diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt --- a/libcxx/include/CMakeLists.txt +++ b/libcxx/include/CMakeLists.txt @@ -64,6 +64,7 @@ __algorithm/pop_heap.h __algorithm/prev_permutation.h __algorithm/push_heap.h + __algorithm/ranges_max_element.h __algorithm/ranges_min_element.h __algorithm/ranges_swap_ranges.h __algorithm/remove.h diff --git a/libcxx/include/__algorithm/ranges_max_element.h b/libcxx/include/__algorithm/ranges_max_element.h new file mode 100644 --- /dev/null +++ b/libcxx/include/__algorithm/ranges_max_element.h @@ -0,0 +1,71 @@ +//===----------------------------------------------------------------------===// +// +// 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_RANGES_MAX_ELEMENT_H +#define _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H + +#include <__config> +#include <__functional/identity.h> +#include <__functional/invoke.h> +#include <__functional/ranges_operations.h> +#include <__iterator/concepts.h> +#include <__iterator/projected.h> +#include <__ranges/access.h> +#include <__ranges/concepts.h> +#include <__ranges/dangling.h> + +#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) +# pragma GCC system_header +#endif + +#ifndef _LIBCPP_HAS_NO_RANGES + +_LIBCPP_BEGIN_NAMESPACE_STD + +namespace ranges { +namespace __max_element { +struct __fn { + template + _LIBCPP_HIDE_FROM_ABI constexpr static + _Ip __go(_Ip __first, _Sp __last, _Comp& __comp, _Proj& __proj) { + if (__first == __last) + return __first; + + _Ip __i = __first; + while (++__i != __last) + if (std::invoke(__comp, std::invoke(__proj, *__first), std::invoke(__proj, *__i))) + __first = __i; + return __first; + } + + template _Sp, class _Proj = identity, + indirect_strict_weak_order> _Comp = ranges::less> + _LIBCPP_HIDE_FROM_ABI constexpr + _Ip operator()(_Ip __first, _Sp __last, _Comp __comp = {}, _Proj __proj = {}) const { + return __go(__first, __last, __comp, __proj); + } + + template , _Proj>> _Comp = ranges::less> + _LIBCPP_HIDE_FROM_ABI constexpr + borrowed_iterator_t<_Rp> operator()(_Rp&& __r, _Comp __comp = {}, _Proj __proj = {}) const { + return __go(ranges::begin(__r), ranges::end(__r), __comp, __proj); + } +}; +} // namespace __max_element + +inline namespace __cpo { + inline constexpr auto max_element = __max_element::__fn{}; +} // namespace __cpo +} // namespace ranges + +_LIBCPP_END_NAMESPACE_STD + +#endif // _LIBCPP_HAS_NO_RANGES + +#endif // _LIBCPP___ALGORITHM_RANGES_MAX_ELEMENT_H diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm --- a/libcxx/include/algorithm +++ b/libcxx/include/algorithm @@ -754,6 +754,7 @@ #include <__algorithm/pop_heap.h> #include <__algorithm/prev_permutation.h> #include <__algorithm/push_heap.h> +#include <__algorithm/ranges_max_element.h> #include <__algorithm/ranges_min_element.h> #include <__algorithm/ranges_swap_ranges.h> #include <__algorithm/remove.h> diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap --- a/libcxx/include/module.modulemap +++ b/libcxx/include/module.modulemap @@ -285,6 +285,7 @@ module pop_heap { private header "__algorithm/pop_heap.h" } module prev_permutation { private header "__algorithm/prev_permutation.h" } module push_heap { private header "__algorithm/push_heap.h" } + module ranges_max_element { private header "__algorithm/ranges_max_element.h" } module ranges_min_element { private header "__algorithm/ranges_min_element.h" } module ranges_swap_ranges { private header "__algorithm/ranges_swap_ranges.h" } module remove { private header "__algorithm/remove.h" } diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/algorithm/ranges_max_element.module.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/algorithm/ranges_max_element.module.verify.cpp new file mode 100644 --- /dev/null +++ b/libcxx/test/libcxx/diagnostics/detail.headers/algorithm/ranges_max_element.module.verify.cpp @@ -0,0 +1,15 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +// REQUIRES: modules-build + +// WARNING: This test was generated by 'generate_private_header_tests.py' +// and should not be edited manually. + +// expected-error@*:* {{use of private header from outside its module: '__algorithm/ranges_max_element.h'}} +#include <__algorithm/ranges_max_element.h> diff --git a/libcxx/test/std/algorithms/alg.sorting/alg.min.max/ranges.max_element.pass.cpp b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/ranges.max_element.pass.cpp new file mode 100644 --- /dev/null +++ b/libcxx/test/std/algorithms/alg.sorting/alg.min.max/ranges.max_element.pass.cpp @@ -0,0 +1,194 @@ +//===----------------------------------------------------------------------===// +// +// 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 +// +//===----------------------------------------------------------------------===// + +// + +// UNSUPPORTED: c++03, c++11, c++14, c++17 +// UNSUPPORTED: libcpp-no-concepts +// UNSUPPORTED: libcpp-has-no-incomplete-ranges + +// template S, class Proj = identity, +// indirect_strict_weak_order> Comp = ranges::less> +// constexpr I ranges::max_element(I first, S last, Comp comp = {}, Proj proj = {}); +// +// template, Proj>> Comp = ranges::less> +// constexpr borrowed_iterator_t ranges::max_element(R&& r, Comp comp = {}, Proj proj = {}); + +#include +#include +#include +#include +#include + +#include "test_macros.h" +#include "test_iterators.h" + +template +concept HasMinElement = requires (T t) { std::ranges::max_element(t); }; + +struct NoLessThanOp {}; +struct NotTotallyOrdered { + int i; + bool operator<(const NotTotallyOrdered& o) const { return i < o.i; } +}; + +static_assert(HasMinElement>); +static_assert(!HasMinElement); +static_assert(!HasMinElement); +static_assert(!HasMinElement); + +template +constexpr void test_iterators(Iter first, Iter last) { + std::same_as auto it = std::ranges::max_element(first, last); + if (first != last) { + for (Iter j = first; j != last; ++j) + assert(!(*j > *it)); + } else { + assert(it == first); + } +} + +template +constexpr void test_range(Range&& rng, Iter begin, Iter end) { + std::same_as auto it = std::ranges::max_element(std::forward(rng)); + if (begin != end) { + for (Iter j = begin; j != end; ++j) + assert(!(*j > *it)); + } else { + assert(it == begin); + } +} + +template +constexpr void test(std::initializer_list a, int expected) { + const int* first = a.begin(); + const int* last = a.end(); + { + std::same_as auto it = std::ranges::max_element(It(first), It(last)); + assert(base(it) == first + expected); + } + { + using Sent = sentinel_wrapper; + std::same_as auto it = std::ranges::max_element(It(first), Sent(It(last))); + assert(base(it) == first + expected); + } + { + auto range = std::ranges::subrange(It(first), It(last)); + std::same_as auto it = std::ranges::max_element(range); + assert(base(it) == first + expected); + } + { + using Sent = sentinel_wrapper; + auto range = std::ranges::subrange(It(first), Sent(It(last))); + std::same_as auto it = std::ranges::max_element(range); + assert(base(it) == first + expected); + } +} + +template +constexpr bool test() { + test({}, 0); + test({1}, 0); + test({1, 2}, 1); + test({2, 1}, 0); + test({2, 1, 2}, 0); + test({2, 1, 1}, 0); + + return true; +} + +constexpr void test_borrowed_range_and_sentinel() { + int a[] = {7, 6, 1, 3, 5, 1, 2, 4}; + + int* ret = std::ranges::max_element(std::views::all(a)); + assert(ret == a + 0); + assert(*ret == 7); +} + +constexpr void test_comparator() { + int a[] = {7, 6, 9, 3, 5, 1, 2, 4}; + int* ret = std::ranges::max_element(a, std::ranges::greater{}); + assert(ret == a + 5); + assert(*ret == 1); +} + +constexpr void test_projection() { + int a[] = {7, 6, 9, 3, 5, 1, 2, 4}; + { + int* ret = std::ranges::max_element(a, std::ranges::less{}, [](int i) { return i == 5 ? 100 : i; }); + assert(ret == a + 4); + assert(*ret == 5); + } + { + int* ret = std::ranges::max_element(a, std::less{}, [](int& i) { return &i; }); + assert(ret == a + 7); + assert(*ret == 4); + } +} + +struct Immobile { + int i; + + constexpr Immobile(int i_) : i(i_) {} + Immobile(const Immobile&) = delete; + Immobile(Immobile&&) = delete; + + auto operator<=>(const Immobile&) const = default; +}; + +constexpr void test_immobile() { + + Immobile arr[] {1, 2, 3}; + assert(std::ranges::max_element(arr) == arr); + assert(std::ranges::max_element(arr, arr + 3) == arr); +} + +constexpr void test_dangling() { + int compares = 0; + int projections = 0; + auto comparator = [&](int a, int b) { + ++compares; + return a < b; + }; + auto projection = [&](int a) { + ++projections; + return a; + }; + [[maybe_unused]] std::same_as auto ret = + std::ranges::max_element(std::array{1, 2, 3}, comparator, projection); + assert(compares == 2); + assert(projections == 4); +} + +constexpr bool test() { + + test>(); + test>(); + test>(); + test(); + + int a[] = {7, 6, 5, 3, 4, 2, 1, 8}; + test_iterators(a, a + 8); + int a2[] = {7, 6, 5, 3, 4, 2, 1, 8}; + test_range(a2, a2, a2 + 8); + + test_borrowed_range_and_sentinel(); + test_comparator(); + test_projection(); + test_dangling(); + + return true; +} + +int main(int, char**) { + test(); + static_assert(test()); + + return 0; +}