formatfwd.h
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// <format> Formatting -*- C++ -*-
// Copyright The GNU Toolchain Authors.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file bits/formatfwd.h
* This is an internal header file, included by other library headers.
* Do not attempt to use it directly. @headername{format}
*/
#ifndef _GLIBCXX_FORMAT_FWD_H
#define _GLIBCXX_FORMAT_FWD_H 1
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
// <bits/version.h> must have been included before this header:
#ifdef __glibcxx_format // C++ >= 20 && HOSTED
#include <concepts>
#include <type_traits>
#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
# include <bits/ranges_base.h> // input_range, range_reference_t
#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// [format.context], class template basic_format_context
template<typename _Out, typename _CharT> class basic_format_context;
// [format.parse.ctx], class template basic_format_parse_context
template<typename _CharT> class basic_format_parse_context;
// [format.formatter], formatter
template<typename _Tp, typename _CharT = char> struct formatter;
namespace __format
{
#ifdef _GLIBCXX_USE_WCHAR_T
template<typename _CharT>
concept __char = same_as<_CharT, char> || same_as<_CharT, wchar_t>;
#else
template<typename _CharT>
concept __char = same_as<_CharT, char>;
#endif
enum class _Align : unsigned char {
_Align_default,
_Align_left,
_Align_right,
_Align_centre,
};
using enum _Align;
template<typename _CharT> struct _Spec;
template<__char _CharT> struct __formatter_str;
template<__char _CharT> struct __formatter_int;
template<__char _CharT> struct __formatter_ptr;
template<typename _Tp, typename _Context,
typename _Formatter
= typename _Context::template formatter_type<remove_const_t<_Tp>>,
typename _ParseContext
= basic_format_parse_context<typename _Context::char_type>>
concept __parsable_with
= semiregular<_Formatter>
&& requires (_Formatter __f, _ParseContext __pc)
{
{ __f.parse(__pc) } -> same_as<typename _ParseContext::iterator>;
};
template<typename _Tp, typename _Context,
typename _Formatter
= typename _Context::template formatter_type<remove_const_t<_Tp>>,
typename _ParseContext
= basic_format_parse_context<typename _Context::char_type>>
concept __formattable_with
= semiregular<_Formatter>
&& requires (const _Formatter __cf, _Tp&& __t, _Context __fc)
{
{ __cf.format(__t, __fc) } -> same_as<typename _Context::iterator>;
};
// An unspecified output iterator type used in the `formattable` concept.
template<typename _CharT>
struct _Iter_for;
template<typename _CharT>
using _Iter_for_t = typename _Iter_for<_CharT>::type;
template<typename _Tp, typename _CharT,
typename _Context = basic_format_context<_Iter_for_t<_CharT>, _CharT>>
concept __formattable_impl
= __parsable_with<_Tp, _Context> && __formattable_with<_Tp, _Context>;
template<typename _Formatter>
concept __has_debug_format = requires(_Formatter __f)
{
__f.set_debug_format();
};
} // namespace __format
/// @endcond
#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
// [format.formattable], concept formattable
template<typename _Tp, typename _CharT>
concept formattable
= __format::__formattable_impl<remove_reference_t<_Tp>, _CharT>;
template<typename _Tp, __format::__char _CharT = char>
requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT>
class range_formatter;
/// @cond undocumented
namespace __format
{
template<typename _Rg, typename _CharT>
concept __const_formattable_range
= ranges::input_range<const _Rg>
&& formattable<ranges::range_reference_t<const _Rg>, _CharT>;
// _Rg& and const _Rg& are both formattable and use same formatter
// specialization for their references.
template<typename _Rg, typename _CharT>
concept __simply_formattable_range
= __const_formattable_range<_Rg, _CharT>
&& same_as<remove_cvref_t<ranges::range_reference_t<_Rg>>,
remove_cvref_t<ranges::range_reference_t<const _Rg>>>;
template<typename _Rg, typename _CharT>
using __maybe_const_range
= __conditional_t<__const_formattable_range<_Rg, _CharT>, const _Rg, _Rg>;
template<typename _Tp, typename _CharT>
using __maybe_const
= __conditional_t<formattable<const _Tp, _CharT>, const _Tp, _Tp>;
}
// [format.range], formatting of ranges
// [format.range.fmtkind], variable template format_kind
enum class range_format {
disabled,
map,
set,
sequence,
string,
debug_string
};
/** @brief A constant determining how a range should be formatted.
*
* The primary template of `std::format_kind` cannot be instantiated.
* There is a partial specialization for input ranges and you can
* specialize the variable template for your own cv-unqualified types
* that satisfy the `ranges::input_range` concept.
*
* @since C++23
*/
template<typename _Rg>
constexpr auto format_kind = []{
static_assert(false, "cannot use primary template of 'std::format_kind'");
return type_identity<_Rg>{};
}();
#endif // format_ranges
#if __glibcxx_print >= 202403L
template<typename>
constexpr bool enable_nonlocking_formatter_optimization = false;
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif // __glibcxx_format
#endif // _GLIBCXX_FORMAT_FWD_H
concepts
type_traits
ranges_base.h
std::string
basic_string< char > string
A string of char.
Definition stringfwd.h:79
std
ISO C++ entities toplevel namespace is std.
std::map
A standard container made up of (key,value) pairs, which can be retrieved based on a key,...
Definition stl_map.h:107
std::set
A standard container made up of unique keys, which can be retrieved in logarithmic time.
Definition stl_set.h:101
std::same_as
[concept.same], concept same_as
Definition concepts:65