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