Merging upstream version 0.4.
Signed-off-by: Daniel Baumann <daniel@debian.org>
This commit is contained in:
parent
3de47bdbc0
commit
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GPG key ID:
FBB4F0E80A80222F
16 changed files with 536 additions and 317 deletions
110
decoder.h
110
decoder.h
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@ -25,10 +25,9 @@
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Public License.
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*/
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const int min_available_bytes = 8 + sizeof( File_trailer );
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class Input_buffer : public Circular_buffer
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{
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enum { min_available_bytes = 8 + sizeof( File_trailer ) };
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bool at_stream_end_;
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public:
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@ -42,6 +41,12 @@ public:
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bool finished() const throw() { return at_stream_end_ && !used_bytes(); }
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void purge() throw() { at_stream_end_ = true; Circular_buffer::reset(); }
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bool enough_available_bytes() const throw()
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{
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return ( used_bytes() > 0 &&
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( at_stream_end_ || used_bytes() >= min_available_bytes ) );
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}
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int write_data( uint8_t * const in_buffer, const int in_size ) throw()
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{
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if( at_stream_end_ || in_size <= 0 ) return 0;
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@ -55,6 +60,7 @@ class Range_decoder
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mutable long long member_pos;
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uint32_t code;
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uint32_t range;
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bool reload_pending;
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Input_buffer & ibuf;
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public:
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@ -63,62 +69,86 @@ public:
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member_pos( header_size ),
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code( 0 ),
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range( 0xFFFFFFFF ),
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reload_pending( false ),
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ibuf( buf )
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{ for( int i = 0; i < 5; ++i ) code = (code << 8) | get_byte(); }
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bool at_stream_end() const throw() { return ibuf.at_stream_end(); }
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int available_bytes() const throw() { return ibuf.used_bytes(); }
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bool enough_available_bytes() const throw()
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{ return ibuf.enough_available_bytes(); }
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bool finished() const throw() { return ibuf.finished(); }
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long long member_position() const throw() { return member_pos; }
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uint8_t get_byte() const
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{
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++member_pos;
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return ibuf.get_byte();
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}
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bool at_stream_end() const throw() { return ibuf.at_stream_end(); }
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int available_bytes() const throw() { return ibuf.used_bytes(); }
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bool finished() const throw() { return ibuf.finished(); }
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long long member_position() const throw() { return member_pos; }
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bool try_reload( const bool force = false ) throw()
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{
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if( force ) reload_pending = true;
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if( reload_pending && available_bytes() >= 5 )
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{
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code = 0;
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range = 0xFFFFFFFF;
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reload_pending = false;
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for( int i = 0; i < 5; ++i ) code = (code << 8) | get_byte();
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}
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return !reload_pending;
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}
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void normalize()
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{
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if( range <= 0x00FFFFFF )
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{ range <<= 8; code = (code << 8) | get_byte(); }
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}
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int decode( const int num_bits )
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{
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int symbol = 0;
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for( int i = num_bits - 1; i >= 0; --i )
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for( int i = num_bits; i > 0; --i )
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{
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range >>= 1;
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symbol <<= 1;
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if( code >= range )
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{ code -= range; symbol |= 1; }
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if( range <= 0x00FFFFFF )
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{ range <<= 8; code = (code << 8) | get_byte(); }
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{
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range <<= 7; code = (code << 8) | get_byte();
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if( code >= range ) { code -= range; symbol |= 1; }
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}
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else
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{
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range >>= 1;
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if( code >= range ) { code -= range; symbol |= 1; }
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}
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}
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return symbol;
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}
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int decode_bit( Bit_model & bm )
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{
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int symbol;
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normalize();
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const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability;
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if( code < bound )
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{
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range = bound;
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bm.probability += (bit_model_total - bm.probability) >> bit_model_move_bits;
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symbol = 0;
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return 0;
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}
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else
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{
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range -= bound;
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code -= bound;
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bm.probability -= bm.probability >> bit_model_move_bits;
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symbol = 1;
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return 1;
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}
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if( range <= 0x00FFFFFF )
