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| -rw-r--r-- | mtester.h | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/mtester.h b/mtester.h new file mode 100644 index 0000000..12c7d2d --- /dev/null +++ b/mtester.h @@ -0,0 +1,395 @@ +/* Lziprecover - Data recovery tool for the lzip format + Copyright (C) 2009-2022 Antonio Diaz Diaz. + + This program 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 2 of the License, or + (at your option) any later version. + + This program 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/>. +*/ + +class Range_mtester + { + const uint8_t * const buffer; // input buffer + const long long buffer_size; + long long pos; // current pos in buffer + uint32_t code; + uint32_t range; + bool at_stream_end; + +public: + Range_mtester( const uint8_t * const buf, const long long buf_size ) + : + buffer( buf ), + buffer_size( buf_size ), + pos( Lzip_header::size ), + code( 0 ), + range( 0xFFFFFFFFU ), + at_stream_end( false ) + {} + + bool finished() { return pos >= buffer_size; } + unsigned long long member_position() const { return pos; } + + uint8_t get_byte() + { + // 0xFF avoids decoder error if member is truncated at EOS marker + if( finished() ) return 0xFF; + return buffer[pos++]; + } + + const Lzip_trailer * get_trailer() + { + if( buffer_size - pos < Lzip_trailer::size ) return 0; + const Lzip_trailer * const p = (const Lzip_trailer *)( buffer + pos ); + pos += Lzip_trailer::size; + return p; + } + + void load() + { + code = 0; + for( int i = 0; i < 5; ++i ) code = ( code << 8 ) | get_byte(); + range = 0xFFFFFFFFU; + code &= range; // make sure that first byte is discarded + } + + void normalize() + { + if( range <= 0x00FFFFFFU ) + { range <<= 8; code = ( code << 8 ) | get_byte(); } + } + + unsigned decode( const int num_bits ) + { + unsigned symbol = 0; + for( int i = num_bits; i > 0; --i ) + { + normalize(); + range >>= 1; +// symbol <<= 1; +// if( code >= range ) { code -= range; symbol |= 1; } + const bool bit = ( code >= range ); + symbol <<= 1; symbol += bit; + code -= range & ( 0U - bit ); + } + return symbol; + } + + unsigned 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 + { + code -= bound; + range -= bound; + bm.probability -= bm.probability >> bit_model_move_bits; + return 1; + } + } + + void decode_symbol_bit( Bit_model & bm, unsigned & symbol ) + { + normalize(); + symbol <<= 1; + 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; + } + else + { + code -= bound; + range -= bound; + bm.probability -= bm.probability >> bit_model_move_bits; + symbol |= 1; + } + } + + void decode_symbol_bit_reversed( Bit_model & bm, unsigned & model, + unsigned & symbol, const int i ) + { + normalize(); + model <<= 1; + 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; + } + else + { + code -= bound; + range -= bound; + bm.probability -= bm.probability >> bit_model_move_bits; + model |= 1; + symbol |= 1 << i; + } + } + + unsigned decode_tree6( Bit_model bm[] ) + { + unsigned symbol = 1; + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + return symbol & 0x3F; + } + + unsigned decode_tree8( Bit_model bm[] ) + { + unsigned symbol = 1; + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + return symbol & 0xFF; + } + + unsigned decode_tree_reversed( Bit_model bm[], const int num_bits ) + { + unsigned model = 1; + unsigned symbol = 0; + for( int i = 0; i < num_bits; ++i ) + decode_symbol_bit_reversed( bm[model], model, symbol, i ); + return symbol; + } + + unsigned decode_tree_reversed4( Bit_model bm[] ) + { + unsigned model = 1; + unsigned symbol = 0; + decode_symbol_bit_reversed( bm[model], model, symbol, 0 ); + decode_symbol_bit_reversed( bm[model], model, symbol, 1 ); + decode_symbol_bit_reversed( bm[model], model, symbol, 2 ); + decode_symbol_bit_reversed( bm[model], model, symbol, 3 ); + return symbol; + } + + unsigned decode_matched( Bit_model bm[], unsigned match_byte ) + { + Bit_model * const bm1 = bm + 0x100; + unsigned symbol = 1; + while( symbol < 0x100 ) + { + const unsigned match_bit = ( match_byte <<= 1 ) & 0x100; + const bool bit = decode_bit( bm1[symbol+match_bit] ); + symbol <<= 1; symbol |= bit; + if( match_bit >> 8 != bit ) + { + while( symbol < 0x100 ) decode_symbol_bit( bm[symbol], symbol ); + break; + } + } + return symbol & 0xFF; + } + + unsigned decode_len( Len_model & lm, const int pos_state ) + { + Bit_model * bm; + unsigned mask, offset, symbol = 1; + + if( decode_bit( lm.choice1 ) == 0 ) + { bm = lm.bm_low[pos_state]; mask = 7; offset = 0; goto len3; } + if( decode_bit( lm.choice2 ) == 0 ) + { bm = lm.bm_mid[pos_state]; mask = 7; offset = len_low_symbols; goto len3; } + bm = lm.bm_high; mask = 0xFF; offset = len_low_symbols + len_mid_symbols; + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); +len3: + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + decode_symbol_bit( bm[symbol], symbol ); + return ( symbol & mask ) + min_match_len + offset; + } + }; + +class MD5SUM; // forward declaration + +class LZ_mtester + { + unsigned long long partial_data_pos; + Range_mtester rdec; + const unsigned dictionary_size; + uint8_t * buffer; // output buffer + unsigned pos; // current pos in buffer + unsigned stream_pos; // first byte not yet written to file + uint32_t crc_; + const int outfd; // output file descriptor + unsigned rep0; // rep[0-3] latest four distances + unsigned rep1; // used for efficient coding of + unsigned rep2; // repeated distances + unsigned rep3; + State state; + MD5SUM * const md5sum; + unsigned long long total_packets_; // total number of packets in member + unsigned long long max_rep0_pos; // file position of maximum distance + unsigned max_rep0; // maximum distance found + std::vector< unsigned long long > max_packet_posv_; // file pos of large packets + unsigned max_packet_size_; // maximum packet size found + unsigned max_marker_size_; // maximum marker size found + bool pos_wrapped; + bool buffer_is_external; + + Bit_model bm_literal[1<<literal_context_bits][0x300]; + 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[len_states][1<<dis_slot_bits]; + Bit_model bm_dis[modeled_distances-end_dis_model+1]; + Bit_model bm_align[dis_align_size]; + + Len_model match_len_model; + Len_model rep_len_model; + + void print_block( const int len ); + void flush_data(); + bool verify_trailer( FILE * const f = 0, unsigned long long byte_pos = 0 ); + + uint8_t peek_prev() const + { return buffer[((pos > 0) ? pos : dictionary_size)-1]; } + + uint8_t peek( const unsigned distance ) const + { + const unsigned i = ( ( pos > distance ) ? 0 : dictionary_size ) + + pos - distance - 1; + return buffer[i]; + } + + void put_byte( const uint8_t b ) + { + buffer[pos] = b; + if( ++pos >= dictionary_size ) flush_data(); + } + + void copy_block( const unsigned distance, unsigned len ) + { + unsigned lpos = pos, i = lpos - distance - 1; + bool fast, fast2; + if( lpos > distance ) + { + fast = ( len < dictionary_size - lpos ); + fast2 = ( fast && len <= lpos - i ); + } + else + { + i += dictionary_size; + fast = ( len < dictionary_size - i ); // (i == pos) may happen + fast2 = ( fast && len <= i - lpos ); + } + if( fast ) // no wrap + { + pos += len; + if( fast2 ) // no wrap, no overlap + std::memcpy( buffer + lpos, buffer + i, len ); + else + for( ; len > 0; --len ) buffer[lpos++] = buffer[i++]; + } + else for( ; len > 0; --len ) + { + buffer[pos] = buffer[i]; + if( ++pos >= dictionary_size ) flush_data(); + if( ++i >= dictionary_size ) i = 0; + } + } + +void set_max_packet( const unsigned new_size, const unsigned long long pos ) + { + if( max_packet_size_ > new_size || new_size == 0 ) return; + if( max_packet_size_ < new_size ) // new max size + { max_packet_size_ = new_size; max_packet_posv_.clear(); } + max_packet_posv_.push_back( pos - new_size ); // pos of first byte + } + +void set_max_marker( const unsigned new_size ) + { if( max_marker_size_ < new_size ) max_marker_size_ = new_size; } + +public: + LZ_mtester( const uint8_t * const ibuf, const long long ibuf_size, + const unsigned dict_size, const int ofd = -1, + MD5SUM * const md5sum_ = 0 ) + : + partial_data_pos( 0 ), + rdec( ibuf, ibuf_size ), + dictionary_size( dict_size ), + buffer( new uint8_t[dictionary_size] ), + pos( 0 ), + stream_pos( 0 ), + crc_( 0xFFFFFFFFU ), + outfd( ofd ), + rep0( 0 ), + rep1( 0 ), + rep2( 0 ), + rep3( 0 ), + md5sum( md5sum_ ), + total_packets_( -1ULL ), // don't count EOS marker + max_rep0_pos( 0 ), + max_rep0( 0 ), + max_packet_size_( 0 ), + max_marker_size_( 0 ), + pos_wrapped( false ), buffer_is_external( false ) + // prev_byte of first byte; also for peek( 0 ) on corrupt file + { buffer[dictionary_size-1] = 0; } + + ~LZ_mtester() { if( !buffer_is_external ) delete[] buffer; } + + unsigned crc() const { return crc_ ^ 0xFFFFFFFFU; } + unsigned long long data_position() const { return partial_data_pos + pos; } + bool finished() { return rdec.finished(); } + unsigned long long member_position() const { return rdec.member_position(); } + unsigned long long total_packets() const { return total_packets_; } + unsigned long long max_distance_pos() const { return max_rep0_pos; } + unsigned max_distance() const { return max_rep0 + 1; } + const std::vector< unsigned long long > & max_packet_posv() const + { return max_packet_posv_; } + unsigned max_packet_size() const { return max_packet_size_; } + unsigned max_marker_size() const { return max_marker_size_; } + + const uint8_t * get_buffers( const uint8_t ** const prev_bufferp, + int * const sizep, int * const prev_sizep ) const + { *sizep = ( pos_wrapped && pos == 0 ) ? dictionary_size : pos; + *prev_sizep = ( pos_wrapped && pos > 0 ) ? dictionary_size - pos : 0; + *prev_bufferp = buffer + pos; return buffer; } + + void duplicate_buffer( uint8_t * const buffer2 ); + + // these two functions set max_rep0 + int test_member( const unsigned long long mpos_limit = LLONG_MAX, + const unsigned long long dpos_limit = LLONG_MAX, + FILE * const f = 0, const unsigned long long byte_pos = 0 ); + /* this function also sets max_rep0_pos, total_packets_, max_packet_size_, + max_packet_posv_, and max_marker_size_ */ + int debug_decode_member( const long long dpos, const long long mpos, + const bool show_packets ); + }; |