diff options
Diffstat (limited to 'decoder.h')
| -rw-r--r-- | decoder.h | 66 |
1 files changed, 29 insertions, 37 deletions
@@ -1,4 +1,4 @@ -/* Lzip - A data compressor based on the LZMA algorithm +/* Lzip - Data compressor based on the LZMA algorithm Copyright (C) 2008, 2009, 2010 Antonio Diaz Diaz. This program is free software: you can redistribute it and/or modify @@ -20,17 +20,17 @@ class Range_decoder enum { buffer_size = 16384 }; long long partial_member_pos; uint8_t * const buffer; // input buffer - int pos; + int pos; // current pos in buffer int stream_pos; // when reached, a new block must be read uint32_t code; uint32_t range; - const int infd_; // input file descriptor + const int infd; // input file descriptor bool at_stream_end; bool read_block(); public: - Range_decoder( const int infd ) + Range_decoder( const int ifd ) : partial_member_pos( 0 ), buffer( new uint8_t[buffer_size] ), @@ -38,13 +38,13 @@ public: stream_pos( 0 ), code( 0 ), range( 0xFFFFFFFFU ), - infd_( infd ), + infd( ifd ), at_stream_end( false ) {} ~Range_decoder() { delete[] buffer; } bool code_is_zero() const throw() { return ( code == 0 ); } - bool finished() const throw() { return at_stream_end && pos >= stream_pos; } + bool finished() { return pos >= stream_pos && !read_block(); } long long member_position() const throw() { return partial_member_pos + pos; } void reset_member_position() throw() @@ -52,11 +52,11 @@ public: uint8_t get_byte() { - if( pos >= stream_pos && !read_block() ) return 0; + if( finished() ) return 0; return buffer[pos++]; } - void load() throw() + void load() { code = 0; range = 0xFFFFFFFFU; @@ -185,36 +185,32 @@ public: 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 ); } + { return range_decoder.decode_matched( bm_literal[lstate(prev_byte)], + match_byte ); } }; class LZ_decoder { long long partial_data_pos; - const int member_version; const int dictionary_size; const int buffer_size; - uint8_t * const buffer; - int pos; + uint8_t * const buffer; // output buffer + int pos; // current pos in buffer int stream_pos; // first byte not yet written to file uint32_t crc_; - const int outfd_; // output file descriptor - - 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]; - Bit_model bm_align[dis_align_size]; - + const int outfd; // output file descriptor + const int member_version; Range_decoder & range_decoder; - Len_decoder len_decoder; - Len_decoder rep_match_len_decoder; - Literal_decoder literal_decoder; + + void flush_data(); + bool verify_trailer( const Pretty_print & pp ) const; + + uint8_t get_prev_byte() const throw() + { + const int i = ( ( pos > 0 ) ? pos : buffer_size ) - 1; + return buffer[i]; + } uint8_t get_byte( const int distance ) const throw() { @@ -238,7 +234,7 @@ class LZ_decoder std::memcpy( buffer + pos, buffer + i, len ); pos += len; } - else for( ; len > 0 ; --len ) + else for( ; len > 0; --len ) { buffer[pos] = buffer[i]; if( ++pos >= buffer_size ) flush_data(); @@ -246,31 +242,27 @@ class LZ_decoder } } - void flush_data(); - bool verify_trailer( const Pretty_print & pp ) const; - public: - LZ_decoder( const File_header & header, Range_decoder & rdec, const int outfd ) + LZ_decoder( const File_header & header, Range_decoder & rdec, const int ofd ) : partial_data_pos( 0 ), - member_version( header.version() ), dictionary_size( header.dictionary_size() ), buffer_size( std::max( 65536, dictionary_size ) ), buffer( new uint8_t[buffer_size] ), pos( 0 ), stream_pos( 0 ), crc_( 0xFFFFFFFFU ), - outfd_( outfd ), + outfd( ofd ), + member_version( header.version() ), range_decoder( rdec ) { buffer[buffer_size-1] = 0; } // prev_byte of first_byte ~LZ_decoder() { delete[] buffer; } uint32_t crc() const throw() { return crc_ ^ 0xFFFFFFFFU; } - int decode_member( const Pretty_print & pp ); - long long member_position() const throw() - { return range_decoder.member_position(); } long long data_position() const throw() { return partial_data_pos + pos; } + + int decode_member( const Pretty_print & pp ); }; |