ceph/src/boost/boost/icl/type_traits/element_type_of.hpp

   1 /*-----------------------------------------------------------------------------+
   2 Copyright (c) 2008-2009: Joachim Faulhaber
   3 +------------------------------------------------------------------------------+
   4    Distributed under the Boost Software License, Version 1.0.
   5       (See accompanying file LICENCE.txt or copy at
   6            http://www.boost.org/LICENSE_1_0.txt)
   7 +-----------------------------------------------------------------------------*/
   8 #ifndef BOOST_ICL_TYPE_TRAITS_ELEMENT_TYPE_OF_HPP_JOFA_100902
   9 #define BOOST_ICL_TYPE_TRAITS_ELEMENT_TYPE_OF_HPP_JOFA_100902
  10
  11 #include <boost/mpl/has_xxx.hpp>
  12 #include <boost/mpl/bool.hpp>
  13 #include <boost/icl/type_traits/no_type.hpp>
  14
  15 namespace boost{ namespace icl
  16 {
  17     namespace detail
  18     {
  19         BOOST_MPL_HAS_XXX_TRAIT_DEF(element_type)
  20         BOOST_MPL_HAS_XXX_TRAIT_DEF(value_type)
  21         BOOST_MPL_HAS_XXX_TRAIT_DEF(key_type)
  22     }
  23
  24     //--------------------------------------------------------------------------
  25     template <class Type>
  26     struct has_element_type
  27       : mpl::bool_<detail::has_element_type<Type>::value>
  28     {};
  29
  30     template <class Type, bool has_element_type>
  31     struct get_element_type;
  32
  33     template <class Type>
  34     struct get_element_type<Type, false>
  35     {
  36         typedef no_type type;
  37     };
  38
  39     template <class Type>
  40     struct get_element_type<Type, true>
  41     {
  42         typedef typename Type::element_type type;
  43     };
  44
  45     template <class Type>
  46     struct element_type_of
  47     {
  48         typedef typename
  49             get_element_type<Type, has_element_type<Type>::value>::type type;
  50     };
  51
  52     //--------------------------------------------------------------------------
  53     template <class Type>
  54     struct has_value_type
  55       : mpl::bool_<detail::has_value_type<Type>::value>
  56     {};
  57
  58     template <class Type, bool has_value_type>
  59     struct get_value_type;
  60
  61     template <class Type>
  62     struct get_value_type<Type, false>
  63     {
  64         typedef no_type type;
  65     };
  66
  67     template <class Type>
  68     struct get_value_type<Type, true>
  69     {
  70         typedef typename Type::value_type type;
  71     };
  72
  73     template <class Type>
  74     struct value_type_of
  75     {
  76         typedef typename
  77             get_value_type<Type, has_value_type<Type>::value>::type type;
  78     };
  79
  80     //--------------------------------------------------------------------------
  81     template <class Type>
  82     struct has_key_type
  83       : mpl::bool_<detail::has_key_type<Type>::value>
  84     {};
  85
  86     template <class Type, bool has_key_type>
  87     struct get_key_type;
  88
  89     template <class Type>
  90     struct get_key_type<Type, false>
  91     {
  92         typedef no_type type;
  93     };
  94
  95     template <class Type>
  96     struct get_key_type<Type, true>
  97     {
  98         typedef typename Type::key_type type;
  99     };
 100
 101     template <class Type>
 102     struct key_type_of
 103     {
 104         typedef typename
 105             get_key_type<Type, has_key_type<Type>::value>::type type;
 106     };
 107
 108 }} // namespace boost icl
 109
 110 #endif
 111
 112