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Diffstat (limited to 'zcat.cc')
| -rw-r--r-- | zcat.cc | 213 |
1 files changed, 213 insertions, 0 deletions
@@ -0,0 +1,213 @@ +/* Zcat - decompress and concatenate files to standard output + Copyright (C) 2010 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/>. +*/ + +struct Cat_options + { + int number_lines; // 0 = no, 1 = nonblank, 2 = all + bool show_ends; + bool show_nonprinting; + bool show_tabs; + bool squeeze_blank; + + Cat_options() throw() + : number_lines( 0 ), show_ends( false ), show_nonprinting( false ), + show_tabs( false ), squeeze_blank( false ) {} + }; + + +class Line_number // unlimited size line counter + { + std::string str; + int first_digit_pos; + +public: + Line_number() : str( " 0\t" ), first_digit_pos( 5 ) {} + + void next() + { + for( int i = str.size() - 2; i >= first_digit_pos; --i ) + { + if( str[i] < '9' ) { ++str[i]; return; } + str[i] = '0'; + } + if( first_digit_pos > 0 ) str[--first_digit_pos] = '1'; + else str.insert( 0, 1, '1' ); + } + + int sprint( uint8_t * const buf ) + { + std::memcpy( buf, str.c_str(), str.size() ); + return str.size(); + } + }; + +Line_number line_number; + + +void show_zcat_help() throw() + { + std::printf( "Zcat copies each given file (\"-\" means standard input), to standard\n" ); + std::printf( "output. If any given file is compressed, its uncompressed content is\n" ); + std::printf( "used. If a given file does not exist, and its name does not end with one\n" ); + std::printf( "of the known extensions, zcat tries the compressed file names\n" ); + std::printf( "corresponding to the supported compressors. If no files are specified,\n" ); + std::printf( "data is read from standard input, decompressed if needed, and sent to\n" ); + std::printf( "standard output. Data read from standard input must be of the same type;\n" ); + std::printf( "all uncompressed or all compressed with the same compressor.\n" ); + std::printf( "The supported compressors are bzip2, gzip, lzip and xz.\n" ); + std::printf( "\nUsage: zcat [options] [files]\n" ); + std::printf( "\nExit status is 0 if no errors occurred, 1 otherwise.\n" ); + std::printf( "\nOptions:\n" ); + std::printf( " -h, --help display this help and exit\n" ); + std::printf( " -V, --version output version information and exit\n" ); + std::printf( " -A, --show-all equivalent to `-vET'\n" ); + std::printf( " -b, --number-nonblank number nonblank output lines\n" ); + std::printf( " -e equivalent to `-vE'\n" ); + std::printf( " -E, --show-ends display `$' at end of each line\n" ); + std::printf( " -n, --number number all output lines\n" ); + std::printf( " -q, --quiet suppress all messages\n" ); + std::printf( " -r, --recursive operate recursively on directories\n" ); + std::printf( " -s, --squeeze-blank never more than one single blank line\n" ); + std::printf( " -t equivalent to `-vT'\n" ); + std::printf( " -T, --show-tabs display TAB characters as `^I'\n" ); + std::printf( " -v, --show-nonprinting use `^' and `M-' notation, except for LF and TAB\n" ); + std::printf( " --verbose verbose mode (show error messages)\n" ); + show_help_addr(); + } + + +int do_cat( const int infd, const int buffer_size, + uint8_t * const inbuf, uint8_t * const outbuf, + const std::string & input_filename, + const Cat_options & cat_options ) + { + static int at_bol = 1; // at begin of line. 0 = false, 1 = true, + // 2 = at begin of second blank line. + int inpos = 0; // positions in buffers + int outpos = 0; + int rd = -1; // bytes read by the last readblock + unsigned char c; + + while( true ) + { + do { + if( outpos >= buffer_size ) + { + if( writeblock( STDOUT_FILENO, outbuf, outpos ) != outpos ) + { show_error( "Write error", errno ); return 1; } + outpos = 0; + } + if( inpos > rd ) // inbuf is empty + { + rd = readblock( infd, inbuf, buffer_size ); + if( rd != buffer_size && errno ) + { + if( verbosity >= 0 ) + std::fprintf( stderr, "%s: Error reading file `%s': %s.\n", + util_name, input_filename.c_str(), + std::strerror( errno ) ); + return 1; + } + if( rd == 0 ) + { + if( writeblock( STDOUT_FILENO, outbuf, outpos ) != outpos ) + { show_error( "Write error", errno ); return 1; } + outpos = 0; + return 0; + } + inpos = 0; + inbuf[rd] = '\n'; // sentinel newline + } + else // a real newline was found + { + if( at_bol > 1 ) + { + if( cat_options.squeeze_blank ) { c = inbuf[inpos++]; continue; } + } + else ++at_bol; + if( at_bol > 1 && cat_options.number_lines == 2 ) + { + line_number.next(); + outpos += line_number.sprint( &outbuf[outpos] ); + } + if( cat_options.show_ends ) outbuf[outpos++] = '$'; + outbuf[outpos++] = '\n'; // output the newline + } + c = inbuf[inpos++]; + } + while( c == '\n' ); + + if( at_bol > 0 && cat_options.number_lines ) + { + line_number.next(); + outpos += line_number.sprint( &outbuf[outpos] ); + } + at_bol = 0; + + // the loops below continue until a newline (real or sentinel) is found + + if( cat_options.show_nonprinting ) + while( true ) + { + if( c < 32 || c >= 127 ) + { + if( c == '\n' ) break; + if( c != '\t' || cat_options.show_tabs ) + { + if( c >= 128 ) + { c -= 128; outbuf[outpos++] = 'M'; outbuf[outpos++] = '-'; } + if( c < 32 ) { c += 64; outbuf[outpos++] = '^'; } + else if( c == 127 ) { c = '?'; outbuf[outpos++] = '^'; } + } + } + outbuf[outpos++] = c; + c = inbuf[inpos++]; + } + else // not quoting + while( c != '\n' ) + { + if( c == '\t' && cat_options.show_tabs ) + { c += 64; outbuf[outpos++] = '^'; } + outbuf[outpos++] = c; + c = inbuf[inpos++]; + } + } + } + + +int cat( int infd, const std::string & input_filename, + const Cat_options & cat_options ) + { + enum { buffer_size = 4096 }; + // buffer with space for sentinel newline at the end + uint8_t * const inbuf = new uint8_t[buffer_size+1]; + // buffer with space for character quoting and 255-digit line number + uint8_t * const outbuf = new uint8_t[(4*buffer_size)+256]; + pid_t pid = 0; + int retval = 0; + if( !set_data_feeder( &infd, &pid ) ) retval = 1; + else + { + retval = do_cat( infd, buffer_size, inbuf, outbuf, + input_filename, cat_options ); + if( pid && wait_for_child( pid, "data feeder" ) != 0 ) retval = 1; + if( close( infd ) != 0 ) + { show_error( "Can't close output of data feeder", errno ); retval = 1; } + } + delete[] inbuf; delete[] outbuf; + return retval; + } |