1// <format> Formatting -*- C++ -*-
2
3// Copyright The GNU Toolchain Authors.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file bits/formatfwd.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{format}
28 */
29
30#ifndef _GLIBCXX_FORMAT_FWD_H
31#define _GLIBCXX_FORMAT_FWD_H 1
32
33#ifdef _GLIBCXX_SYSHDR
34#pragma GCC system_header
35#endif
36
37// <bits/version.h> must have been included before this header:
38#ifdef __glibcxx_format // C++ >= 20 && HOSTED
39
40#include <concepts>
41#include <type_traits>
42#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
43# include <bits/ranges_base.h> // input_range, range_reference_t
44#endif
45
46namespace std _GLIBCXX_VISIBILITY(default)
47{
48_GLIBCXX_BEGIN_NAMESPACE_VERSION
49
50 // [format.context], class template basic_format_context
51 template<typename _Out, typename _CharT> class basic_format_context;
52
53 // [format.parse.ctx], class template basic_format_parse_context
54 template<typename _CharT> class basic_format_parse_context;
55
56 // [format.formatter], formatter
57 template<typename _Tp, typename _CharT = char> struct formatter;
58
59/// @cond undocumented
60namespace __format
61{
62#ifdef _GLIBCXX_USE_WCHAR_T
63 template<typename _CharT>
64 concept __char = same_as<_CharT, char> || same_as<_CharT, wchar_t>;
65#else
66 template<typename _CharT>
67 concept __char = same_as<_CharT, char>;
68#endif
69
70 template<typename _Tp, typename _Context,
71 typename _Formatter
72 = typename _Context::template formatter_type<remove_const_t<_Tp>>,
73 typename _ParseContext
74 = basic_format_parse_context<typename _Context::char_type>>
75 concept __parsable_with
76 = semiregular<_Formatter>
77 && requires (_Formatter __f, _ParseContext __pc)
78 {
79 { __f.parse(__pc) } -> same_as<typename _ParseContext::iterator>;
80 };
81
82 template<typename _Tp, typename _Context,
83 typename _Formatter
84 = typename _Context::template formatter_type<remove_const_t<_Tp>>,
85 typename _ParseContext
86 = basic_format_parse_context<typename _Context::char_type>>
87 concept __formattable_with
88 = semiregular<_Formatter>
89 && requires (const _Formatter __cf, _Tp&& __t, _Context __fc)
90 {
91 { __cf.format(__t, __fc) } -> same_as<typename _Context::iterator>;
92 };
93
94 // An unspecified output iterator type used in the `formattable` concept.
95 template<typename _CharT>
96 struct _Iter_for;
97 template<typename _CharT>
98 using _Iter_for_t = typename _Iter_for<_CharT>::type;
99
100 template<typename _Tp, typename _CharT,
101 typename _Context = basic_format_context<_Iter_for_t<_CharT>, _CharT>>
102 concept __formattable_impl
103 = __parsable_with<_Tp, _Context> && __formattable_with<_Tp, _Context>;
104
105 template<typename _Formatter>
106 concept __has_debug_format = requires(_Formatter __f)
107 {
108 __f.set_debug_format();
109 };
110
111 template<__char _CharT>
112 struct __formatter_int;
113} // namespace __format
114/// @endcond
115
116#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
117 // [format.formattable], concept formattable
118 template<typename _Tp, typename _CharT>
119 concept formattable
120 = __format::__formattable_impl<remove_reference_t<_Tp>, _CharT>;
121
122 template<typename _Tp, __format::__char _CharT = char>
123 requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT>
124 class range_formatter;
125
126/// @cond undocumented
127namespace __format
128{
129 template<typename _Rg, typename _CharT>
130 concept __const_formattable_range
131 = ranges::input_range<const _Rg>
132 && formattable<ranges::range_reference_t<const _Rg>, _CharT>;
133
134 template<typename _Rg, typename _CharT>
135 using __maybe_const_range
136 = __conditional_t<__const_formattable_range<_Rg, _CharT>, const _Rg, _Rg>;
137
138 template<typename _Tp, typename _CharT>
139 using __maybe_const
140 = __conditional_t<formattable<const _Tp, _CharT>, const _Tp, _Tp>;
141}
142#endif // format_ranges
143
144
145_GLIBCXX_END_NAMESPACE_VERSION
146} // namespace std
147#endif // __glibcxx_format
148#endif // _GLIBCXX_FORMAT_FWD_H
149