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 include/format
26 * This is a Standard C++ Library header.
27 */
28
29#ifndef _GLIBCXX_FORMAT
30#define _GLIBCXX_FORMAT 1
31
32#ifdef _GLIBCXX_SYSHDR
33#pragma GCC system_header
34#endif
35
36#include <bits/requires_hosted.h> // for std::string
37
38#define __glibcxx_want_format
39#define __glibcxx_want_format_ranges
40#define __glibcxx_want_format_uchar
41#define __glibcxx_want_constexpr_exceptions
42#include <bits/version.h>
43
44#ifdef __cpp_lib_format // C++ >= 20 && HOSTED
45
46#include <array>
47#include <charconv>
48#include <concepts>
49#include <limits>
50#include <locale>
51#include <optional>
52#include <span>
53#include <string_view>
54#include <string>
55#include <bits/monostate.h>
56#include <bits/formatfwd.h>
57#include <bits/ranges_base.h> // input_range, range_reference_t
58#include <bits/ranges_util.h> // subrange
59#include <bits/ranges_algobase.h> // ranges::copy
60#include <bits/stl_iterator.h> // counted_iterator
61#include <bits/stl_pair.h> // __is_pair
62#include <bits/unicode.h> // __is_scalar_value, _Utf_view, etc.
63#include <bits/utility.h> // tuple_size_v
64#include <ext/numeric_traits.h> // __int_traits
65
66#if !__has_builtin(__builtin_toupper)
67# include <cctype>
68#endif
69
70#pragma GCC diagnostic push
71#pragma GCC diagnostic ignored "-Wpedantic" // __int128
72#pragma GCC diagnostic ignored "-Wc++23-extensions" // bf16
73
74namespace std _GLIBCXX_VISIBILITY(default)
75{
76_GLIBCXX_BEGIN_NAMESPACE_VERSION
77
78 // [format.fmt.string], class template basic_format_string
79 template<typename _CharT, typename... _Args> struct basic_format_string;
80
81/// @cond undocumented
82namespace __format
83{
84 // STATICALLY-WIDEN, see C++20 [time.general]
85 // It doesn't matter for format strings (which can only be char or wchar_t)
86 // but this returns the narrow string for anything that isn't wchar_t. This
87 // is done because const char* can be inserted into any ostream type, and
88 // will be widened at runtime if necessary.
89 template<typename _CharT>
90 consteval auto
91 _Widen(const char* __narrow, const wchar_t* __wide)
92 {
93 if constexpr (is_same_v<_CharT, wchar_t>)
94 return __wide;
95 else
96 return __narrow;
97 }
98#define _GLIBCXX_WIDEN_(C, S) ::std::__format::_Widen<C>(S, L##S)
99#define _GLIBCXX_WIDEN(S) _GLIBCXX_WIDEN_(_CharT, S)
100
101 // Size for stack located buffer
102 template<typename _CharT>
103 constexpr size_t __stackbuf_size = 32 * sizeof(void*) / sizeof(_CharT);
104
105 // Type-erased character sinks.
106 template<typename _CharT> class _Sink;
107 template<typename _CharT> class _Fixedbuf_sink;
108 template<typename _Out, typename _CharT> class _Padding_sink;
109 template<typename _Out, typename _CharT> class _Escaping_sink;
110
111 // Output iterator that writes to a type-erase character sink.
112 template<typename _CharT>
113 class _Sink_iter;
114
115 // Output iterator that ignores the characters
116 template<typename _CharT>
117 class _Drop_iter;
118
119 // An unspecified output iterator type used in the `formattable` concept.
120 template<typename _CharT>
121 struct _Iter_for
122 { using type = _Drop_iter<_CharT>; };
123
124 template<typename _CharT>
125 using __format_context = basic_format_context<_Sink_iter<_CharT>, _CharT>;
126
127 template<typename _CharT>
128 struct _Dynamic_format_string
129 {
130 [[__gnu__::__always_inline__]]
131 _Dynamic_format_string(basic_string_view<_CharT> __s) noexcept
132 : _M_str(__s) { }
133
134 _Dynamic_format_string(const _Dynamic_format_string&) = delete;
135 void operator=(const _Dynamic_format_string&) = delete;
136
137 private:
138 basic_string_view<_CharT> _M_str;
139
140 template<typename, typename...> friend struct std::basic_format_string;
141 };
142
143} // namespace __format
144/// @endcond
145
146 using format_context = __format::__format_context<char>;
147#ifdef _GLIBCXX_USE_WCHAR_T
148 using wformat_context = __format::__format_context<wchar_t>;
149#endif
150
151 // [format.args], class template basic_format_args
152 template<typename _Context> class basic_format_args;
153 using format_args = basic_format_args<format_context>;
154#ifdef _GLIBCXX_USE_WCHAR_T
155 using wformat_args = basic_format_args<wformat_context>;
156#endif
157
158 // [format.arguments], arguments
159 // [format.arg], class template basic_format_arg
160 template<typename _Context>
161 class basic_format_arg;
162
163 /** A compile-time checked format string for the specified argument types.
