409 lines
13 KiB
C++
409 lines
13 KiB
C++
/* Lziprecover - Data recovery tool for lzip files
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Copyright (C) 2009, 2010, 2011, 2012, 2013, 2014 Antonio Diaz Diaz.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#define _FILE_OFFSET_BITS 64
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#include <cerrno>
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#include <climits>
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <string>
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#include <vector>
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#include <stdint.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include "lzip.h"
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#include "decoder.h"
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#include "file_index.h"
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namespace {
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// Add 'bv' to 'block_vector' splitting blocks as needed to keep all the
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// edges (pos and end of every block).
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// 'block_vector' contains the result. 'bv' is destroyed.
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void combine( std::vector< Block > & block_vector, std::vector< Block > & bv )
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{
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if( block_vector.empty() ) { block_vector.swap( bv ); return; }
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unsigned i1 = 0, i2 = 0;
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while( i1 < block_vector.size() && i2 < bv.size() )
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{
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Block & b1 = block_vector[i1];
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Block & b2 = bv[i2];
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if( b1.overlaps( b2 ) )
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{
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if( b1 < b2 )
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{
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Block b = b1.split( b2.pos() );
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block_vector.insert( block_vector.begin() + i1, b ); ++i1;
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}
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else if( b2 < b1 )
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{
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Block b( b2.pos(), b1.pos() - b2.pos() );
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b2.split( b1.pos() );
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block_vector.insert( block_vector.begin() + i1, b ); ++i1;
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}
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else if( b1.end() < b2.end() ) { b2.split( b1.end() ); ++i1; }
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else if( b2.end() < b1.end() )
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{
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Block b = b1.split( b2.end() );
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block_vector.insert( block_vector.begin() + i1, b ); ++i1; ++i2;
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}
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else { ++i1; ++i2; } // blocks are identical
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}
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else if( b1 < b2 ) ++i1;
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else { block_vector.insert( block_vector.begin() + i1, b2 ); ++i1; ++i2; }
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}
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if( i2 < bv.size() ) // tail copy
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block_vector.insert( block_vector.end(), bv.begin() + i2, bv.end() );
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}
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// positions in 'block_vector' are absolute file positions.
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bool diff_member( const long long mpos, const long long msize,
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const std::vector< int > & infd_vector,
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std::vector< Block > & block_vector )
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{
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const int files = infd_vector.size();
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const int buffer_size = 65536;
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uint8_t * const buffer1 = new uint8_t[buffer_size];
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uint8_t * const buffer2 = new uint8_t[buffer_size];
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bool error = false;
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for( int i1 = 0; i1 + 1 < files && !error; ++i1 )
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{
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for( int i2 = i1 + 1; i2 < files && !error; ++i2 )
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{
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std::vector< Block > bv;
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long long partial_pos = 0;
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const int fd1 = infd_vector[i1], fd2 = infd_vector[i2];
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int begin = -1; // begin of block. -1 means no block
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bool prev_equal = true;
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if( !safe_seek( fd1, mpos ) || !safe_seek( fd2, mpos ) )
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{ error = true; break; }
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while( msize > partial_pos )
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{
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const int size = std::min( (long long)buffer_size, msize - partial_pos );
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const int rd = readblock( fd1, buffer1, size );
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if( rd != size && errno )
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{ show_error( "Error reading input file", errno ); error = true; break; }
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if( rd > 0 )
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{
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if( readblock( fd2, buffer2, rd ) != rd )
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{ show_error( "Error reading input file", errno );
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error = true; break; }
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for( int i = 0; i < rd; ++i )
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{
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if( buffer1[i] != buffer2[i] )
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{
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prev_equal = false;
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if( begin < 0 ) begin = partial_pos + i; // begin block
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}
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else if( !prev_equal ) prev_equal = true;
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else if( begin >= 0 ) // end block
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{
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Block b( mpos + begin, partial_pos + i - 1 - begin );
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begin = -1;
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bv.push_back( b );
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}
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}
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partial_pos += rd;
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}
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if( rd < buffer_size ) break; // EOF
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}
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if( begin >= 0 ) // finish last block
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{
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Block b( mpos + begin, partial_pos - prev_equal - begin );
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bv.push_back( b );
