Nhat Nguyen 8d151f804f
[libc++] Check correctly ref-qualified __is_callable in algorithms (#73451)
We were only checking that the comparator was rvalue callable,
when in reality the algorithms always call comparators as lvalues.
This patch also refactors the tests for callable requirements and
expands it to a few missing algorithms.

Fixes #69554
2024-08-01 14:08:21 -04:00

101 lines
3.3 KiB
C++

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
#define _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H
#include <__algorithm/comp.h>
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
#include <__iterator/iterator_traits.h>
#include <__type_traits/is_callable.h>
#include <__utility/pair.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Comp, class _Proj>
class _MinmaxElementLessFunc {
_Comp& __comp_;
_Proj& __proj_;
public:
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _MinmaxElementLessFunc(_Comp& __comp, _Proj& __proj)
: __comp_(__comp), __proj_(__proj) {}
template <class _Iter>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 bool operator()(_Iter& __it1, _Iter& __it2) {
return std::__invoke(__comp_, std::__invoke(__proj_, *__it1), std::__invoke(__proj_, *__it2));
}
};
template <class _Iter, class _Sent, class _Proj, class _Comp>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_Iter, _Iter>
__minmax_element_impl(_Iter __first, _Sent __last, _Comp& __comp, _Proj& __proj) {
auto __less = _MinmaxElementLessFunc<_Comp, _Proj>(__comp, __proj);
pair<_Iter, _Iter> __result(__first, __first);
if (__first == __last || ++__first == __last)
return __result;
if (__less(__first, __result.first))
__result.first = __first;
else
__result.second = __first;
while (++__first != __last) {
_Iter __i = __first;
if (++__first == __last) {
if (__less(__i, __result.first))
__result.first = __i;
else if (!__less(__i, __result.second))
__result.second = __i;
return __result;
}
if (__less(__first, __i)) {
if (__less(__first, __result.first))
__result.first = __first;
if (!__less(__i, __result.second))
__result.second = __i;
} else {
if (__less(__i, __result.first))
__result.first = __i;
if (!__less(__first, __result.second))
__result.second = __first;
}
}
return __result;
}
template <class _ForwardIterator, class _Compare>
_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_ForwardIterator, _ForwardIterator>
minmax_element(_ForwardIterator __first, _ForwardIterator __last, _Compare __comp) {
static_assert(
__has_forward_iterator_category<_ForwardIterator>::value, "std::minmax_element requires a ForwardIterator");
static_assert(
__is_callable<_Compare&, decltype(*__first), decltype(*__first)>::value, "The comparator has to be callable");
auto __proj = __identity();
return std::__minmax_element_impl(__first, __last, __comp, __proj);
}
template <class _ForwardIterator>
_LIBCPP_NODISCARD inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 pair<_ForwardIterator, _ForwardIterator>
minmax_element(_ForwardIterator __first, _ForwardIterator __last) {
return std::minmax_element(__first, __last, __less<>());
}
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ALGORITHM_MINMAX_ELEMENT_H