110 lines
2.6 KiB
C++
110 lines
2.6 KiB
C++
/*
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*
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* Copyright (c) 1998-2002
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* John Maddock
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*
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* Use, modification and distribution are subject to the
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* Boost Software License, Version 1.0. (See accompanying file
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* LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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*
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*/
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/*
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* LOCATION: see http://www.boost.org for most recent version.
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* FILE partial_regex_grep.cpp
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* VERSION see <boost/version.hpp>
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* DESCRIPTION: Search example using partial matches.
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*/
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#include <boost/regex.hpp>
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#include <iostream>
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#include <fstream>
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#include <sstream>
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#include <string>
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#include <cstring>
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#ifdef BOOST_NO_STDC_NAMESPACE
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namespace std{ using ::memmove; }
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#endif
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// match some kind of html tag:
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boost::regex e("<[^>]*>");
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// count how many:
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unsigned int tags = 0;
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// saved position of partial match:
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const char* next_pos = 0;
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bool grep_callback(const boost::match_results<const char*>& m)
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{
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if(m[0].matched == false)
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{
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// save position and return:
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next_pos = m[0].first;
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}
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else
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++tags;
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return true;
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}
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void search(std::istream& is)
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{
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char buf[4096];
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next_pos = buf + sizeof(buf);
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bool have_more = true;
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while(have_more)
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{
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// how much do we copy forward from last try:
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std::ptrdiff_t leftover = (buf + sizeof(buf)) - next_pos;
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// and how much is left to fill:
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std::ptrdiff_t size = next_pos - buf;
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// copy forward whatever we have left:
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std::memmove(buf, next_pos, leftover);
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// fill the rest from the stream:
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is.read(buf + leftover, size);
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std::streamsize read = is.gcount();
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// check to see if we've run out of text:
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have_more = read == size;
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// reset next_pos:
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next_pos = buf + sizeof(buf);
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// and then grep:
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boost::regex_grep<bool(*)(const boost::cmatch&), const char*>(grep_callback,
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static_cast<const char*>(buf),
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static_cast<const char*>(buf + read + leftover),
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e,
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boost::match_default | boost::match_partial);
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}
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}
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int main(int argc, char* argv[])
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{
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if(argc > 1)
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{
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for(int i = 1; i < argc; ++i)
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{
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std::ifstream fs(argv[i]);
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if(fs.bad()) continue;
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search(fs);
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fs.close();
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}
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}
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else
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{
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std::string one("<META NAME=\"keywords\" CONTENT=\"regex++, regular expressions, regular expression library, C++\">");
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std::string what;
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while(what.size() < 10000)
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{
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what.append(one);
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what.append(13, ' ');
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}
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std::stringstream ss;
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ss.str(what);
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search(ss);
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}
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std::cout << "total tag count was " << tags << std::endl;
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return 0;
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}
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