libcxx/include/__algorithm/make_heap.h

   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_MAKE_HEAP_H
  10 #define _LIBCPP___ALGORITHM_MAKE_HEAP_H
  11
  12 #include <__algorithm/comp.h>
  13 #include <__algorithm/comp_ref_type.h>
  14 #include <__algorithm/iterator_operations.h>
  15 #include <__algorithm/sift_down.h>
  16 #include <__config>
  17 #include <__iterator/iterator_traits.h>
  18 #include <__utility/move.h>
  19
  20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  21 #  pragma GCC system_header
  22 #endif
  23
  24 _LIBCPP_PUSH_MACROS
  25 #include <__undef_macros>
  26
  27 _LIBCPP_BEGIN_NAMESPACE_STD
  28
  29 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
  30 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
  31 __make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
  32   __comp_ref_type<_Compare> __comp_ref = __comp;
  33
  34   using difference_type = typename iterator_traits<_RandomAccessIterator>::difference_type;
  35   difference_type __n   = __last - __first;
  36   if (__n > 1) {
  37     // start from the first parent, there is no need to consider children
  38     for (difference_type __start = (__n - 2) / 2; __start >= 0; --__start) {
  39       std::__sift_down<_AlgPolicy>(__first, __comp_ref, __n, __first + __start);
  40     }
  41   }
  42 }
  43
  44 template <class _RandomAccessIterator, class _Compare>
  45 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
  46 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
  47   std::__make_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
  48 }
  49
  50 template <class _RandomAccessIterator>
  51 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
  52 make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
  53   std::make_heap(std::move(__first), std::move(__last), __less<>());
  54 }
  55
  56 _LIBCPP_END_NAMESPACE_STD
  57
  58 _LIBCPP_POP_MACROS
  59
  60 #endif // _LIBCPP___ALGORITHM_MAKE_HEAP_H