164 *
165 * @since C++23 but available as an extension in C++20.
166 */
167 template<typename _CharT, typename... _Args>
168 struct basic_format_string
169 {
170 template<typename _Tp>
171 requires convertible_to<const _Tp&, basic_string_view<_CharT>>
172 consteval
173 basic_format_string(const _Tp& __s);
174
175 [[__gnu__::__always_inline__]]
176 basic_format_string(__format::_Dynamic_format_string<_CharT> __s) noexcept
177 : _M_str(__s._M_str)
178 { }
179
180 [[__gnu__::__always_inline__]]
181 constexpr basic_string_view<_CharT>
182 get() const noexcept
183 { return _M_str; }
184
185 private:
186 basic_string_view<_CharT> _M_str;
187 };
188
189 template<typename... _Args>
190 using format_string = basic_format_string<char, type_identity_t<_Args>...>;
191
192#ifdef _GLIBCXX_USE_WCHAR_T
193 template<typename... _Args>
194 using wformat_string
195 = basic_format_string<wchar_t, type_identity_t<_Args>...>;
196#endif
197
198#if __cpp_lib_format >= 202603L // >= C++26
199 [[__gnu__::__always_inline__]]
200 inline __format::_Dynamic_format_string<char>
201 dynamic_format(string_view __fmt) noexcept
202 { return __fmt; }
203
204#ifdef _GLIBCXX_USE_WCHAR_T
205 [[__gnu__::__always_inline__]]
206 inline __format::_Dynamic_format_string<wchar_t>
207 dynamic_format(wstring_view __fmt) noexcept
208 { return __fmt; }
209#endif
210#endif // C++26
211
212 // [format.formatter], formatter
213
214 /// The primary template of std::formatter is disabled.
215 template<typename _Tp, typename _CharT>
216 struct formatter
217 {
218 formatter() = delete; // No std::formatter specialization for this type.
219 formatter(const formatter&) = delete;
220 formatter& operator=(const formatter&) = delete;
221 };
222
223#if __cpp_lib_constexpr_exceptions >= 202502L
224#define _GLIBCXX_CONSTEXPR_FORMAT_ERROR constexpr
225#else
226#define _GLIBCXX_CONSTEXPR_FORMAT_ERROR
227#endif
228
229 // [format.error], class format_error
230 class format_error : public runtime_error
231 {
232 public:
233 _GLIBCXX_CONSTEXPR_FORMAT_ERROR explicit format_error(const string& __what)
234 : runtime_error(__what) { }
235 _GLIBCXX_CONSTEXPR_FORMAT_ERROR explicit format_error(const char* __what)
236 : runtime_error(__what) { }
237 };
238
239 /// @cond undocumented
240 [[noreturn]]
241 inline void
242 __throw_format_error(const char* __what)
243 { _GLIBCXX_THROW_OR_ABORT(format_error(__what)); }
244
245#undef _GLIBCXX_CONSTEXPR_FORMAT_ERROR
246
247namespace __format
248{
249 // XXX use named functions for each constexpr error?
