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// Boost token_iterator.hpp  -------------------------------------------------//

// Copyright John R. Bandela 2001
// Distributed under the Boost Software License, Version 1.0. (See
// accompanying file LICENSE_1_0.txt or copy at

// See for documentation.

// Revision History:
// 16 Jul 2003   John Bandela
//      Allowed conversions from convertible base iterators
// 03 Jul 2003   John Bandela
//      Converted to new iterator adapter



namespace boost
  template <class TokenizerFunc, class Iterator, class Type>
  class token_iterator
      : public iterator_facade<
            token_iterator<TokenizerFunc, Iterator, Type>
          , Type
          , typename detail::minimum_category<
              , typename iterator_traversal<Iterator>::type
          , const Type&

      friend class iterator_core_access;

      TokenizerFunc f_;
      Iterator begin_;
      Iterator end_;
      bool valid_;
      Type tok_;

      void increment(){
          valid_ = f_(begin_,end_,tok_);

      const Type&  dereference() const {
          return tok_;
      template<class Other>
      bool equal(const Other& a) const{
          return (a.valid_ && valid_)
              ?( (a.begin_==begin_) && (a.end_ == end_) )


      void initialize(){
          if(valid_) return;
          valid_ = (begin_ != end_)?
      token_iterator():begin_(),end_(),valid_(false),tok_() { }

      token_iterator(TokenizerFunc f, Iterator begin, Iterator e = Iterator())
          : f_(f),begin_(begin),end_(e),valid_(false),tok_(){ initialize(); }

      token_iterator(Iterator begin, Iterator e = Iterator())
            : f_(),begin_(begin),end_(e),valid_(false),tok_() {initialize();}

      template<class OtherIter>
            token_iterator<TokenizerFunc, OtherIter,Type> const& t
            , typename enable_if_convertible<OtherIter, Iterator>::type* = 0)
            : f_(t.tokenizer_function()),begin_(t.base())
            ,end_(t.end()),valid_(!t.at_end()),tok_(t.current_token()) {}

      Iterator base()const{return begin_;}

      Iterator end()const{return end_;};

      TokenizerFunc tokenizer_function()const{return f_;}

      Type current_token()const{return tok_;}

      bool at_end()const{return !valid_;}

    template <
        class TokenizerFunc = char_delimiters_separator<char>, 
        class Iterator = std::string::const_iterator,
        class Type = std::string
    class token_iterator_generator {

        typedef token_iterator<TokenizerFunc,Iterator,Type> type;
    // Type has to be first because it needs to be explicitly specified
    // because there is no way the function can deduce it.
    template<class Type, class Iterator, class TokenizerFunc>
        typename token_iterator_generator<TokenizerFunc,Iterator,Type>::type 
    make_token_iterator(Iterator begin, Iterator end,const TokenizerFunc& fun){
        typedef typename 
            token_iterator_generator<TokenizerFunc,Iterator,Type>::type ret_type;
        return ret_type(fun,begin,end);

} // namespace boost