boost/boost/token_iterator.hpp

   1 // Boost token_iterator.hpp  -------------------------------------------------//
   2
   3 // Copyright John R. Bandela 2001
   4 // Permission to copy, use, modify, sell and distribute this software
   5 // is granted provided this copyright notice appears in all
   6 // copies. This software is provided "as is" without express or
   7 // implied warranty, and with no claim as to its suitability for any
   8 // purpose.
   9
  10 // See http://www.boost.org/libs/tokenizer for documentation.
  11
  12 // Revision History:
  13 // 16 Jul 2003   John Bandela
  14 //      Allowed conversions from convertible base iterators
  15 // 03 Jul 2003   John Bandela
  16 //      Converted to new iterator adapter
  17
  18
  19
  20 #ifndef BOOST_TOKENIZER_POLICY_JRB070303_HPP_
  21 #define BOOST_TOKENIZER_POLICY_JRB070303_HPP_
  22
  23 #include<boost/iterator/iterator_adaptor.hpp>
  24 #include<boost/iterator/detail/minimum_category.hpp>
  25 #include<boost/token_functions.hpp>
  26 #include<utility>
  27 #include<cassert>
  28
  29
  30 namespace boost
  31 {
  32   template <class TokenizerFunc, class Iterator, class Type>
  33   class token_iterator
  34       : public iterator_facade<
  35             token_iterator<TokenizerFunc, Iterator, Type>
  36           , Type
  37           , typename detail::minimum_category<
  38                 forward_traversal_tag
  39               , typename iterator_traversal<Iterator>::type
  40             >::type
  41           , const Type&
  42         >
  43   {
  44
  45       friend class iterator_core_access;
  46
  47       TokenizerFunc f_;
  48       Iterator begin_;
  49       Iterator end_;
  50       bool valid_;
  51       Type tok_;
  52
  53       void increment(){
  54           assert(valid_);
  55           valid_ = f_(begin_,end_,tok_);
  56       }
  57
  58       const Type&  dereference() const {
  59           assert(valid_);
  60           return tok_;
  61       }
  62       template<class Other>
  63       bool equal(const Other& a) const{
  64           return (a.valid_ && valid_)
  65               ?( (a.begin_==begin_) && (a.end_ == end_) )
  66               :(a.valid_==valid_);
  67
  68       }
  69
  70       void initialize(){
  71           if(valid_) return;
  72           f_.reset();
  73           valid_ = (begin_ != end_)?
  74               f_(begin_,end_,tok_):false;
  75       }
  76   public:
  77       token_iterator():begin_(),end_(),valid_(false),tok_() { }
  78
  79       token_iterator(TokenizerFunc f, Iterator begin, Iterator e = Iterator())
  80           : f_(f),begin_(begin),end_(e),valid_(false),tok_(){ initialize(); }
  81
  82       token_iterator(Iterator begin, Iterator e = Iterator())
  83             : f_(),begin_(begin),end_(e),valid_(false),tok_() {initialize();}
  84
  85       template<class OtherIter>
  86       token_iterator(
  87             token_iterator<TokenizerFunc, OtherIter,Type> const& t
  88             , typename enable_if_convertible<OtherIter, Iterator>::type* = 0)
  89             : f_(t.tokenizer_function()),begin_(t.base())
  90             ,end_(t.end()),valid_(t.at_end()),tok_(t.current_token()) {}
  91
  92       Iterator base()const{return begin_;}
  93
  94       Iterator end()const{return end_;};
  95
  96       TokenizerFunc tokenizer_function()const{return f_;}
  97
  98       Type current_token()const{return tok_;}
  99
 100       bool at_end()const{return valid_;}
 101
 102
 103
 104
 105   };
 106     template <
 107         class TokenizerFunc = char_delimiters_separator<char>,
 108         class Iterator = std::string::const_iterator,
 109         class Type = std::string
 110     >
 111     class token_iterator_generator {
 112
 113     private:
 114     public:
 115         typedef token_iterator<TokenizerFunc,Iterator,Type> type;
 116     };
 117
 118
 119     // Type has to be first because it needs to be explicitly specified
 120     // because there is no way the function can deduce it.
 121     template<class Type, class Iterator, class TokenizerFunc>
 122         typename token_iterator_generator<TokenizerFunc,Iterator,Type>::type
 123     make_token_iterator(Iterator begin, Iterator end,const TokenizerFunc& fun){
 124         typedef typename
 125             token_iterator_generator<TokenizerFunc,Iterator,Type>::type ret_type;
 126         return ret_type(fun,begin,end);
 127     }
 128
 129 } // namespace boost
 130
 131 #endif