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 <__availability> 14 #include <__config> 15 #include <__format/format_arg.h> 16 #include <__format/format_arg_store.h> 17 #include <__format/format_fwd.h> 18 #include <cstddef> 19 #include <cstdint> 20 21 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 22 # pragma GCC system_header 23 #endif 24 25 _LIBCPP_BEGIN_NAMESPACE_STD 26 27 #if _LIBCPP_STD_VER >= 20 28 29 template <class _Context> 30 class _LIBCPP_TEMPLATE_VIS basic_format_args { 31 public: 32 basic_format_args() noexcept = default; 33 34 template <class... _Args> 35 _LIBCPP_HIDE_FROM_ABI basic_format_args(const __format_arg_store<_Context, _Args...>& __store) noexcept 36 : __size_(sizeof...(_Args)) { 37 if constexpr (sizeof...(_Args) != 0) { 38 if constexpr (__format::__use_packed_format_arg_store(sizeof...(_Args))) { 39 __values_ = __store.__storage.__values_; 40 __types_ = __store.__storage.__types_; 41 } else 42 __args_ = __store.__storage.__args_; 43 } 44 } 45 46 _LIBCPP_HIDE_FROM_ABI basic_format_arg<_Context> get(size_t __id) const noexcept { 47 if (__id >= __size_) 48 return basic_format_arg<_Context>{}; 49 50 if (__format::__use_packed_format_arg_store(__size_)) 51 return basic_format_arg<_Context>{__format::__get_packed_type(__types_, __id), __values_[__id]}; 52 53 return __args_[__id]; 54 } 55 56 _LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; } 57 58 private: 59 size_t __size_{0}; 60 // [format.args]/5 61 // [Note 1: Implementations are encouraged to optimize the representation of 62 // basic_format_args for small number of formatting arguments by storing 63 // indices of type alternatives separately from values and packing the 64 // former. - end note] 65 union { 66 struct { 67 const __basic_format_arg_value<_Context>* __values_; 68 uint64_t __types_; 69 }; 70 const basic_format_arg<_Context>* __args_; 71 }; 72 }; 73 74 template <class _Context, class... _Args> 75 basic_format_args(__format_arg_store<_Context, _Args...>) -> basic_format_args<_Context>; 76 77 #endif //_LIBCPP_STD_VER >= 20 78 79 _LIBCPP_END_NAMESPACE_STD 80 81 #endif // _LIBCPP___FORMAT_FORMAT_ARGS_H 82