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_MERGE_H
10#define _LIBCPP___ALGORITHM_MERGE_H
11
12#include <__algorithm/comp.h>
13#include <__algorithm/comp_ref_type.h>
14#include <__algorithm/copy.h>
15#include <__config>
16
17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18#  pragma GCC system_header
19#endif
20
21_LIBCPP_BEGIN_NAMESPACE_STD
22
23template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
24_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator __merge(
25    _InputIterator1 __first1,
26    _InputIterator1 __last1,
27    _InputIterator2 __first2,
28    _InputIterator2 __last2,
29    _OutputIterator __result,
30    _Compare __comp) {
31  for (; __first1 != __last1; ++__result) {
32    if (__first2 == __last2)
33      return std::copy(__first1, __last1, __result);
34    if (__comp(*__first2, *__first1)) {
35      *__result = *__first2;
36      ++__first2;
37    } else {
38      *__result = *__first1;
39      ++__first1;
40    }
41  }
42  return std::copy(__first2, __last2, __result);
43}
44
45template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
46inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
47merge(_InputIterator1 __first1,
48      _InputIterator1 __last1,
49      _InputIterator2 __first2,
50      _InputIterator2 __last2,
51      _OutputIterator __result,
52      _Compare __comp) {
53  return std::__merge<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __result, __comp);
54}
55
56template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
57inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator
58merge(_InputIterator1 __first1,
59      _InputIterator1 __last1,
60      _InputIterator2 __first2,
61      _InputIterator2 __last2,
62      _OutputIterator __result) {
63  return std::merge(__first1, __last1, __first2, __last2, __result, __less<>());
64}
65
66_LIBCPP_END_NAMESPACE_STD
67
68#endif // _LIBCPP___ALGORITHM_MERGE_H