diff options
Diffstat (limited to 'range_dec.cc')
| -rw-r--r-- | range_dec.cc | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/range_dec.cc b/range_dec.cc new file mode 100644 index 0000000..ea7f7e7 --- /dev/null +++ b/range_dec.cc @@ -0,0 +1,185 @@ +/* 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/>. +*/ + +#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 <sys/stat.h> + +#include "lzip.h" +#include "decoder.h" +#include "lzip_index.h" + + +namespace { + +bool decompress_member( const int infd, const Pretty_print & pp, + const unsigned long long mpos, + const unsigned long long outskip, + const unsigned long long outend ) + { + Range_decoder rdec( infd ); + Lzip_header header; + rdec.read_data( header.data, Lzip_header::size ); + if( rdec.finished() ) // End Of File + { pp( "File ends unexpectedly at member header." ); return false; } + if( !header.verify_magic() ) { pp( bad_magic_msg ); return false; } + if( !header.verify_version() ) + { pp( bad_version( header.version() ) ); return false; } + const unsigned dictionary_size = header.dictionary_size(); + if( !isvalid_ds( dictionary_size ) ) { pp( bad_dict_msg ); return false; } + + if( verbosity >= 2 ) pp(); + + LZ_decoder decoder( rdec, dictionary_size, outfd, outskip, outend ); + const int result = decoder.decode_member( pp ); + if( result != 0 ) + { + if( verbosity >= 0 && result <= 2 ) + { + pp(); + std::fprintf( stderr, "%s at pos %llu\n", ( result == 2 ) ? + "File ends unexpectedly" : "Decoder error", + mpos + rdec.member_position() ); + } + return false; + } + if( decoder.data_position() < outend - outskip ) + { + if( verbosity >= 0 ) + { pp(); std::fprintf( stderr, + "%sMember at pos %llu contains only %llu bytes of %llu requested.\n", + ( verbosity >= 2 ) ? "\n" : "", mpos, + decoder.data_position() - outskip, outend - outskip ); } + return false; + } + if( verbosity >= 2 ) std::fputs( "done\n", stderr ); + return true; + } + +} // end namespace + + +const char * format_num( unsigned long long num, + unsigned long long limit, + const int set_prefix ) + { + const char * const si_prefix[8] = + { "k", "M", "G", "T", "P", "E", "Z", "Y" }; + const char * const binary_prefix[8] = + { "Ki", "Mi", "Gi", "Ti", "Pi", "Ei", "Zi", "Yi" }; + enum { buffers = 8, bufsize = 32 }; + static char buffer[buffers][bufsize]; // circle of static buffers for printf + static int current = 0; + static bool si = true; + + if( set_prefix ) si = ( set_prefix > 0 ); + unsigned long long den = 1; + const unsigned factor = ( si ? 1000 : 1024 ); + char * const buf = buffer[current++]; current %= buffers; + const char * const * prefix = ( si ? si_prefix : binary_prefix ); + const char * p = ""; + + for( int i = 0; i < 8 && num / den >= factor && den * factor > den; ++i ) + { if( num / den <= limit && num % ( den * factor ) != 0 ) break; + den *= factor; p = prefix[i]; } + if( num % den == 0 ) + snprintf( buf, bufsize, "%llu %s", num / den, p ); + else + snprintf( buf, bufsize, "%3.2f %s", (double)num / den, p ); + return buf; + } + + +bool safe_seek( const int fd, const long long pos ) + { + if( lseek( fd, pos, SEEK_SET ) == pos ) return true; + show_error( "Seek error", errno ); return false; + } + + +int range_decompress( const std::string & input_filename, + const std::string & default_output_filename, + Block range, const bool force, const bool ignore_errors, + const bool ignore_trailing, const bool loose_trailing, + const bool to_stdout ) + { + struct stat in_stats; + const int infd = + open_instream( input_filename.c_str(), &in_stats, false, true ); + if( infd < 0 ) return 1; + + const Lzip_index lzip_index( infd, ignore_trailing, loose_trailing, + ignore_errors, ignore_errors ); + if( lzip_index.retval() != 0 ) + { show_file_error( input_filename.c_str(), lzip_index.error().c_str() ); + return lzip_index.retval(); } + + const long long udata_size = lzip_index.udata_size(); + if( range.end() > udata_size ) + range.size( std::max( 0LL, udata_size - range.pos() ) ); + if( range.size() <= 0 ) + { if( udata_size > 0 ) + show_file_error( input_filename.c_str(), "Nothing to do." ); + return 0; } + + if( to_stdout || default_output_filename.empty() ) outfd = STDOUT_FILENO; + else + { + output_filename = default_output_filename; + set_signal_handler(); + if( !open_outstream( force, true, false, false ) ) return 1; + } + + if( verbosity >= 1 ) + std::fprintf( stderr, "Decompressing range %sB to %sB (%sB of %sBytes)\n", + format_num( range.pos() ), + format_num( range.pos() + range.size() ), + format_num( range.size() ), format_num( udata_size ) ); + + Pretty_print pp( input_filename ); + bool error = false; + for( long i = 0; i < lzip_index.members(); ++i ) + { + const Block & db = lzip_index.dblock( i ); + if( range.overlaps( db ) ) + { + if( verbosity >= 3 && lzip_index.members() > 1 ) + std::fprintf( stderr, "Decompressing member %3ld\n", i + 1 ); + const long long outskip = std::max( 0LL, range.pos() - db.pos() ); + const long long outend = std::min( db.size(), range.end() - db.pos() ); + const long long mpos = lzip_index.mblock( i ).pos(); + if( !safe_seek( infd, mpos ) ) cleanup_and_fail( 1 ); + if( !decompress_member( infd, pp, mpos, outskip, outend ) ) + { if( !ignore_errors ) cleanup_and_fail( 2 ); else error = true; } + pp.reset(); + } + } + close( infd ); + if( close_outstream( &in_stats ) != 0 ) cleanup_and_fail( 1 ); + if( verbosity >= 2 && !error ) + std::fputs( "Byte range decompressed successfully.\n", stderr ); + return 0; // either no error or ignored + } |