mirror of
https://github.com/boostorg/utility.git
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444 lines
16 KiB
C++
444 lines
16 KiB
C++
// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
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// Use, modification and distribution are subject to the Boost Software License,
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// Version 1.0. (See 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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//
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// See http://www.boost.org/libs/utility for most recent version including documentation.
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// compressed_pair: pair that "compresses" empty members
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// (see libs/utility/compressed_pair.htm)
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//
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// JM changes 25 Jan 2004:
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// For the case where T1 == T2 and both are empty, then first() and second()
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// should return different objects.
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// JM changes 25 Jan 2000:
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// Removed default arguments from compressed_pair_switch to get
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// C++ Builder 4 to accept them
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// rewriten swap to get gcc and C++ builder to compile.
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// added partial specialisations for case T1 == T2 to avoid duplicate constructor defs.
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#ifndef BOOST_DETAIL_COMPRESSED_PAIR_HPP
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#define BOOST_DETAIL_COMPRESSED_PAIR_HPP
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#include <algorithm>
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#include <boost/type_traits/remove_cv.hpp>
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#include <boost/type_traits/is_empty.hpp>
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#include <boost/type_traits/is_same.hpp>
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#include <boost/call_traits.hpp>
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#ifdef BOOST_MSVC
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# pragma warning(push)
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# pragma warning(disable:4512)
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#endif
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namespace boost
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{
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template <class T1, class T2>
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class compressed_pair;
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// compressed_pair
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namespace details
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{
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// JM altered 26 Jan 2000:
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template <class T1, class T2, bool IsSame, bool FirstEmpty, bool SecondEmpty>
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struct compressed_pair_switch;
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template <class T1, class T2>
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struct compressed_pair_switch<T1, T2, false, false, false>
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{static const int value = 0;};
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template <class T1, class T2>
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struct compressed_pair_switch<T1, T2, false, true, true>
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{static const int value = 3;};
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template <class T1, class T2>
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struct compressed_pair_switch<T1, T2, false, true, false>
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{static const int value = 1;};
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template <class T1, class T2>
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struct compressed_pair_switch<T1, T2, false, false, true>
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{static const int value = 2;};
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template <class T1, class T2>
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struct compressed_pair_switch<T1, T2, true, true, true>
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{static const int value = 4;};
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template <class T1, class T2>
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struct compressed_pair_switch<T1, T2, true, false, false>
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{static const int value = 5;};
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template <class T1, class T2, int Version> class compressed_pair_imp;
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#ifdef __GNUC__
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// workaround for GCC (JM):
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using std::swap;
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#endif
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//
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// can't call unqualified swap from within classname::swap
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// as Koenig lookup rules will find only the classname::swap
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// member function not the global declaration, so use cp_swap
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// as a forwarding function (JM):
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template <typename T>
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inline void cp_swap(T& t1, T& t2)
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{
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#ifndef __GNUC__
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using std::swap;
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#endif
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swap(t1, t2);
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}
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// 0 derive from neither
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template <class T1, class T2>
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class compressed_pair_imp<T1, T2, 0>
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{
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair_imp() {}
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compressed_pair_imp(first_param_type x, second_param_type y)
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: first_(x), second_(y) {}
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compressed_pair_imp(first_param_type x)
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: first_(x) {}
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compressed_pair_imp(second_param_type y)
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: second_(y) {}
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first_reference first() {return first_;}
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first_const_reference first() const {return first_;}
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second_reference second() {return second_;}
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second_const_reference second() const {return second_;}
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void swap(::boost::compressed_pair<T1, T2>& y)
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{
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cp_swap(first_, y.first());
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cp_swap(second_, y.second());
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}
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private:
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first_type first_;
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second_type second_;
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};
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// 1 derive from T1
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template <class T1, class T2>
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class compressed_pair_imp<T1, T2, 1>
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: protected ::boost::remove_cv<T1>::type
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{
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair_imp() {}
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compressed_pair_imp(first_param_type x, second_param_type y)
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: first_type(x), second_(y) {}
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compressed_pair_imp(first_param_type x)
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: first_type(x) {}
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compressed_pair_imp(second_param_type y)
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: second_(y) {}
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first_reference first() {return *this;}
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first_const_reference first() const {return *this;}
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second_reference second() {return second_;}
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second_const_reference second() const {return second_;}
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void swap(::boost::compressed_pair<T1,T2>& y)
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{
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// no need to swap empty base class:
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cp_swap(second_, y.second());
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}
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private:
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second_type second_;
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};
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// 2 derive from T2
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template <class T1, class T2>
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class compressed_pair_imp<T1, T2, 2>
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: protected ::boost::remove_cv<T2>::type
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{
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair_imp() {}
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compressed_pair_imp(first_param_type x, second_param_type y)
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: second_type(y), first_(x) {}
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compressed_pair_imp(first_param_type x)
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: first_(x) {}
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compressed_pair_imp(second_param_type y)
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: second_type(y) {}
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first_reference first() {return first_;}
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first_const_reference first() const {return first_;}
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second_reference second() {return *this;}
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second_const_reference second() const {return *this;}
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void swap(::boost::compressed_pair<T1,T2>& y)
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{
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// no need to swap empty base class:
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cp_swap(first_, y.first());
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}
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private:
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first_type first_;
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};
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// 3 derive from T1 and T2
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template <class T1, class T2>
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class compressed_pair_imp<T1, T2, 3>
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: protected ::boost::remove_cv<T1>::type,
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protected ::boost::remove_cv<T2>::type
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{
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair_imp() {}
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compressed_pair_imp(first_param_type x, second_param_type y)
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: first_type(x), second_type(y) {}
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compressed_pair_imp(first_param_type x)
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: first_type(x) {}
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compressed_pair_imp(second_param_type y)
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: second_type(y) {}
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first_reference first() {return *this;}
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first_const_reference first() const {return *this;}
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second_reference second() {return *this;}
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second_const_reference second() const {return *this;}
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//
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// no need to swap empty bases:
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void swap(::boost::compressed_pair<T1,T2>&) {}
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};
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// JM
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// 4 T1 == T2, T1 and T2 both empty
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// Originally this did not store an instance of T2 at all
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// but that led to problems beause it meant &x.first() == &x.second()
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// which is not true for any other kind of pair, so now we store an instance
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// of T2 just in case the user is relying on first() and second() returning
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// different objects (albeit both empty).
