libcxx/include/__algorithm/push_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_PUSH_HEAP_H
  10 #define _LIBCPP___ALGORITHM_PUSH_HEAP_H
  11
  12 #include <__algorithm/comp.h>
  13 #include <__algorithm/comp_ref_type.h>
  14 #include <__algorithm/iterator_operations.h>
  15 #include <__config>
  16 #include <__iterator/iterator_traits.h>
  17 #include <__type_traits/is_assignable.h>
  18 #include <__type_traits/is_constructible.h>
  19 #include <__utility/move.h>
  20
  21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  22 #  pragma GCC system_header
  23 #endif
  24
  25 _LIBCPP_PUSH_MACROS
  26 #include <__undef_macros>
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 template <class _AlgPolicy, class _Compare, class _RandomAccessIterator>
  31 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
  32 __sift_up(_RandomAccessIterator __first,
  33           _RandomAccessIterator __last,
  34           _Compare&& __comp,
  35           typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
  36   using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
  37
  38   if (__len > 1) {
  39     __len                       = (__len - 2) / 2;
  40     _RandomAccessIterator __ptr = __first + __len;
  41
  42     if (__comp(*__ptr, *--__last)) {
  43       value_type __t(_IterOps<_AlgPolicy>::__iter_move(__last));
  44       do {
  45         *__last = _IterOps<_AlgPolicy>::__iter_move(__ptr);
  46         __last  = __ptr;
  47         if (__len == 0)
  48           break;
  49         __len = (__len - 1) / 2;
  50         __ptr = __first + __len;
  51       } while (__comp(*__ptr, __t));
  52
  53       *__last = std::move(__t);
  54     }
  55   }
  56 }
  57
  58 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
  59 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14 void
  60 __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
  61   typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
  62   std::__sift_up<_AlgPolicy, __comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp, __len);
  63 }
  64
  65 template <class _RandomAccessIterator, class _Compare>
  66 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
  67 push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
  68   static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
  69   static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
  70
  71   std::__push_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
  72 }
  73
  74 template <class _RandomAccessIterator>
  75 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void
  76 push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
  77   std::push_heap(std::move(__first), std::move(__last), __less<>());
  78 }
  79
  80 _LIBCPP_END_NAMESPACE_STD
  81
  82 _LIBCPP_POP_MACROS
  83
  84 #endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H