libcxx/include/__algorithm/merge.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_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
  24 template <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
  48 template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
  49 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
  50 _OutputIterator
  51 merge(_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
  57 template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
  58 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20
  59 _OutputIterator
  60 merge(_InputIterator1 __first1, _InputIterator1 __last1,
  61       _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
  62 {
  63     return _VSTD::merge(__first1, __last1, __first2, __last2, __result, __less<>());
  64 }
  65
  66 _LIBCPP_END_NAMESPACE_STD
  67
  68 #endif // _LIBCPP___ALGORITHM_MERGE_H