Chris@16: //  (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
Chris@16: //  Use, modification and distribution are subject to the Boost Software License,
Chris@16: //  Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt).
Chris@16: //
Chris@16: //  See http://www.boost.org/libs/utility for most recent version including documentation.
Chris@16: 
Chris@16: // compressed_pair: pair that "compresses" empty members
Chris@101: // (see libs/utility/doc/html/compressed_pair.html)
Chris@16: //
Chris@16: // JM changes 25 Jan 2004:
Chris@16: // For the case where T1 == T2 and both are empty, then first() and second()
Chris@16: // should return different objects.
Chris@16: // JM changes 25 Jan 2000:
Chris@16: // Removed default arguments from compressed_pair_switch to get
Chris@16: // C++ Builder 4 to accept them
Chris@16: // rewriten swap to get gcc and C++ builder to compile.
Chris@16: // added partial specialisations for case T1 == T2 to avoid duplicate constructor defs.
Chris@16: 
Chris@16: #ifndef BOOST_DETAIL_COMPRESSED_PAIR_HPP
Chris@16: #define BOOST_DETAIL_COMPRESSED_PAIR_HPP
Chris@16: 
Chris@16: #include <algorithm>
Chris@16: 
Chris@16: #include <boost/type_traits/remove_cv.hpp>
Chris@16: #include <boost/type_traits/is_empty.hpp>
Chris@16: #include <boost/type_traits/is_same.hpp>
Chris@16: #include <boost/call_traits.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_MSVC
Chris@16: # pragma warning(push)
Chris@16: # pragma warning(disable:4512)
Chris@16: #endif 
Chris@16: namespace boost
Chris@16: {
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair;
Chris@16: 
Chris@16: 
Chris@16: // compressed_pair
Chris@16: 
Chris@16: namespace details
Chris@16: {
Chris@16:    // JM altered 26 Jan 2000:
Chris@16:    template <class T1, class T2, bool IsSame, bool FirstEmpty, bool SecondEmpty>
Chris@16:    struct compressed_pair_switch;
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    struct compressed_pair_switch<T1, T2, false, false, false>
Chris@16:       {static const int value = 0;};
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    struct compressed_pair_switch<T1, T2, false, true, true>
Chris@16:       {static const int value = 3;};
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    struct compressed_pair_switch<T1, T2, false, true, false>
Chris@16:       {static const int value = 1;};
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    struct compressed_pair_switch<T1, T2, false, false, true>
Chris@16:       {static const int value = 2;};
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    struct compressed_pair_switch<T1, T2, true, true, true>
Chris@16:       {static const int value = 4;};
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    struct compressed_pair_switch<T1, T2, true, false, false>
Chris@16:       {static const int value = 5;};
Chris@16: 
Chris@16:    template <class T1, class T2, int Version> class compressed_pair_imp;
Chris@16: 
Chris@16: #ifdef __GNUC__
Chris@16:    // workaround for GCC (JM):
Chris@16:    using std::swap;
Chris@16: #endif
Chris@16:    //
Chris@16:    // can't call unqualified swap from within classname::swap
Chris@16:    // as Koenig lookup rules will find only the classname::swap
Chris@16:    // member function not the global declaration, so use cp_swap
Chris@16:    // as a forwarding function (JM):
Chris@16:    template <typename T>
Chris@16:    inline void cp_swap(T& t1, T& t2)
Chris@16:    {
Chris@16: #ifndef __GNUC__
Chris@16:       using std::swap;
Chris@16: #endif
Chris@16:       swap(t1, t2);
Chris@16:    }
Chris@16: 
Chris@16:    // 0    derive from neither
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    class compressed_pair_imp<T1, T2, 0>
Chris@16:    {
Chris@16:    public:
Chris@16:       typedef T1                                                 first_type;
Chris@16:       typedef T2                                                 second_type;
Chris@16:       typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:       typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:       typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:       typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:       typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:       typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:       compressed_pair_imp() {} 
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x, second_param_type y)
Chris@16:          : first_(x), second_(y) {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x)
Chris@16:          : first_(x) {}
Chris@16: 
Chris@16:       compressed_pair_imp(second_param_type y)
Chris@16:          : second_(y) {}
Chris@16: 
Chris@16:       first_reference       first()       {return first_;}
Chris@16:       first_const_reference first() const {return first_;}
Chris@16: 
Chris@16:       second_reference       second()       {return second_;}
Chris@16:       second_const_reference second() const {return second_;}
Chris@16: 
Chris@16:       void swap(::boost::compressed_pair<T1, T2>& y)
Chris@16:       {
Chris@16:          cp_swap(first_, y.first());
Chris@16:          cp_swap(second_, y.second());
Chris@16:       }
Chris@16:    private:
Chris@16:       first_type first_;
Chris@16:       second_type second_;
Chris@16:    };
Chris@16: 
Chris@16:    // 1    derive from T1
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    class compressed_pair_imp<T1, T2, 1>
Chris@16:       : protected ::boost::remove_cv<T1>::type
