libs/regex/example/snippets/regex_search_example.cpp
/*
*
* Copyright (c) 1998-2002
* 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)
*
*/
/*
* LOCATION: see http://www.boost.org for most recent version.
* FILE regex_search_example.cpp
* VERSION see <boost/version.hpp>
* DESCRIPTION: regex_search example: searches a cpp file for class definitions.
*/
#include <boost/regex.hpp>
#include <string>
#include <map>
// purpose:
// takes the contents of a file in the form of a string
// and searches for all the C++ class definitions, storing
// their locations in a map of strings/int's
typedef std::map<std::string, std::string::difference_type, std::less<std::string> > map_type;
const char* re =
// possibly leading whitespace:
"^[[:space:]]*"
// possible template declaration:
"(template[[:space:]]*<[^;:{]+>[[:space:]]*)?"
// class or struct:
"(class|struct)[[:space:]]*"
// leading declspec macros etc:
"("
"\\<\\w+\\>"
"("
"[[:blank:]]*\\([^)]*\\)"
")?"
"[[:space:]]*"
")*"
// the class name
"(\\<\\w*\\>)[[:space:]]*"
// template specialisation parameters
"(<[^;:{]+>)?[[:space:]]*"
// terminate in { or :
"(\\{|:[^;\\{()]*\\{)";
boost::regex expression(re);
void IndexClasses(map_type& m, const std::string& file)
{
std::string::const_iterator start, end;
start = file.begin();
end = file.end();
boost::match_results<std::string::const_iterator> what;
boost::match_flag_type flags = boost::match_default;
while(boost::regex_search(start, end, what, expression, flags))
{
// what[0] contains the whole string
// what[5] contains the class name.
// what[6] contains the template specialisation if any.
// add class name and position to map:
m[std::string(what[5].first, what[5].second) + std::string(what[6].first, what[6].second)] =
what[5].first - file.begin();
// update search position:
start = what[0].second;
// update flags:
flags |= boost::match_prev_avail;
flags |= boost::match_not_bob;
}
}
#include <iostream>
#include <fstream>
using namespace std;
void load_file(std::string& s, std::istream& is)
{
s.erase();
if(is.bad()) return;
s.reserve(static_cast<std::string::size_type>(is.rdbuf()->in_avail()));
char c;
while(is.get(c))
{
if(s.capacity() == s.size())
s.reserve(s.capacity() * 3);
s.append(1, c);
}
}
int main(int argc, const char** argv)
{
std::string text;
for(int i = 1; i < argc; ++i)
{
cout << "Processing file " << argv[i] << endl;
map_type m;
std::ifstream fs(argv[i]);
load_file(text, fs);
fs.close();
IndexClasses(m, text);
cout << m.size() << " matches found" << endl;
map_type::iterator c, d;
c = m.begin();
d = m.end();
while(c != d)
{
cout << "class \"" << (*c).first << "\" found at index: " << (*c).second << endl;
++c;
}
}
return 0;
}