250
251 [[noreturn]]
252 inline void
253 __unmatched_left_brace_in_format_string()
254 { __throw_format_error(what: "format error: unmatched '{' in format string"); }
255
256 [[noreturn]]
257 inline void
258 __unmatched_right_brace_in_format_string()
259 { __throw_format_error(what: "format error: unmatched '}' in format string"); }
260
261 [[noreturn]]
262 inline void
263 __conflicting_indexing_in_format_string()
264 { __throw_format_error(what: "format error: conflicting indexing style in format string"); }
265
266 [[noreturn]]
267 inline void
268 __invalid_arg_id_in_format_string()
269 { __throw_format_error(what: "format error: invalid arg-id in format string"); }
270
271 [[noreturn]]
272 inline void
273 __failed_to_parse_format_spec()
274 { __throw_format_error(what: "format error: failed to parse format-spec"); }
275
276 template<typename _CharT> class _Scanner;
277
278} // namespace __format
279 /// @endcond
280
281 // [format.parse.ctx], class template basic_format_parse_context
282 template<typename _CharT> class basic_format_parse_context;
283 using format_parse_context = basic_format_parse_context<char>;
284#ifdef _GLIBCXX_USE_WCHAR_T
285 using wformat_parse_context = basic_format_parse_context<wchar_t>;
286#endif
287
288 template<typename _CharT>
289 class basic_format_parse_context
290 {
291 public:
292 using char_type = _CharT;
293 using const_iterator = typename basic_string_view<_CharT>::const_iterator;
294 using iterator = const_iterator;
295
296 constexpr explicit
297 basic_format_parse_context(basic_string_view<_CharT> __fmt) noexcept
298 : _M_begin(__fmt.begin()), _M_end(__fmt.end())
299 { }
300
301 basic_format_parse_context(const basic_format_parse_context&) = delete;
302 void operator=(const basic_format_parse_context&) = delete;
303
304 constexpr const_iterator begin() const noexcept { return _M_begin; }
305 constexpr const_iterator end() const noexcept { return _M_end; }
306
307 constexpr void
308 advance_to(const_iterator __it) noexcept
309 { _M_begin = __it; }
310
311 constexpr size_t
312 next_arg_id()
313 {
314 if (_M_indexing == _Manual)
315 __format::__conflicting_indexing_in_format_string();
316 _M_indexing = _Auto;
317
318 // _GLIBCXX_RESOLVE_LIB_DEFECTS
319 // 3825. Missing compile-time argument id check in next_arg_id
320 if (std::is_constant_evaluated())
321 if (_M_next_arg_id == _M_num_args)
322 __format::__invalid_arg_id_in_format_string();
323 return _M_next_arg_id++;
324 }
325
326 constexpr void
327 check_arg_id(size_t __id)
328 {
329 if (_M_indexing == _Auto)
330 __format::__conflicting_indexing_in_format_string();
331 _M_indexing = _Manual;
332
333 if (std::is_constant_evaluated())
334 if (__id >= _M_num_args)
335 __format::__invalid_arg_id_in_format_string();
336 }
337
338#if __cpp_lib_format >= 202305L
339 template<typename... _Ts>
340 constexpr void
341 check_dynamic_spec(size_t __id) noexcept
342 {
343 static_assert(__valid_types_for_check_dynamic_spec<_Ts...>(),
344 "template arguments for check_dynamic_spec<Ts...>(id) "
345 "must be unique and must be one of the allowed types");
346 if consteval {
347 __check_dynamic_spec<_Ts...>(__id);
348 }
349 }
350
351 constexpr void
352 check_dynamic_spec_integral(size_t __id) noexcept
353 {
354 if consteval {
355 __check_dynamic_spec<int, unsigned, long long,
356 unsigned long long>(__id);
357 }
358 }
359
360 constexpr void
361 check_dynamic_spec_string(size_t __id) noexcept
362 {
363 if consteval {
364 __check_dynamic_spec<const _CharT*, basic_string_view<_CharT>>(__id);
365 }
366 }
367
368 private:
369 // True if _Tp occurs exactly once in _Ts.
370 template<typename _Tp, typename... _Ts>
371 static constexpr bool __once = (is_same_v<_Tp, _Ts> + ...) == 1;
372
373 template<typename... _Ts>
374 consteval bool
375 __valid_types_for_check_dynamic_spec()
376 {
377 // _GLIBCXX_RESOLVE_LIB_DEFECTS
378 // 4142. check_dynamic_spec should require at least one type
379 if constexpr (sizeof...(_Ts) == 0)
380 return false;
381 else
382 {
383 // The types in Ts... are unique. Each type in Ts... is one of
384 // bool, char_type, int, unsigned int, long long int,
385 // unsigned long long int, float, double, long double,
386 // const char_type*, basic_string_view<char_type>, or const void*.
387 unsigned __sum
388 = __once<bool, _Ts...>
389 + __once<char_type, _Ts...>
390 + __once<int, _Ts...>
391 + __once<unsigned int, _Ts...>
392 + __once<long long int, _Ts...>
393 + __once<unsigned long long int, _Ts...>
394 + __once<float, _Ts...>
395 + __once<double, _Ts...>
396 + __once<long double, _Ts...>
397 + __once<const char_type*, _Ts...>
398 + __once<basic_string_view<char_type>, _Ts...>
399 + __once<const void*, _Ts...>;
400 return __sum == sizeof...(_Ts);
401 }
402 }
403
404 template<typename... _Ts>
405 consteval void
406 __check_dynamic_spec(size_t __id) noexcept;
407
408 // This must not be constexpr.
409 static void __invalid_dynamic_spec(const char*);
410
411 friend __format::_Scanner<_CharT>;
412#endif
413
414 // This constructor should only be used by the implementation.
