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- /*
- *
- * 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 partial_regex_grep.cpp
- * VERSION see <boost/version.hpp>
- * DESCRIPTION: Search example using partial matches.
- */
- #include <boost/regex.hpp>
- #include <iostream>
- #include <fstream>
- #include <sstream>
- #include <string>
- #include <cstring>
- #ifdef BOOST_NO_STDC_NAMESPACE
- namespace std{ using ::memmove; }
- #endif
- // match some kind of html tag:
- boost::regex e("<[^>]*>");
- // count how many:
- unsigned int tags = 0;
- // saved position of partial match:
- const char* next_pos = 0;
- bool grep_callback(const boost::match_results<const char*>& m)
- {
- if(m[0].matched == false)
- {
- // save position and return:
- next_pos = m[0].first;
- }
- else
- ++tags;
- return true;
- }
- void search(std::istream& is)
- {
- char buf[4096];
- next_pos = buf + sizeof(buf);
- bool have_more = true;
- while(have_more)
- {
- // how much do we copy forward from last try:
- std::ptrdiff_t leftover = (buf + sizeof(buf)) - next_pos;
- // and how much is left to fill:
- std::ptrdiff_t size = next_pos - buf;
- // copy forward whatever we have left:
- std::memmove(buf, next_pos, leftover);
- // fill the rest from the stream:
- is.read(buf + leftover, size);
- std::streamsize read = is.gcount();
- // check to see if we've run out of text:
- have_more = read == size;
- // reset next_pos:
- next_pos = buf + sizeof(buf);
- // and then grep:
- boost::regex_grep<bool(*)(const boost::cmatch&), const char*>(grep_callback,
- static_cast<const char*>(buf),
- static_cast<const char*>(buf + read + leftover),
- e,
- boost::match_default | boost::match_partial);
- }
- }
- int main(int argc, char* argv[])
- {
- if(argc > 1)
- {
- for(int i = 1; i < argc; ++i)
- {
- std::ifstream fs(argv[i]);
- if(fs.bad()) continue;
- search(fs);
- fs.close();
- }
- }
- else
- {
- std::string one("<META NAME=\"keywords\" CONTENT=\"regex++, regular expressions, regular expression library, C++\">");
- std::string what;
- while(what.size() < 10000)
- {
- what.append(one);
- what.append(13, ' ');
- }
- std::stringstream ss;
- ss.str(what);
- search(ss);
- }
- std::cout << "total tag count was " << tags << std::endl;
- return 0;
- }
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