ceph/src/boost/libs/intrusive/include/boost/intrusive/detail/pointer_element.hpp

   1 //////////////////////////////////////////////////////////////////////////////
   2 //
   3 // (C) Copyright Ion Gaztanaga 2014-2014. Distributed under the Boost
   4 // Software License, Version 1.0. (See accompanying file
   5 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // See http://www.boost.org/libs/intrusive for documentation.
   8 //
   9 //////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef BOOST_INTRUSIVE_DETAIL_POINTER_ELEMENT_HPP
  12 #define BOOST_INTRUSIVE_DETAIL_POINTER_ELEMENT_HPP
  13
  14 #ifndef BOOST_CONFIG_HPP
  15 #  include <boost/config.hpp>
  16 #endif
  17
  18 #if defined(BOOST_HAS_PRAGMA_ONCE)
  19 #  pragma once
  20 #endif
  21
  22 #ifndef BOOST_INTRUSIVE_DETAIL_WORKAROUND_HPP
  23 #include <boost/intrusive/detail/workaround.hpp>
  24 #endif   //BOOST_INTRUSIVE_DETAIL_WORKAROUND_HPP
  25
  26 namespace boost {
  27 namespace intrusive {
  28 namespace detail{
  29
  30 //////////////////////
  31 //struct first_param
  32 //////////////////////
  33
  34 template <typename T> struct first_param
  35 {  typedef void type;   };
  36
  37 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
  38
  39    template <template <typename, typename...> class TemplateClass, typename T, typename... Args>
  40    struct first_param< TemplateClass<T, Args...> >
  41    {
  42       typedef T type;
  43    };
  44
  45 #else //C++03 compilers
  46
  47    template < template  //0arg
  48                <class
  49                > class TemplateClass, class T
  50             >
  51    struct first_param
  52       < TemplateClass<T> >
  53    {  typedef T type;   };
  54
  55    template < template  //1arg
  56                <class,class
  57                > class TemplateClass, class T
  58             , class P0>
  59    struct first_param
  60       < TemplateClass<T, P0> >
  61    {  typedef T type;   };
  62
  63    template < template  //2arg
  64                <class,class,class
  65                > class TemplateClass, class T
  66             , class P0, class P1>
  67    struct first_param
  68       < TemplateClass<T, P0, P1> >
  69    {  typedef T type;   };
  70
  71    template < template  //3arg
  72                <class,class,class,class
  73                > class TemplateClass, class T
  74             , class P0, class P1, class P2>
  75    struct first_param
  76       < TemplateClass<T, P0, P1, P2> >
  77    {  typedef T type;   };
  78
  79    template < template  //4arg
  80                <class,class,class,class,class
  81                > class TemplateClass, class T
  82             , class P0, class P1, class P2, class P3>
  83    struct first_param
  84       < TemplateClass<T, P0, P1, P2, P3> >
  85    {  typedef T type;   };
  86
  87    template < template  //5arg
  88                <class,class,class,class,class,class
  89                > class TemplateClass, class T
  90             , class P0, class P1, class P2, class P3, class P4>
  91    struct first_param
  92       < TemplateClass<T, P0, P1, P2, P3, P4> >
  93    {  typedef T type;   };
  94
  95    template < template  //6arg
  96                <class,class,class,class,class,class,class
  97                > class TemplateClass, class T
  98             , class P0, class P1, class P2, class P3, class P4, class P5>
  99    struct first_param
 100       < TemplateClass<T, P0, P1, P2, P3, P4, P5> >
 101    {  typedef T type;   };
 102
 103    template < template  //7arg
 104                <class,class,class,class,class,class,class,class
 105                > class TemplateClass, class T
 106             , class P0, class P1, class P2, class P3, class P4, class P5, class P6>
 107    struct first_param
 108       < TemplateClass<T, P0, P1, P2, P3, P4, P5, P6> >
 109    {  typedef T type;   };
 110
 111    template < template  //8arg
 112                <class,class,class,class,class,class,class,class,class
 113                > class TemplateClass, class T
 114             , class P0, class P1, class P2, class P3, class P4, class P5, class P6, class P7>
 115    struct first_param
 116       < TemplateClass<T, P0, P1, P2, P3, P4, P5, P6, P7> >
 117    {  typedef T type;   };
 118
 119    template < template  //9arg
 120                <class,class,class,class,class,class,class,class,class,class
 121                > class TemplateClass, class T
 122             , class P0, class P1, class P2, class P3, class P4, class P5, class P6, class P7, class P8>
 123    struct first_param
 124       < TemplateClass<T, P0, P1, P2, P3, P4, P5, P6, P7, P8> >
 125    {  typedef T type;   };
 126
 127 #endif   //!defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
 128
 129 template <typename T>
 130 struct has_internal_pointer_element
 131 {
 132    template <typename X>
 133    static char test(int, typename X::element_type*);
 134
 135    template <typename X>
 136    static int test(...);
 137
 138    static const bool value = (1 == sizeof(test<T>(0, 0)));
 139 };
 140
 141 template<class Ptr, bool = has_internal_pointer_element<Ptr>::value>
 142 struct pointer_element_impl
 143 {
 144    typedef typename Ptr::element_type type;
 145 };
 146
 147 template<class Ptr>
 148 struct pointer_element_impl<Ptr, false>
 149 {
 150    typedef typename boost::intrusive::detail::first_param<Ptr>::type type;
 151 };
 152
 153 }  //namespace detail{
 154
 155 template <typename Ptr>
 156 struct pointer_element
 157 {
 158    typedef typename ::boost::intrusive::detail::pointer_element_impl<Ptr>::type type;
 159 };
 160
 161 template <typename T>
 162 struct pointer_element<T*>
 163 {  typedef T type; };
 164
 165 }  //namespace container {
 166 }  //namespace boost {
 167
 168 #endif // defined(BOOST_INTRUSIVE_DETAIL_POINTER_ELEMENT_HPP)