415 constexpr explicit
416 basic_format_parse_context(basic_string_view<_CharT> __fmt,
417 size_t __num_args) noexcept
418 : _M_begin(__fmt.begin()), _M_end(__fmt.end()), _M_num_args(__num_args)
419 { }
420
421 private:
422 iterator _M_begin;
423 iterator _M_end;
424 enum _Indexing { _Unknown, _Manual, _Auto };
425 _Indexing _M_indexing = _Unknown;
426 size_t _M_next_arg_id = 0;
427 size_t _M_num_args = 0;
428 };
429
430/// @cond undocumented
431 template<typename _Tp, template<typename...> class _Class>
432 constexpr bool __is_specialization_of = false;
433 template<template<typename...> class _Class, typename... _Args>
434 constexpr bool __is_specialization_of<_Class<_Args...>, _Class> = true;
435
436namespace __format
437{
438 // pre: first != last
439 template<typename _CharT>
440 constexpr pair<unsigned short, const _CharT*>
441 __parse_integer(const _CharT* __first, const _CharT* __last)
442 {
443 if (__first == __last)
444 __builtin_unreachable();
445
446 if constexpr (is_same_v<_CharT, char>)
447 {
448 const auto __start = __first;
449 unsigned short __val = 0;
450 // N.B. std::from_chars is not constexpr in C++20.
451 if (__detail::__from_chars_alnum<true>(__first, __last, __val, 10)
452 && __first != __start) [[likely]]
453 return {__val, __first};
454 }
455 else
456 {
457 constexpr int __n = 32;
458 char __buf[__n]{};
459 for (int __i = 0; __i < __n && (__first + __i) != __last; ++__i)
460 __buf[__i] = __first[__i];
461 auto [__v, __ptr] = __format::__parse_integer(first: __buf, last: __buf + __n);
462 if (__ptr) [[likely]]
463 return {__v, __first + (__ptr - __buf)};
464 }
465 return {0, nullptr};
466 }
467
468 template<typename _CharT>
469 constexpr pair<unsigned short, const _CharT*>
470 __parse_arg_id(const _CharT* __first, const _CharT* __last)
471 {
472 if (__first == __last)
473 __builtin_unreachable();
474
475 if (*__first == '0')
476 return {0, __first + 1}; // No leading zeros allowed, so '0...' == 0
477
478 if ('1' <= *__first && *__first <= '9')
479 {
480 const unsigned short __id = *__first - '0';
481 const auto __next = __first + 1;
482 // Optimize for most likely case of single digit arg-id.
483 if (__next == __last || !('0' <= *__next && *__next <= '9'))
484 return {__id, __next};
485 else
486 return __format::__parse_integer(__first, __last);
487 }
488 return {0, nullptr};
489 }
490
491 enum class _Pres_type : unsigned char {
492 _Pres_none = 0, // Default type (not valid for integer presentation types).
493 _Pres_s = 1, // For strings, bool, ranges
494 // Presentation types for integral types (including bool and charT).
495 _Pres_c = 2, _Pres_x, _Pres_X, _Pres_d, _Pres_o, _Pres_b, _Pres_B,
496 // Presentation types for floating-point types
497 _Pres_g = 1, _Pres_G, _Pres_a, _Pres_A, _Pres_e, _Pres_E, _Pres_f, _Pres_F,
498 // For pointers, the value are same as hexadecimal presentations for integers
499 _Pres_p = _Pres_x, _Pres_P = _Pres_X,
500 _Pres_max = 0xf,
501 };
502 using enum _Pres_type;
503
504 enum class _Sign : unsigned char {
505 _Sign_default,
506 _Sign_plus,
507 _Sign_minus, // XXX does this need to be distinct from _Sign_default?
508 _Sign_space,
509 };
510 using enum _Sign;
511
512 enum _WidthPrec : unsigned char {
513 _WP_none, // No width/prec specified.
514 _WP_value, // Fixed width/prec specified.
515 _WP_from_arg // Use a formatting argument for width/prec.
516 };
517 using enum _WidthPrec;
518
519 template<typename _Context>
520 size_t
521 __int_from_arg(const basic_format_arg<_Context>& __arg);
522
523 constexpr bool __is_digit(char __c)
524 { return std::__detail::__from_chars_alnum_to_val(__c) < 10; }
525
526 constexpr bool __is_xdigit(char __c)
527 { return std::__detail::__from_chars_alnum_to_val(__c) < 16; }
528
529 // Used to make _Spec a non-C++98 POD, so the tail-padding is used.