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}
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combine( block_vector, bv );
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}
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}
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delete[] buffer2; delete[] buffer1;
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return !error;
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}
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int ipow( const unsigned base, const unsigned exponent )
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{
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unsigned result = 1;
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for( unsigned i = 0; i < exponent; ++i )
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{
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if( INT_MAX / base >= result ) result *= base;
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else { result = INT_MAX; break; }
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}
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return result;
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}
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int open_input_files( const std::vector< std::string > & filenames,
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std::vector< int > & infd_vector,
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File_index & file_index, const int verbosity )
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{
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const int files = filenames.size();
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bool identical = false;
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for( int i = 1; i < files; ++i )
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if( filenames[0] == filenames[i] )
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{ identical = true; break; }
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if( !identical )
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for( int i = 0; i < files; ++i )
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{
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struct stat in_stats;
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ino_t st_ino0 = 0;
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dev_t st_dev0 = 0;
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infd_vector[i] = open_instream( filenames[i].c_str(), &in_stats, true, true );
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if( infd_vector[i] < 0 ) return 1;
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if( i == 0 ) { st_ino0 = in_stats.st_ino; st_dev0 = in_stats.st_dev; }
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else if( st_ino0 == in_stats.st_ino && st_dev0 == in_stats.st_dev )
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{ identical = true; break; }
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}
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if( identical ) { show_error( "Two input files are the same." ); return 2; }
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long long isize = 0;
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for( int i = 0; i < files; ++i )
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{
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long long tmp;
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const File_index fi( infd_vector[i] );
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if( fi.retval() == 0 ) // file format is intact
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{
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if( file_index.retval() != 0 ) file_index = fi;
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else if( file_index != fi )
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{ show_error( "Input files are different." ); return 2; }
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tmp = file_index.file_size();
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}
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else // file format is damaged
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{
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tmp = lseek( infd_vector[i], 0, SEEK_END );
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if( tmp < 0 )
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{
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show_error2( "Input file", filenames[i].c_str(), "is not seekable." );
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return 1;
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}
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}
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if( i == 0 )
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{
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isize = tmp;
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if( isize < min_member_size )
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{ show_error2( "Input file", filenames[i].c_str(), "is too short." );
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return 2; }
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}
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else if( isize != tmp )
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{ show_error( "Sizes of input files are different." ); return 2; }
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}
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if( file_index.retval() != 0 )
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{
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const File_index fi( infd_vector, isize );
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if( fi.retval() == 0 ) // file format could be recovered
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file_index = fi;
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else
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{ show_error( "Format damaged in all input files." ); return 2; }
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}
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for( int i = 0; i < files; ++i )
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{
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const int infd = infd_vector[i];
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bool error = false;
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for( long j = 0; j < file_index.members(); ++j )
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{
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const long long mpos = file_index.mblock( j ).pos();
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const long long msize = file_index.mblock( j ).size();
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if( !safe_seek( infd, mpos ) ) return 1;
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if( !try_decompress_member( infd, msize ) ) { error = true; break; }
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}
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if( !error )
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{
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if( verbosity >= 1 )
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std::printf( "File '%s' has no errors. Recovery is not needed.\n",
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filenames[i].c_str() );
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return 0;
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}
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}
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return -1;
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}
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} // end namespace
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void cleanup_and_fail( const std::string & output_filename,
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const int outfd, const int retval )
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{
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if( outfd >= 0 ) close( outfd );
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if( std::remove( output_filename.c_str() ) != 0 && errno != ENOENT )
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show_error( "WARNING: deletion of output file (apparently) failed." );
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std::exit( retval );
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}
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// max_size < 0 means no size limit.
