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// -*- 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_PARSE_CONTEXT_H
#define _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
#include <__config>
#include <__format/format_error.h>
#include <string_view>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_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) && !defined(_LIBCPP_HAS_NO_BUILTIN_IS_CONSTANT_EVALUATED)
template <class _CharT>
class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT basic_format_parse_context {
public:
using char_type = _CharT;
using const_iterator = typename basic_string_view<_CharT>::const_iterator;
using iterator = const_iterator;
_LIBCPP_HIDE_FROM_ABI
constexpr explicit basic_format_parse_context(basic_string_view<_CharT> __fmt,
size_t __num_args = 0) noexcept
: __begin_(__fmt.begin()),
__end_(__fmt.end()),
__indexing_(__unknown),
__next_arg_id_(0),
__num_args_(__num_args) {}
basic_format_parse_context(const basic_format_parse_context&) = delete;
basic_format_parse_context&
operator=(const basic_format_parse_context&) = delete;
_LIBCPP_HIDE_FROM_ABI constexpr const_iterator begin() const noexcept {
return __begin_;
}
_LIBCPP_HIDE_FROM_ABI constexpr const_iterator end() const noexcept {
return __end_;
}
_LIBCPP_HIDE_FROM_ABI constexpr void advance_to(const_iterator __it) {
__begin_ = __it;
}
_LIBCPP_HIDE_FROM_ABI constexpr size_t next_arg_id() {
if (__indexing_ == __manual)
__throw_format_error("Using automatic argument numbering in manual "
"argument numbering mode");
if (__indexing_ == __unknown)
__indexing_ = __automatic;
return __next_arg_id_++;
}
_LIBCPP_HIDE_FROM_ABI constexpr void check_arg_id(size_t __id) {
if (__indexing_ == __automatic)
__throw_format_error("Using manual argument numbering in automatic "
"argument numbering mode");
if (__indexing_ == __unknown)
__indexing_ = __manual;
// Throws an exception to make the expression a non core constant
// expression as required by:
// [format.parse.ctx]/11
// Remarks: Call expressions where id >= num_args_ are not core constant
// expressions ([expr.const]).
// Note: the Throws clause [format.parse.ctx]/10 doesn't specify the
// behavior when id >= num_args_.
if (is_constant_evaluated() && __id >= __num_args_)
__throw_format_error("Argument index outside the valid range");
}
private:
iterator __begin_;
iterator __end_;
enum _Indexing { __unknown, __manual, __automatic };
_Indexing __indexing_;
size_t __next_arg_id_;
size_t __num_args_;
};
using format_parse_context = basic_format_parse_context<char>;
#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
using wformat_parse_context = basic_format_parse_context<wchar_t>;
#endif
#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
#endif //_LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FORMAT_FORMAT_PARSE_CONTEXT_H
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