530 // https://itanium-cxx-abi.github.io/cxx-abi/abi.html#pod
531 struct _SpecBase
532 { };
533
534 template<typename _CharT>
535 struct _Spec : _SpecBase
536 {
537 unsigned short _M_width;
538 unsigned short _M_prec;
539 char32_t _M_fill = ' ';
540 _Align _M_align : 2;
541 _Sign _M_sign : 2;
542 unsigned _M_alt : 1;
543 unsigned _M_localized : 1;
544 unsigned _M_zero_fill : 1;
545 _WidthPrec _M_width_kind : 2;
546 _WidthPrec _M_prec_kind : 2;
547 unsigned _M_debug : 1;
548 _Pres_type _M_type : 4;
549 unsigned _M_reserved : 8;
550 // This class has 8 bits of tail padding, that can be used by
551 // derived classes.
552
553 using iterator = typename basic_string_view<_CharT>::iterator;
554
555 static constexpr _Align
556 _S_align(_CharT __c) noexcept
557 {
558 switch (__c)
559 {
560 case '<': return _Align_left;
561 case '>': return _Align_right;
562 case '^': return _Align_centre;
563 default: return _Align_default;
564 }
565 }
566
567 // pre: __first != __last
568 constexpr iterator
569 _M_parse_fill_and_align(iterator __first, iterator __last) noexcept
570 { return _M_parse_fill_and_align(__first, __last, "{"); }
571
572 // pre: __first != __last
573 constexpr iterator
574 _M_parse_fill_and_align(iterator __first, iterator __last, string_view __not_fill) noexcept
575 {
576 for (char __c : __not_fill)
577 if (*__first == static_cast<_CharT>(__c))
578 return __first;
579
580 using namespace __unicode;
581 if constexpr (__literal_encoding_is_unicode<_CharT>())
582 {
583 // Accept any UCS scalar value as fill character.
584 _Utf32_view<ranges::subrange<iterator>> __uv({__first, __last});
585 if (!__uv.empty())
586 {
587 auto __beg = __uv.begin();
588 char32_t __c = *__beg++;
589 if (__is_scalar_value(__c))
590 if (auto __next = __beg.base(); __next != __last)
591 if (_Align __align = _S_align(c: *__next); __align != _Align_default)
592 {
593 _M_fill = __c;
594 _M_align = __align;
595 return ++__next;
596 }
597 }
598 }
599 else if (__last - __first >= 2)
600 if (_Align __align = _S_align(c: __first[1]); __align != _Align_default)
601 {
602 _M_fill = *__first;
603 _M_align = __align;
604 return __first + 2;
605 }
606
607 if (_Align __align = _S_align(c: __first[0]); __align != _Align_default)
608 {
609 _M_fill = ' ';
610 _M_align = __align;
611 return __first + 1;
612 }
613 return __first;
614 }
615
616 static constexpr _Sign
617 _S_sign(_CharT __c) noexcept
618 {
619 switch (__c)
620 {
621 case '+': return _Sign_plus;
622 case '-': return _Sign_minus;
623 case ' ': return _Sign_space;
624 default: return _Sign_default;
625 }
626 }
627
628 // pre: __first != __last
629 constexpr iterator
630 _M_parse_sign(iterator __first, iterator) noexcept
631 {
632 if (_Sign __sign = _S_sign(c: *__first); __sign != _Sign_default)
633 {
634 _M_sign = __sign;
635 return __first + 1;
636 }
637 return __first;
638 }
639
640 // pre: *__first is valid
641 constexpr iterator
642 _M_parse_alternate_form(iterator __first, iterator) noexcept
643 {
644 if (*__first == '#')
645 {
646 _M_alt = true;
647 ++__first;
648 }
649 return __first;
650 }
651
652 // pre: __first != __last
653 constexpr iterator
654 _M_parse_zero_fill(iterator __first, iterator /* __last */) noexcept
655 {
656 if (*__first == '0')
657 {
658 _M_zero_fill = true;
659 ++__first;
660 }
661 return __first;
662 }
663
664 // pre: __first != __last
665 static constexpr iterator
666 _S_parse_width_or_precision(iterator __first, iterator __last,
667 unsigned short& __val, bool& __arg_id,
668 basic_format_parse_context<_CharT>& __pc)
669 {
670 if (__format::__is_digit(c: *__first))
671 {
672 auto [__v, __ptr] = __format::__parse_integer(__first, __last);
673 if (!__ptr)
674 __throw_format_error(what: "format error: invalid width or precision "
675 "in format-spec");
676 __first = __ptr;
677 __val = __v;
678 }
679 else if (*__first == '{')
680 {
681 __arg_id = true;
682 ++__first;
683 if (__first == __last)
684 __format::__unmatched_left_brace_in_format_string();
685 if (*__first == '}')
686 __val = __pc.next_arg_id();
687 else
688 {
689 auto [__v, __ptr] = __format::__parse_arg_id(__first, __last);
690 if (__ptr == nullptr || __ptr == __last || *__ptr != '}')
691 __format::__invalid_arg_id_in_format_string();
692 __first = __ptr;
693 __pc.check_arg_id(__v);
694 __val = __v;
695 }
696#if __cpp_lib_format >= 202305L
697 __pc.check_dynamic_spec_integral(__val);
698#endif
699 ++__first; // past the '}'
700 }
701 return __first;
702 }
703
704 // pre: __first != __last
705 constexpr iterator
706 _M_parse_width(iterator __first, iterator __last,
707 basic_format_parse_context<_CharT>& __pc)
708 {
709 bool __arg_id = false;
710 if (*__first == '0')
711 __throw_format_error(what: "format error: width must be non-zero in "
712 "format string");
713 auto __next = _S_parse_width_or_precision(__first, __last, val&: _M_width,
714 __arg_id, __pc);
715 if (__next != __first)
716 _M_width_kind = __arg_id ? _WP_from_arg : _WP_value;
717 return __next;
718 }
719
720 // pre: __first != __last
721 constexpr iterator
722 _M_parse_precision(iterator __first, iterator __last,
723 basic_format_parse_context<_CharT>& __pc)
724 {
725 if (__first[0] != '.')
