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_ARGS_H 11 #define _LIBCPP___FORMAT_FORMAT_ARGS_H 12 13 #include <__config> 14 #include <__format/format_arg.h> 15 #include <__format/format_arg_store.h> 16 #include <__fwd/format.h> 17 #include <cstddef> 18 #include <cstdint> 19 20 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 21 # pragma GCC system_header 22 #endif 23 24 _LIBCPP_BEGIN_NAMESPACE_STD 25 26 #if _LIBCPP_STD_VER >= 20 27 28 template <class _Context> 29 class _LIBCPP_TEMPLATE_VIS basic_format_args { 30 public: 31 template <class... _Args> basic_format_args(const __format_arg_store<_Context,_Args...> & __store)32 _LIBCPP_HIDE_FROM_ABI basic_format_args(const __format_arg_store<_Context, _Args...>& __store) noexcept 33 : __size_(sizeof...(_Args)) { 34 if constexpr (sizeof...(_Args) != 0) { 35 if constexpr (__format::__use_packed_format_arg_store(sizeof...(_Args))) { 36 __values_ = __store.__storage.__values_; 37 __types_ = __store.__storage.__types_; 38 } else 39 __args_ = __store.__storage.__args_; 40 } 41 } 42 get(size_t __id)43 _LIBCPP_HIDE_FROM_ABI basic_format_arg<_Context> get(size_t __id) const noexcept { 44 if (__id >= __size_) 45 return basic_format_arg<_Context>{}; 46 47 if (__format::__use_packed_format_arg_store(__size_)) 48 return basic_format_arg<_Context>{__format::__get_packed_type(__types_, __id), __values_[__id]}; 49 50 return __args_[__id]; 51 } 52 __size()53 _LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; } 54 55 private: 56 size_t __size_{0}; 57 // [format.args]/5 58 // [Note 1: Implementations are encouraged to optimize the representation of 59 // basic_format_args for small number of formatting arguments by storing 60 // indices of type alternatives separately from values and packing the 61 // former. - end note] 62 union { 63 struct { 64 const __basic_format_arg_value<_Context>* __values_; 65 uint64_t __types_; 66 }; 67 const basic_format_arg<_Context>* __args_; 68 }; 69 }; 70 71 template <class _Context, class... _Args> 72 basic_format_args(__format_arg_store<_Context, _Args...>) -> basic_format_args<_Context>; 73 74 #endif //_LIBCPP_STD_VER >= 20 75 76 _LIBCPP_END_NAMESPACE_STD 77 78 #endif // _LIBCPP___FORMAT_FORMAT_ARGS_H 79