llvm-project/libcxx/include/__format/format_args.h

72 lines
2.3 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FORMAT_FORMAT_ARGS_H
#define _LIBCPP___FORMAT_FORMAT_ARGS_H
#include <__availability>
#include <__config>
#include <__format/format_fwd.h>
#include <cstddef>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
// TODO FMT Remove this once we require compilers with proper C++20 support.
// If the compiler has no concepts support, the format header will be disabled.
// Without concepts support enable_if needs to be used and that too much effort
// to support compilers with partial C++20 support.
#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
template <class _Context>
class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_args {
public:
// TODO FMT Implement [format.args]/5
// [Note 1: Implementations are encouraged to optimize the representation of
// basic_format_args for small number of formatting arguments by storing
// indices of type alternatives separately from values and packing the
// former. - end note]
// Note: Change __format_arg_store to use a built-in array.
_LIBCPP_HIDE_FROM_ABI basic_format_args() noexcept = default;
template <class... _Args>
_LIBCPP_HIDE_FROM_ABI basic_format_args(
const __format_arg_store<_Context, _Args...>& __store) noexcept
: __size_(sizeof...(_Args)), __data_(__store.__args.data()) {}
_LIBCPP_HIDE_FROM_ABI
basic_format_arg<_Context> get(size_t __id) const noexcept {
return __id < __size_ ? __data_[__id] : basic_format_arg<_Context>{};
}
_LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; }
private:
size_t __size_{0};
const basic_format_arg<_Context>* __data_{nullptr};
};
#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
#endif //_LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___FORMAT_FORMAT_ARGS_H