libcxx/include/__cxx03/__ranges/data.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___CXX03___RANGES_DATA_H
  11 #define _LIBCPP___CXX03___RANGES_DATA_H
  12
  13 #include <__cxx03/__concepts/class_or_enum.h>
  14 #include <__cxx03/__config>
  15 #include <__cxx03/__iterator/concepts.h>
  16 #include <__cxx03/__iterator/iterator_traits.h>
  17 #include <__cxx03/__memory/pointer_traits.h>
  18 #include <__cxx03/__ranges/access.h>
  19 #include <__cxx03/__type_traits/decay.h>
  20 #include <__cxx03/__type_traits/is_object.h>
  21 #include <__cxx03/__type_traits/is_pointer.h>
  22 #include <__cxx03/__type_traits/is_reference.h>
  23 #include <__cxx03/__type_traits/remove_pointer.h>
  24 #include <__cxx03/__type_traits/remove_reference.h>
  25 #include <__cxx03/__utility/auto_cast.h>
  26
  27 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  28 #  pragma GCC system_header
  29 #endif
  30
  31 _LIBCPP_BEGIN_NAMESPACE_STD
  32
  33 #if _LIBCPP_STD_VER >= 20
  34
  35 // [range.prim.data]
  36
  37 namespace ranges {
  38 namespace __data {
  39 template <class _Tp>
  40 concept __ptr_to_object = is_pointer_v<_Tp> && is_object_v<remove_pointer_t<_Tp>>;
  41
  42 template <class _Tp>
  43 concept __member_data = __can_borrow<_Tp> && requires(_Tp&& __t) {
  44   { _LIBCPP_AUTO_CAST(__t.data()) } -> __ptr_to_object;
  45 };
  46
  47 template <class _Tp>
  48 concept __ranges_begin_invocable = !__member_data<_Tp> && __can_borrow<_Tp> && requires(_Tp&& __t) {
  49   { ranges::begin(__t) } -> contiguous_iterator;
  50 };
  51
  52 struct __fn {
  53   template <__member_data _Tp>
  54   _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const noexcept(noexcept(__t.data())) {
  55     return __t.data();
  56   }
  57
  58   template <__ranges_begin_invocable _Tp>
  59   _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
  60       noexcept(noexcept(std::to_address(ranges::begin(__t)))) {
  61     return std::to_address(ranges::begin(__t));
  62   }
  63 };
  64 } // namespace __data
  65
  66 inline namespace __cpo {
  67 inline constexpr auto data = __data::__fn{};
  68 } // namespace __cpo
  69 } // namespace ranges
  70
  71 // [range.prim.cdata]
  72
  73 namespace ranges {
  74 namespace __cdata {
  75 struct __fn {
  76   template <class _Tp>
  77     requires is_lvalue_reference_v<_Tp&&>
  78   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const
  79       noexcept(noexcept(ranges::data(static_cast<const remove_reference_t<_Tp>&>(__t))))
  80           -> decltype(ranges::data(static_cast<const remove_reference_t<_Tp>&>(__t))) {
  81     return ranges::data(static_cast<const remove_reference_t<_Tp>&>(__t));
  82   }
  83
  84   template <class _Tp>
  85     requires is_rvalue_reference_v<_Tp&&>
  86   [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const noexcept(
  87       noexcept(ranges::data(static_cast<const _Tp&&>(__t)))) -> decltype(ranges::data(static_cast<const _Tp&&>(__t))) {
  88     return ranges::data(static_cast<const _Tp&&>(__t));
  89   }
  90 };
  91 } // namespace __cdata
  92
  93 inline namespace __cpo {
  94 inline constexpr auto cdata = __cdata::__fn{};
  95 } // namespace __cpo
  96 } // namespace ranges
  97
  98 #endif // _LIBCPP_STD_VER >= 20
  99
 100 _LIBCPP_END_NAMESPACE_STD
 101
 102 #endif // _LIBCPP___CXX03___RANGES_DATA_H