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126 lines
3.0 KiB
C++
126 lines
3.0 KiB
C++
// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
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// Permission to copy, use, modify, sell and
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// distribute this software is granted provided this copyright notice appears
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// in all copies. This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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// See http://www.boost.org for most recent version including documentation.
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//
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// Crippled version for crippled compilers:
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// see libs/utility/call_traits.htm
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//
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/* Release notes:
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01st October 2000:
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Fixed call_traits on VC6, using "poor man's partial specialisation",
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using ideas taken from "Generative programming" by Krzysztof Czarnecki
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& Ulrich Eisenecker.
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*/
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#ifndef BOOST_OB_CALL_TRAITS_HPP
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#define BOOST_OB_CALL_TRAITS_HPP
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#ifndef BOOST_CONFIG_HPP
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#include <boost/config.hpp>
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#endif
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#ifndef BOOST_TYPE_TRAITS_HPP
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#include <boost/type_traits.hpp>
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#endif
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namespace boost{
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#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
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//
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// use member templates to emulate
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// partial specialisation:
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//
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namespace detail{
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template <class T>
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struct standard_call_traits
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{
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typedef T value_type;
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typedef T& reference;
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typedef const T& const_reference;
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typedef const T& param_type;
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};
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template <class T>
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struct simple_call_traits
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{
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typedef T value_type;
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typedef T& reference;
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typedef const T& const_reference;
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typedef const T param_type;
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};
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template <class T>
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struct reference_call_traits
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{
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typedef T value_type;
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typedef T reference;
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typedef T const_reference;
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typedef T param_type;
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};
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template <bool simple, bool reference>
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struct call_traits_chooser
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{
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template <class T>
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struct rebind
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{
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typedef standard_call_traits<T> type;
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};
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};
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template <>
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struct call_traits_chooser<true, false>
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{
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template <class T>
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struct rebind
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{
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typedef simple_call_traits<T> type;
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};
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};
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template <>
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struct call_traits_chooser<false, true>
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{
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template <class T>
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struct rebind
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{
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typedef reference_call_traits<T> type;
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};
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};
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} // namespace detail
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template <typename T>
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struct call_traits
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{
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private:
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typedef detail::call_traits_chooser<(is_pointer<T>::value || is_arithmetic<T>::value) && sizeof(T) <= sizeof(void*), is_reference<T>::value> chooser;
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typedef typename chooser::template rebind<T> bound_type;
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typedef typename bound_type::type call_traits_type;
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public:
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typedef typename call_traits_type::value_type value_type;
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typedef typename call_traits_type::reference reference;
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typedef typename call_traits_type::const_reference const_reference;
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typedef typename call_traits_type::param_type param_type;
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};
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#else
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//
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// sorry call_traits is completely non-functional
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// blame your broken compiler:
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//
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template <typename T>
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struct call_traits
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{
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typedef T value_type;
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typedef T& reference;
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typedef const T& const_reference;
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typedef const T& param_type;
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};
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#endif // member templates
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}
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#endif // BOOST_OB_CALL_TRAITS_HPP
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