726 return __first;
727
728 iterator __next = ++__first;
729 bool __arg_id = false;
730 if (__next != __last)
731 __next = _S_parse_width_or_precision(__first, __last, val&: _M_prec,
732 __arg_id, __pc);
733 if (__next == __first)
734 __throw_format_error(what: "format error: missing precision after '.' in "
735 "format string");
736 _M_prec_kind = __arg_id ? _WP_from_arg : _WP_value;
737 return __next;
738 }
739
740 // pre: __first != __last
741 constexpr iterator
742 _M_parse_locale(iterator __first, iterator /* __last */) noexcept
743 {
744 if (*__first == 'L')
745 {
746 _M_localized = true;
747 ++__first;
748 }
749 return __first;
750 }
751
752 template<typename _Context>
753 size_t
754 _M_get_width(_Context& __ctx) const
755 {
756 size_t __width = 0;
757 if (_M_width_kind == _WP_value)
758 __width = _M_width;
759 else if (_M_width_kind == _WP_from_arg)
760 __width = __format::__int_from_arg(__ctx.arg(_M_width));
761 return __width;
762 }
763
764 template<typename _Context>
765 size_t
766 _M_get_precision(_Context& __ctx) const
767 {
768 size_t __prec = -1;
769 if (_M_prec_kind == _WP_value)
770 __prec = _M_prec;
771 else if (_M_prec_kind == _WP_from_arg)
772 __prec = __format::__int_from_arg(__ctx.arg(_M_prec));
773 return __prec;
774 }
775 };
776
777 template<typename _Int>
778 inline char*
779 __put_sign(_Int __i, _Sign __sign, char* __dest) noexcept
780 {
781 if (__i < 0)
782 *__dest = '-';
783 else if (__sign == _Sign_plus)
784 *__dest = '+';
785 else if (__sign == _Sign_space)
786 *__dest = ' ';
787 else
788 ++__dest;
789 return __dest;
790 }
791
792 // Write STR to OUT (and do so efficiently if OUT is a _Sink_iter).
793 template<typename _Out, typename _CharT>
794 requires output_iterator<_Out, const _CharT&>
795 inline _Out
796 __write(_Out __out, basic_string_view<_CharT> __str)
797 {
798 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
799 {
800 if (__str.size())
801 __out = __str;
802 }
803 else
804 for (_CharT __c : __str)
805 *__out++ = __c;
806 return __out;
807 }
808
809 // Write STR to OUT with NFILL copies of FILL_CHAR specified by ALIGN.
810 // pre: __align != _Align_default
811 template<typename _Out, typename _CharT>
812 _Out
813 __write_padded(_Out __out, basic_string_view<_CharT> __str,
814 _Align __align, size_t __nfill, char32_t __fill_char)
815 {
816 const size_t __buflen = 0x20;
817 _CharT __padding_chars[__buflen];
818 __padding_chars[0] = _CharT();
819 basic_string_view<_CharT> __padding{__padding_chars, __buflen};
820
821 auto __pad = [&__padding] (size_t __n, _Out& __o) {
822 if (__n == 0)
823 return;
824 while (__n > __padding.size())
825 {
826 __o = __format::__write(std::move(__o), __padding);
827 __n -= __padding.size();
828 }
829 if (__n != 0)
830 __o = __format::__write(std::move(__o), __padding.substr(0, __n));
831 };
832
833 size_t __l, __r, __max;
834 if (__align == _Align_centre)
835 {
836 __l = __nfill / 2;
837 __r = __l + (__nfill & 1);
838 __max = __r;
839 }
840 else if (__align == _Align_right)
841 {
842 __l = __nfill;
843 __r = 0;
844 __max = __l;
845 }
846 else
847 {
848 __l = 0;
849 __r = __nfill;
850 __max = __r;
851 }
852
853 using namespace __unicode;
854 if constexpr (__literal_encoding_is_unicode<_CharT>())
855 if (!__is_single_code_unit<_CharT>(__fill_char)) [[unlikely]]
856 {
857 // Encode fill char as multiple code units of type _CharT.
