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Diffstat (limited to 'lzip.h')
| -rw-r--r-- | lzip.h | 276 |
1 files changed, 276 insertions, 0 deletions
@@ -0,0 +1,276 @@ +/* Lzlib - A compression library for lzip files + Copyright (C) 2009 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 program. 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. +*/ + +class State + { + unsigned char st; + +public: + enum { states = 12 }; + State() throw() : st( 0 ) {} + int operator()() const throw() { return st; } + bool is_char() const throw() { return st < 7; } + + void set_char() throw() + { + static const unsigned char next[states] = {0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 4, 5}; + st = next[st]; + } + void set_match() throw() + { + static const unsigned char next[states] = {7, 7, 7, 7, 7, 7, 7, 10, 10, 10, 10, 10}; + st = next[st]; + } + void set_rep() throw() + { + static const unsigned char next[states] = {8, 8, 8, 8, 8, 8, 8, 11, 11, 11, 11, 11}; + st = next[st]; + } + void set_short_rep() throw() + { + static const unsigned char next[states] = {9, 9, 9, 9, 9, 9, 9, 11, 11, 11, 11, 11}; + st = next[st]; + } + }; + + +const int literal_context_bits = 3; +const int pos_state_bits = 2; +const int pos_states = 1 << pos_state_bits; +const int pos_state_mask = pos_states - 1; + +const int dis_slot_bits = 6; +const int start_dis_model = 4; +const int end_dis_model = 14; +const int modeled_distances = 1 << (end_dis_model / 2); +const int dis_align_bits = 4; +const int dis_align_size = 1 << dis_align_bits; + +const int len_low_bits = 3; +const int len_mid_bits = 3; +const int len_high_bits = 8; +const int len_low_symbols = 1 << len_low_bits; +const int len_mid_symbols = 1 << len_mid_bits; +const int len_high_symbols = 1 << len_high_bits; +const int max_len_symbols = len_low_symbols + len_mid_symbols + len_high_symbols; + +const int min_match_len = 2; // must be 2 +const int max_match_len = min_match_len + max_len_symbols - 1; // 273 + +const int max_dis_states = 4; + +inline int get_dis_state( int len ) throw() + { + len -= min_match_len; + if( len >= max_dis_states ) len = max_dis_states - 1; + return len; + } + + +const int bit_model_move_bits = 5; +const int bit_model_total_bits = 11; +const int bit_model_total = 1 << bit_model_total_bits; + +struct Bit_model + { + unsigned int probability; + Bit_model() throw() : probability( bit_model_total / 2 ) {} + }; + + +class CRC32 + { + uint32_t data[256]; // Table of CRCs of all 8-bit messages. + +public: + CRC32() + { + for( unsigned int n = 0; n < 256; ++n ) + { + unsigned int c = n; + for( int k = 0; k < 8; ++k ) + { if( c & 1 ) c = 0xEDB88320 ^ ( c >> 1 ); else c >>= 1; } + data[n] = c; + } + } + + uint32_t operator[]( const uint8_t byte ) const throw() { return data[byte]; } + void update( uint32_t & crc, const uint8_t byte ) const throw() + { crc = data[(crc^byte)&0xFF] ^ ( crc >> 8 ); } + }; + +extern const CRC32 crc32; + + +const char * const magic_string = "LZIP"; + +struct File_header + { + char magic[4]; + uint8_t version; + uint8_t coded_dict_size; + + void set_magic() throw() + { std::memcpy( magic, magic_string, sizeof magic ); version = 1; } + + bool verify_magic() const throw() + { + return ( std::memcmp( magic, magic_string, sizeof magic ) == 0 ); + } + + bool verify_version() const throw() + { + return ( version <= 1 ); + } + + static int real_bits( const int value ) throw() + { + int bits = 0; + for( int i = 1, mask = 1; mask > 0; ++i, mask <<= 1 ) + if( value & mask ) bits = i; + return bits; + } + + int dictionary_size() const throw() + { + int size = ( 1 << ( coded_dict_size & 0x1F ) ); + if( size > min_dictionary_size && size <= max_dictionary_size ) + size -= ( size / 16 ) * ( ( coded_dict_size >> 5 ) & 0x07 ); + return size; + } + + bool dictionary_size( const int size ) throw() + { + if( size >= min_dictionary_size && size <= max_dictionary_size ) + { + coded_dict_size = real_bits( size - 1 ); + if( size > min_dictionary_size ) + { + const int base_size = 1 << coded_dict_size; + const int wedge = base_size / 16; + for( int i = 7; i >= 1; --i ) + if( base_size - ( i * wedge ) >= size ) + { coded_dict_size |= ( i << 5 ); break; } + } + return true; + } + return false; + } + }; + + +struct File_trailer + { + uint8_t data_crc_[4]; // CRC32 of the uncompressed data + uint8_t data_size_[8]; // size of the uncompressed data + uint8_t member_size_[8]; // member size including header and trailer + + static int size( const int version ) + { return sizeof( File_trailer ) - ( ( version >= 1 ) ? 0 : 8 ); } + + uint32_t data_crc() const throw() + { + uint32_t tmp = 0; + for( int i = 3; i >= 0; --i ) { tmp <<= 8; tmp += data_crc_[i]; } + return tmp; + } + + void data_crc( uint32_t crc ) throw() + { + for( int i = 0; i < 4; ++i ) + { data_crc_[i] = (uint8_t)crc; crc >>= 8; } + } + + long long data_size() const throw() + { + long long tmp = 0; + for( int i = 7; i >= 0; --i ) { tmp <<= 8; tmp += data_size_[i]; } + return tmp; + } + + void data_size( long long size ) throw() + { + for( int i = 0; i < 8; ++i ) + { data_size_[i] = (uint8_t)size; size >>= 8; } + } + + long long member_size() const throw() + { + long long tmp = 0; + for( int i = 7; i >= 0; --i ) { tmp <<= 8; tmp += member_size_[i]; } + return tmp; + } + + void member_size( long long size ) throw() + { + for( int i = 0; i < 8; ++i ) + { member_size_[i] = (uint8_t)size; size >>= 8; } + } + }; + + +class Circular_buffer + { +protected: + const int buffer_size; + uint8_t * const buffer; + int get; + int put; + + void reset() throw() { get = 0; put = 0; } + +public: + Circular_buffer( const int buf_size ) + : + buffer_size( buf_size + 1 ), + buffer( new uint8_t[buffer_size] ), + get( 0 ), + put( 0 ) {} + + ~Circular_buffer() { delete[] buffer; } + + int used_bytes() const throw() + { return ( (get <= put) ? 0 : buffer_size ) + put - get; } + int free_bytes() const throw() + { return ( (get <= put) ? buffer_size : 0 ) - put + get - 1; } + + uint8_t get_byte() throw() + { + const uint8_t b = buffer[get]; + if( ++get >= buffer_size ) get = 0; + return b; + } + + void put_byte( const uint8_t b ) throw() + { + buffer[put] = b; + if( ++put >= buffer_size ) put = 0; + } + + int read_data( uint8_t * const out_buffer, const int out_size ) throw(); + int write_data( uint8_t * const in_buffer, const int in_size ) throw(); + }; |