232 lines
6.5 KiB
C
232 lines
6.5 KiB
C
/* Lzlib - A compression library for lzip files
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Copyright (C) 2009, 2010, 2011, 2012 Antonio Diaz Diaz.
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This library is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this library. If not, see <http://www.gnu.org/licenses/>.
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As a special exception, you may use this file as part of a free
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software library without restriction. Specifically, if other files
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instantiate templates or use macros or inline functions from this
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file, or you compile this file and link it with other files to
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produce an executable, this file does not by itself cause the
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resulting executable to be covered by the GNU General Public
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License. This exception does not however invalidate any other
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reasons why the executable file might be covered by the GNU General
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Public License.
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*/
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#ifndef max
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#define max(x,y) ((x) >= (y) ? (x) : (y))
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#endif
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#ifndef min
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#define min(x,y) ((x) <= (y) ? (x) : (y))
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#endif
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typedef uint8_t State;
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enum { states = 12 };
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static inline bool St_is_char( const State st ) { return st < 7; }
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static inline void St_set_char( State * const st )
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{
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static const uint8_t next[states] =
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{ 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 };
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*st = next[*st];
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}
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static inline void St_set_match( State * const st )
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{
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static const uint8_t next[states] =
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{ 7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10 };
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*st = next[*st];
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}
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static inline void St_set_rep( State * const st )
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{
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static const uint8_t next[states] =
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{ 8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11 };
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*st = next[*st];
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}
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static inline void St_set_short_rep( State * const st )
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{
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static const uint8_t next[states] =
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{ 9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11 };
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*st = next[*st];
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}
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enum {
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min_dictionary_bits = 12,
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min_dictionary_size = 1 << min_dictionary_bits,
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max_dictionary_bits = 29,
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max_dictionary_size = 1 << max_dictionary_bits,
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literal_context_bits = 3,
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pos_state_bits = 2,
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pos_states = 1 << pos_state_bits,
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pos_state_mask = pos_states - 1,
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dis_slot_bits = 6,
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start_dis_model = 4,
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end_dis_model = 14,
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modeled_distances = 1 << (end_dis_model / 2),
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dis_align_bits = 4,
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dis_align_size = 1 << dis_align_bits,
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len_low_bits = 3,
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len_mid_bits = 3,
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len_high_bits = 8,
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len_low_symbols = 1 << len_low_bits,
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len_mid_symbols = 1 << len_mid_bits,
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len_high_symbols = 1 << len_high_bits,
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max_len_symbols = len_low_symbols + len_mid_symbols + len_high_symbols,
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min_match_len = 2, /* must be 2 */
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max_match_len = min_match_len + max_len_symbols - 1, /* 273 */
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min_match_len_limit = 5,
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max_dis_states = 4 };
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static inline int get_dis_state( int len )
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{
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len -= min_match_len;
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if( len >= max_dis_states ) len = max_dis_states - 1;
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return len;
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}
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enum { bit_model_move_bits = 5,
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bit_model_total_bits = 11,
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bit_model_total = 1 << bit_model_total_bits };
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typedef unsigned int Bit_model;
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static inline void Bm_init( Bit_model * const probability )
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{ *probability = bit_model_total / 2; }
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static inline int real_bits( const unsigned int value )
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{
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int bits = 0, i = 1;
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unsigned int mask = 1;
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for( ; mask > 0; ++i, mask <<= 1 ) if( value & mask ) bits = i;
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return bits;
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}
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static const uint8_t magic_string[4] = { 'L', 'Z', 'I', 'P' };
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typedef uint8_t File_header[6]; /* 0-3 magic bytes */
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/* 4 version */
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/* 5 coded_dict_size */
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enum { Fh_size = 6 };
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static inline void Fh_set_magic( File_header data )
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{ memcpy( data, magic_string, 4 ); data[4] = 1; }
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static inline bool Fh_verify_magic( const File_header data )
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{ return ( memcmp( data, magic_string, 4 ) == 0 ); }
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static inline uint8_t Fh_version( const File_header data )
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{ return data[4]; }
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static inline bool Fh_verify_version( const File_header data )
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{ return ( data[4] <= 1 ); }
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static inline int Fh_get_dictionary_size( const File_header data )
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{
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int sz = ( 1 << ( data[5] & 0x1F ) );
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if( sz > min_dictionary_size && sz <= max_dictionary_size )
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sz -= ( sz / 16 ) * ( ( data[5] >> 5 ) & 0x07 );
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return sz;
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}
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static inline bool Fh_set_dictionary_size( File_header data, const int sz )
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{
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if( sz >= min_dictionary_size && sz <= max_dictionary_size )
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{
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data[5] = real_bits( sz - 1 );
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if( sz > min_dictionary_size )
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{
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const int base_size = 1 << data[5];
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const int wedge = base_size / 16;
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int i;
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for( i = 7; i >= 1; --i )
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if( base_size - ( i * wedge ) >= sz )
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{ data[5] |= ( i << 5 ); break; }
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}
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return true;
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}
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return false;
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}
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static inline bool Fh_verify( const File_header data )
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{
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return ( Fh_verify_magic( data ) && Fh_verify_version( data ) &&
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Fh_get_dictionary_size( data ) >= min_dictionary_size &&
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Fh_get_dictionary_size( data ) <= max_dictionary_size );
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}
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typedef uint8_t File_trailer[20];
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/* 0-3 CRC32 of the uncompressed data */
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/* 4-11 size of the uncompressed data */
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/* 12-19 member size including header and trailer */
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enum { Ft_size = 20 };
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static inline int Ft_versioned_size( const int version )
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{ return ( ( version >= 1 ) ? 20 : 12 ); }
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static inline uint32_t Ft_get_data_crc( const File_trailer data )
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{
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uint32_t tmp = 0;
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int i;
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for( i = 3; i >= 0; --i ) { tmp <<= 8; tmp += data[i]; }
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return tmp;
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}
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static inline void Ft_set_data_crc( File_trailer data, uint32_t crc )
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{
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int i;
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for( i = 0; i <= 3; ++i ) { data[i] = (uint8_t)crc; crc >>= 8; }
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}
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static inline long long Ft_get_data_size( const File_trailer data )
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{
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long long tmp = 0;
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int i;
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for( i = 11; i >= 4; --i ) { tmp <<= 8; tmp += data[i]; }
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return tmp;
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}
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static inline void Ft_set_data_size( File_trailer data, long long sz )
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{
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int i;
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for( i = 4; i <= 11; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; }
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}
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static inline long long Ft_get_member_size( const File_trailer data )
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{
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long long tmp = 0;
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int i;
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for( i = 19; i >= 12; --i ) { tmp <<= 8; tmp += data[i]; }
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return tmp;
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}
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static inline void Ft_set_member_size( File_trailer data, long long sz )
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{
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int i;
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for( i = 12; i <= 19; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; }
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}
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