Chris@16:    {
Chris@16:    public:
Chris@16:       typedef T1                                                 first_type;
Chris@16:       typedef T2                                                 second_type;
Chris@16:       typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:       typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:       typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:       typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:       typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:       typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:       compressed_pair_imp() {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x, second_param_type y)
Chris@16:          : first_type(x), second_(y) {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x)
Chris@16:          : first_type(x) {}
Chris@16: 
Chris@16:       compressed_pair_imp(second_param_type y)
Chris@16:          : second_(y) {}
Chris@16: 
Chris@16:       first_reference       first()       {return *this;}
Chris@16:       first_const_reference first() const {return *this;}
Chris@16: 
Chris@16:       second_reference       second()       {return second_;}
Chris@16:       second_const_reference second() const {return second_;}
Chris@16: 
Chris@16:       void swap(::boost::compressed_pair<T1,T2>& y)
Chris@16:       {
Chris@16:          // no need to swap empty base class:
Chris@16:          cp_swap(second_, y.second());
Chris@16:       }
Chris@16:    private:
Chris@16:       second_type second_;
Chris@16:    };
Chris@16: 
Chris@16:    // 2    derive from T2
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    class compressed_pair_imp<T1, T2, 2>
Chris@16:       : protected ::boost::remove_cv<T2>::type
Chris@16:    {
Chris@16:    public:
Chris@16:       typedef T1                                                 first_type;
Chris@16:       typedef T2                                                 second_type;
Chris@16:       typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:       typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:       typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:       typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:       typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:       typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:       compressed_pair_imp() {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x, second_param_type y)
Chris@16:          : second_type(y), first_(x) {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x)
Chris@16:          : first_(x) {}
Chris@16: 
Chris@16:       compressed_pair_imp(second_param_type y)
Chris@16:          : second_type(y) {}
Chris@16: 
Chris@16:       first_reference       first()       {return first_;}
Chris@16:       first_const_reference first() const {return first_;}
Chris@16: 
Chris@16:       second_reference       second()       {return *this;}
Chris@16:       second_const_reference second() const {return *this;}
Chris@16: 
Chris@16:       void swap(::boost::compressed_pair<T1,T2>& y)
Chris@16:       {
Chris@16:          // no need to swap empty base class:
Chris@16:          cp_swap(first_, y.first());
Chris@16:       }
Chris@16: 
Chris@16:    private:
Chris@16:       first_type first_;
Chris@16:    };
Chris@16: 
Chris@16:    // 3    derive from T1 and T2
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    class compressed_pair_imp<T1, T2, 3>
Chris@16:       : protected ::boost::remove_cv<T1>::type,
Chris@16:         protected ::boost::remove_cv<T2>::type
Chris@16:    {
Chris@16:    public:
Chris@16:       typedef T1                                                 first_type;
Chris@16:       typedef T2                                                 second_type;
Chris@16:       typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:       typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:       typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:       typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:       typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:       typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:       compressed_pair_imp() {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x, second_param_type y)
Chris@16:          : first_type(x), second_type(y) {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x)
Chris@16:          : first_type(x) {}
Chris@16: 
Chris@16:       compressed_pair_imp(second_param_type y)
Chris@16:          : second_type(y) {}
Chris@16: 
Chris@16:       first_reference       first()       {return *this;}
Chris@16:       first_const_reference first() const {return *this;}
Chris@16: 
Chris@16:       second_reference       second()       {return *this;}
Chris@16:       second_const_reference second() const {return *this;}
Chris@16:       //
Chris@16:       // no need to swap empty bases:
Chris@16:       void swap(::boost::compressed_pair<T1,T2>&) {}
Chris@16:    };
Chris@16: 
Chris@16:    // JM
Chris@16:    // 4    T1 == T2, T1 and T2 both empty
Chris@16:    //      Originally this did not store an instance of T2 at all
Chris@16:    //      but that led to problems beause it meant &x.first() == &x.second()
Chris@16:    //      which is not true for any other kind of pair, so now we store an instance
Chris@16:    //      of T2 just in case the user is relying on first() and second() returning
Chris@16:    //      different objects (albeit both empty).
