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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___ALGORITHM_POP_HEAP_H 10 #define _LIBCPP___ALGORITHM_POP_HEAP_H 11 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 <__utility/move.h> 21 #include <type_traits> 22 23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 24 # pragma GCC system_header 25 #endif 26 27 _LIBCPP_BEGIN_NAMESPACE_STD 28 29 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator> 30 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 31 void __pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp, 32 typename iterator_traits<_RandomAccessIterator>::difference_type __len) { 33 _LIBCPP_ASSERT(__len > 0, "The heap given to pop_heap must be non-empty"); 34 35 using _CompRef = typename __comp_ref_type<_Compare>::type; 36 _CompRef __comp_ref = __comp; 37 38 using value_type = typename iterator_traits<_RandomAccessIterator>::value_type; 39 if (__len > 1) { 40 value_type __top = _IterOps<_AlgPolicy>::__iter_move(__first); // create a hole at __first 41 _RandomAccessIterator __hole = std::__floyd_sift_down<_AlgPolicy>(__first, __comp_ref, __len); 42 --__last; 43 44 if (__hole == __last) { 45 *__hole = std::move(__top); 46 } else { 47 *__hole = _IterOps<_AlgPolicy>::__iter_move(__last); 48 ++__hole; 49 *__last = std::move(__top); 50 std::__sift_up<_AlgPolicy>(__first, __hole, __comp_ref, __hole - __first); 51 } 52 } 53 } 54 55 template <class _RandomAccessIterator, class _Compare> 56 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 57 void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) { 58 static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible."); 59 static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable."); 60 61 typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first; 62 std::__pop_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp, __len); 63 } 64 65 template <class _RandomAccessIterator> 66 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 67 void pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) { 68 std::pop_heap(std::move(__first), std::move(__last), 69 __less<typename iterator_traits<_RandomAccessIterator>::value_type>()); 70 } 71 72 _LIBCPP_END_NAMESPACE_STD 73 74 #endif // _LIBCPP___ALGORITHM_POP_HEAP_H 75