gplib/include/gp/pair.hpp

#pragma once

#include "gp/algorithm/move.hpp"

namespace gp{
	template<typename T1, typename T2>
	struct pair{
		T1 first;
		T2 second;

		constexpr pair() 
		: first()
		, second() 
		{}

		constexpr pair(const T1& a, const T2& b) 
		: first(a)
		, second(b) 
		{}

		constexpr pair(pair&& v)
		: first(gp::move(v.first))
		, second(gp::move(v.second))
		{}

		template<typename U1, typename U2>
		constexpr pair(U1&& a, U2&& b) 
		: first(gp::forward<U1>(a))
		, second(gp::forward<U2>(b))
		{}

		template<typename U1, typename U2>
		constexpr pair(pair<U1, U2>&& v)
		: first(gp::move(v.first))
		, second(gp::move(v.second))
		{}

		constexpr pair& operator=(pair&& v)
		{
			first = gp::move(v.first);
			second = gp::move(v.second);
			return *this;
		}
	};

	template<typename F, typename S>
	constexpr bool operator==(const pair<F, S>& lhs, const pair<F, S>& rhs) {
		return lhs.first == rhs.first and lhs.second == rhs.second;
	}

	template<typename F, typename S>
	constexpr bool operator!=(const pair<F, S>& lhs, const pair<F, S>& rhs) {
		return lhs.first != rhs.first or lhs.second != rhs.second;
	}

	template<typename F, typename S>
	constexpr bool operator<=(const pair<F, S>& lhs, const pair<F, S>& rhs) {
		if(lhs.first > rhs.first) {
			return false;
		} else if(lhs.first == rhs.first) {
			return lhs.second <= rhs.second;
		}
		return true;
	}

	template<typename F, typename S>
	constexpr bool operator>=(const pair<F, S>& lhs, const pair<F, S>& rhs) {
		if(lhs.first < rhs.first) {
			return false;
		} else if(lhs.first == rhs.first) {
			return lhs.second >= rhs.second;
		}
		return true;
	}

	template<typename F, typename S>
	constexpr bool operator<(const pair<F, S>& lhs, const pair<F, S>& rhs) {
		return !(lhs >= rhs);
	}

	template<typename F, typename S>
	constexpr bool operator>(const pair<F, S>& lhs, const pair<F, S>& rhs) {
		return !(lhs <= rhs);
	}
}