mid_symbols + len_high_symbols, + + min_match_len = 2, /* must be 2 */ + max_match_len = min_match_len + max_len_symbols - 1, /* 273 */ + min_match_len_limit = 5, + + max_dis_states = 4 }; + +static inline int get_dis_state( int len ) + { + len -= min_match_len; + if( len >= max_dis_states ) len = max_dis_states - 1; + return len; + } + + +enum { bit_model_move_bits = 5, + bit_model_total_bits = 11, + bit_model_total = 1 << bit_model_total_bits }; + +typedef unsigned int Bit_model; + +static inline void Bm_init( Bit_model * const probability ) + { *probability = bit_model_total / 2; } + + +static inline int real_bits( const unsigned int value ) + { + int bits = 0, i = 1; + unsigned int mask = 1; + for( ; mask > 0; ++i, mask <<= 1 ) if( value & mask ) bits = i; + return bits; + } + + +static const uint8_t magic_string[4] = { 'L', 'Z', 'I', 'P' }; + +typedef uint8_t File_header[6]; /* 0-3 magic bytes */ + /* 4 version */ + /* 5 coded_dict_size */ +enum { Fh_size = 6 }; + +static inline void Fh_set_magic( File_header data ) + { memcpy( data, magic_string, 4 ); data[4] = 1; } + +static inline bool Fh_verify_magic( const File_header data ) + { return ( memcmp( data, magic_string, 4 ) == 0 ); } + +static inline uint8_t Fh_version( const File_header data ) + { return data[4]; } + +static inline bool Fh_verify_version( const File_header data ) + { return ( data[4] <= 1 ); } + +static inline int Fh_get_dictionary_size( const File_header data ) + { + int sz = ( 1 << ( data[5] & 0x1F ) ); + if( sz > min_dictionary_size && sz <= max_dictionary_size ) + sz -= ( sz / 16 ) * ( ( data[5] >> 5 ) & 0x07 ); + return sz; + } + +static inline bool Fh_set_dictionary_size( File_header data, const int sz ) + { + if( sz >= min_dictionary_size && sz <= max_dictionary_size ) + { + data[5] = real_bits( sz - 1 ); + if( sz > min_dictionary_size ) + { + const int base_size = 1 << data[5]; + const int wedge = base_size / 16; + int i; + for( i = 7; i >= 1; --i ) + if( base_size - ( i * wedge ) >= sz ) + { data[5] |= ( i << 5 ); break; } + } + return true; + } + return false; + } + +static inline bool Fh_verify( const File_header data ) + { + return ( Fh_verify_magic( data ) && Fh_verify_version( data ) && + Fh_get_dictionary_size( data ) >= min_dictionary_size && + Fh_get_dictionary_size( data ) <= max_dictionary_size ); + } + + +typedef uint8_t File_trailer[20]; + /* 0-3 CRC32 of the uncompressed data */ + /* 4-11 size of the uncompressed data */ + /* 12-19 member size including header and trailer */ + +enum { Ft_size = 20 }; + +static inline int Ft_versioned_size( const int version ) + { return ( ( version >= 1 ) ? 20 : 12 ); } + +static inline uint32_t Ft_get_data_crc( const File_trailer data ) + { + uint32_t tmp = 0; + int i; + for( i = 3; i >= 0; --i ) { tmp <<= 8; tmp += data[i]; } + return tmp; + } + +static inline void Ft_set_data_crc( File_trailer data, uint32_t crc ) + { + int i; + for( i = 0; i <= 3; ++i ) { data[i] = (uint8_t)crc; crc >>= 8; } + } + +static inline long long Ft_get_data_size( const File_trailer data ) + { + long long tmp = 0; + int i; + for( i = 11; i >= 4; --i ) { tmp <<= 8; tmp += data[i]; } + return tmp; + } + +static inline void Ft_set_data_size( File_trailer data, long long sz ) + { + int i; + for( i = 4; i <= 11; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; } + } + +static inline long long Ft_get_member_size( const File_trailer data ) + { + long long tmp = 0; + int i; + for( i = 19; i >= 12; --i ) { tmp <<= 8; tmp += data[i]; } + return tmp; + } + +static inline void Ft_set_member_size( File_trailer data, long long sz ) + { + int i; + for( i = 12; i <= 19; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; } + } |