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-rw-r--r--decoder.cc310
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+/* Lziprecover - Data recovery tool for lzipped files
+ Copyright (C) 2009, 2010, 2011 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 3 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/>.
+*/
+
+#define _FILE_OFFSET_BITS 64
+
+#include <algorithm>
+#include <cerrno>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <vector>
+#include <stdint.h>
+#include <unistd.h>
+
+#include "lzip.h"
+#include "decoder.h"
+
+
+const CRC32 crc32;
+
+
+void Pretty_print::operator()( const char * const msg ) const throw()
+ {
+ if( verbosity_ >= 0 )
+ {
+ if( first_post )
+ {
+ first_post = false;
+ std::fprintf( stderr, " %s: ", name_.c_str() );
+ for( unsigned int i = 0; i < longest_name - name_.size(); ++i )
+ std::fprintf( stderr, " " );
+ if( !msg ) std::fflush( stderr );
+ }
+ if( msg ) std::fprintf( stderr, "%s.\n", msg );
+ }
+ }
+
+
+// Returns the number of bytes really read.
+// If (returned value < size) and (errno == 0), means EOF was reached.
+//
+int readblock( const int fd, uint8_t * const buf, const int size ) throw()
+ {
+ int rest = size;
+ errno = 0;
+ while( rest > 0 )
+ {
+ errno = 0;
+ const int n = read( fd, buf + size - rest, rest );
+ if( n > 0 ) rest -= n;
+ else if( n == 0 ) break;
+ else if( errno != EINTR && errno != EAGAIN ) break;
+ }
+ return ( rest > 0 ) ? size - rest : size;
+ }
+
+
+// Returns the number of bytes really written.
+// If (returned value < size), it is always an error.
+//
+int writeblock( const int fd, const uint8_t * const buf, const int size ) throw()
+ {
+ int rest = size;
+ errno = 0;
+ while( rest > 0 )
+ {
+ errno = 0;
+ const int n = write( fd, buf + size - rest, rest );
+ if( n > 0 ) rest -= n;
+ else if( errno && errno != EINTR && errno != EAGAIN ) break;
+ }
+ return ( rest > 0 ) ? size - rest : size;
+ }
+
+
+bool Range_decoder::read_block()
+ {
+ if( !at_stream_end )
+ {
+ stream_pos = readblock( infd, buffer, buffer_size );
+ if( stream_pos != buffer_size && errno ) throw Error( "Read error" );
+ at_stream_end = ( stream_pos < buffer_size );
+ partial_member_pos += pos;
+ pos = 0;
+ }
+ return pos < stream_pos;
+ }
+
+
+void LZ_decoder::flush_data()
+ {
+ const int size = pos - stream_pos;
+ if( size > 0 )
+ {
+ crc32.update( crc_, buffer + stream_pos, size );
+ if( outfd >= 0 &&
+ writeblock( outfd, buffer + stream_pos, size ) != size )
+ throw Error( "Write error" );
+ if( pos >= buffer_size ) { partial_data_pos += pos; pos = 0; }
+ stream_pos = pos;
+ }
+ }
+
+
+bool LZ_decoder::verify_trailer( const Pretty_print & pp ) const
+ {
+ File_trailer trailer;
+ const int trailer_size = File_trailer::size( member_version );
+ const long long member_size = range_decoder.member_position() + trailer_size;
+ bool error = false;
+
+ for( int i = 0; i < trailer_size && !error; ++i )
+ {
+ if( !range_decoder.finished() )
+ trailer.data[i] = range_decoder.get_byte();
+ else
+ {
+ error = true;
+ if( pp.verbosity() >= 0 )
+ {
+ pp();
+ std::fprintf( stderr, "Trailer truncated at trailer position %d;"
+ " some checks may fail.\n", i );
+ }
+ for( ; i < trailer_size; ++i ) trailer.data[i] = 0;
+ }
+ }
+ if( member_version == 0 ) trailer.member_size( member_size );
+ if( !range_decoder.code_is_zero() )
+ {
+ error = true;
+ pp( "Range decoder final code is not zero" );
+ }
+ if( trailer.data_crc() != crc() )
+ {
+ error = true;
+ if( pp.verbosity() >= 0 )
+ {
+ pp();
+ std::fprintf( stderr, "CRC mismatch; trailer says %08X, data CRC is %08X.\n",
+ (unsigned int)trailer.data_crc(), (unsigned int)crc() );
+ }
+ }
+ if( trailer.data_size() != data_position() )
+ {
+ error = true;
+ if( pp.verbosity() >= 0 )
+ {
+ pp();
+ std::fprintf( stderr, "Data size mismatch; trailer says %lld, data size is %lld (0x%llX).\n",
+ trailer.data_size(), data_position(), data_position() );
+ }
+ }
+ if( trailer.member_size() != member_size )
+ {
+ error = true;
+ if( pp.verbosity() >= 0 )
+ {
+ pp();
+ std::fprintf( stderr, "Member size mismatch; trailer says %lld, member size is %lld (0x%llX).\n",
+ trailer.member_size(), member_size, member_size );
+ }
+ }
+ if( !error && pp.verbosity() >= 3 && data_position() > 0 && member_size > 0 )
+ std::fprintf( stderr, "%6.3f:1, %6.3f bits/byte, %5.2f%% saved. ",
+ (double)data_position() / member_size,
+ ( 8.0 * member_size ) / data_position(),
+ 100.0 * ( 1.0 - ( (double)member_size / data_position() ) ) );
+ if( !error && pp.verbosity() >= 4 )
+ std::fprintf( stderr, "data CRC %08X, data size %9lld, member size %8lld. ",
+ (unsigned int)trailer.data_crc(), trailer.data_size(),
+ trailer.member_size() );
+ return !error;
+ }
+
+
+// Return value: 0 = OK, 1 = decoder error, 2 = unexpected EOF,
+// 3 = trailer error, 4 = unknown marker found.