858 const char32_t __arr[1]{ __fill_char };
859 _Utf_view<_CharT, span<const char32_t, 1>> __v(__arr);
860 basic_string<_CharT> __padstr(__v.begin(), __v.end());
861 __padding = __padstr;
862 while (__l-- > 0)
863 __out = __format::__write(std::move(__out), __padding);
864 __out = __format::__write(std::move(__out), __str);
865 while (__r-- > 0)
866 __out = __format::__write(std::move(__out), __padding);
867 return __out;
868 }
869
870 if (__max < __buflen)
871 __padding.remove_suffix(__buflen - __max);
872 else
873 __max = __buflen;
874
875 char_traits<_CharT>::assign(__padding_chars, __max, __fill_char);
876 __pad(__l, __out);
877 __out = __format::__write(std::move(__out), __str);
878 __pad(__r, __out);
879
880 return __out;
881 }
882
883 // Write STR to OUT, with alignment and padding as determined by SPEC.
884 // pre: __spec._M_align != _Align_default || __align != _Align_default
885 template<typename _CharT, typename _Out>
886 _Out
887 __write_padded_as_spec(basic_string_view<type_identity_t<_CharT>> __str,
888 size_t __estimated_width,
889 basic_format_context<_Out, _CharT>& __fc,
890 const _Spec<_CharT>& __spec,
891 _Align __align = _Align_left)
892 {
893 size_t __width = __spec._M_get_width(__fc);
894
895 if (__width <= __estimated_width)
896 return __format::__write(__fc.out(), __str);
897
898 const size_t __nfill = __width - __estimated_width;
899
900 if (__spec._M_align != _Align_default)
901 __align = __spec._M_align;
902
903 return __format::__write_padded(__fc.out(), __str, __align, __nfill,
904 __spec._M_fill);
905 }
906
907 template<typename _CharT>
908 size_t
909 __truncate(basic_string_view<_CharT>& __s, size_t __prec)
910 {
911 if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
912 {
913 if (__prec != (size_t)-1)
914 return __unicode::__truncate(__s, __prec);
915 else
916 return __unicode::__field_width(__s);
917 }
918 else
919 {
920 __s = __s.substr(0, __prec);
921 return __s.size();
922 }
923 }
924
925 enum class _Term_char : unsigned char {
926 _Term_none,
927 _Term_quote,
928 _Term_apos,
929 };
930 using enum _Term_char;
931
932 template<typename _CharT>
933 struct _Escapes
934 {
935 using _Str_view = basic_string_view<_CharT>;
936
937 static consteval
938 _Str_view _S_all()
939 { return _GLIBCXX_WIDEN("\t\\t\n\\n\r\\r\\\\\\\"\\\"'\\'\\u\\x"); }
940
941 static consteval
942 _Str_view _S_tab()
943 { return _S_all().substr(0, 3); }
944
945 static consteval
946 _Str_view _S_newline()
947 { return _S_all().substr(3, 3); }
948
949 static consteval
950 _Str_view _S_return()
951 { return _S_all().substr(6, 3); }
952
953 static consteval
954 _Str_view _S_bslash()
955 { return _S_all().substr(9, 3); }
956
957 static consteval
958 _Str_view _S_quote()
959 { return _S_all().substr(12, 3); }
960
961 static consteval
962 _Str_view _S_apos()
963 { return _S_all().substr(15, 3); }
964
965 static consteval
966 _Str_view _S_u()
967 { return _S_all().substr(18, 2); }
968
969 static consteval
970 _Str_view _S_x()
971 { return _S_all().substr(20, 2); }
972
973 static constexpr
974 _Str_view _S_term(_Term_char __term)
975 {
976 switch (__term)
977 {
978 case _Term_none:
979 return _Str_view();
980 case _Term_quote:
981 return _S_quote().substr(0, 1);
982 case _Term_apos:
983 return _S_apos().substr(0, 1);
984 }
985 __builtin_unreachable();
986 }
987 };
988
989 template<typename _CharT>
990 struct _Separators
991 {
992 using _Str_view = basic_string_view<_CharT>;
993
994 static consteval
995 _Str_view _S_all()
