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

80 lines
2.4 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_arg.h>
#include <__format/format_arg_store.h>
#include <__format/format_fwd.h>
#include <cstddef>
#include <cstdint>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
template <class _Context>
class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_args {
public:
_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)) {
if constexpr (sizeof...(_Args) != 0) {
if constexpr (__format::__use_packed_format_arg_store(sizeof...(_Args))) {
__values_ = __store.__storage.__values_;
__types_ = __store.__storage.__types_;
} else
__args_ = __store.__storage.__args_;
}
}
_LIBCPP_HIDE_FROM_ABI
basic_format_arg<_Context> get(size_t __id) const noexcept {
if (__id >= __size_)
return basic_format_arg<_Context>{};
if (__format::__use_packed_format_arg_store(__size_))
return basic_format_arg<_Context>{__format::__get_packed_type(__types_, __id), __values_[__id]};
return __args_[__id];
}
_LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; }
private:
size_t __size_{0};
// [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]
union {
struct {
const __basic_format_arg_value<_Context>* __values_;
uint64_t __types_;
};
const basic_format_arg<_Context>* __args_;
};
};
#endif //_LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FORMAT_FORMAT_ARGS_H