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pilotclient/src/blackmisc/predicates.h
2014-06-13 13:16:04 +01:00

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3.2 KiB
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/* Copyright (C) 2013 VATSIM Community / contributors
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*!
\file
*/
#ifndef BLACKMISC_PREDICATES_H
#define BLACKMISC_PREDICATES_H
#include <functional>
#include <QObject>
namespace BlackMisc
{
namespace Predicates
{
namespace Private
{
//! \private
template <class...> struct MemberEqual;
//! \private
template <class T, class M, class V> struct MemberEqual<T, M, V>
{
M m;
V v;
MemberEqual(M m_, V v_) : m(m_), v(v_) {}
bool operator()(const T &obj) const { return (obj.*m)() == v; }
};
//! \private
template <class T, class M, class V, class... Tail> struct MemberEqual<T, M, V, Tail...>
{
MemberEqual<T, M, V> head;
MemberEqual<T, Tail...> tail;
MemberEqual(M m, V v, Tail... tail_) : head(m, v), tail(tail_...) {}
bool operator()(const T &obj) const { return head(obj) && tail(obj); }
};
//! \private
template <class...> struct MemberLess;
//! \private
template <class T, class M> struct MemberLess<T, M>
{
M m;
MemberLess(M m_) : m(m_) {}
bool operator()(const T &a, const T &b) const { return (a.*m)() < (b.*m)(); }
bool isStable(const T &a, const T &b) const { return (a.*m)() != (b.*m)(); }
};
//! \private
template <class T, class M, class... Tail> struct MemberLess<T, M, Tail...>
{
MemberLess<T, M> head;
MemberLess<T, Tail...> tail;
MemberLess(M m, Tail... tail_) : head(m), tail(tail_...) {}
bool operator()(const T &a, const T &b) const { return head.isStable(a, b) ? head(a, b) : tail(a, b); }
};
} //namespace Private
/*!
* \brief Predicate which tests whether some member functions return some values.
* \param vs Pairs of { pointer to member function of T, value to compare it against }.
* \return A unary functor whose operator() which will perform the actual test.
*/
template <class T, class... Ts>
typename Private::MemberEqual<T, Ts...> MemberEqual(Ts... vs)
{
return typename Private::MemberEqual<T, Ts...>(vs...);
}
/*!
* \brief Predicate which compares the return values of some member functions of two objects.
* \param vs Pointers to member functions of T.
* \return A binary functor whose operator() which will perform the actual test.
*/
template <class T, class... Ts>
typename Private::MemberLess<T, Ts...> MemberLess(Ts... vs)
{
return typename Private::MemberLess<T, Ts...>(vs...);
}
} //namespace Predicates
} //namespace BlackMisc
#endif //BLACKMISC_PREDICATES_H