Chris@16:    template <class T1, class T2>
Chris@16:    class compressed_pair_imp<T1, T2, 4>
Chris@16:       : protected ::boost::remove_cv<T1>::type
Chris@16:    {
Chris@16:    public:
Chris@16:       typedef T1                                                 first_type;
Chris@16:       typedef T2                                                 second_type;
Chris@16:       typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:       typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:       typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:       typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:       typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:       typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:       compressed_pair_imp() {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x, second_param_type y)
Chris@16:          : first_type(x), m_second(y) {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x)
Chris@16:          : first_type(x), m_second(x) {}
Chris@16: 
Chris@16:       first_reference       first()       {return *this;}
Chris@16:       first_const_reference first() const {return *this;}
Chris@16: 
Chris@16:       second_reference       second()       {return m_second;}
Chris@16:       second_const_reference second() const {return m_second;}
Chris@16: 
Chris@16:       void swap(::boost::compressed_pair<T1,T2>&) {}
Chris@16:    private:
Chris@16:       T2 m_second;
Chris@16:    };
Chris@16: 
Chris@16:    // 5    T1 == T2 and are not empty:   //JM
Chris@16: 
Chris@16:    template <class T1, class T2>
Chris@16:    class compressed_pair_imp<T1, T2, 5>
Chris@16:    {
Chris@16:    public:
Chris@16:       typedef T1                                                 first_type;
Chris@16:       typedef T2                                                 second_type;
Chris@16:       typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:       typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:       typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:       typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:       typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:       typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:       compressed_pair_imp() {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x, second_param_type y)
Chris@16:          : first_(x), second_(y) {}
Chris@16: 
Chris@16:       compressed_pair_imp(first_param_type x)
Chris@16:          : first_(x), second_(x) {}
Chris@16: 
Chris@16:       first_reference       first()       {return first_;}
Chris@16:       first_const_reference first() const {return first_;}
Chris@16: 
Chris@16:       second_reference       second()       {return second_;}
Chris@16:       second_const_reference second() const {return second_;}
Chris@16: 
Chris@16:       void swap(::boost::compressed_pair<T1, T2>& y)
Chris@16:       {
Chris@16:          cp_swap(first_, y.first());
Chris@16:          cp_swap(second_, y.second());
Chris@16:       }
Chris@16:    private:
Chris@16:       first_type first_;
Chris@16:       second_type second_;
Chris@16:    };
Chris@16: 
Chris@16: }  // details
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair
Chris@16:    : private ::boost::details::compressed_pair_imp<T1, T2,
Chris@16:              ::boost::details::compressed_pair_switch<
Chris@16:                     T1,
Chris@16:                     T2,
Chris@16:                     ::boost::is_same<typename remove_cv<T1>::type, typename remove_cv<T2>::type>::value,
Chris@16:                     ::boost::is_empty<T1>::value,
Chris@16:                     ::boost::is_empty<T2>::value>::value>
Chris@16: {
Chris@16: private:
Chris@16:    typedef details::compressed_pair_imp<T1, T2,
Chris@16:              ::boost::details::compressed_pair_switch<
Chris@16:                     T1,
Chris@16:                     T2,
Chris@16:                     ::boost::is_same<typename remove_cv<T1>::type, typename remove_cv<T2>::type>::value,
Chris@16:                     ::boost::is_empty<T1>::value,
Chris@16:                     ::boost::is_empty<T2>::value>::value> base;
Chris@16: public:
Chris@16:    typedef T1                                                 first_type;
Chris@16:    typedef T2                                                 second_type;
Chris@16:    typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:    typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:    typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:    typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:    typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:    typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:             compressed_pair() : base() {}
Chris@16:             compressed_pair(first_param_type x, second_param_type y) : base(x, y) {}
Chris@16:    explicit compressed_pair(first_param_type x) : base(x) {}
Chris@16:    explicit compressed_pair(second_param_type y) : base(y) {}
Chris@16: 
Chris@16:    first_reference       first()       {return base::first();}
Chris@16:    first_const_reference first() const {return base::first();}
Chris@16: 
Chris@16:    second_reference       second()       {return base::second();}
Chris@16:    second_const_reference second() const {return base::second();}
Chris@16: 
Chris@16:    void swap(compressed_pair& y) { base::swap(y); }
Chris@16: };
Chris@16: 
Chris@16: // JM
Chris@16: // Partial specialisation for case where T1 == T2:
Chris@16: //
Chris@16: template <class T>
Chris@16: class compressed_pair<T, T>
Chris@16:    : private details::compressed_pair_imp<T, T,
Chris@16:              ::boost::details::compressed_pair_switch<
Chris@16:                     T,
Chris@16:                     T,
Chris@16:                     ::boost::is_same<typename remove_cv<T>::type, typename remove_cv<T>::type>::value,
Chris@16:                     ::boost::is_empty<T>::value,
Chris@16:                     ::boost::is_empty<T>::value>::value>
Chris@16: {
Chris@16: private:
Chris@16:    typedef details::compressed_pair_imp<T, T,
Chris@16:              ::boost::details::compressed_pair_switch<
Chris@16:                     T,
Chris@16:                     T,
Chris@16:                     ::boost::is_same<typename remove_cv<T>::type, typename remove_cv<T>::type>::value,
Chris@16:                     ::boost::is_empty<T>::value,
Chris@16:                     ::boost::is_empty<T>::value>::value> base;
Chris@16: public:
Chris@16:    typedef T                                                  first_type;
Chris@16:    typedef T                                                  second_type;
Chris@16:    typedef typename call_traits<first_type>::param_type       first_param_type;
Chris@16:    typedef typename call_traits<second_type>::param_type      second_param_type;
Chris@16:    typedef typename call_traits<first_type>::reference        first_reference;
Chris@16:    typedef typename call_traits<second_type>::reference       second_reference;
Chris@16:    typedef typename call_traits<first_type>::const_reference  first_const_reference;
Chris@16:    typedef typename call_traits<second_type>::const_reference second_const_reference;
Chris@16: 
Chris@16:             compressed_pair() : base() {}
Chris@16:             compressed_pair(first_param_type x, second_param_type y) : base(x, y) {}
Chris@16: #if !(defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530))
Chris@16:    explicit 
Chris@16: #endif
Chris@16:       compressed_pair(first_param_type x) : base(x) {}
Chris@16: 
Chris@16:    first_reference       first()       {return base::first();}
Chris@16:    first_const_reference first() const {return base::first();}
Chris@16: 
Chris@16:    second_reference       second()       {return base::second();}
Chris@16:    second_const_reference second() const {return base::second();}
Chris@16: 
Chris@16:    void swap(::boost::compressed_pair<T,T>& y) { base::swap(y); }
Chris@16: };
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: inline
Chris@16: void
Chris@16: swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
Chris@16: {
Chris@16:    x.swap(y);
Chris@16: }
Chris@16: 
Chris@16: } // boost
Chris@16: 
Chris@16: #ifdef BOOST_MSVC
Chris@16: # pragma warning(pop)
Chris@16: #endif 
Chris@16: 
Chris@16: #endif // BOOST_DETAIL_COMPRESSED_PAIR_HPP
Chris@16: