1 /*

     2  *

     3  * Copyright (c) 2002

     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_match.hpp

    15   *   VERSION      see <boost/version.hpp>

    16   *   DESCRIPTION: Iterator traits for selecting an iterator type as

    17   *                an integral constant expression.

    18   */

    19 

    20 

    21 #ifndef BOOST_REGEX_ITERATOR_CATEGORY_HPP

    22 #define BOOST_REGEX_ITERATOR_CATEGORY_HPP

    23 

    24 #include <iterator>

    25 #include <boost/type_traits/is_convertible.hpp>

    26 #include <boost/type_traits/is_pointer.hpp>

    27 

    28 namespace boost{

    29 namespace detail{

    30 

    31 template <class I>

    32 struct is_random_imp

    33 {

    34 private:

    35    typedef typename std::iterator_traits<I>::iterator_category cat;

    36 public:

    37    BOOST_STATIC_CONSTANT(bool, value = (::boost::is_convertible<cat*, std::random_access_iterator_tag*>::value));

    38 };

    39 

    40 template <class I>

    41 struct is_random_pointer_imp

    42 {

    43    BOOST_STATIC_CONSTANT(bool, value = true);

    44 };

    45 

    46 template <bool is_pointer_type>

    47 struct is_random_imp_selector

    48 {

    49    template <class I>

    50    struct rebind

    51    {

    52       typedef is_random_imp<I> type;

    53    };

    54 };

    55 

    56 template <>

    57 struct is_random_imp_selector<true>

    58 {

    59    template <class I>

    60    struct rebind

    61    {

    62       typedef is_random_pointer_imp<I> type;

    63    };

    64 };

    65 

    66 }

    67 

    68 template <class I>

    69 struct is_random_access_iterator

    70 {

    71 private:

    72    typedef detail::is_random_imp_selector< ::boost::is_pointer<I>::value> selector;

    73    typedef typename selector::template rebind<I> bound_type;

    74    typedef typename bound_type::type answer;

    75 public:

    76    BOOST_STATIC_CONSTANT(bool, value = answer::value);

    77 };

    78 

    79 #ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION

    80 template <class I>

    81 const bool is_random_access_iterator<I>::value;

    82 #endif

    83 

    84 }

    85 

    86 #endif

    87