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template <class T1, class T2>
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class compressed_pair_imp<T1, T2, 4>
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: protected ::boost::remove_cv<T1>::type
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{
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair_imp() {}
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compressed_pair_imp(first_param_type x, second_param_type y)
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: first_type(x), m_second(y) {}
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compressed_pair_imp(first_param_type x)
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: first_type(x), m_second(x) {}
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first_reference first() {return *this;}
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first_const_reference first() const {return *this;}
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second_reference second() {return m_second;}
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second_const_reference second() const {return m_second;}
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void swap(::boost::compressed_pair<T1,T2>&) {}
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private:
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T2 m_second;
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};
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// 5 T1 == T2 and are not empty: //JM
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template <class T1, class T2>
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class compressed_pair_imp<T1, T2, 5>
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{
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair_imp() {}
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compressed_pair_imp(first_param_type x, second_param_type y)
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: first_(x), second_(y) {}
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compressed_pair_imp(first_param_type x)
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: first_(x), second_(x) {}
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first_reference first() {return first_;}
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first_const_reference first() const {return first_;}
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second_reference second() {return second_;}
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second_const_reference second() const {return second_;}
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void swap(::boost::compressed_pair<T1, T2>& y)
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{
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cp_swap(first_, y.first());
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cp_swap(second_, y.second());
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}
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private:
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first_type first_;
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second_type second_;
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};
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} // details
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template <class T1, class T2>
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class compressed_pair
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: private ::boost::details::compressed_pair_imp<T1, T2,
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::boost::details::compressed_pair_switch<
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T1,
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T2,
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::boost::is_same<typename remove_cv<T1>::type, typename remove_cv<T2>::type>::value,
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::boost::is_empty<T1>::value,
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::boost::is_empty<T2>::value>::value>
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{
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private:
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typedef details::compressed_pair_imp<T1, T2,
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::boost::details::compressed_pair_switch<
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T1,
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T2,
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::boost::is_same<typename remove_cv<T1>::type, typename remove_cv<T2>::type>::value,
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::boost::is_empty<T1>::value,
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::boost::is_empty<T2>::value>::value> base;
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public:
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typedef T1 first_type;
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typedef T2 second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair() : base() {}
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compressed_pair(first_param_type x, second_param_type y) : base(x, y) {}
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explicit compressed_pair(first_param_type x) : base(x) {}
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explicit compressed_pair(second_param_type y) : base(y) {}
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first_reference first() {return base::first();}
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first_const_reference first() const {return base::first();}
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second_reference second() {return base::second();}
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second_const_reference second() const {return base::second();}
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void swap(compressed_pair& y) { base::swap(y); }
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};
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// JM
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// Partial specialisation for case where T1 == T2:
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//
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template <class T>
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class compressed_pair<T, T>
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: private details::compressed_pair_imp<T, T,
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::boost::details::compressed_pair_switch<
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T,
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T,
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::boost::is_same<typename remove_cv<T>::type, typename remove_cv<T>::type>::value,
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::boost::is_empty<T>::value,
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::boost::is_empty<T>::value>::value>
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{
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private:
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typedef details::compressed_pair_imp<T, T,
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::boost::details::compressed_pair_switch<
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T,
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T,
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::boost::is_same<typename remove_cv<T>::type, typename remove_cv<T>::type>::value,
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::boost::is_empty<T>::value,
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::boost::is_empty<T>::value>::value> base;
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public:
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typedef T first_type;
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typedef T second_type;
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typedef typename call_traits<first_type>::param_type first_param_type;
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typedef typename call_traits<second_type>::param_type second_param_type;
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typedef typename call_traits<first_type>::reference first_reference;
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typedef typename call_traits<second_type>::reference second_reference;
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typedef typename call_traits<first_type>::const_reference first_const_reference;
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typedef typename call_traits<second_type>::const_reference second_const_reference;
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compressed_pair() : base() {}
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compressed_pair(first_param_type x, second_param_type y) : base(x, y) {}
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#if !(defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530))
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explicit
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#endif
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compressed_pair(first_param_type x) : base(x) {}
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first_reference first() {return base::first();}
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first_const_reference first() const {return base::first();}
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second_reference second() {return base::second();}
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second_const_reference second() const {return base::second();}
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void swap(::boost::compressed_pair<T,T>& y) { base::swap(y); }
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};
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template <class T1, class T2>
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inline
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void
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swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
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{
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x.swap(y);
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}
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} // boost
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#ifdef BOOST_MSVC
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# pragma warning(pop)
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#endif
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#endif // BOOST_DETAIL_COMPRESSED_PAIR_HPP
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