forked from boostorg/core
90 lines
2.8 KiB
C++
90 lines
2.8 KiB
C++
// Copyright (C) 2007, 2008 Steven Watanabe, Joseph Gauterin, Niels Dekker
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// For more information, see http://www.boost.org
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#ifndef BOOST_CORE_SWAP_HPP
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#define BOOST_CORE_SWAP_HPP
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// Note: the implementation of this utility contains various workarounds:
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// - swap_impl is put outside the boost namespace, to avoid infinite
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// recursion (causing stack overflow) when swapping objects of a primitive
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// type.
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// - std::swap is imported with a using-directive, rather than
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// a using-declaration, because some compilers (including MSVC 7.1,
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// Borland 5.9.3, and Intel 8.1) don't do argument-dependent lookup
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// when it has a using-declaration instead.
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// - boost::swap has two template arguments, instead of one, to
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// avoid ambiguity when swapping objects of a Boost type that does
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// not have its own boost::swap overload.
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#include <boost/core/enable_if.hpp>
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#include <boost/config.hpp>
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#if __cplusplus >= 201103L || defined(BOOST_DINKUMWARE_STDLIB)
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#include <utility> // for std::swap (C++11)
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#else
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#include <algorithm> // for std::swap (C++98)
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#endif
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#include <cstddef> // for std::size_t
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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#if defined(BOOST_GCC) && (BOOST_GCC < 40700)
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// gcc 4.6 ICEs on noexcept specifications below
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#define BOOST_CORE_SWAP_NOEXCEPT_IF(x)
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#else
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#define BOOST_CORE_SWAP_NOEXCEPT_IF(x) BOOST_NOEXCEPT_IF(x)
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#endif
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namespace boost_swap_impl
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{
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// we can't use type_traits here
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template<class T> struct is_const { enum _vt { value = 0 }; };
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template<class T> struct is_const<T const> { enum _vt { value = 1 }; };
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// Use std::swap if argument dependent lookup fails.
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// We need to have this at namespace scope to be able to use unqualified swap() call
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// in noexcept specification.
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using namespace std;
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template<class T>
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BOOST_GPU_ENABLED
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void swap_impl(T& left, T& right) BOOST_CORE_SWAP_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(swap(left, right)))
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{
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swap(left, right);
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}
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template<class T, std::size_t N>
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BOOST_GPU_ENABLED
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void swap_impl(T (& left)[N], T (& right)[N])
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BOOST_CORE_SWAP_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(::boost_swap_impl::swap_impl(left[0], right[0])))
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{
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for (std::size_t i = 0; i < N; ++i)
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{
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::boost_swap_impl::swap_impl(left[i], right[i]);
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}
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}
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}
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namespace boost
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{
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template<class T1, class T2>
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BOOST_GPU_ENABLED
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typename enable_if_c< !boost_swap_impl::is_const<T1>::value && !boost_swap_impl::is_const<T2>::value >::type
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swap(T1& left, T2& right)
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BOOST_CORE_SWAP_NOEXCEPT_IF(BOOST_NOEXCEPT_EXPR(::boost_swap_impl::swap_impl(left, right)))
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{
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::boost_swap_impl::swap_impl(left, right);
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}
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}
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#undef BOOST_CORE_SWAP_NOEXCEPT_IF
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#endif // BOOST_CORE_SWAP_HPP
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