82 lines · c
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___ALGORITHM_POP_HEAP_H10#define _LIBCPP___ALGORITHM_POP_HEAP_H11 12#include <__algorithm/comp.h>13#include <__algorithm/comp_ref_type.h>14#include <__algorithm/iterator_operations.h>15#include <__algorithm/push_heap.h>16#include <__algorithm/sift_down.h>17#include <__assert>18#include <__config>19#include <__iterator/iterator_traits.h>20#include <__type_traits/is_assignable.h>21#include <__type_traits/is_constructible.h>22#include <__utility/move.h>23 24#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)25# pragma GCC system_header26#endif27 28_LIBCPP_PUSH_MACROS29#include <__undef_macros>30 31_LIBCPP_BEGIN_NAMESPACE_STD32 33template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>34inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void35__pop_heap(_RandomAccessIterator __first,36 _RandomAccessIterator __last,37 _Compare& __comp,38 typename iterator_traits<_RandomAccessIterator>::difference_type __len) {39 // Calling `pop_heap` on an empty range is undefined behavior, but in practice it will be a no-op.40 _LIBCPP_ASSERT_PEDANTIC(__len > 0, "The heap given to pop_heap must be non-empty");41 42 __comp_ref_type<_Compare> __comp_ref = __comp;43 44 using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;45 if (__len > 1) {46 value_type __top = _IterOps<_AlgPolicy>::__iter_move(__first); // create a hole at __first47 _RandomAccessIterator __hole = std::__floyd_sift_down<_AlgPolicy>(__first, __comp_ref, __len);48 --__last;49 50 if (__hole == __last) {51 *__hole = std::move(__top);52 } else {53 *__hole = _IterOps<_AlgPolicy>::__iter_move(__last);54 ++__hole;55 *__last = std::move(__top);56 std::__sift_up<_AlgPolicy>(__first, __hole, __comp_ref, __hole - __first);57 }58 }59}60 61template <class _RandomAccessIterator, class _Compare>62inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void63pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {64 static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");65 static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");66 67 typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;68 std::__pop_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp, __len);69}70 71template <class _RandomAccessIterator>72inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void73pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {74 std::pop_heap(std::move(__first), std::move(__last), __less<>());75}76 77_LIBCPP_END_NAMESPACE_STD78 79_LIBCPP_POP_MACROS80 81#endif // _LIBCPP___ALGORITHM_POP_HEAP_H82