diff options
Diffstat (limited to 'mtester.h')
| -rw-r--r-- | mtester.h | 125 |
1 files changed, 60 insertions, 65 deletions
@@ -1,5 +1,5 @@ /* Lziprecover - Data recovery tool for the lzip format - Copyright (C) 2009-2018 Antonio Diaz Diaz. + Copyright (C) 2009-2019 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 @@ -31,7 +31,7 @@ public: : buffer( buf ), buffer_size( buf_size ), - pos( File_header::size ), + pos( Lzip_header::size ), code( 0 ), range( 0xFFFFFFFFU ), at_stream_end( false ) @@ -47,11 +47,11 @@ public: return buffer[pos++]; } - const File_trailer * get_trailer() + const Lzip_trailer * get_trailer() { - if( buffer_size - pos < File_trailer::size ) return 0; - const File_trailer * const p = (File_trailer *)( buffer + pos ); - pos += File_trailer::size; + 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; } @@ -69,24 +69,23 @@ public: { range <<= 8; code = (code << 8) | get_byte(); } } - int decode( const int num_bits ) + unsigned decode( const int num_bits ) { - int symbol = 0; + unsigned symbol = 0; for( int i = num_bits; i > 0; --i ) { normalize(); range >>= 1; // symbol <<= 1; // if( code >= range ) { code -= range; symbol |= 1; } - const uint32_t mask = 0U - (code < range); - code -= range; - code += range & mask; - symbol = (symbol << 1) + (mask + 1); + const bool bit = ( code >= range ); + symbol = ( symbol << 1 ) + bit; + code -= range & ( 0U - bit ); } return symbol; } - int decode_bit( Bit_model & bm ) + unsigned decode_bit( Bit_model & bm ) { normalize(); const uint32_t bound = ( range >> bit_model_total_bits ) * bm.probability; @@ -105,18 +104,18 @@ public: } } - int decode_tree3( Bit_model bm[] ) + unsigned decode_tree3( Bit_model bm[] ) { - int symbol = 1; + unsigned symbol = 1; symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); return symbol & 7; } - int decode_tree6( Bit_model bm[] ) + unsigned decode_tree6( Bit_model bm[] ) { - int symbol = 1; + unsigned symbol = 1; symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); @@ -126,49 +125,47 @@ public: return symbol & 0x3F; } - int decode_tree8( Bit_model bm[] ) + unsigned decode_tree8( Bit_model bm[] ) { - int symbol = 1; - while( symbol < 0x100 ) + unsigned symbol = 1; + for( int i = 0; i < 8; ++i ) symbol = ( symbol << 1 ) | decode_bit( bm[symbol] ); return symbol & 0xFF; } - int decode_tree_reversed( Bit_model bm[], const int num_bits ) + unsigned decode_tree_reversed( Bit_model bm[], const int num_bits ) { - int model = 1; - int symbol = 0; + unsigned model = 1; + unsigned symbol = 0; for( int i = 0; i < num_bits; ++i ) { - const bool bit = decode_bit( bm[model] ); - model <<= 1; - if( bit ) { ++model; symbol |= (1 << i); } + const unsigned bit = decode_bit( bm[model] ); + model = ( model << 1 ) + bit; + symbol |= ( bit << i ); } return symbol; } - int decode_tree_reversed4( Bit_model bm[] ) + unsigned decode_tree_reversed4( Bit_model bm[] ) { - int model = 1; - int symbol = decode_bit( bm[model] ); - model = (model << 1) + symbol; - int bit = decode_bit( bm[model] ); - model = (model << 1) + bit; symbol |= (bit << 1); + unsigned symbol = decode_bit( bm[1] ); + unsigned model = 2 + symbol; + unsigned bit = decode_bit( bm[model] ); + model = ( model << 1 ) + bit; symbol |= ( bit << 1 ); bit = decode_bit( bm[model] ); - model = (model << 1) + bit; symbol |= (bit << 2); - if( decode_bit( bm[model] ) ) symbol |= 8; + model = ( model << 1 ) + bit; symbol |= ( bit << 2 ); + symbol |= ( decode_bit( bm[model] ) << 3 ); return symbol; } - int decode_matched( Bit_model bm[], int match_byte ) + unsigned decode_matched( Bit_model bm[], unsigned match_byte ) { Bit_model * const bm1 = bm + 0x100; - int symbol = 1; + unsigned symbol = 1; while( symbol < 0x100 ) { - match_byte <<= 1; - const int match_bit = match_byte & 0x100; - const int bit = decode_bit( bm1[match_bit+symbol] ); + const unsigned match_bit = ( match_byte <<= 1 ) & 0x100; + const unsigned bit = decode_bit( bm1[match_bit+symbol] ); symbol = ( symbol << 1 ) | bit; if( match_bit != bit << 8 ) { @@ -180,7 +177,7 @@ public: return symbol & 0xFF; } - int decode_len( Len_model & lm, const int pos_state ) + unsigned decode_len( Len_model & lm, const int pos_state ) { if( decode_bit( lm.choice1 ) == 0 ) return decode_tree3( lm.bm_low[pos_state] ); @@ -223,20 +220,17 @@ class LZ_mtester Len_model match_len_model; Len_model rep_len_model; + void print_block( const int len ); void flush_data(); bool verify_trailer(); - void print_block( const int len ); uint8_t peek_prev() const - { - const unsigned i = ( ( pos > 0 ) ? pos : dictionary_size ) - 1; - return buffer[i]; - } + { return buffer[((pos > 0) ? pos : dictionary_size)-1]; } uint8_t peek( const unsigned distance ) const { - unsigned i = pos - distance - 1; - if( pos <= distance ) i += dictionary_size; + const unsigned i = ( ( pos > distance ) ? 0 : dictionary_size ) + + pos - distance - 1; return buffer[i]; } @@ -248,17 +242,26 @@ class LZ_mtester void copy_block( const unsigned distance, unsigned len ) { - unsigned i = pos - distance - 1; - bool fast; - if( pos <= distance ) - { i += dictionary_size; - fast = ( len <= dictionary_size - i && len <= i - pos ); } + unsigned lpos = pos, i = lpos - distance - 1; + bool fast, fast2; + if( lpos > distance ) + { + fast = ( len < dictionary_size - lpos ); + fast2 = ( fast && len <= lpos - i ); + } else - fast = ( len < dictionary_size - pos && len <= pos - i ); - if( fast ) // no wrap, no overlap { - std::memcpy( buffer + pos, buffer + i, len ); + 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 ) { @@ -288,7 +291,8 @@ public: rep3( 0 ), max_rep0( 0 ), pos_wrapped( false ) - { buffer[dictionary_size-1] = 0; } // prev_byte of first byte + // prev_byte of first byte; also for peek( 0 ) on corrupt file + { buffer[dictionary_size-1] = 0; } ~LZ_mtester() { delete[] buffer; } @@ -303,12 +307,3 @@ public: int debug_decode_member( const long long dpos, const long long mpos, const bool show_packets ); // sets max_rep0 }; - - -uint8_t * read_member( const int infd, const long long mpos, - const long long msize ); -const LZ_mtester * prepare_master( const uint8_t * const buffer, - const long buffer_size, - const unsigned long pos_limit, - const unsigned dictionary_size ); -bool test_member_rest( const LZ_mtester & master, long * const failure_posp = 0 ); |