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bool copy_file( const int infd, const int outfd, const long long max_size )
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{
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const int buffer_size = 65536;
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// remaining number of bytes to copy
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long long rest = ( ( max_size >= 0 ) ? max_size : buffer_size );
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uint8_t * const buffer = new uint8_t[buffer_size];
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bool error = false;
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while( rest > 0 )
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{
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const int size = std::min( (long long)buffer_size, rest );
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if( max_size >= 0 ) rest -= size;
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const int rd = readblock( infd, buffer, size );
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if( rd != size && errno )
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{ show_error( "Error reading input file", errno ); error = true; break; }
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if( rd > 0 )
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{
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const int wr = writeblock( outfd, buffer, rd );
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if( wr != rd )
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{ show_error( "Error writing output file", errno );
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error = true; break; }
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}
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if( rd < size ) break; // EOF
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}
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delete[] buffer;
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return !error;
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}
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bool try_decompress_member( const int fd, const unsigned long long msize,
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long long * failure_posp )
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{
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Range_decoder rdec( fd );
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File_header header;
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rdec.read_data( header.data, File_header::size );
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if( !rdec.finished() && // End Of File
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header.verify_magic() && header.verify_version() &&
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header.dictionary_size() >= min_dictionary_size &&
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header.dictionary_size() <= max_dictionary_size )
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{
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LZ_decoder decoder( header, rdec, -1 );
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Pretty_print dummy( "", -1 );
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if( decoder.decode_member( dummy ) == 0 &&
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rdec.member_position() == msize ) return true;
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if( failure_posp ) *failure_posp = rdec.member_position();
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}
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return false;
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}
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int merge_files( const std::vector< std::string > & filenames,
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const std::string & output_filename, const int verbosity,
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const bool force )
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{
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const int files = filenames.size();
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std::vector< int > infd_vector( files );
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File_index file_index;
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const int retval =
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open_input_files( filenames, infd_vector, file_index, verbosity );
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if( retval >= 0 ) return retval;
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if( !safe_seek( infd_vector[0], 0 ) ) return 1;
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const int outfd = open_outstream_rw( output_filename, force );
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if( outfd < 0 ) return 1;
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if( !copy_file( infd_vector[0], outfd ) ) // copy whole file
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cleanup_and_fail( output_filename, outfd, 1 );
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for( long j = 0; j < file_index.members(); ++j )
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{
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const long long mpos = file_index.mblock( j ).pos();
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const long long msize = file_index.mblock( j ).size();
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// vector of data blocks differing among the copies of the current member
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std::vector< Block > block_vector;
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if( !diff_member( mpos, msize, infd_vector, block_vector ) ||
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!safe_seek( outfd, mpos ) )
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cleanup_and_fail( output_filename, outfd, 1 );
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if( block_vector.empty() )
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{
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if( file_index.members() > 1 && try_decompress_member( outfd, msize ) )
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continue;
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show_error( "Input files are (partially) identical. Recovery is not possible." );
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cleanup_and_fail( output_filename, outfd, 2 );
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}
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const int size0 = block_vector[0].size();
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const bool single_block = ( block_vector.size() == 1 );
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if( ipow( files, block_vector.size() ) >= INT_MAX ||
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( single_block && ipow( files, 2 ) >= INT_MAX / size0 ) )
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{ show_error( "Input files are too damaged. Recovery is not possible." );
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cleanup_and_fail( output_filename, outfd, 2 ); }
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const int shifts = ( single_block && size0 > 1 ) ? size0 - 1 : 1;
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if( single_block && size0 > 1 )
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{
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Block b( block_vector[0].pos() + 1, size0 - 1 );
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block_vector[0].size( 1 );
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block_vector.push_back( b );
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}
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if( verbosity >= 1 && file_index.members() > 1 )
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{
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std::printf( "Merging member %ld\n", j + 1 );
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std::fflush( stdout );
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}
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const int base_variations = ipow( files, block_vector.size() );
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const int variations = base_variations * shifts;
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bool done = false;
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for( int var = 0; var < variations; ++var )
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{
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if( verbosity >= 1 )
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{
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std::printf( "Trying variation %d of %d \r", var + 1, variations );
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std::fflush( stdout );
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}
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int tmp = var;
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for( unsigned i = 0; i < block_vector.size(); ++i )
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{
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const int infd = infd_vector[tmp % files];
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tmp /= files;
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if( !safe_seek( infd, block_vector[i].pos() ) ||
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!safe_seek( outfd, block_vector[i].pos() ) ||
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!copy_file( infd, outfd, block_vector[i].size() ) )
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cleanup_and_fail( output_filename, outfd, 1 );
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}
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if( !safe_seek( outfd, mpos ) )
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cleanup_and_fail( output_filename, outfd, 1 );
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if( try_decompress_member( outfd, msize ) )
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{ done = true; break; }
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if( var > 0 && var % base_variations == 0 )
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block_vector[0].shift( block_vector[1] );
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}
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if( verbosity >= 1 ) std::printf( "\n" );
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if( !done )
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{
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if( verbosity >= 2 )
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for( unsigned i = 0; i < block_vector.size(); ++i )
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std::fprintf( stderr, "area %2d from offset %6lld to %6lld\n", i + 1,
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block_vector[i].pos(), block_vector[i].end() - 1 );
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show_error( "Some error areas overlap. Can't recover input file." );
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cleanup_and_fail( output_filename, outfd, 2 );
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}
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}
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if( close( outfd ) != 0 )
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{
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show_error( "Error closing output file", errno );
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cleanup_and_fail( output_filename, -1, 1 );
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}
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if( verbosity >= 1 )
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std::printf( "Input files merged successfully.\n" );
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return 0;
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}
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