libcxx/include/__iterator/mergeable.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___ITERATOR_MERGEABLE_H
  11 #define _LIBCPP___ITERATOR_MERGEABLE_H
  12
  13 #include <__config>
  14 #include <__functional/identity.h>
  15 #include <__functional/ranges_operations.h>
  16 #include <__iterator/concepts.h>
  17 #include <__iterator/projected.h>
  18
  19 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  20 #  pragma GCC system_header
  21 #endif
  22
  23 _LIBCPP_BEGIN_NAMESPACE_STD
  24
  25 #if _LIBCPP_STD_VER >= 20
  26
  27 template <class _Input1, class _Input2, class _Output,
  28           class _Comp = ranges::less, class _Proj1 = identity, class _Proj2 = identity>
  29 concept mergeable =
  30     input_iterator<_Input1> &&
  31     input_iterator<_Input2> &&
  32     weakly_incrementable<_Output> &&
  33     indirectly_copyable<_Input1, _Output> &&
  34     indirectly_copyable<_Input2, _Output> &&
  35     indirect_strict_weak_order<_Comp, projected<_Input1, _Proj1>, projected<_Input2, _Proj2>>;
  36
  37 #endif // _LIBCPP_STD_VER >= 20
  38
  39 _LIBCPP_END_NAMESPACE_STD
  40
  41 #endif // _LIBCPP___ITERATOR_MERGEABLE_H