regex/example/grep/grep.cpp

218 lines
6.7 KiB
C++

/*
*
* Copyright (c) 2004
* John Maddock
*
* Use, modification and distribution are subject to the
* Boost Software License, Version 1.0. (See accompanying file
* LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
*
*/
#include <boost/regex.hpp>
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#ifdef BOOST_MSVC
#pragma warning(disable:4512 4244)
#endif
#include <boost/program_options.hpp>
namespace po = boost::program_options;
int after_context;
int before_context;
bool print_byte_offset;
bool count_only;
std::string pattern;
bool print_non_matching_files;
bool files_only;
bool print_line_numbers;
boost::regex_constants::syntax_option_type flags = boost::regex_constants::basic;
boost::regex re;
boost::smatch what;
std::string current_file;
int file_count;
void process_stream(std::istream& is)
{
std::string line;
int match_found = 0;
int linenum = 1;
while(std::getline(is, line))
{
bool result = boost::regex_search(line, what, re);
if(result)
{
if(print_non_matching_files)
return;
if(files_only)
{
std::cout << current_file << std::endl;
return;
}
if(!match_found && !count_only && (file_count > 1))
{
std::cout << current_file << ":\n";
}
++match_found;
if(!count_only)
{
if(print_line_numbers)
{
std::cout << linenum << ":";
}
if(print_byte_offset)
{
std::cout << what.position() << ":";
}
std::cout << what[0] << std::endl;
}
}
++linenum;
}
if(count_only && match_found)
{
std::cout << match_found << " matches found in file " << current_file << std::endl;
}
else if(print_non_matching_files && !match_found)
{
std::cout << current_file << std::endl;
}
}
void process_file(const std::string& name)
{
current_file = name;
std::ifstream is(name.c_str());
if(is.bad())
{
std::cerr << "Unable to open file " << name << std::endl;
}
process_stream(is);
}
int main(int argc, char * argv[])
{
try{
po::options_description opts("Options");
opts.add_options()
("help,h", "produce help message")
//("after-context,A", po::value<int>(&after_context)->default_value(0), "Print arg lines of trailing context after matching lines. Places a line containing -- between contiguous groups of matches.")
//("before-context,B", po::value<int>(&before_context)->default_value(0), "Print arg lines of leading context before matching lines. Places a line containing -- between contiguous groups of matches.")
//("context,C", po::value<int>(), "Print arg lines of output context. Places a line containing -- between contiguous groups of matches.")
("byte-offset,b", "Print the byte offset within the input file before each line of output.")
("count,c", "Suppress normal output; instead print a count of matching lines for each input file. With the -v, --invert-match option (see below), count non-matching lines.")
("extended-regexp,E", "Interpret PATTERN as an POSIX-extended regular expression.")
("perl-regexp,P", "Interpret PATTERN as a Perl regular expression.")
//("regexp,e", po::value<std::string>(&pattern), "Use PATTERN as the pattern; useful to protect patterns beginning with -.")
("basic-regexp,G", "Interpret arg as a POSIX-basic regular expression (see below). This is the default.")
("ignore-case,i", "Ignore case distinctions in both the PATTERN and the input files.")
("files-without-match,L", "Suppress normal output; instead print the name of each input file from which no output would normally have been printed. The scanning will stop on the first match.")
("files-with-matches,l", "Suppress normal output; instead print the name of each input file from which output would normally have been printed. The scanning will stop on the first match.")
("line-number,n", "Prefix each line of output with the line number within its input file.")
;
// Hidden options, will be allowed both on command line and
// in config file, but will not be shown to the user.
po::options_description hidden("Hidden options");
hidden.add_options()
("input-file", po::value< std::vector<std::string> >(), "input file")
("input-pattern", po::value< std::string >(), "input file")
;
po::options_description cmdline_options;
cmdline_options.add(opts).add(hidden);
po::positional_options_description p;
p.add("input-pattern", 1);
p.add("input-file", -1);
po::variables_map vm;
po::store(po::command_line_parser(argc, argv).options(cmdline_options)/*.options(hidden)*/.positional(p).run(), vm);
po::notify(vm);
if (vm.count("help"))
{
std::cout << opts << "\n";
return 0;
}
if (vm.count("context"))
{
after_context = vm["context"].as< int >();
before_context = after_context;
}
if(vm.count("extended-regexp"))
{
flags = boost::regex_constants::extended;
}
if(vm.count("basic-regexp"))
{
flags = boost::regex_constants::basic;
}
if(vm.count("perl-regexp"))
{
flags = boost::regex_constants::perl;
}
if(vm.count("ignore-case"))
{
flags |= boost::regex_constants::icase;
}
if(vm.count("byte-offset"))
{
print_byte_offset = true;
}
if(vm.count("count"))
{
count_only = true;
}
if(vm.count("files-without-match"))
{
print_non_matching_files = true;
}
if(vm.count("files-with-matches"))
{
files_only = true;
}
if(vm.count("line-number"))
{
print_line_numbers = true;
}
if(vm.count("input-pattern"))
{
pattern = vm["input-pattern"].as< std::string >();
re.assign(pattern, flags);
}
else
{
std::cerr << "No pattern specified" << std::endl;
return 1;
}
if (vm.count("input-file"))
{
const std::vector<std::string>& files = vm["input-file"].as< std::vector<std::string> >();
file_count = files.size();
for(std::vector<std::string>::const_iterator i = files.begin(); i != files.end(); ++i)
{
process_file(*i);
}
}
else
{
// no input files, scan stdin instead:
process_stream(std::cin);
}
}
catch(const std::exception& e)
{
std::cerr << e.what() << std::endl;
}
return 0;
}