forked from OSchip/llvm-project
110 lines
3.6 KiB
C++
110 lines
3.6 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_PARSE_CONTEXT_H
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#define _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
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#include <__config>
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#include <__format/format_error.h>
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#include <string_view>
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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_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 _CharT>
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class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context {
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public:
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using char_type = _CharT;
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using const_iterator = typename basic_string_view<_CharT>::const_iterator;
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using iterator = const_iterator;
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_LIBCPP_HIDE_FROM_ABI
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constexpr explicit basic_format_parse_context(basic_string_view<_CharT> __fmt,
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size_t __num_args = 0) noexcept
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: __begin_(__fmt.begin()),
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__end_(__fmt.end()),
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__indexing_(__unknown),
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__next_arg_id_(0),
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__num_args_(__num_args) {}
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basic_format_parse_context(const basic_format_parse_context&) = delete;
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basic_format_parse_context&
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operator=(const basic_format_parse_context&) = delete;
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_LIBCPP_HIDE_FROM_ABI constexpr const_iterator begin() const noexcept {
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return __begin_;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr const_iterator end() const noexcept {
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return __end_;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr void advance_to(const_iterator __it) {
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__begin_ = __it;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr size_t next_arg_id() {
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if (__indexing_ == __manual)
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__throw_format_error("Using automatic argument numbering in manual "
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"argument numbering mode");
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if (__indexing_ == __unknown)
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__indexing_ = __automatic;
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return __next_arg_id_++;
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}
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_LIBCPP_HIDE_FROM_ABI constexpr void check_arg_id(size_t __id) {
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if (__indexing_ == __automatic)
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__throw_format_error("Using manual argument numbering in automatic "
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"argument numbering mode");
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if (__indexing_ == __unknown)
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__indexing_ = __manual;
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// Throws an exception to make the expression a non core constant
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// expression as required by:
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// [format.parse.ctx]/11
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// Remarks: Call expressions where id >= num_args_ are not core constant
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// expressions ([expr.const]).
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// Note: the Throws clause [format.parse.ctx]/10 doesn't specify the
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// behavior when id >= num_args_.
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if (is_constant_evaluated() && __id >= __num_args_)
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__throw_format_error("Argument index outside the valid range");
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}
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private:
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iterator __begin_;
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iterator __end_;
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enum _Indexing { __unknown, __manual, __automatic };
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_Indexing __indexing_;
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size_t __next_arg_id_;
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size_t __num_args_;
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};
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using format_parse_context = basic_format_parse_context<char>;
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#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
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using wformat_parse_context = basic_format_parse_context<wchar_t>;
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#endif
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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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#endif // _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
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