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___FORMAT_FORMAT_ARG_STORE_H 11#define _LIBCPP___FORMAT_FORMAT_ARG_STORE_H 12 13#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 14# pragma GCC system_header 15#endif 16 17#include <__concepts/arithmetic.h> 18#include <__concepts/same_as.h> 19#include <__config> 20#include <__format/concepts.h> 21#include <__format/format_arg.h> 22#include <__type_traits/conditional.h> 23#include <__type_traits/extent.h> 24#include <__type_traits/remove_const.h> 25#include <string> 26#include <string_view> 27 28_LIBCPP_BEGIN_NAMESPACE_STD 29 30#if _LIBCPP_STD_VER >= 20 31 32namespace __format { 33 34/// \returns The @c __arg_t based on the type of the formatting argument. 35/// 36/// \pre \c __formattable<_Tp, typename _Context::char_type> 37template <class _Context, class _Tp> 38consteval __arg_t __determine_arg_t(); 39 40// Boolean 41template <class, same_as<bool> _Tp> 42consteval __arg_t __determine_arg_t() { 43 return __arg_t::__boolean; 44} 45 46// Char 47template <class _Context, same_as<typename _Context::char_type> _Tp> 48consteval __arg_t __determine_arg_t() { 49 return __arg_t::__char_type; 50} 51# ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS 52template <class _Context, class _CharT> 53 requires(same_as<typename _Context::char_type, wchar_t> && same_as<_CharT, char>) 54consteval __arg_t __determine_arg_t() { 55 return __arg_t::__char_type; 56} 57# endif 58 59// Signed integers 60template <class, __libcpp_signed_integer _Tp> 61consteval __arg_t __determine_arg_t() { 62 if constexpr (sizeof(_Tp) <= sizeof(int)) 63 return __arg_t::__int; 64 else if constexpr (sizeof(_Tp) <= sizeof(long long)) 65 return __arg_t::__long_long; 66# ifndef _LIBCPP_HAS_NO_INT128 67 else if constexpr (sizeof(_Tp) == sizeof(__int128_t)) 68 return __arg_t::__i128; 69# endif 70 else 71 static_assert(sizeof(_Tp) == 0, "an unsupported signed integer was used"); 72} 73 74// Unsigned integers 75template <class, __libcpp_unsigned_integer _Tp> 76consteval __arg_t __determine_arg_t() { 77 if constexpr (sizeof(_Tp) <= sizeof(unsigned)) 78 return __arg_t::__unsigned; 79 else if constexpr (sizeof(_Tp) <= sizeof(unsigned long long)) 80 return __arg_t::__unsigned_long_long; 81# ifndef _LIBCPP_HAS_NO_INT128 82 else if constexpr (sizeof(_Tp) == sizeof(__uint128_t)) 83 return __arg_t::__u128; 84# endif 85 else 86 static_assert(sizeof(_Tp) == 0, "an unsupported unsigned integer was used"); 87} 88 89// Floating-point 90template <class, same_as<float> _Tp> 91consteval __arg_t __determine_arg_t() { 92 return __arg_t::__float; 93} 94template <class, same_as<double> _Tp> 95consteval __arg_t __determine_arg_t() { 96 return __arg_t::__double; 97} 98template <class, same_as<long double> _Tp> 99consteval __arg_t __determine_arg_t() { 100 return __arg_t::__long_double; 101} 102 103// Char pointer 104template <class _Context, class _Tp> 105 requires(same_as<typename _Context::char_type*, _Tp> || same_as<const typename _Context::char_type*, _Tp>) 106consteval __arg_t __determine_arg_t() { 107 return __arg_t::__const_char_type_ptr; 108} 109 110// Char array 111template <class _Context, class _Tp> 112 requires(is_array_v<_Tp> && same_as<_Tp, typename _Context::char_type[extent_v<_Tp>]>) 113consteval __arg_t __determine_arg_t() { 114 return __arg_t::__string_view; 115} 116 117// String view 118template <class _Context, class _Tp> 119 requires(same_as<typename _Context::char_type, typename _Tp::value_type> && 120 same_as<_Tp, basic_string_view<typename _Tp::value_type, typename _Tp::traits_type>>) 121consteval __arg_t __determine_arg_t() { 122 return __arg_t::__string_view; 123} 124 125// String 126template <class _Context, class _Tp> 127 requires( 128 same_as<typename _Context::char_type, typename _Tp::value_type> && 129 same_as<_Tp, basic_string<typename _Tp::value_type, typename _Tp::traits_type, typename _Tp::allocator_type>>) 130consteval __arg_t __determine_arg_t() { 131 return __arg_t::__string_view; 132} 133 134// Pointers 135template <class, class _Ptr> 136 requires(same_as<_Ptr, void*> || same_as<_Ptr, const void*> || same_as<_Ptr, nullptr_t>) 137consteval __arg_t __determine_arg_t() { 138 return __arg_t::__ptr; 139} 140 141// Handle 142// 143// Note this version can't be constrained avoiding ambiguous overloads. 144// That means it can be instantiated by disabled formatters. To solve this, a 145// constrained version for not formattable formatters is added. 146template <class _Context, class _Tp> 147consteval __arg_t __determine_arg_t() { 148 return __arg_t::__handle; 149} 150 151// The overload for not formattable types allows triggering the static 152// assertion below. 153template <class _Context, class _Tp> 154 requires(!