+int LZ_decoder::decode_member( const Pretty_print & pp )
+ {
+ 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];
+
+ unsigned int rep0 = 0; // rep[0-3] latest four distances
+ unsigned int rep1 = 0; // used for efficient coding of
+ unsigned int rep2 = 0; // repeated distances
+ unsigned int rep3 = 0;
+
+ Len_decoder len_decoder;
+ Len_decoder rep_match_len_decoder;
+ Literal_decoder literal_decoder;
+ State state;
+ range_decoder.load();
+
+ while( true )
+ {
+ if( range_decoder.finished() ) { flush_data(); return 2; }
+ const int pos_state = data_position() & pos_state_mask;
+ if( range_decoder.decode_bit( bm_match[state()][pos_state] ) == 0 )
+ {
+ const uint8_t prev_byte = get_prev_byte();
+ if( state.is_char() )
+ put_byte( literal_decoder.decode( range_decoder, prev_byte ) );
+ else
+ put_byte( literal_decoder.decode_matched( range_decoder, prev_byte,
+ get_byte( rep0 ) ) );
+ state.set_char();
+ }
+ else
+ {
+ int len;
+ if( range_decoder.decode_bit( bm_rep[state()] ) == 1 )
+ {
+ len = 0;
+ if( range_decoder.decode_bit( bm_rep0[state()] ) == 1 )
+ {
+ unsigned int distance;
+ if( range_decoder.decode_bit( bm_rep1[state()] ) == 0 )
+ distance = rep1;
+ else
+ {
+ if( range_decoder.decode_bit( bm_rep2[state()] ) == 0 )
+ distance = rep2;
+ else { distance = rep3; rep3 = rep2; }
+ rep2 = rep1;
+ }
+ rep1 = rep0;
+ rep0 = distance;
+ }
+ else
+ {
+ if( range_decoder.decode_bit( bm_len[state()][pos_state] ) == 0 )
+ { state.set_short_rep(); len = 1; }
+ }
+ if( len == 0 )
+ {
+ state.set_rep();
+ len = min_match_len + rep_match_len_decoder.decode( range_decoder, pos_state );
+ }
+ }
+ else
+ {
+ const unsigned int rep0_saved = rep0;
+ len = min_match_len + len_decoder.decode( range_decoder, pos_state );
+ const int dis_slot = range_decoder.decode_tree( bm_dis_slot[get_dis_state(len)], dis_slot_bits );
+ if( dis_slot < start_dis_model ) rep0 = dis_slot;
+ else
+ {
+ const int direct_bits = ( dis_slot >> 1 ) - 1;
+ rep0 = ( 2 | ( dis_slot & 1 ) ) << direct_bits;
+ if( dis_slot < end_dis_model )
+ rep0 += range_decoder.decode_tree_reversed( bm_dis + rep0 - dis_slot, direct_bits );
+ else
+ {
+ rep0 += range_decoder.decode( direct_bits - dis_align_bits ) << dis_align_bits;
+ rep0 += range_decoder.decode_tree_reversed( bm_align, dis_align_bits );
+ if( rep0 == 0xFFFFFFFFU ) // Marker found
+ {
+ rep0 = rep0_saved;
+ range_decoder.normalize();
+ flush_data();
+ if( len == min_match_len ) // End Of Stream marker
+ {
+ if( verify_trailer( pp ) ) return 0; else return 3;
+ }
+ if( len == min_match_len + 1 ) // Sync Flush marker
+ {
+ range_decoder.load(); continue;
+ }
+ if( pp.verbosity() >= 0 )
+ {
+ pp();
+ std::fprintf( stderr, "Unsupported marker code `%d'.\n", len );
+ }
+ return 4;
+ }
+ }
+ }
+ rep3 = rep2; rep2 = rep1; rep1 = rep0_saved;
+ state.set_match();
+ if( rep0 >= (unsigned int)dictionary_size ||
+ ( rep0 >= (unsigned int)pos && !partial_data_pos ) )
+ { flush_data(); return 1; }
+ }
+ copy_block( rep0, len );
+ }
+ }
+ }