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{ range <<= 8; code = (code << 8) | get_byte(); }
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return symbol;
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}
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int decode_tree( Bit_model bm[], const int num_bits )
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{
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int model = 1;
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for( int i = num_bits; i > 0; --i )
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model = ( model << 1 ) | decode_bit( bm[model-1] );
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model = ( model << 1 ) | decode_bit( bm[model] );
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return model - (1 << num_bits);
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}
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@ -126,27 +156,31 @@ public:
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{
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int model = 1;
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int symbol = 0;
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for( int i = 1; i < (1 << num_bits); i <<= 1 )
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for( int i = 0; i < num_bits; ++i )
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{
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const int bit = decode_bit( bm[model-1] );
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model = ( model << 1 ) | bit;
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if( bit ) symbol |= i;
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const int bit = decode_bit( bm[model] );
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model <<= 1;
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if( bit ) { model |= 1; symbol |= (1 << i); }
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}
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return symbol;
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}
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int decode_matched( Bit_model bm[], const int match_byte )
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{
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Bit_model *bm1 = bm + 0x100;
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int symbol = 1;
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for( int i = 7; i >= 0; --i )
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for( int i = 1; i <= 8; ++i )
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{
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const int match_bit = ( match_byte >> i ) & 1;
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const int bit = decode_bit( bm[(match_bit<<8)+symbol+0xFF] );
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const int match_bit = ( match_byte << i ) & 0x100;
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const int bit = decode_bit( bm1[match_bit+symbol] );
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symbol = ( symbol << 1 ) | bit;
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if( match_bit != bit ) break;
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if( ( match_bit && !bit ) || ( !match_bit && bit ) )
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{
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while( ++i <= 8 )
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symbol = ( symbol << 1 ) | decode_bit( bm[symbol] );
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break;
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}
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}
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while( symbol < 0x100 )
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symbol = ( symbol << 1 ) | decode_bit( bm[symbol-1] );
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return symbol & 0xFF;
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}
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};
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@ -193,6 +227,7 @@ public:
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class LZ_decoder : public Circular_buffer
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{
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enum { min_free_bytes = max_match_len };
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long long partial_data_pos;
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const int format_version;
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const int dictionary_size;
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@ -220,7 +255,6 @@ class LZ_decoder : public Circular_buffer
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Len_decoder rep_match_len_decoder;
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Literal_decoder literal_decoder;
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// using Circular_buffer::get_byte;
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uint8_t get_byte( const int distance ) const throw()
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{
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int i = put - distance - 1;
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@ -235,20 +269,23 @@ class LZ_decoder : public Circular_buffer
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if( ++put >= buffer_size ) { partial_data_pos += put; put = 0; }
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}
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bool copy_block( const int distance, int len )
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void copy_block( const int distance, int len )
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{
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if( distance < 0 || distance >= dictionary_size ||
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len <= 0 || len > max_match_len ) return false;
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int i = put - distance - 1;
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if( i < 0 ) i += buffer_size;
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for( ; len > 0 ; --len )
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if( len < buffer_size - std::max( put, i ) && len <= distance )
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{
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crc32.update( crc_, buffer + i, len );
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std::memcpy( buffer + put, buffer + i, len );
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put += len;
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}
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else for( ; len > 0 ; --len )
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{
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crc32.update( crc_, buffer[i] );
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buffer[put] = buffer[i];
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if( ++put >= buffer_size ) { partial_data_pos += put; put = 0; }
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if( ++i >= buffer_size ) i = 0;
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}
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return true;
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}
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bool verify_trailer();
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@ -256,7 +293,7 @@ class LZ_decoder : public Circular_buffer
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public:
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LZ_decoder( const File_header & header, Input_buffer & ibuf )
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:
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Circular_buffer( std::max( 65536, header.dictionary_size() ) + max_match_len ),
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Circular_buffer( std::max( 65536, header.dictionary_size() ) + min_free_bytes ),
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partial_data_pos( 0 ),
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format_version( header.version ),
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dictionary_size( header.dictionary_size() ),
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@ -270,6 +307,9 @@ public:
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range_decoder( sizeof header, ibuf ),
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literal_decoder() {}
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bool enough_free_bytes() const throw()
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{ return free_bytes() >= min_free_bytes; }
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uint32_t crc() const throw() { return crc_ ^ 0xFFFFFFFF; }
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int decode_member();
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bool member_finished() const throw()
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