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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___RANGES_SIZE_H11#define _LIBCPP___RANGES_SIZE_H12 13#include <__concepts/arithmetic.h>14#include <__concepts/class_or_enum.h>15#include <__config>16#include <__cstddef/ptrdiff_t.h>17#include <__cstddef/size_t.h>18#include <__iterator/concepts.h>19#include <__iterator/iterator_traits.h>20#include <__ranges/access.h>21#include <__type_traits/decay.h>22#include <__type_traits/make_signed.h>23#include <__type_traits/make_unsigned.h>24#include <__type_traits/remove_cvref.h>25#include <__utility/auto_cast.h>26#include <__utility/declval.h>27 28#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)29# pragma GCC system_header30#endif31 32_LIBCPP_BEGIN_NAMESPACE_STD33 34#if _LIBCPP_STD_VER >= 2035 36namespace ranges {37template <class>38inline constexpr bool disable_sized_range = false;39} // namespace ranges40 41// [range.prim.size]42 43namespace ranges {44namespace __size {45void size() = 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> && 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) const84 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) const91 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) const98 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 __size105 106inline namespace __cpo {107inline constexpr auto size = __size::__fn{};108} // namespace __cpo109} // namespace ranges110 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) const119 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 else124 return static_cast<_Signed>(ranges::size(__t));125 }126};127} // namespace __ssize128 129inline namespace __cpo {130inline constexpr auto ssize = __ssize::__fn{};131} // namespace __cpo132} // namespace ranges133 134#endif // _LIBCPP_STD_VER >= 20135 136_LIBCPP_END_NAMESPACE_STD137 138#endif // _LIBCPP___RANGES_SIZE_H139