__formattable<_Tp, typename _Context::char_type>) 155consteval __arg_t __determine_arg_t() { 156 return __arg_t::__none; 157} 158 159// Pseudo constuctor for basic_format_arg 160// 161// Modeled after template<class T> explicit basic_format_arg(T& v) noexcept; 162// [format.arg]/4-6 163template <class _Context, class _Tp> 164_LIBCPP_HIDE_FROM_ABI basic_format_arg<_Context> __create_format_arg(_Tp& __value) noexcept { 165 using _Dp = remove_const_t<_Tp>; 166 constexpr __arg_t __arg = __determine_arg_t<_Context, _Dp>(); 167 static_assert(__arg != __arg_t::__none, "the supplied type is not formattable"); 168 169 static_assert(__formattable_with<_Tp, _Context>); 170 171 // Not all types can be used to directly initialize the 172 // __basic_format_arg_value. First handle all types needing adjustment, the 173 // final else requires no adjustment. 174 if constexpr (__arg == __arg_t::__char_type) 175 176# ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS 177 if constexpr (same_as<typename _Context::char_type, wchar_t> && same_as<_Dp, char>) 178 return basic_format_arg<_Context>{__arg, static_cast<wchar_t>(static_cast<unsigned char>(__value))}; 179 else 180# endif 181 return basic_format_arg<_Context>{__arg, __value}; 182 else if constexpr (__arg == __arg_t::__int) 183 return basic_format_arg<_Context>{__arg, static_cast<int>(__value)}; 184 else if constexpr (__arg == __arg_t::__long_long) 185 return basic_format_arg<_Context>{__arg, static_cast<long long>(__value)}; 186 else if constexpr (__arg == __arg_t::__unsigned) 187 return basic_format_arg<_Context>{__arg, static_cast<unsigned>(__value)}; 188 else if constexpr (__arg == __arg_t::__unsigned_long_long) 189 return basic_format_arg<_Context>{__arg, static_cast<unsigned long long>(__value)}; 190 else if constexpr (__arg == __arg_t::__string_view) 191 // Using std::size on a character array will add the NUL-terminator to the size. 192 if constexpr (is_array_v<_Dp>) 193 return basic_format_arg<_Context>{ 194 __arg, basic_string_view<typename _Context::char_type>{__value, extent_v<_Dp> - 1}}; 195 else 196 // When the _Traits or _Allocator are different an implicit conversion will 197 // fail. 198 return basic_format_arg<_Context>{ 199 __arg, basic_string_view<typename _Context::char_type>{__value.data(), __value.size()}}; 200 else if constexpr (__arg == __arg_t::__ptr) 201 return basic_format_arg<_Context>{__arg, static_cast<const void*>(__value)}; 202 else if constexpr (__arg == __arg_t::__handle) 203 return basic_format_arg<_Context>{__arg, typename __basic_format_arg_value<_Context>::__handle{__value}}; 204 else 205 return basic_format_arg<_Context>{__arg, __value}; 206} 207 208template <class _Context, class... _Args> 209_LIBCPP_HIDE_FROM_ABI void 210__create_packed_storage(uint64_t& __types, __basic_format_arg_value<_Context>* __values, _Args&... __args) noexcept { 211 int __shift = 0; 212 ( 213 [&] { 214 basic_format_arg<_Context> __arg = __format::__create_format_arg<_Context>(__args); 215 if (__shift != 0) 216 __types |= static_cast<uint64_t>(__arg.__type_) << __shift; 217 else 218 // Assigns the initial value. 219 __types = static_cast<uint64_t>(__arg.__type_); 220 __shift += __packed_arg_t_bits; 221 *__values++ = __arg.__value_; 222 }(), 223 ...); 224} 225 226template <class _Context, class... _Args> 227_LIBCPP_HIDE_FROM_ABI void __store_basic_format_arg(basic_format_arg<_Context>* __data, _Args&... __args) noexcept { 228 ([&] { *__data++ = __format::__create_format_arg<_Context>(__args); }(), ...); 229} 230 231template <class _Context, size_t _Np> 232struct __packed_format_arg_store { 233 __basic_format_arg_value<_Context> __values_[_Np]; 234 uint64_t __types_ = 0; 235}; 236 237template <class _Context, size_t _Np> 238struct __unpacked_format_arg_store { 239 basic_format_arg<_Context> __args_[_Np]; 240}; 241 242} // namespace __format 243 244template <class _Context, class... _Args> 245struct _LIBCPP_TEMPLATE_VIS __format_arg_store { 246 _LIBCPP_HIDE_FROM_ABI __format_arg_store(_Args&... __args) noexcept { 247 if constexpr (sizeof...(_Args) != 0) { 248 if constexpr (__format::__use_packed_format_arg_store(sizeof...(_Args))) 249 __format::__create_packed_storage(__storage.__types_, __storage.__values_, __args...); 250 else 251 __format::__store_basic_format_arg<_Context>(__storage.__args_, __args...); 252 } 253 } 254 255 using _Storage = 256 conditional_t<__format::__use_packed_format_arg_store(sizeof...(_Args)), 257 __format::__packed_format_arg_store<_Context, sizeof...(_Args)>, 258 __format::__unpacked_format_arg_store<_Context, sizeof...(_Args)>>; 259 260 _Storage __storage; 261}; 262 263#endif //_LIBCPP_STD_VER >= 20 264 265_LIBCPP_END_NAMESPACE_STD 266 267#endif // _LIBCPP___FORMAT_FORMAT_ARG_STORE_H 268