refs #698 Avoid recursive templates by using C++14 generic lambda.

This commit is contained in:
Mathew Sutcliffe
2016-07-03 01:54:05 +01:00
parent b859bead0c
commit 8a46a11dd8
2 changed files with 74 additions and 71 deletions

View File

@@ -12,6 +12,8 @@
#ifndef BLACKMISC_ALGORITHM_H
#define BLACKMISC_ALGORITHM_H
#include "integersequence.h"
#include <QThreadStorage>
#include <QtGlobal>
#include <algorithm>
@@ -138,6 +140,50 @@ namespace BlackMisc
"BlackMisc::topologicallySortedInsert", "Cyclic less-than relation detected (not a partial ordering)");
container.insert(rit.base(), std::forward<T>(value));
}
namespace Private
{
//! \private
template <typename T, typename F, size_t... Is>
void tupleForEachImpl(T &&tuple, F &&visitor, index_sequence<Is...>)
{
// parameter pack swallow idiom
static_cast<void>(std::initializer_list<int>
{
(static_cast<void>(std::forward<F>(visitor)(std::get<Is>(std::forward<T>(tuple)))), 0)...
});
}
//! \private
template <typename T, typename F, size_t... Is>
void tupleForEachPairImpl(T &&tuple, F &&visitor, index_sequence<Is...>)
{
// parameter pack swallow idiom
static_cast<void>(std::initializer_list<int>
{
(static_cast<void>(std::forward<F>(visitor)(std::get<Is * 2>(std::forward<T>(tuple)), std::get<Is * 2 + 1>(std::forward<T>(tuple)))), 0)...
});
}
}
/*!
* Invoke a visitor function on each element of a tuple in order.
*/
template <typename T, typename F>
void tupleForEach(T &&tuple, F &&visitor)
{
using seq = Private::make_index_sequence<std::tuple_size<std::decay_t<T>>::value>;
return Private::tupleForEachImpl(std::forward<T>(tuple), std::forward<F>(visitor), seq());
}
/*!
* Invoke a visitor function on each pair of elements of a tuple in order.
*/
template <typename T, typename F>
void tupleForEachPair(T &&tuple, F &&visitor)
{
using seq = Private::make_index_sequence<std::tuple_size<std::decay_t<T>>::value / 2>;
return Private::tupleForEachPairImpl(std::forward<T>(tuple), std::forward<F>(visitor), seq());
}
}
#endif

View File

@@ -15,6 +15,7 @@
#define BLACKMISC_PREDICATES_H
#include "integersequence.h"
#include "algorithm.h"
#include <QObject>
#include <functional>
@@ -29,69 +30,6 @@ namespace BlackMisc
namespace Private
{
//! \private
template <class...> struct MemberEqual;
//! \private
template <class M, class V> struct MemberEqual<M, V>
{
M m;
V v;
MemberEqual(M m_, V v_) : m(m_), v(v_) {}
template <class T> bool operator()(const T &obj) const { return (obj.*m)() == v; }
};
//! \private
template <class M, class V, class... Tail> struct MemberEqual<M, V, Tail...>
{
MemberEqual<M, V> head;
MemberEqual<Tail...> tail;
MemberEqual(M m, V v, Tail... tail_) : head(m, v), tail(tail_...) {}
template <class T> bool operator()(const T &obj) const { return head(obj) && tail(obj); }
};
//! \private
template <class...> struct MemberLess;
//! \private
template <class M> struct MemberLess<M>
{
M m;
MemberLess(M m_) : m(m_) {}
template <class T> bool operator()(const T &a, const T &b) const { return (a.*m)() < (b.*m)(); }
template <class T> bool isStable(const T &a, const T &b) const { return (a.*m)() != (b.*m)(); }
};
//! \private
template <class M, class... Tail> struct MemberLess<M, Tail...>
{
MemberLess<M> head;
MemberLess<Tail...> tail;
MemberLess(M m, Tail... tail_) : head(m), tail(tail_...) {}
template <class T> bool operator()(const T &a, const T &b) const { return head.isStable(a, b) ? head(a, b) : tail(a, b); }
};
//! \private
template <class...> struct EqualsByMembers;
//! \private
template <class M> struct EqualsByMembers<M>
{
M m;
EqualsByMembers(M m_) : m(m_) {}
template <class T> bool operator()(const T &a, const T &b) const { return (a.*m)() == (b.*m)(); }
};
//! \private
template <class M, class... Tail> struct EqualsByMembers<M, Tail...>
{
EqualsByMembers<M> head;
EqualsByMembers<Tail...> tail;
EqualsByMembers(M m, Tail... tail_) : head(m), tail(tail_...) {}
template <class T> bool operator()(const T &a, const T &b) const { return head(a, b) && tail(a, b); }
};
//! \private
struct Matches
{
@@ -99,8 +37,7 @@ namespace BlackMisc
Matches(const CPropertyIndexVariantMap &map) : m_map(map) {}
template <class T> bool operator()(const T &value) const;
};
} //namespace Private
}
/*!
* Predicate which tests whether some member functions return some values.
@@ -108,9 +45,14 @@ namespace BlackMisc
* \return A unary functor whose operator() which will perform the actual test.
*/
template <class... Ts>
Private::MemberEqual<Ts...> MemberEqual(Ts... vs)
auto MemberEqual(Ts... vs)
{
return { vs... };
return [vs...](const auto &object)
{
bool equal = true;
tupleForEachPair(std::make_tuple(vs...), [ & ](auto member, const auto &value) { equal = equal && (object.*member)() == value; });
return equal;
};
}
/*!
@@ -119,9 +61,19 @@ namespace BlackMisc
* \return A binary functor whose operator() which will perform the actual test.
*/
template <class... Ts>
Private::MemberLess<Ts...> MemberLess(Ts... vs)
auto MemberLess(Ts... vs)
{
return { vs... };
return [vs...](const auto &a, const auto &b)
{
bool less = true;
bool greater = false;
tupleForEach(std::make_tuple(vs...), [ & ](auto member)
{
less = less && ! greater && (a.*member)() < (b.*member)();
greater = (b.*member)() < (a.*member)();
});
return less;
};
}
/*!
@@ -165,9 +117,14 @@ namespace BlackMisc
* Returns a predicate that returns true if its arguments compare equal to each other, considering only the captured members.
*/
template <class... Ts>
Private::EqualsByMembers<Ts...> EqualsByMembers(Ts... vs)
auto EqualsByMembers(Ts... vs)
{
return { vs... };
return [vs...](const auto &a, const auto &b)
{
bool equal = true;
tupleForEach(std::make_tuple(vs...), [ & ](auto member) { equal = equal && (a.*member)() == (b.*member)(); });
return equal;
};
}
/*!