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,
  28           class _Input2,
  29           class _Output,
  30           class _Comp  = ranges::less,
  31           class _Proj1 = identity,
  32           class _Proj2 = identity>
  33 concept mergeable =
  34     input_iterator<_Input1> && input_iterator<_Input2> && weakly_incrementable<_Output> &&
  35     indirectly_copyable<_Input1, _Output> && indirectly_copyable<_Input2, _Output> &&
  36     indirect_strict_weak_order<_Comp, projected<_Input1, _Proj1>, projected<_Input2, _Proj2>>;
  37
  38 #endif // _LIBCPP_STD_VER >= 20
  39
  40 _LIBCPP_END_NAMESPACE_STD
  41
  42 #endif // _LIBCPP___ITERATOR_MERGEABLE_H