ceph/src/boost/libs/xpressive/include/boost/xpressive/detail/utility/traits_utils.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // traits_utils.hpp
   3 //
   4 //  Copyright 2008 Eric Niebler. Distributed under the Boost
   5 //  Software License, Version 1.0. (See accompanying file
   6 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef BOOST_XPRESSIVE_DETAIL_UTILITY_TRAITS_UTILS_HPP_EAN_10_04_2005
   9 #define BOOST_XPRESSIVE_DETAIL_UTILITY_TRAITS_UTILS_HPP_EAN_10_04_2005
  10
  11 // MS compatible compilers support #pragma once
  12 #if defined(_MSC_VER)
  13 # pragma once
  14 # pragma warning(push)
  15 # pragma warning(disable : 4100) // unreferenced formal parameter
  16 #endif
  17
  18 #include <string>
  19 #include <boost/mpl/bool.hpp>
  20 #include <boost/mpl/assert.hpp>
  21 #include <boost/utility/enable_if.hpp>
  22 #include <boost/type_traits/is_same.hpp>
  23 #include <boost/iterator/transform_iterator.hpp>
  24 #include <boost/xpressive/detail/utility/algorithm.hpp>
  25
  26 namespace boost { namespace xpressive { namespace detail
  27 {
  28
  29     ///////////////////////////////////////////////////////////////////////////////
  30     // char_cast
  31     //
  32     template<typename ToChar, typename FromChar, typename Traits>
  33     inline ToChar
  34     char_cast(FromChar from, Traits const &, typename enable_if<is_same<ToChar, FromChar> >::type * = 0)
  35     {
  36         return from;
  37     }
  38
  39     template<typename ToChar, typename FromChar, typename Traits>
  40     inline ToChar
  41     char_cast(FromChar from, Traits const &tr, typename disable_if<is_same<ToChar, FromChar> >::type * = 0)
  42     {
  43         BOOST_MPL_ASSERT((is_same<FromChar, char>));
  44         return tr.widen(from);
  45     }
  46
  47     ///////////////////////////////////////////////////////////////////////////////
  48     // widen_fun
  49     //
  50     template<typename Traits>
  51     struct widen_fun
  52     {
  53         typedef typename Traits::char_type result_type;
  54         explicit widen_fun(Traits const &tr)
  55           : traits_(tr)
  56         {}
  57
  58         result_type operator()(char ch) const
  59         {
  60             return this->traits_.widen(ch);
  61         }
  62
  63         Traits const &traits_;
  64     };
  65
  66     ///////////////////////////////////////////////////////////////////////////////
  67     // string_cast_
  68     //
  69     template<
  70         typename To
  71       , typename From
  72       , typename ToChar = typename detail::range_data<To>::type
  73       , typename FromChar = typename detail::range_data<From>::type
  74     >
  75     struct string_cast_
  76     {
  77         BOOST_MPL_ASSERT((is_same<FromChar, char>));
  78         typedef To const result_type;
  79         template<typename Traits>
  80         result_type operator()(From const &from, Traits const &tr) const
  81         {
  82             widen_fun<Traits> widen(tr);
  83             To to(
  84                 boost::make_transform_iterator(detail::data_begin(from), widen)
  85               , boost::make_transform_iterator(detail::data_end(from), widen)
  86             );
  87             return to;
  88         }
  89     };
  90
  91     template<typename To, typename From, typename Char>
  92     struct string_cast_<To, From, Char, Char>
  93     {
  94         typedef To const result_type;
  95         template<typename Traits>
  96         result_type operator()(From const &from, Traits const &) const
  97         {
  98             To to(detail::data_begin(from), detail::data_end(from));
  99             return to;
 100         }
 101     };
 102
 103     template<typename From, typename Char>
 104     struct string_cast_<From, From, Char, Char>
 105     {
 106         typedef From const &result_type;
 107         template<typename Traits>
 108         result_type operator()(From const &from, Traits const &) const
 109         {
 110             return from;
 111         }
 112     };
 113
 114     ///////////////////////////////////////////////////////////////////////////////
 115     // string_cast
 116     //
 117     template<typename To, typename From, typename Traits>
 118     typename string_cast_<To, From>::result_type
 119     string_cast(From const &from, Traits const &tr)
 120     {
 121         return string_cast_<To, From>()(from, tr);
 122     }
 123
 124     ///////////////////////////////////////////////////////////////////////////////
 125     // translate
 126     //
 127     template<typename Char, typename Traits>
 128     inline Char translate(Char ch, Traits const &tr, mpl::false_) // case-sensitive
 129     {
 130         return tr.translate(ch);
 131     }
 132
 133     template<typename Char, typename Traits>
 134     inline Char translate(Char ch, Traits const &tr, mpl::true_) // case-insensitive
 135     {
 136         return tr.translate_nocase(ch);
 137     }
 138
 139 }}} // namespace boost::xpressive::detail
 140
 141 #if defined(_MSC_VER)
 142 # pragma warning(pop)
 143 #endif
 144
 145 #endif