regex_test.cpp -- learning boost.regex

boost.regex 库的用法，看来这可能是 boost 当中写法最“常规”的库之一了。

regex_test.cpp:

#include
#include
#include
#include
#include

using namespace std;

// 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 map > 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:
   "("
      "//"
      "("
         "[[:blank:]]*//([^)]*//)"
      ")?"
      "[[:space:]]*"
   ")*"
   // the class name
   "(//)[[:space:]]*"
   // template specialisation parameters
   "(<[^;:{]+>)?[[:space:]]*"
   // terminate in { or :
   "(//{|:[^;//{()]*//{)";
 
boost::regex expression(re);
map_type class_index;

bool regex_callback(const boost::match_results& what)
{
  // 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:
  class_index[what[5].str() + what[6].str()] = what.position(5);
  return true;
}

void load_file(string& s, istream& is)
{
  s.erase();
  s.reserve(is.rdbuf()->in_avail());
  cout << s.capacity();
  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)
{
  string text;
  for(int i = 1; i < argc; ++i)
  {
    cout << "Processing file " << argv[i] << endl;
    ifstream fs(argv[i]);
    load_file(text, fs);
    // construct our iterators:
    boost::sregex_iterator m1(text.begin(), text.end(), expression);
    boost::sregex_iterator m2;
    for_each(m1, m2, ®ex_callback);
    // copy results:
    cout << class_index.size() << " matches found" << endl;
    map_type::iterator c, d;
    c = class_index.begin();
    d = class_index.end();
    while(c != d)
    {
      cout << "class /"" << (*c).first << "/" found at index: " << (*c).second << endl;
      ++c;
    }
    class_index.erase(class_index.begin(), class_index.end());
  }
 
  return 0;
}

//========== For Test =============
class Person
{};

template
class Temp
{
};

template <>
class Temp
{
};

=================================================================================
cl /EHsc regex_test.cpp

regex_test regex_test.cpp

OUTPUT:

Processing file regex_test.cpp
153 matches found
class "Person" found at index: 2331
class "Temp" found at index: 2368
class "Temp" found at index: 2397