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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-exception7//8//===----------------------------------------------------------------------===//9 10#ifndef _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H11#define _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H12 13#include <__config>14#include <__format/format_error.h>15#include <__type_traits/is_constant_evaluated.h>16#include <string_view>17 18#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)19# pragma GCC system_header20#endif21 22_LIBCPP_BEGIN_NAMESPACE_STD23 24#if _LIBCPP_STD_VER >= 2025 26template <class _CharT>27class basic_format_parse_context {28public:29 using char_type = _CharT;30 using const_iterator = typename basic_string_view<_CharT>::const_iterator;31 using iterator = const_iterator;32 33 _LIBCPP_HIDE_FROM_ABI constexpr explicit basic_format_parse_context(34 basic_string_view<_CharT> __fmt, size_t __num_args = 0) noexcept35 : __begin_(__fmt.begin()),36 __end_(__fmt.end()),37 __indexing_(__unknown),38 __next_arg_id_(0),39 __num_args_(__num_args) {}40 41 basic_format_parse_context(const basic_format_parse_context&) = delete;42 basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;43 44 _LIBCPP_HIDE_FROM_ABI constexpr const_iterator begin() const noexcept { return __begin_; }45 _LIBCPP_HIDE_FROM_ABI constexpr const_iterator end() const noexcept { return __end_; }46 _LIBCPP_HIDE_FROM_ABI constexpr void advance_to(const_iterator __it) { __begin_ = __it; }47 48 _LIBCPP_HIDE_FROM_ABI constexpr size_t next_arg_id() {49 if (__indexing_ == __manual)50 std::__throw_format_error("Using automatic argument numbering in manual argument numbering mode");51 52 if (__indexing_ == __unknown)53 __indexing_ = __automatic;54 55 // Throws an exception to make the expression a non core constant56 // expression as required by:57 // [format.parse.ctx]/858 // Remarks: Let cur-arg-id be the value of next_arg_id_ prior to this59 // call. Call expressions where cur-arg-id >= num_args_ is true are not60 // core constant expressions (7.7 [expr.const]).61 // Note: the Throws clause [format.parse.ctx]/9 doesn't specify the62 // behavior when id >= num_args_.63 if (is_constant_evaluated() && __next_arg_id_ >= __num_args_)64 std::__throw_format_error("Argument index outside the valid range");65 66 return __next_arg_id_++;67 }68 _LIBCPP_HIDE_FROM_ABI constexpr void check_arg_id(size_t __id) {69 if (__indexing_ == __automatic)70 std::__throw_format_error("Using manual argument numbering in automatic argument numbering mode");71 72 if (__indexing_ == __unknown)73 __indexing_ = __manual;74 75 // Throws an exception to make the expression a non core constant76 // expression as required by:77 // [format.parse.ctx]/1178 // Remarks: Call expressions where id >= num_args_ are not core constant79 // expressions ([expr.const]).80 // Note: the Throws clause [format.parse.ctx]/10 doesn't specify the81 // behavior when id >= num_args_.82 if (is_constant_evaluated() && __id >= __num_args_)83 std::__throw_format_error("Argument index outside the valid range");84 }85 86private:87 iterator __begin_;88 iterator __end_;89 enum _Indexing { __unknown, __manual, __automatic };90 _Indexing __indexing_;91 size_t __next_arg_id_;92 size_t __num_args_;93};94_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(basic_format_parse_context);95 96using format_parse_context = basic_format_parse_context<char>;97# if _LIBCPP_HAS_WIDE_CHARACTERS98using wformat_parse_context = basic_format_parse_context<wchar_t>;99# endif100 101#endif // _LIBCPP_STD_VER >= 20102 103_LIBCPP_END_NAMESPACE_STD104 105#endif // _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H106