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// Copyright (C) 2010 Davis E. King (davis@dlib.net)
// License: Boost Software License See LICENSE.txt for the full license.
#ifndef DLIB_UNORDERED_PAiR_Hh_
#define DLIB_UNORDERED_PAiR_Hh_
#include "serialize.h"
namespace dlib
{
// ----------------------------------------------------------------------------------------
template <
typename T
>
struct unordered_pair
{
/*!
REQUIREMENTS ON T
T must be default constructable, copyable, and comparable using
operator < and ==
WHAT THIS OBJECT REPRESENTS
This object is very similar to the std::pair struct except unordered_pair
is only capable of representing an unordered set of two items rather than
an ordered list of two items like std::pair.
This is best illustrated by example. Suppose we have the following
five variables:
std::pair<int,int> p1(1, 5), p2(5,1);
unordered_pair<int> up1(1,5), up2(5,1), up3(6,7);
Then it is the case that:
up1 == up2
up1 != up3
p1 != p2
So the unordered_pair doesn't care about the order of the arguments.
In this case, up1 and up2 are both equivalent.
!*/
typedef T type;
typedef T first_type;
typedef T second_type;
const T first;
const T second;
unordered_pair() : first(), second()
/*!
ensures
- #first and #second are default initialized
!*/ {}
unordered_pair(
const T& a,
const T& b
) :
first( a < b ? a : b),
second(a < b ? b : a)
/*!
ensures
- #first <= #second
- #first and #second contain copies of the items a and b.
!*/ {}
template <typename U>
unordered_pair (
const unordered_pair <U>& p
) :
first(p.first),
second(p.second)
/*!
ensures
- #*this is a copy of p
!*/ {}
unordered_pair& operator= (
const unordered_pair& item
)
/*!
ensures
- #*this == item
!*/
{
const_cast<T&>(first) = item.first;
const_cast<T&>(second) = item.second;
return *this;
}
};
// ----------------------------------------------------------------------------------------
template <typename T>
bool operator==(const unordered_pair<T>& a, const unordered_pair <T>& b)
{
return a.first == b.first && a.second == b.second;
}
template <typename T>
bool operator!=(const unordered_pair<T>& a, const unordered_pair <T>& b)
{
return !(a == b);
}
template <typename T>
bool operator<(const unordered_pair<T>& a, const unordered_pair<T>& b)
{
return (a.first < b.first || (!(b.first < a.first) && a.second < b.second));
}
template <typename T>
bool operator>(const unordered_pair<T>& a, const unordered_pair <T>& b)
{
return b < a;
}
template <typename T>
bool operator<=(const unordered_pair<T>& a, const unordered_pair <T>& b)
{
return !(b < a);
}
template <typename T>
bool operator>=(const unordered_pair<T>& a, const unordered_pair <T>& b)
{
return !(a < b);
}
template <typename T>
unordered_pair<T> make_unordered_pair (const T& a, const T& b)
{
return unordered_pair<T>(a,b);
}
// ----------------------------------------------------------------------------------------
template <typename T>
void serialize (
const unordered_pair<T>& item,
std::ostream& out
)
{
try
{
serialize(item.first,out);
serialize(item.second,out);
}
catch (serialization_error& e)
{ throw serialization_error(e.info + "\n while serializing object of type unordered_pair"); }
}
template <typename T>
void deserialize (
unordered_pair<T>& item,
std::istream& in
)
{
try
{
T a, b;
deserialize(a,in);
deserialize(b,in);
item = make_unordered_pair(a,b);
}
catch (serialization_error& e)
{ throw serialization_error(e.info + "\n while deserializing object of type unordered_pair"); }
}
// ----------------------------------------------------------------------------------------
}
#endif // DLIB_UNORDERED_PAiR_Hh_
|
