libcxx/include/__algorithm/is_heap_until.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_IS_HEAP_UNTIL_H
  10 #define _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H
  11
  12 #include <__algorithm/comp.h>
  13 #include <__algorithm/comp_ref_type.h>
  14 #include <__config>
  15 #include <__iterator/iterator_traits.h>
  16
  17 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  18 #  pragma GCC system_header
  19 #endif
  20
  21 _LIBCPP_BEGIN_NAMESPACE_STD
  22
  23 template <class _Compare, class _RandomAccessIterator>
  24 _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
  25 __is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare&& __comp) {
  26   typedef typename iterator_traits<_RandomAccessIterator>::difference_type difference_type;
  27   difference_type __len      = __last - __first;
  28   difference_type __p        = 0;
  29   difference_type __c        = 1;
  30   _RandomAccessIterator __pp = __first;
  31   while (__c < __len) {
  32     _RandomAccessIterator __cp = __first + __c;
  33     if (__comp(*__pp, *__cp))
  34       return __cp;
  35     ++__c;
  36     ++__cp;
  37     if (__c == __len)
  38       return __last;
  39     if (__comp(*__pp, *__cp))
  40       return __cp;
  41     ++__p;
  42     ++__pp;
  43     __c = 2 * __p + 1;
  44   }
  45   return __last;
  46 }
  47
  48 template <class _RandomAccessIterator, class _Compare>
  49 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
  50 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp) {
  51   return std::__is_heap_until(__first, __last, static_cast<__comp_ref_type<_Compare> >(__comp));
  52 }
  53
  54 template <class _RandomAccessIterator>
  55 [[__nodiscard__]] inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _RandomAccessIterator
  56 is_heap_until(_RandomAccessIterator __first, _RandomAccessIterator __last) {
  57   return std::__is_heap_until(__first, __last, __less<>());
  58 }
  59
  60 _LIBCPP_END_NAMESPACE_STD
  61
  62 #endif // _LIBCPP___ALGORITHM_IS_HEAP_UNTIL_H