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author | Daniel Baumann <mail@daniel-baumann.ch> | 2015-11-07 13:46:00 +0000 |
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committer | Daniel Baumann <mail@daniel-baumann.ch> | 2015-11-07 13:46:00 +0000 |
commit | 4b2126b14346d29e15ddd4867930e96c857e168c (patch) | |
tree | 5d7d29e06e931313b47e55c2baf16914efdd62e5 /decoder.h | |
parent | Adding debian version 1.2-1. (diff) | |
download | lzlib-4b2126b14346d29e15ddd4867930e96c857e168c.tar.xz lzlib-4b2126b14346d29e15ddd4867930e96c857e168c.zip |
Merging upstream version 1.3.
Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>
Diffstat (limited to '')
-rw-r--r-- | decoder.h | 323 |
1 files changed, 0 insertions, 323 deletions
diff --git a/decoder.h b/decoder.h deleted file mode 100644 index 1b89bd8..0000000 --- a/decoder.h +++ /dev/null @@ -1,323 +0,0 @@ -/* Lzlib - A compression library for lzip files - Copyright (C) 2009, 2010, 2011 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 library. 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. -*/ - -namespace Lzlib { - -class Range_decoder : public Circular_buffer - { - enum { min_available_bytes = 8 }; - long long member_pos; - uint32_t code; - uint32_t range; - bool reload_pending; - bool at_stream_end_; - -public: - Range_decoder() - : - Circular_buffer( 65536 + min_available_bytes ), - member_pos( 0 ), - code( 0 ), - range( 0xFFFFFFFFU ), - reload_pending( false ), - at_stream_end_( false ) {} - - bool at_stream_end() const throw() { return at_stream_end_; } - int available_bytes() const throw() { return used_bytes(); } - bool code_is_zero() const throw() { return ( code == 0 ); } - void finish() throw() { at_stream_end_ = true; } - bool finished() const throw() { return at_stream_end_ && !used_bytes(); } - int free_bytes() const throw() - { if( at_stream_end_ ) return 0; return Circular_buffer::free_bytes(); } - long long member_position() const throw() - { return member_pos; } - void purge() throw() { at_stream_end_ = true; Circular_buffer::reset(); } - void reset() throw() { at_stream_end_ = false; Circular_buffer::reset(); } - - bool find_header() throw(); - bool read_header( File_header & header ) throw(); - - bool enough_available_bytes() const throw() - { - return ( used_bytes() > 0 && - ( at_stream_end_ || used_bytes() >= min_available_bytes ) ); - } - - int write_data( const uint8_t * const in_buffer, const int in_size ) throw() - { - if( at_stream_end_ || in_size <= 0 ) return 0; - return Circular_buffer::write_data( in_buffer, in_size ); - } - - uint8_t get_byte() - { - ++member_pos; - return Circular_buffer::get_byte(); - } - - bool try_reload( const bool force = false ) throw() - { - if( force ) reload_pending = true; - if( reload_pending && available_bytes() >= 5 ) - { - reload_pending = false; - code = 0; - range = 0xFFFFFFFFU; - for( int i = 0; i < 5; ++i ) code = (code << 8) | get_byte(); - } - return !reload_pending; - } - - void normalize() - { - if( range <= 0x00FFFFFFU ) - { range <<= 8; code = (code << 8) | get_byte(); } - } - - int decode( const int num_bits ) - { - int symbol = 0; - for( int i = num_bits; i > 0; --i ) - { - symbol <<= 1; - if( range <= 0x00FFFFFFU ) - { - range <<= 7; code = (code << 8) | get_byte(); - if( code >= range ) { code -= range; symbol |= 1; } - } - else - { - range >>= 1; - if( code >= range ) { code -= range; symbol |= 1; } - } - } - return symbol; - } - - int decode_bit( Bit_model & bm ) - { - normalize(); - const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability; - if( code < bound ) - { - range = bound; - bm.probability += (bit_model_total - bm.probability) >> bit_model_move_bits; - return 0; - } - else - { - range -= bound; - code -= bound; - bm.probability -= bm.probability >> bit_model_move_bits; - return 1; - } - } - - int decode_tree( Bit_model bm[], const int num_bits ) - { - int model = 1; - for( int i = num_bits; i > 0; --i ) - model = ( model << 1 ) | decode_bit( bm[model] ); - return model - (1 << num_bits); - } - - int decode_tree_reversed( Bit_model bm[], const int num_bits ) - { - int model = 1; - int symbol = 0; - for( int i = 0; i < num_bits; ++i ) - { - const int bit = decode_bit( bm[model] ); - model <<= 1; - if( bit ) { model |= 1; symbol |= (1 << i); } - } - return symbol; - } - - int decode_matched( Bit_model