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___RANGES_VIEW_H 11 #define _LIBCPP___RANGES_VIEW_H 12 13 #include <__config> 14 #include <__ranges/concepts.h> 15 #include <concepts> 16 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 #pragma GCC system_header 20 #endif 21 22 _LIBCPP_PUSH_MACROS 23 #include <__undef_macros> 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 #if !defined(_LIBCPP_HAS_NO_RANGES) 28 29 namespace ranges { 30 31 struct view_base { }; 32 33 template <class _Tp> 34 inline constexpr bool enable_view = derived_from<_Tp, view_base>; 35 36 template <class _Tp> 37 concept view = 38 range<_Tp> && 39 movable<_Tp> && 40 default_initializable<_Tp> && 41 enable_view<_Tp>; 42 43 } // end namespace ranges 44 45 #endif // !_LIBCPP_HAS_NO_RANGES 46 47 _LIBCPP_END_NAMESPACE_STD 48 49 _LIBCPP_POP_MACROS 50 51 #endif // _LIBCPP___RANGES_VIEW_H 52