utility/include/boost/detail/ob_compressed_pair.hpp
2013-09-30 00:21:39 +00:00

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// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
// Use, modification and distribution are subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt).
//
// See http://www.boost.org/libs/utility for most recent version including documentation.
// see libs/utility/compressed_pair.hpp
//
/* Release notes:
20 Jan 2001:
Fixed obvious bugs (David Abrahams)
07 Oct 2000:
Added better single argument constructor support.
03 Oct 2000:
Added VC6 support (JM).
23rd July 2000:
Additional comments added. (JM)
Jan 2000:
Original version: this version crippled for use with crippled compilers
- John Maddock Jan 2000.
*/
#ifndef BOOST_OB_COMPRESSED_PAIR_HPP
#define BOOST_OB_COMPRESSED_PAIR_HPP
#include <algorithm>
#ifndef BOOST_OBJECT_TYPE_TRAITS_HPP
#include <boost/type_traits/object_traits.hpp>
#endif
#ifndef BOOST_SAME_TRAITS_HPP
#include <boost/type_traits/same_traits.hpp>
#endif
#ifndef BOOST_CALL_TRAITS_HPP
#include <boost/call_traits.hpp>
#endif
namespace boost
{
#ifdef BOOST_MSVC6_MEMBER_TEMPLATES
//
// use member templates to emulate
// partial specialisation. Note that due to
// problems with overload resolution with VC6
// each of the compressed_pair versions that follow
// have one template single-argument constructor
// in place of two specific constructors:
//
template <class T1, class T2>
class compressed_pair;
namespace detail{
template <class A, class T1, class T2>
struct best_conversion_traits
{
typedef char one;
typedef char (&two)[2];
static A a;
static one test(T1);
static two test(T2);
enum { value = sizeof(test(a)) };
};
template <int>
struct init_one;
template <>
struct init_one<1>
{
template <class A, class T1, class T2>
static void init(const A& a, T1* p1, T2*)
{
*p1 = a;
}
};
template <>
struct init_one<2>
{
template <class A, class T1, class T2>
static void init(const A& a, T1*, T2* p2)
{
*p2 = a;
}
};
// T1 != T2, both non-empty
template <class T1, class T2>
class compressed_pair_0
{
private:
T1 _first;
T2 _second;
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair_0() : _first(), _second() {}
compressed_pair_0(first_param_type x, second_param_type y) : _first(x), _second(y) {}
template <class A>
explicit compressed_pair_0(const A& val)
{
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, &_first, &_second);
}
compressed_pair_0(const ::boost::compressed_pair<T1,T2>& x)
: _first(x.first()), _second(x.second()) {}
#if 0
compressed_pair_0& operator=(const compressed_pair_0& x) {
cout << "assigning compressed pair 0" << endl;
_first = x._first;
_second = x._second;
cout << "finished assigning compressed pair 0" << endl;
return *this;
}
#endif
first_reference first() { return _first; }
first_const_reference first() const { return _first; }
second_reference second() { return _second; }
second_const_reference second() const { return _second; }
void swap(compressed_pair_0& y)
{
using std::swap;
swap(_first, y._first);
swap(_second, y._second);
}
};
// T1 != T2, T2 empty
template <class T1, class T2>
class compressed_pair_1 : T2
{
private:
T1 _first;
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair_1() : T2(), _first() {}
compressed_pair_1(first_param_type x, second_param_type y) : T2(y), _first(x) {}
template <class A>
explicit compressed_pair_1(const A& val)
{
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, &_first, static_cast<T2*>(this));
}
compressed_pair_1(const ::boost::compressed_pair<T1,T2>& x)
: T2(x.second()), _first(x.first()) {}
first_reference first() { return _first; }
first_const_reference first() const { return _first; }
second_reference second() { return *this; }
second_const_reference second() const { return *this; }
void swap(compressed_pair_1& y)
{
// no need to swap empty base class:
using std::swap;
swap(_first, y._first);
}
};
// T1 != T2, T1 empty
template <class T1, class T2>
class compressed_pair_2 : T1
{
private:
T2 _second;
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair_2() : T1(), _second() {}
compressed_pair_2(first_param_type x, second_param_type y) : T1(x), _second(y) {}
template <class A>
explicit compressed_pair_2(const A& val)
{
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, static_cast<T1*>(this), &_second);
}
compressed_pair_2(const ::boost::compressed_pair<T1,T2>& x)
: T1(x.first()), _second(x.second()) {}
#if 0
compressed_pair_2& operator=(const compressed_pair_2& x) {
cout << "assigning compressed pair 2" << endl;
T1::operator=(x);
_second = x._second;
cout << "finished assigning compressed pair 2" << endl;
return *this;
}
#endif
first_reference first() { return *this; }
first_const_reference first() const { return *this; }
second_reference second() { return _second; }
second_const_reference second() const { return _second; }
void swap(compressed_pair_2& y)
{
// no need to swap empty base class:
using std::swap;
swap(_second, y._second);
}
};
// T1 != T2, both empty
template <class T1, class T2>
class compressed_pair_3 : T1, T2
{
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair_3() : T1(), T2() {}
compressed_pair_3(first_param_type x, second_param_type y) : T1(x), T2(y) {}
template <class A>
explicit compressed_pair_3(const A& val)
{
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, static_cast<T1*>(this), static_cast<T2*>(this));
}
compressed_pair_3(const ::boost::compressed_pair<T1,T2>& x)
