diff options
Diffstat (limited to 'lzip.h')
| -rw-r--r-- | lzip.h | 278 |
1 files changed, 278 insertions, 0 deletions
@@ -0,0 +1,278 @@ +/* Lunzip - Decompressor for the lzip format + Copyright (C) 2010-2022 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 <http://www.gnu.org/licenses/>. +*/ + +#ifndef max + #define max(x,y) ((x) >= (y) ? (x) : (y)) +#endif +#ifndef min + #define min(x,y) ((x) <= (y) ? (x) : (y)) +#endif + +typedef int State; + +enum { states = 12 }; + +static inline bool St_is_char( const State st ) { return st < 7; } + +static inline State St_set_char( const State st ) + { + static const State next[states] = { 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5 }; + return next[st]; + } + +static inline State St_set_match( const State st ) + { return ( ( st < 7 ) ? 7 : 10 ); } + +static inline State St_set_rep( const State st ) + { return ( ( st < 7 ) ? 8 : 11 ); } + +static inline State St_set_short_rep( const State st ) + { return ( ( st < 7 ) ? 9 : 11 ); } + + +enum { + min_dictionary_bits = 12, + min_dictionary_size = 1 << min_dictionary_bits, /* >= modeled_distances */ + max_dictionary_bits = 29, + max_dictionary_size = 1 << max_dictionary_bits, + min_member_size = 36, + literal_context_bits = 3, + literal_pos_state_bits = 0, /* not used */ + pos_state_bits = 2, + pos_states = 1 << pos_state_bits, + pos_state_mask = pos_states - 1, + + len_states = 4, + dis_slot_bits = 6, + start_dis_model = 4, + end_dis_model = 14, + modeled_distances = 1 << (end_dis_model / 2), /* 128 */ + 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 }; + +static inline int get_len_state( const int len ) + { return min( len - min_match_len, len_states - 1 ); } + +static inline int get_lit_state( const uint8_t prev_byte ) + { return prev_byte >> ( 8 - literal_context_bits ); } + + +enum { bit_model_move_bits = 5, + bit_model_total_bits = 11, + bit_model_total = 1 << bit_model_total_bits }; + +typedef int Bit_model; + +static inline void Bm_init( Bit_model * const probability ) + { *probability = bit_model_total / 2; } + +static inline void Bm_array_init( Bit_model bm[], const int size ) + { int i; for( i = 0; i < size; ++i ) Bm_init( &bm[i] ); } + +struct Len_model + { + Bit_model choice1; + Bit_model choice2; + Bit_model bm_low[pos_states][len_low_symbols]; + Bit_model bm_mid[pos_states][len_mid_symbols]; + Bit_model bm_high[len_high_symbols]; + }; + +static inline void Lm_init( struct Len_model * const lm ) + { + Bm_init( &lm->choice1 ); + Bm_init( &lm->choice2 ); + Bm_array_init( lm->bm_low[0], pos_states * len_low_symbols ); + Bm_array_init( lm->bm_mid[0], pos_states * len_mid_symbols ); + Bm_array_init( lm->bm_high, len_high_symbols ); + } + + +typedef uint32_t CRC32[256]; /* Table of CRCs of all 8-bit messages. */ + +extern CRC32 crc32; + +static inline void CRC32_init( void ) + { + unsigned n; + for( n = 0; n < 256; ++n ) + { + unsigned c = n; + int k; + for( k = 0; k < 8; ++k ) + { if( c & 1 ) c = 0xEDB88320U ^ ( c >> 1 ); else c >>= 1; } + crc32[n] = c; + } + } + +/* about as fast as it is possible without messing with endianness */ +static inline void CRC32_update_buf( uint32_t * const crc, + const uint8_t * const buffer, + const int size ) + { + int i; + uint32_t c = *crc; + for( i = 0; i < size; ++i ) + c = crc32[(c^buffer[i])&0xFF] ^ ( c >> 8 ); + *crc = c; + } + + +static inline bool isvalid_ds( const unsigned dictionary_size ) + { return ( dictionary_size >= min_dictionary_size && + dictionary_size <= max_dictionary_size ); } + + +static const uint8_t lzip_magic[4] = { 0x4C, 0x5A, 0x49, 0x50 }; /* "LZIP" */ + +typedef uint8_t Lzip_header[6]; /* 0-3 magic bytes */ + /* 4 version */ + /* 5 coded dictionary size */ +enum { Lh_size = 6 }; + +static inline bool Lh_verify_magic( const Lzip_header data ) + { return ( memcmp( data, lzip_magic, 4 ) == 0 ); } + +/* detect (truncated) header */ +static inline bool Lh_verify_prefix( const Lzip_header data, const int sz ) + { + int i; for( i = 0; i < sz && i < 4; ++i ) + if( data[i] != lzip_magic[i] ) return false; + return ( sz > 0 ); + } + +/* detect corrupt header */ +static inline bool Lh_verify_corrupt( const Lzip_header data ) + { + int matches = 0; + int i; for( i = 0; i < 4; ++i ) + if( data[i] == lzip_magic[i] ) ++matches; + return ( matches > 1 && matches < 4 ); + } + +static inline uint8_t Lh_version( const Lzip_header data ) + { return data[4]; } + +static inline bool Lh_verify_version( const Lzip_header data ) + { return ( data[4] == 1 ); } + +static inline unsigned Lh_get_dictionary_size( const Lzip_header data ) + { + unsigned sz = ( 1 << ( data[5] & 0x1F ) ); + if( sz > min_dictionary_size ) + sz -= ( sz / 16 ) * ( ( data[5] >> 5 ) & 7 ); + return sz; + } + +static inline bool Lh_verify( const Lzip_header data ) + { + return Lh_verify_magic( data ) && Lh_verify_version( data ) && + isvalid_ds( Lh_get_dictionary_size( data ) ); + } + + +typedef uint8_t Lzip_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 { Lt_size = 20 }; + +static inline unsigned Lt_get_data_crc( const Lzip_trailer data ) + { + unsigned tmp = 0; + int i; for( i = 3; i >= 0; --i ) { tmp <<= 8; tmp += data[i]; } + return tmp; + } + +static inline unsigned long long Lt_get_data_size( const Lzip_trailer data ) + { + unsigned long long tmp = 0; + int i; for( i = 11; i >= 4; --i ) { tmp <<= 8; tmp += data[i]; } + return tmp; + } + +static inline unsigned long long Lt_get_member_size( const Lzip_trailer data ) + { + unsigned long long tmp = 0; + int i; for( i = 19; i >= 12; --i ) { tmp <<= 8; tmp += data[i]; } + return tmp; + } + +/* check internal consistency */ +static inline bool Lt_verify_consistency( const Lzip_trailer data ) + { + const unsigned crc = Lt_get_data_crc( data ); + const unsigned long long dsize = Lt_get_data_size( data ); + if( ( crc == 0 ) != ( dsize == 0 ) ) return false; + const unsigned long long msize = Lt_get_member_size( data ); + if( msize < min_member_size ) return false; + const unsigned long long mlimit = ( 9 * dsize + 7 ) / 8 + min_member_size; + if( mlimit > dsize && msize > mlimit ) return false; + const unsigned long long dlimit = 7090 * ( msize - 26 ) - 1; + if( dlimit > msize && dsize > dlimit ) return false; + return true; + } + + +static inline void set_retval( int * retval, const int new_val ) + { if( *retval < new_val ) *retval = new_val; } + +static const char * const bad_magic_msg = "Bad magic number (file not in lzip format)."; +static const char * const bad_dict_msg = "Invalid dictionary size in member header."; +static const char * const corrupt_mm_msg = "Corrupt header in multimember file."; +static const char * const trailing_msg = "Trailing data not allowed."; +static const char * const mem_msg = "Not enough memory."; + +/* defined in decoder.c */ +int readblock( const int fd, uint8_t * const buf, const int size ); + +/* defined in list.c */ +int list_files( const char * const filenames[], const int num_filenames, + const bool ignore_trailing, const bool loose_trailing ); + +/* defined in main.c */ +struct stat; +struct Pretty_print; +extern int verbosity; +void * resize_buffer( void * buf, const unsigned min_size ); +void Pp_show_msg( struct Pretty_print * const pp, const char * const msg ); +const char * bad_version( const unsigned version ); +const char * format_ds( const unsigned dictionary_size ); +void show_header( const unsigned dictionary_size ); +int open_instream( const char * const name, struct stat * const in_statsp, + const bool one_to_one, const bool reg_only ); +void cleanup_and_fail( const int retval ); +void show_error( const char * const msg, const int errcode, const bool help ); +void show_file_error( const char * const filename, const char * const msg, + const int errcode ); +struct Range_decoder; +void show_dprogress( const unsigned long long cfile_size, + const unsigned long long partial_size, + const struct Range_decoder * const d, + struct Pretty_print * const p ); 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