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: //  see libs/utility/compressed_pair.hpp
Chris@16: //
Chris@16: /* Release notes:
Chris@16:    20 Jan 2001:
Chris@16:         Fixed obvious bugs (David Abrahams)
Chris@16:    07 Oct 2000:
Chris@16:       Added better single argument constructor support.
Chris@16:    03 Oct 2000:
Chris@16:       Added VC6 support (JM).
Chris@16:    23rd July 2000:
Chris@16:       Additional comments added. (JM)
Chris@16:    Jan 2000:
Chris@16:       Original version: this version crippled for use with crippled compilers
Chris@16:       - John Maddock Jan 2000.
Chris@16: */
Chris@16: 
Chris@16: 
Chris@16: #ifndef BOOST_OB_COMPRESSED_PAIR_HPP
Chris@16: #define BOOST_OB_COMPRESSED_PAIR_HPP
Chris@16: 
Chris@16: #include <algorithm>
Chris@16: #ifndef BOOST_OBJECT_TYPE_TRAITS_HPP
Chris@16: #include <boost/type_traits/object_traits.hpp>
Chris@16: #endif
Chris@16: #ifndef BOOST_SAME_TRAITS_HPP
Chris@16: #include <boost/type_traits/same_traits.hpp>
Chris@16: #endif
Chris@16: #ifndef BOOST_CALL_TRAITS_HPP
Chris@16: #include <boost/call_traits.hpp>
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: #ifdef BOOST_MSVC6_MEMBER_TEMPLATES
Chris@16: //
Chris@16: // use member templates to emulate
Chris@16: // partial specialisation.  Note that due to
Chris@16: // problems with overload resolution with VC6
Chris@16: // each of the compressed_pair versions that follow
Chris@16: // have one template single-argument constructor
Chris@16: // in place of two specific constructors:
Chris@16: //
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair;
Chris@16: 
Chris@16: namespace detail{
Chris@16: 
Chris@16: template <class A, class T1, class T2>
Chris@16: struct best_conversion_traits
Chris@16: {
Chris@16:    typedef char one;
Chris@16:    typedef char (&two)[2];
Chris@16:    static A a;
Chris@16:    static one test(T1);
Chris@16:    static two test(T2);
Chris@16: 
Chris@16:    enum { value = sizeof(test(a)) };
Chris@16: };
Chris@16: 
Chris@16: template <int>
Chris@16: struct init_one;
Chris@16: 
Chris@16: template <>
Chris@16: struct init_one<1>
Chris@16: {
Chris@16:    template <class A, class T1, class T2>
Chris@16:    static void init(const A& a, T1* p1, T2*)
Chris@16:    {
Chris@16:       *p1 = a;
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: template <>
Chris@16: struct init_one<2>
Chris@16: {
Chris@16:    template <class A, class T1, class T2>
Chris@16:    static void init(const A& a, T1*, T2* p2)
Chris@16:    {
Chris@16:       *p2 = a;
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: // T1 != T2, both non-empty
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair_0
Chris@16: {
Chris@16: private:
Chris@16:    T1 _first;
Chris@16:    T2 _second;
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_0() : _first(), _second() {}
Chris@16:             compressed_pair_0(first_param_type x, second_param_type y) : _first(x), _second(y) {}
Chris@16:    template <class A>
Chris@16:    explicit compressed_pair_0(const A& val)
Chris@16:    {
Chris@16:       init_one<best_conversion_traits<A, T1, T2>::value>::init(val, &_first, &_second);
Chris@16:    }
Chris@16:    compressed_pair_0(const ::boost::compressed_pair<T1,T2>& x)
Chris@16:       : _first(x.first()), _second(x.second()) {}
Chris@16: 
Chris@16: #if 0
Chris@16:   compressed_pair_0& operator=(const compressed_pair_0& x) {
Chris@16:     cout << "assigning compressed pair 0" << endl;
Chris@16:     _first = x._first;
Chris@16:     _second = x._second;
Chris@16:     cout << "finished assigning compressed pair 0" << endl;
Chris@16:     return *this;
Chris@16:   }
Chris@16: #endif
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(compressed_pair_0& y)
Chris@16:    {
Chris@16:       using std::swap;
Chris@16:       swap(_first, y._first);
Chris@16:       swap(_second, y._second);
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: // T1 != T2, T2 empty
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair_1 : T2
Chris@16: {
Chris@16: private:
Chris@16:    T1 _first;
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_1() : T2(), _first() {}
Chris@16:             compressed_pair_1(first_param_type x, second_param_type y) : T2(y), _first(x) {}
Chris@16: 
Chris@16:    template <class A>
Chris@16:    explicit compressed_pair_1(const A& val)
Chris@16:    {
