regex/v5/regex_iterator.hpp

/*
 *
 * Copyright (c) 2003
 * 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_iterator.hpp
  *   VERSION      see <boost/version.hpp>
  *   DESCRIPTION: Provides regex_iterator implementation.
  */

#ifndef BOOST_REGEX_V5_REGEX_ITERATOR_HPP
#define BOOST_REGEX_V5_REGEX_ITERATOR_HPP

#include <memory>

namespace boost{

template <class BidirectionalIterator,
          class charT,
          class traits>
class regex_iterator_implementation
{
   typedef basic_regex<charT, traits> regex_type;

   match_results<BidirectionalIterator> what;  // current match
   BidirectionalIterator                base;  // start of sequence
   BidirectionalIterator                end;   // end of sequence
   const regex_type                     re;   // the expression
   match_flag_type                      flags; // flags for matching

public:
   regex_iterator_implementation(const regex_type* p, BidirectionalIterator last, match_flag_type f)
      : base(), end(last), re(*p), flags(f){}
   regex_iterator_implementation(const regex_iterator_implementation& other)
      :what(other.what), base(other.base), end(other.end), re(other.re), flags(other.flags){}
   bool init(BidirectionalIterator first)
   {
      base = first;
      return regex_search(first, end, what, re, flags);
   }
   bool compare(const regex_iterator_implementation& that)
   {
      if(this == &that) return true;
      return (&re.get_data() == &that.re.get_data()) && (end == that.end) && (flags == that.flags) && (what[0].first == that.what[0].first) && (what[0].second == that.what[0].second);
   }
   const match_results<BidirectionalIterator>& get()
   { return what; }
   bool next()
   {
      //if(what.prefix().first != what[0].second)
      //   flags |= match_prev_avail;
      BidirectionalIterator next_start = what[0].second;
      match_flag_type f(flags);
      if(!what.length() || (f & regex_constants::match_posix))
         f |= regex_constants::match_not_initial_null;
      //if(base != next_start)
      //   f |= regex_constants::match_not_bob;
      bool result = regex_search(next_start, end, what, re, f, base);
      if(result)
         what.set_base(base);
      return result;
   }
private:
   regex_iterator_implementation& operator=(const regex_iterator_implementation&);
};

template <class BidirectionalIterator,
          class charT = typename std::iterator_traits<BidirectionalIterator>::value_type,
          class traits = regex_traits<charT> >
class regex_iterator
{
private:
   typedef regex_iterator_implementation<BidirectionalIterator, charT, traits> impl;
   typedef std::shared_ptr<impl> pimpl;
public:
   typedef          basic_regex<charT, traits>                   regex_type;
   typedef          match_results<BidirectionalIterator>                    value_type;
   typedef typename std::iterator_traits<BidirectionalIterator>::difference_type
                                                                            difference_type;
   typedef          const value_type*                                       pointer;
   typedef          const value_type&                                       reference;
   typedef          std::forward_iterator_tag                               iterator_category;

   regex_iterator(){}
   regex_iterator(BidirectionalIterator a, BidirectionalIterator b,
                  const regex_type& re,
                  match_flag_type m = match_default)
                  : pdata(new impl(&re, b, m))
   {
      if(!pdata->init(a))
      {
         pdata.reset();
      }
   }
   regex_iterator(const regex_iterator& that)
      : pdata(that.pdata) {}
   regex_iterator& operator=(const regex_iterator& that)
   {
      pdata = that.pdata;
      return *this;
   }
   bool operator==(const regex_iterator& that)const
   {
      if((pdata.get() == 0) || (that.pdata.get() == 0))
         return pdata.get() == that.pdata.get();
      return pdata->compare(*(that.pdata.get()));
   }
   bool operator!=(const regex_iterator& that)const
   { return !(*this == that); }
   const value_type& operator*()const
   { return pdata->get(); }
   const value_type* operator->()const
   { return &(pdata->get()); }
   regex_iterator& operator++()
   {
      cow();
      if(0 == pdata->next())
      {
         pdata.reset();
      }
      return *this;
   }
   regex_iterator operator++(int)
   {
      regex_iterator result(*this);
      ++(*this);
      return result;
   }
private:

   pimpl pdata;

   void cow()
   {
      // copy-on-write
      if(pdata.get() && (pdata.use_count() > 1))
      {
         pdata.reset(new impl(*(pdata.get())));
      }
   }
};

typedef regex_iterator<const char*> cregex_iterator;
typedef regex_iterator<std::string::const_iterator> sregex_iterator;
#ifndef BOOST_NO_WREGEX
typedef regex_iterator<const wchar_t*> wcregex_iterator;
typedef regex_iterator<std::wstring::const_iterator> wsregex_iterator;
#endif

// make_regex_iterator:
template <class charT, class traits>
inline regex_iterator<const charT*, charT, traits> make_regex_iterator(const charT* p, const basic_regex<charT, traits>& e, regex_constants::match_flag_type m = regex_constants::match_default)
{
   return regex_iterator<const charT*, charT, traits>(p, p+traits::length(p), e, m);
}
template <class charT, class traits, class ST, class SA>
inline regex_iterator<typename std::basic_string<charT, ST, SA>::const_iterator, charT, traits> make_regex_iterator(const std::basic_string<charT, ST, SA>& p, const basic_regex<charT, traits>& e, regex_constants::match_flag_type m = regex_constants::match_default)
{
   return regex_iterator<typename std::basic_string<charT, ST, SA>::const_iterator, charT, traits>(p.begin(), p.end(), e, m);
}

} // namespace boost

#endif // BOOST_REGEX_V5_REGEX_ITERATOR_HPP