diff options
Diffstat (limited to 'lzip.h')
| -rw-r--r-- | lzip.h | 205 |
1 files changed, 205 insertions, 0 deletions
@@ -0,0 +1,205 @@ +/* Pdlzip - LZMA lossless data compressor + Copyright (C) 2010-2022 Antonio Diaz Diaz. + + This program 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 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. +*/ + +#ifndef max + #define max(x,y) ((x) >= (y) ? (x) : (y)) +#endif + +typedef int State; + +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, + max_dictionary_bits_c = 27, /* kDicLogSizeMaxCompress */ + max_dictionary_size_c = 1 << max_dictionary_bits_c, + literal_context_bits = 3, + literal_pos_state_bits = 0, /* not used */ + pos_state_bits = 2, + + 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 }; + + +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 inline int real_bits( unsigned value ) + { + int bits = 0; + while( value > 0 ) { value >>= 1; ++bits; } + return bits; + } + + +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 void Lh_set_magic( Lzip_header data ) + { memcpy( data, lzip_magic, 4 ); data[4] = 1; } + +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_set_dictionary_size( Lzip_header data, const unsigned sz ) + { + if( !isvalid_ds( sz ) ) return false; + data[5] = real_bits( sz - 1 ); + if( sz > min_dictionary_size ) + { + const unsigned base_size = 1 << data[5]; + const unsigned fraction = base_size / 16; + unsigned i; + for( i = 7; i >= 1; --i ) + if( base_size - ( i * fraction ) >= sz ) + { data[5] |= ( i << 5 ); break; } + } + return true; + } + + +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 void Lt_set_data_crc( Lzip_trailer data, unsigned crc ) + { int i; for( i = 0; i <= 3; ++i ) { data[i] = (uint8_t)crc; crc >>= 8; } } + +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 void Lt_set_data_size( Lzip_trailer data, unsigned long long sz ) + { int i; for( i = 4; i <= 11; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; } } + +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; + } + +static inline void Lt_set_member_size( Lzip_trailer data, unsigned long long sz ) + { int i; for( i = 12; i <= 19; ++i ) { data[i] = (uint8_t)sz; sz >>= 8; } } + + +static inline void set_retval( int * retval, const int new_val ) + { if( *retval < new_val ) *retval = new_val; } + +static const char * const trailing_msg = "Trailing data not allowed."; +static const char * const mem_msg = "Not enough memory."; + +/* defined in main.c */ +extern int verbosity; +int readblock( const int fd, uint8_t * const buf, const int size ); +int writeblock( const int fd, const uint8_t * const buf, const int size ); + +#define SZ_OK 0 + +#define SZ_ERROR_READ 8 +#define SZ_ERROR_WRITE 9 |