Chris@16:       init_one<best_conversion_traits<A, T1, T2>::value>::init(val, &_first, static_cast<T2*>(this));
Chris@16:    }
Chris@16: 
Chris@16:    compressed_pair_1(const ::boost::compressed_pair<T1,T2>& x)
Chris@16:       : T2(x.second()), _first(x.first()) {}
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(compressed_pair_1& y)
Chris@16:    {
Chris@16:       // no need to swap empty base class:
Chris@16:       using std::swap;
Chris@16:       swap(_first, y._first);
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: // T1 != T2, T1 empty
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair_2 : T1
Chris@16: {
Chris@16: private:
Chris@16:    T2 _second;
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_2() : T1(), _second() {}
Chris@16:             compressed_pair_2(first_param_type x, second_param_type y) : T1(x), _second(y) {}
Chris@16:    template <class A>
Chris@16:    explicit compressed_pair_2(const A& val)
Chris@16:    {
Chris@16:       init_one<best_conversion_traits<A, T1, T2>::value>::init(val, static_cast<T1*>(this), &_second);
Chris@16:    }
Chris@16:    compressed_pair_2(const ::boost::compressed_pair<T1,T2>& x)
Chris@16:       : T1(x.first()), _second(x.second()) {}
Chris@16: 
Chris@16: #if 0
Chris@16:   compressed_pair_2& operator=(const compressed_pair_2& x) {
Chris@16:     cout << "assigning compressed pair 2" << endl;
Chris@16:     T1::operator=(x);
Chris@16:     _second = x._second;
Chris@16:     cout << "finished assigning compressed pair 2" << endl;
Chris@16:     return *this;
Chris@16:   }
Chris@16: #endif
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(compressed_pair_2& y)
Chris@16:    {
Chris@16:       // no need to swap empty base class:
Chris@16:       using std::swap;
Chris@16:       swap(_second, y._second);
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: // T1 != T2, both empty
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair_3 : T1, T2
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_3() : T1(), T2() {}
Chris@16:             compressed_pair_3(first_param_type x, second_param_type y) : T1(x), T2(y) {}
Chris@16:    template <class A>
Chris@16:    explicit compressed_pair_3(const A& val)
Chris@16:    {
Chris@16:       init_one<best_conversion_traits<A, T1, T2>::value>::init(val, static_cast<T1*>(this), static_cast<T2*>(this));
Chris@16:    }
Chris@16:    compressed_pair_3(const ::boost::compressed_pair<T1,T2>& x)
Chris@16:       : T1(x.first()), T2(x.second()) {}
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:    void swap(compressed_pair_3& y)
Chris@16:    {
Chris@16:       // no need to swap empty base classes:
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: // T1 == T2, and empty
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair_4 : T1
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_4() : T1() {}
Chris@16:             compressed_pair_4(first_param_type x, second_param_type y) : T1(x), m_second(y) {}
Chris@16:    // only one single argument constructor since T1 == T2
Chris@16:    explicit compressed_pair_4(first_param_type x) : T1(x), m_second(x) {}
Chris@16:    compressed_pair_4(const ::boost::compressed_pair<T1,T2>& x)
Chris@16:       : T1(x.first()), m_second(x.second()) {}
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(compressed_pair_4& y)
Chris@16:    {
Chris@16:       // no need to swap empty base classes:
Chris@16:    }
Chris@16: private:
Chris@16:    T2 m_second;
Chris@16: };
Chris@16: 
Chris@16: // T1 == T2, not empty
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair_5
Chris@16: {
Chris@16: private:
Chris@16:    T1 _first;
Chris@16:    T2 _second;
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_5() : _first(), _second() {}
Chris@16:             compressed_pair_5(first_param_type x, second_param_type y) : _first(x), _second(y) {}
Chris@16:    // only one single argument constructor since T1 == T2
Chris@16:    explicit compressed_pair_5(first_param_type x) : _first(x), _second(x) {}
Chris@16:    compressed_pair_5(const ::boost::compressed_pair<T1,T2>& c) 
Chris@16:       : _first(c.first()), _second(c.second()) {}
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(compressed_pair_5& y)
Chris@16:    {
Chris@16:       using std::swap;
Chris@16:       swap(_first, y._first);
Chris@16:       swap(_second, y._second);