: T1(x.first()), T2(x.second()) {}
first_reference first() { return *this; }
first_const_reference first() const { return *this; }
second_reference second() { return *this; }
second_const_reference second() const { return *this; }
void swap(compressed_pair_3& y)
{
// no need to swap empty base classes:
}
};
// T1 == T2, and empty
template <class T1, class T2>
class compressed_pair_4 : T1
{
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair_4() : T1() {}
compressed_pair_4(first_param_type x, second_param_type y) : T1(x), m_second(y) {}
// only one single argument constructor since T1 == T2
explicit compressed_pair_4(first_param_type x) : T1(x), m_second(x) {}
compressed_pair_4(const ::boost::compressed_pair<T1,T2>& x)
: T1(x.first()), m_second(x.second()) {}
first_reference first() { return *this; }
first_const_reference first() const { return *this; }
second_reference second() { return m_second; }
second_const_reference second() const { return m_second; }
void swap(compressed_pair_4& y)
{
// no need to swap empty base classes:
}
private:
T2 m_second;
};
// T1 == T2, not empty
template <class T1, class T2>
class compressed_pair_5
{
private:
T1 _first;
T2 _second;
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair_5() : _first(), _second() {}
compressed_pair_5(first_param_type x, second_param_type y) : _first(x), _second(y) {}
// only one single argument constructor since T1 == T2
explicit compressed_pair_5(first_param_type x) : _first(x), _second(x) {}
compressed_pair_5(const ::boost::compressed_pair<T1,T2>& c)
: _first(c.first()), _second(c.second()) {}
first_reference first() { return _first; }
first_const_reference first() const { return _first; }
second_reference second() { return _second; }
second_const_reference second() const { return _second; }
void swap(compressed_pair_5& y)
{
using std::swap;
swap(_first, y._first);
swap(_second, y._second);
}
};
template <bool e1, bool e2, bool same>
struct compressed_pair_chooser
{
template <class T1, class T2>
struct rebind
{
typedef compressed_pair_0<T1, T2> type;
};
};
template <>
struct compressed_pair_chooser<false, true, false>
{
template <class T1, class T2>
struct rebind
{
typedef compressed_pair_1<T1, T2> type;
};
};
template <>
struct compressed_pair_chooser<true, false, false>
{
template <class T1, class T2>
struct rebind
{
typedef compressed_pair_2<T1, T2> type;
};
};
template <>
struct compressed_pair_chooser<true, true, false>
{
template <class T1, class T2>
struct rebind
{
typedef compressed_pair_3<T1, T2> type;
};
};
template <>
struct compressed_pair_chooser<true, true, true>
{
template <class T1, class T2>
struct rebind
{
typedef compressed_pair_4<T1, T2> type;
};
};
template <>
struct compressed_pair_chooser<false, false, true>
{
template <class T1, class T2>
struct rebind
{
typedef compressed_pair_5<T1, T2> type;
};
};
template <class T1, class T2>
struct compressed_pair_traits
{
private:
typedef compressed_pair_chooser<is_empty<T1>::value, is_empty<T2>::value, is_same<T1,T2>::value> chooser;
typedef typename chooser::template rebind<T1, T2> bound_type;
public:
typedef typename bound_type::type type;
};
} // namespace detail
template <class T1, class T2>
class compressed_pair : public detail::compressed_pair_traits<T1, T2>::type
{
private:
typedef typename detail::compressed_pair_traits<T1, T2>::type base_type;
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair() : base_type() {}
compressed_pair(first_param_type x, second_param_type y) : base_type(x, y) {}
template <class A>
explicit compressed_pair(const A& x) : base_type(x){}
first_reference first() { return base_type::first(); }
first_const_reference first() const { return base_type::first(); }
second_reference second() { return base_type::second(); }
second_const_reference second() const { return base_type::second(); }
};
template <class T1, class T2>
inline void swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
{
x.swap(y);
}
#else
// no partial specialisation, no member templates:
template <class T1, class T2>
class compressed_pair
{
private:
T1 _first;
T2 _second;
public:
typedef T1 first_type;
typedef T2 second_type;
typedef typename call_traits<first_type>::param_type first_param_type;
typedef typename call_traits<second_type>::param_type second_param_type;
typedef typename call_traits<first_type>::reference first_reference;
typedef typename call_traits<second_type>::reference second_reference;
typedef typename call_traits<first_type>::const_reference first_const_reference;
typedef typename call_traits<second_type>::const_reference second_const_reference;
compressed_pair() : _first(), _second() {}
compressed_pair(first_param_type x, second_param_type y) : _first(x), _second(y) {}
explicit compressed_pair(first_param_type x) : _first(x), _second() {}
// can't define this in case T1 == T2:
// explicit compressed_pair(second_param_type y) : _first(), _second(y) {}
first_reference first() { return _first; }
first_const_reference first() const { return _first; }
second_reference second() { return _second; }
second_const_reference second() const { return _second; }
void swap(compressed_pair& y)
{
using std::swap;
swap(_first, y._first);
swap(_second, y._second);
}
};
template <class T1, class T2>
inline void swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
{
x.swap(y);
}
#endif
} // boost
#endif // BOOST_OB_COMPRESSED_PAIR_HPP