bm[], const int match_byte ) - { - Bit_model * const bm1 = bm + 0x100; - int symbol = 1; - for( int i = 7; i >= 0; --i ) - { - const int match_bit = ( match_byte >> i ) & 1; - const int bit = decode_bit( bm1[(match_bit<<8)+symbol] ); - symbol = ( symbol << 1 ) | bit; - if( match_bit != bit ) - { - while( --i >= 0 ) - symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); - break; - } - } - return symbol & 0xFF; - } - }; - - -class Len_decoder - { - 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]; - -public: - int decode( Range_decoder & range_decoder, const int pos_state ) - { - if( range_decoder.decode_bit( choice1 ) == 0 ) - return range_decoder.decode_tree( bm_low[pos_state], len_low_bits ); - if( range_decoder.decode_bit( choice2 ) == 0 ) - return len_low_symbols + - range_decoder.decode_tree( bm_mid[pos_state], len_mid_bits ); - return len_low_symbols + len_mid_symbols + - range_decoder.decode_tree( bm_high, len_high_bits ); - } - }; - - -class Literal_decoder - { - Bit_model bm_literal[1<<literal_context_bits][0x300]; - - int lstate( const int prev_byte ) const throw() - { return ( prev_byte >> ( 8 - literal_context_bits ) ); } - -public: - uint8_t decode( Range_decoder & range_decoder, const uint8_t prev_byte ) - { return range_decoder.decode_tree( bm_literal[lstate(prev_byte)], 8 ); } - - uint8_t decode_matched( Range_decoder & range_decoder, - const uint8_t prev_byte, const uint8_t match_byte ) - { return range_decoder.decode_matched( bm_literal[lstate(prev_byte)], - match_byte ); } - }; - - -class LZ_decoder : public Circular_buffer - { - enum { min_free_bytes = max_match_len }; - long long partial_data_pos; - const int dictionary_size; - uint32_t crc_; - const int member_version; - bool member_finished_; - bool verify_trailer_pending; - unsigned int rep0; // rep[0-3] latest four distances - unsigned int rep1; // used for efficient coding of - unsigned int rep2; // repeated distances - unsigned int rep3; - State state; - - Bit_model bm_match[State::states][pos_states]; - Bit_model bm_rep[State::states]; - Bit_model bm_rep0[State::states]; - Bit_model bm_rep1[State::states]; - Bit_model bm_rep2[State::states]; - Bit_model bm_len[State::states][pos_states]; - Bit_model bm_dis_slot[max_dis_states][1<<dis_slot_bits]; - Bit_model bm_dis[modeled_distances-end_dis_model+1]; - Bit_model bm_align[dis_align_size]; - - Range_decoder & range_decoder; - Len_decoder len_decoder; - Len_decoder rep_match_len_decoder; - Literal_decoder literal_decoder; - - bool verify_trailer(); - - uint8_t get_prev_byte() const throw() - { - const int i = ( ( put > 0 ) ? put : buffer_size ) - 1; - return buffer[i]; - } - - uint8_t get_byte( const int distance ) const throw() - { - int i = put - distance - 1; - if( i < 0 ) i += buffer_size; - return buffer[i]; - } - - void put_byte( const uint8_t b ) - { - crc32.update( crc_, b ); - buffer[put] = b; - if( ++put >= buffer_size ) { partial_data_pos += put; put = 0; } - } - - void copy_block( const int distance, int len ) - { - int i = put - distance - 1; - if( i < 0 ) i += buffer_size; - if( len < buffer_size - std::max( put, i ) && len <= std::abs( put - i ) ) - { - crc32.update( crc_, buffer + i, len ); - std::memcpy( buffer + put, buffer + i, len ); - put += len; - } - else for( ; len > 0; --len ) - { - crc32.update( crc_, buffer[i] ); - buffer[put] = buffer[i]; - if( ++put >= buffer_size ) { partial_data_pos += put; put = 0; } - if( ++i >= buffer_size ) i = 0; - } - } - -public: - LZ_decoder( const File_header & header, Range_decoder & rdec ) - : - Circular_buffer( std::max( 65536, header.dictionary_size() ) + min_free_bytes ), - partial_data_pos( 0 ), - dictionary_size( header.dictionary_size() ), - crc_( 0xFFFFFFFFU ), - member_version( header.version() ), - member_finished_( false ), - verify_trailer_pending( false ), - rep0( 0 ), - rep1( 0 ), - rep2( 0 ), - rep3( 0 ), - range_decoder( rdec ) - { buffer[buffer_size-1] = 0; } // prev_byte of first_byte - - bool enough_free_bytes() const throw() - { return free_bytes() >= min_free_bytes; } - - uint32_t crc() const throw() { return crc_ ^ 0xFFFFFFFFU; } - bool member_finished() const throw() - { return ( member_finished_ && !used_bytes() ); } - - long long data_position() const throw() - { return partial_data_pos + put; } - - int decode_member(); - }; - -} // end namespace Lzlib |