0922ce56f4
This implements the struct `__format_arg_store` and its dependencies: * the class basic_format_arg, * the class basic_format_args, * the class basic_format_context, * the function make_format_args, * the function wmake_format_args, * the function visit_format_arg, * several Standard required typedefs. The following parts will be implemented in a later patch: * the child class `basic_format_arg::handle`, * the function `basic_format_arg::basic_format_arg(const T* p)`. The following extension has been implemented: * the class basic_format_arg supports `__[u]int128_t` on platform where libc++ supports 128 bit integrals. Implements parts of: * P0645 Text Formatting Completes: * LWG3371 visit_format_arg and make_format_args are not hidden friends * LWG3542 basic_format_arg mishandles basic_string_view with custom traits Note https://mordante.github.io/blog/2021/06/05/format.html gives a bit more information about the goals and non-goals of this initial patch series. Reviewed By: #libc, ldionne, vitaut Differential Revision: https://reviews.llvm.org/D103357
72 lines
2.3 KiB
C++
72 lines
2.3 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___FORMAT_FORMAT_ARGS_H
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#define _LIBCPP___FORMAT_FORMAT_ARGS_H
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#include <__availability>
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#include <__config>
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#include <__format/format_fwd.h>
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#include <cstddef>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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_LIBCPP_PUSH_MACROS
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#include <__undef_macros>
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if _LIBCPP_STD_VER > 17
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// TODO FMT Remove this once we require compilers with proper C++20 support.
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// If the compiler has no concepts support, the format header will be disabled.
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// Without concepts support enable_if needs to be used and that too much effort
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// to support compilers with partial C++20 support.
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#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
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template <class _Context>
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class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_args {
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public:
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// TODO FMT Implement [format.args]/5
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// [Note 1: Implementations are encouraged to optimize the representation of
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// basic_format_args for small number of formatting arguments by storing
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// indices of type alternatives separately from values and packing the
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// former. - end note]
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// Note: Change __format_arg_store to use a built-in array.
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_LIBCPP_HIDE_FROM_ABI basic_format_args() noexcept = default;
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template <class... _Args>
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_LIBCPP_HIDE_FROM_ABI basic_format_args(
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const __format_arg_store<_Context, _Args...>& __store) noexcept
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: __size_(sizeof...(_Args)), __data_(__store.__args.data()) {}
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_LIBCPP_HIDE_FROM_ABI
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basic_format_arg<_Context> get(size_t __id) const noexcept {
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return __id < __size_ ? __data_[__id] : basic_format_arg<_Context>{};
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}
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_LIBCPP_HIDE_FROM_ABI size_t __size() const noexcept { return __size_; }
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private:
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size_t __size_{0};
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const basic_format_arg<_Context>* __data_{nullptr};
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};
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#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
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#endif //_LIBCPP_STD_VER > 17
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_LIBCPP_END_NAMESPACE_STD
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_LIBCPP_POP_MACROS
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#endif // _LIBCPP___FORMAT_FORMAT_ARGS_H
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