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#include <__iterator/iterator_traits.h>
17
18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
19#  pragma GCC system_header
20#endif
21
22_LIBCPP_BEGIN_NAMESPACE_STD
23
24template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
25_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20
26_OutputIterator
27__merge(_InputIterator1 __first1, _InputIterator1 __last1,
28        _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
29{
30    for (; __first1 != __last1; ++__result)
31    {
32        if (__first2 == __last2)
33            return _VSTD::copy(__first1, __last1, __result);
34        if (__comp(*__first2, *__first1))
35        {
36            *__result = *__first2;
37            ++__first2;
38        }
39        else
40        {
41            *__result = *__first1;
42            ++__first1;
43        }
44    }
45    return _VSTD::copy(__first2, __last2, __result);
46}
47
48template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
49inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
50_OutputIterator
51merge(_InputIterator1 __first1, _InputIterator1 __last1,
52      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
53{
54    return _VSTD::__merge<__comp_ref_type<_Compare> >(__first1, __last1, __first2, __last2, __result, __comp);
55}
56
57template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
58inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
59_OutputIterator
60merge(_InputIterator1 __first1, _InputIterator1 __last1,
61      _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
62{
63    typedef typename iterator_traits<_InputIterator1>::value_type __v1;
64    typedef typename iterator_traits<_InputIterator2>::value_type __v2;
65    return _VSTD::merge(__first1, __last1, __first2, __last2, __result, __less<__v1, __v2>());
66}
67
68_LIBCPP_END_NAMESPACE_STD
69
70#endif // _LIBCPP___ALGORITHM_MERGE_H
71