[857] | 1 |
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| 2 | // (C) Copyright Dave Abrahams, Steve Cleary, Beman Dawes,
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| 3 | // Howard Hinnant and John Maddock 2000.
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| 4 | // (C) Copyright Mat Marcus, Jesse Jones and Adobe Systems Inc 2001
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| 5 |
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| 6 | // Use, modification and distribution are subject to the Boost Software License,
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| 7 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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| 8 | // http://www.boost.org/LICENSE_1_0.txt).
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| 9 | //
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| 10 | // See http://www.boost.org/libs/type_traits for most recent version including documentation.
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| 11 |
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| 12 | // Fixed is_pointer, is_reference, is_const, is_volatile, is_same,
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| 13 | // is_member_pointer based on the Simulated Partial Specialization work
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| 14 | // of Mat Marcus and Jesse Jones. See http://opensource.adobe.com or
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| 15 | // http://groups.yahoo.com/group/boost/message/5441
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| 16 | // Some workarounds in here use ideas suggested from "Generic<Programming>:
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| 17 | // Mappings between Types and Values"
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| 18 | // by Andrei Alexandrescu (see http://www.cuj.com/experts/1810/alexandr.html).
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| 19 |
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| 20 |
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| 21 | #ifndef BOOST_TT_IS_CONST_HPP_INCLUDED
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| 22 | #define BOOST_TT_IS_CONST_HPP_INCLUDED
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| 23 |
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| 24 | #include "boost/config.hpp"
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| 25 |
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| 26 | #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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| 27 | # include "boost/type_traits/detail/cv_traits_impl.hpp"
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| 28 | # ifdef __GNUC__
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| 29 | # include <boost/type_traits/is_reference.hpp>
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| 30 | # endif
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| 31 | #else
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| 32 | # include "boost/type_traits/is_reference.hpp"
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| 33 | # include "boost/type_traits/is_array.hpp"
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| 34 | # include "boost/type_traits/detail/yes_no_type.hpp"
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| 35 | # include "boost/type_traits/detail/false_result.hpp"
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| 36 | #endif
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| 37 |
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| 38 | // should be the last #include
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| 39 | #include "boost/type_traits/detail/bool_trait_def.hpp"
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| 40 |
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| 41 | namespace boost {
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| 42 |
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| 43 | #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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| 44 |
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| 45 | //* is a type T declared const - is_const<T>
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| 46 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,::boost::detail::cv_traits_imp<T*>::is_const)
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| 47 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T&,false)
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| 48 |
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| 49 | #if defined(__BORLANDC__) && (__BORLANDC__ < 0x600)
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| 50 | // these are illegal specialisations; cv-qualifies applied to
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| 51 | // references have no effect according to [8.3.2p1],
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| 52 | // C++ Builder requires them though as it treats cv-qualified
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| 53 | // references as distinct types...
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| 54 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& const,false)
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| 55 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& volatile,false)
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| 56 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T& const volatile,false)
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| 57 | #endif
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| 58 |
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| 59 | #if defined(__GNUC__) && (__GNUC__ < 3)
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| 60 | // special case for gcc where illegally cv-qualified reference types can be
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| 61 | // generated in some corner cases:
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| 62 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T const,!(::boost::is_reference<T>::value))
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| 63 | BOOST_TT_AUX_BOOL_TRAIT_PARTIAL_SPEC1_1(typename T,is_const,T volatile const,!(::boost::is_reference<T>::value))
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| 64 | #endif
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| 65 |
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| 66 | #else
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| 67 |
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| 68 | namespace detail {
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| 69 |
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| 70 | using ::boost::type_traits::yes_type;
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| 71 | using ::boost::type_traits::no_type;
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| 72 |
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| 73 | yes_type is_const_tester(const volatile void*);
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| 74 | no_type is_const_tester(volatile void *);
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| 75 |
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| 76 | template <bool is_ref, bool array>
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| 77 | struct is_const_helper
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| 78 | : ::boost::type_traits::false_result
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| 79 | {
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| 80 | };
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| 81 |
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| 82 | template <>
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| 83 | struct is_const_helper<false,false>
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| 84 | {
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| 85 | template <typename T> struct result_
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| 86 | {
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| 87 | static T* t;
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| 88 | BOOST_STATIC_CONSTANT(bool, value = (
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| 89 | sizeof(detail::yes_type) == sizeof(detail::is_const_tester(t))
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| 90 | ));
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| 91 | };
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| 92 | };
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| 93 |
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| 94 | template <>
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| 95 | struct is_const_helper<false,true>
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| 96 | {
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| 97 | template <typename T> struct result_
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| 98 | {
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| 99 | static T t;
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| 100 | BOOST_STATIC_CONSTANT(bool, value = (
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| 101 | sizeof(detail::yes_type) == sizeof(detail::is_const_tester(&t))
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| 102 | ));
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| 103 | };
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| 104 | };
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| 105 |
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| 106 | template <typename T>
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| 107 | struct is_const_impl
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| 108 | : is_const_helper<
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| 109 | is_reference<T>::value
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| 110 | , is_array<T>::value
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| 111 | >::template result_<T>
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| 112 | {
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| 113 | };
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| 114 |
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| 115 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void,false)
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| 116 | #ifndef BOOST_NO_CV_VOID_SPECIALIZATIONS
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| 117 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void const,true)
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| 118 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void volatile,false)
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| 119 | BOOST_TT_AUX_BOOL_TRAIT_IMPL_SPEC1(is_const,void const volatile,true)
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| 120 | #endif
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| 121 |
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| 122 | } // namespace detail
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| 123 |
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| 124 | //* is a type T declared const - is_const<T>
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| 125 | BOOST_TT_AUX_BOOL_TRAIT_DEF1(is_const,T,::boost::detail::is_const_impl<T>::value)
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| 126 |
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| 127 | #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
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| 128 |
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| 129 | } // namespace boost
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| 130 |
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| 131 | #include "boost/type_traits/detail/bool_trait_undef.hpp"
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| 132 |
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| 133 | #endif // BOOST_TT_IS_CONST_HPP_INCLUDED
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| 134 |
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