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_fwd.h> 16 #include <cstddef> 17 18 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 19 # pragma GCC system_header 20 #endif 21 22 _LIBCPP_BEGIN_NAMESPACE_STD 23 24 #if _LIBCPP_STD_VER > 17 25 26 // TODO FMT Remove this once we require compilers with proper C++20 support. 27 // If the compiler has no concepts support, the format header will be disabled. 28 // Without concepts support enable_if needs to be used and that too much effort 29 // to support compilers with partial C++20 support. 30 #if !defined(_LIBCPP_HAS_NO_CONCEPTS) 31 32 template <class _Context> 33 class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_args { 34 public: 35 // TODO FMT Implement [format.args]/5 36 // [Note 1: Implementations are encouraged to optimize the representation of 37 // basic_format_args for small number of formatting arguments by storing 38 // indices of type alternatives separately from values and packing the 39 // former. - end note] 40 // Note: Change __format_arg_store to use a built-in array. 41 _LIBCPP_HIDE_FROM_ABI basic_format_args() noexcept = default; 42 43 template <class... _Args> 44 _LIBCPP_HIDE_FROM_ABI basic_format_args( 45 const __format_arg_store<_Context, _Args...>& __store) noexcept 46 : __size_(sizeof...(_Args)), __data_(__store.__args.data()) {} 47 48 _LIBCPP_HIDE_FROM_ABI 49 basic_format_arg<_Context> get(size_t __id) const noexcept { 50 return __id < __size_ ? __data_[__id] : basic_format_arg<_Context>{}; 51 } 52 53 _LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; } 54 55 private: 56 size_t __size_{0}; 57 const basic_format_arg<_Context>* __data_{nullptr}; 58 }; 59 60 #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS) 61 62 #endif //_LIBCPP_STD_VER > 17 63 64 _LIBCPP_END_NAMESPACE_STD 65 66 #endif // _LIBCPP___FORMAT_FORMAT_ARGS_H 67