ceph/src/boost/libs/regex/example/snippets/regex_token_iterator_eg_2.cpp

   1 /*
   2  *
   3  * Copyright (c) 2003
   4  * John Maddock
   5  *
   6  * Use, modification and distribution are subject to the
   7  * Boost Software License, Version 1.0. (See accompanying file
   8  * LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9  *
  10  */
  11
  12  /*
  13   *   LOCATION:    see http://www.boost.org for most recent version.
  14   *   FILE         regex_token_iterator_example_2.cpp
  15   *   VERSION      see <boost/version.hpp>
  16   *   DESCRIPTION: regex_token_iterator example: spit out linked URL's.
  17   */
  18
  19
  20 #include <fstream>
  21 #include <iostream>
  22 #include <iterator>
  23 #include <boost/regex.hpp>
  24
  25 boost::regex e("<\\s*A\\s+[^>]*href\\s*=\\s*\"([^\"]*)\"",
  26                boost::regex::normal | boost::regbase::icase);
  27
  28 void load_file(std::string& s, std::istream& is)
  29 {
  30    s.erase();
  31    if(is.bad()) return;
  32    //
  33    // attempt to grow string buffer to match file size,
  34    // this doesn't always work...
  35    s.reserve(static_cast<std::string::size_type>(is.rdbuf()->in_avail()));
  36    char c;
  37    while(is.get(c))
  38    {
  39       // use logarithmic growth stategy, in case
  40       // in_avail (above) returned zero:
  41       if(s.capacity() == s.size())
  42          s.reserve(s.capacity() * 3);
  43       s.append(1, c);
  44    }
  45 }
  46
  47 int main(int argc, char** argv)
  48 {
  49    std::string s;
  50    int i;
  51    for(i = 1; i < argc; ++i)
  52    {
  53       std::cout << "Findings URL's in " << argv[i] << ":" << std::endl;
  54       s.erase();
  55       std::ifstream is(argv[i]);
  56       load_file(s, is);
  57       is.close();
  58       boost::sregex_token_iterator i(s.begin(), s.end(), e, 1);
  59       boost::sregex_token_iterator j;
  60       while(i != j)
  61       {
  62          std::cout << *i++ << std::endl;
  63       }
  64    }
  65    //
  66    // alternative method:
  67    // test the array-literal constructor, and split out the whole
  68    // match as well as $1....
  69    //
  70    for(i = 1; i < argc; ++i)
  71    {
  72       std::cout << "Findings URL's in " << argv[i] << ":" << std::endl;
  73       s.erase();
  74       std::ifstream is(argv[i]);
  75       load_file(s, is);
  76       is.close();
  77       const int subs[] = {1, 0,};
  78       boost::sregex_token_iterator i(s.begin(), s.end(), e, subs);
  79       boost::sregex_token_iterator j;
  80       while(i != j)
  81       {
  82          std::cout << *i++ << std::endl;
  83       }
  84    }
  85
  86    return 0;
  87 }
  88
  89