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_SIZE_H 11#define _LIBCPP___RANGES_SIZE_H 12 13#include <__concepts/arithmetic.h> 14#include <__concepts/class_or_enum.h> 15#include <__config> 16#include <__iterator/concepts.h> 17#include <__iterator/iterator_traits.h> 18#include <__ranges/access.h> 19#include <__type_traits/decay.h> 20#include <__type_traits/make_signed.h> 21#include <__type_traits/make_unsigned.h> 22#include <__type_traits/remove_cvref.h> 23#include <__utility/auto_cast.h> 24#include <__utility/declval.h> 25#include <cstddef> 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 35namespace ranges { 36template <class> 37inline constexpr bool disable_sized_range = false; 38} // namespace ranges 39 40// [range.prim.size] 41 42namespace ranges { 43namespace __size { 44void size(auto&) = delete; 45void size(const auto&) = delete; 46 47template <class _Tp> 48concept __size_enabled = !disable_sized_range<remove_cvref_t<_Tp>>; 49 50template <class _Tp> 51concept __member_size = __size_enabled<_Tp> && __workaround_52970<_Tp> && requires(_Tp&& __t) { 52 { _LIBCPP_AUTO_CAST(__t.size()) } -> __integer_like; 53}; 54 55template <class _Tp> 56concept __unqualified_size = 57 __size_enabled<_Tp> && !__member_size<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) { 58 { _LIBCPP_AUTO_CAST(size(__t)) } -> __integer_like; 59 }; 60 61template <class _Tp> 62concept __difference = 63 !__member_size<_Tp> && !__unqualified_size<_Tp> && __class_or_enum<remove_cvref_t<_Tp>> && requires(_Tp&& __t) { 64 { ranges::begin(__t) } -> forward_iterator; 65 { ranges::end(__t) } -> sized_sentinel_for<decltype(ranges::begin(std::declval<_Tp>()))>; 66 }; 67 68struct __fn { 69 // `[range.prim.size]`: the array case (for rvalues). 70 template <class _Tp, size_t _Sz> 71 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&&)[_Sz]) const noexcept { 72 return _Sz; 73 } 74 75 // `[range.prim.size]`: the array case (for lvalues). 76 template <class _Tp, size_t _Sz> 77 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr size_t operator()(_Tp (&)[_Sz]) const noexcept { 78 return _Sz; 79 } 80 81 // `[range.prim.size]`: `auto(t.size())` is a valid expression. 82 template <__member_size _Tp> 83 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 84 noexcept(noexcept(_LIBCPP_AUTO_CAST(__t.size()))) { 85 return _LIBCPP_AUTO_CAST(__t.size()); 86 } 87 88 // `[range.prim.size]`: `auto(size(t))` is a valid expression. 89 template <__unqualified_size _Tp> 90 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr __integer_like auto operator()(_Tp&& __t) const 91 noexcept(noexcept(_LIBCPP_AUTO_CAST(size(__t)))) { 92 return _LIBCPP_AUTO_CAST(size(__t)); 93 } 94 95 // [range.prim.size]: the `to-unsigned-like` case. 96 template <__difference _Tp> 97 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr auto operator()(_Tp&& __t) const 98 noexcept(noexcept(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)))) 99 -> decltype(std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t))) { 100 return std::__to_unsigned_like(ranges::end(__t) - ranges::begin(__t)); 101 } 102}; 103 104} // namespace __size 105 106inline namespace __cpo { 107inline constexpr auto size = __size::__fn{}; 108} // namespace __cpo 109} // namespace ranges 110 111// [range.prim.ssize] 112 113namespace ranges { 114namespace __ssize { 115struct __fn { 116 template <class _Tp> 117 requires requires(_Tp&& __t) { ranges::size(__t); } 118 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr integral auto operator()(_Tp&& __t) const 119 noexcept(noexcept(ranges::size(__t))) { 120 using _Signed = make_signed_t<decltype(ranges::size(__t))>; 121 if constexpr (sizeof(ptrdiff_t) > sizeof(_Signed)) 122 return static_cast<ptrdiff_t>(ranges::size(__t)); 123 else 124 return static_cast<_Signed>(ranges::size(__t)); 125 } 126}; 127} // namespace __ssize 128 129inline namespace __cpo { 130inline constexpr auto ssize = __ssize::__fn{}; 131} // namespace __cpo 132} // namespace ranges 133 134#endif // _LIBCPP_STD_VER >= 20 135 136_LIBCPP_END_NAMESPACE_STD 137 138#endif // _LIBCPP___RANGES_SIZE_H 139