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+/* 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();
+ };