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: template <bool e1, bool e2, bool same>
Chris@16: struct compressed_pair_chooser
Chris@16: {
Chris@16:    template <class T1, class T2>
Chris@16:    struct rebind
Chris@16:    {
Chris@16:       typedef compressed_pair_0<T1, T2> type;
Chris@16:    };
Chris@16: };
Chris@16: 
Chris@16: template <>
Chris@16: struct compressed_pair_chooser<false, true, false>
Chris@16: {
Chris@16:    template <class T1, class T2>
Chris@16:    struct rebind
Chris@16:    {
Chris@16:       typedef compressed_pair_1<T1, T2> type;
Chris@16:    };
Chris@16: };
Chris@16: 
Chris@16: template <>
Chris@16: struct compressed_pair_chooser<true, false, false>
Chris@16: {
Chris@16:    template <class T1, class T2>
Chris@16:    struct rebind
Chris@16:    {
Chris@16:       typedef compressed_pair_2<T1, T2> type;
Chris@16:    };
Chris@16: };
Chris@16: 
Chris@16: template <>
Chris@16: struct compressed_pair_chooser<true, true, false>
Chris@16: {
Chris@16:    template <class T1, class T2>
Chris@16:    struct rebind
Chris@16:    {
Chris@16:       typedef compressed_pair_3<T1, T2> type;
Chris@16:    };
Chris@16: };
Chris@16: 
Chris@16: template <>
Chris@16: struct compressed_pair_chooser<true, true, true>
Chris@16: {
Chris@16:    template <class T1, class T2>
Chris@16:    struct rebind
Chris@16:    {
Chris@16:       typedef compressed_pair_4<T1, T2> type;
Chris@16:    };
Chris@16: };
Chris@16: 
Chris@16: template <>
Chris@16: struct compressed_pair_chooser<false, false, true>
Chris@16: {
Chris@16:    template <class T1, class T2>
Chris@16:    struct rebind
Chris@16:    {
Chris@16:       typedef compressed_pair_5<T1, T2> type;
Chris@16:    };
Chris@16: };
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: struct compressed_pair_traits
Chris@16: {
Chris@16: private:
Chris@16:    typedef compressed_pair_chooser<is_empty<T1>::value, is_empty<T2>::value, is_same<T1,T2>::value> chooser;
Chris@16:    typedef typename chooser::template rebind<T1, T2> bound_type;
Chris@16: public:
Chris@16:    typedef typename bound_type::type type;
Chris@16: };
Chris@16: 
Chris@16: } // namespace detail
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair : public detail::compressed_pair_traits<T1, T2>::type
Chris@16: {
Chris@16: private:
Chris@16:    typedef typename detail::compressed_pair_traits<T1, T2>::type base_type;
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_type() {}
Chris@16:             compressed_pair(first_param_type x, second_param_type y) : base_type(x, y) {}
Chris@16:    template <class A>
Chris@16:    explicit compressed_pair(const A& x) : base_type(x){}
Chris@16: 
Chris@16:    first_reference       first()       { return base_type::first(); }
Chris@16:    first_const_reference first() const { return base_type::first(); }
Chris@16: 
Chris@16:    second_reference       second()       { return base_type::second(); }
Chris@16:    second_const_reference second() const { return base_type::second(); }
Chris@16: };
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: inline void swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
Chris@16: {
Chris@16:    x.swap(y);
Chris@16: }
Chris@16: 
Chris@16: #else
Chris@16: // no partial specialisation, no member templates:
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: class compressed_pair
Chris@16: {
Chris@16: private:
Chris@16:    T1 _first;
Chris@16:    T2 _second;
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() : _first(), _second() {}
Chris@16:             compressed_pair(first_param_type x, second_param_type y) : _first(x), _second(y) {}
Chris@16:    explicit compressed_pair(first_param_type x) : _first(x), _second() {}
Chris@16:    // can't define this in case T1 == T2:
Chris@16:    // explicit compressed_pair(second_param_type y) : _first(), _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(compressed_pair& y)
Chris@16:    {
Chris@16:       using std::swap;
Chris@16:       swap(_first, y._first);
Chris@16:       swap(_second, y._second);
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: template <class T1, class T2>
Chris@16: inline void swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
Chris@16: {
Chris@16:    x.swap(y);
Chris@16: }
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: } // boost
Chris@16: 
Chris@16: #endif // BOOST_OB_COMPRESSED_PAIR_HPP
Chris@16: 
Chris@16: 
Chris@16: