/Src/Dependencies/Boost/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) && (_MSC_VER >= 1020)
 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
 26namespace 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) && (_MSC_VER >= 1020)
142# pragma warning(pop)
143#endif
144
145#endif