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_copy_assignable.h>
  18 #include <__type_traits/is_copy_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
  32 void __sift_up(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp,
  33         typename iterator_traits<_RandomAccessIterator>::difference_type __len) {
  34   using value_type = typename iterator_traits<_RandomAccessIterator>::value_type;
  35
  36   if (__len > 1) {
  37     __len = (__len - 2) / 2;
  38     _RandomAccessIterator __ptr = __first + __len;
  39
  40     if (__comp(*__ptr, *--__last)) {
  41       value_type __t(_IterOps<_AlgPolicy>::__iter_move(__last));
  42       do {
  43         *__last = _IterOps<_AlgPolicy>::__iter_move(__ptr);
  44         __last = __ptr;
  45         if (__len == 0)
  46           break;
  47         __len = (__len - 1) / 2;
  48         __ptr = __first + __len;
  49       } while (__comp(*__ptr, __t));
  50
  51       *__last = std::move(__t);
  52     }
  53   }
  54 }
  55
  56 template <class _AlgPolicy, class _RandomAccessIterator, class _Compare>
  57 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX14
  58 void __push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare& __comp) {
  59   typename iterator_traits<_RandomAccessIterator>::difference_type __len = __last - __first;
  60   std::__sift_up<_AlgPolicy, __comp_ref_type<_Compare> >(std::move(__first), std::move(__last), __comp, __len);
  61 }
  62
  63 template <class _RandomAccessIterator, class _Compare>
  64 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
  65 void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
  66   static_assert(std::is_copy_constructible<_RandomAccessIterator>::value, "Iterators must be copy constructible.");
  67   static_assert(std::is_copy_assignable<_RandomAccessIterator>::value, "Iterators must be copy assignable.");
  68
  69   std::__push_heap<_ClassicAlgPolicy>(std::move(__first), std::move(__last), __comp);
  70 }
  71
  72 template <class _RandomAccessIterator>
  73 inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
  74 void push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last) {
  75   std::push_heap(std::move(__first), std::move(__last), __less<>());
  76 }
  77
  78 _LIBCPP_END_NAMESPACE_STD
  79
  80 _LIBCPP_POP_MACROS
  81
  82 #endif // _LIBCPP___ALGORITHM_PUSH_HEAP_H