996 { return _GLIBCXX_WIDEN("[]{}(), : "); }
997
998 static consteval
999 _Str_view _S_squares()
1000 { return _S_all().substr(0, 2); }
1001
1002 static consteval
1003 _Str_view _S_braces()
1004 { return _S_all().substr(2, 2); }
1005
1006 static consteval
1007 _Str_view _S_parens()
1008 { return _S_all().substr(4, 2); }
1009
1010 static consteval
1011 _Str_view _S_comma()
1012 { return _S_all().substr(6, 2); }
1013
1014 static consteval
1015 _Str_view _S_colon()
1016 { return _S_all().substr(8, 2); }
1017 };
1018
1019 template<typename _CharT>
1020 constexpr bool __should_escape_ascii(_CharT __c, _Term_char __term)
1021 {
1022 using _Esc = _Escapes<_CharT>;
1023 switch (__c)
1024 {
1025 case _Esc::_S_tab()[0]:
1026 case _Esc::_S_newline()[0]:
1027 case _Esc::_S_return()[0]:
1028 case _Esc::_S_bslash()[0]:
1029 return true;
1030 case _Esc::_S_quote()[0]:
1031 return __term == _Term_quote;
1032 case _Esc::_S_apos()[0]:
1033 return __term == _Term_apos;
1034 default:
1035 return (__c >= 0 && __c < 0x20) || __c == 0x7f;
1036 };
1037 }
1038
1039 // @pre __c <= 0x10FFFF
1040 constexpr bool __should_escape_unicode(char32_t __c, bool __prev_esc)
1041 {
1042 if (__unicode::__should_escape_category(__c))
1043 return __c != U' ';
1044 if (!__prev_esc)
1045 return false;
1046 return __unicode::__grapheme_cluster_break_property(__c)
1047 == __unicode::_Gcb_property::_Gcb_Extend;
1048 }
1049
1050 using uint_least32_t = __UINT_LEAST32_TYPE__;
1051 template<typename _Out, typename _CharT>
1052 _Out
1053 __write_escape_seq(_Out __out, uint_least32_t __val,
1054 basic_string_view<_CharT> __prefix)
1055 {
1056 using _Str_view = basic_string_view<_CharT>;
1057 constexpr size_t __max = 8;
1058 char __buf[__max];
1059 const string_view __narrow(
1060 __buf,
1061 std::__to_chars_i<uint_least32_t>(first: __buf, last: __buf + __max, value: __val, base: 16).ptr);
1062
1063 __out = __format::__write(__out, __prefix);
1064 *__out = _Separators<_CharT>::_S_braces()[0];
1065 ++__out;
1066 if constexpr (is_same_v<char, _CharT>)
1067 __out = __format::__write(__out, __narrow);
1068#ifdef _GLIBCXX_USE_WCHAR_T
1069 else
1070 {
1071 _CharT __wbuf[__max];
1072 const size_t __n = __narrow.size();
1073 std::__to_wstring_numeric(__narrow.data(), __n, __wbuf);
1074 __out = __format::__write(__out, _Str_view(__wbuf, __n));
1075 }
1076#endif
1077 *__out = _Separators<_CharT>::_S_braces()[1];
1078 return ++__out;
1079 }
1080
1081 template<typename _Out, typename _CharT>
1082 _Out
1083 __write_escape_seqs(_Out __out, basic_string_view<_CharT> __units)
1084 {
1085 using _UChar = make_unsigned_t<_CharT>;
1086 for (_CharT __c : __units)
1087 __out = __format::__write_escape_seq(
1088 __out, static_cast<_UChar>(__c), _Escapes<_CharT>::_S_x());
1089 return __out;
1090 }
1091
1092 template<typename _Out, typename _CharT>
1093 _Out
1094 __write_escaped_char(_Out __out, _CharT __c)
1095 {
1096 using _UChar = make_unsigned_t<_CharT>;
1097 using _Esc = _Escapes<_CharT>;
1098 switch (__c)
1099 {
1100 case _Esc::_S_tab()[0]:
1101 return __format::__write(__out, _Esc::_S_tab().substr(1, 2));
1102 case _Esc::_S_newline()[0]:
1103 return __format::__write(__out, _Esc::_S_newline().substr(1, 2));
1104 case _Esc::_S_return()[0]:
1105 return __format::__write(__out, _Esc::_S_return().substr(1, 2));
1106 case _Esc::_S_bslash()[0]:
1107 return __format::__write(__out, _Esc::_S_bslash().substr(1, 2));
1108 case _Esc::_S_quote()[0]:
1109 return __format::__write(__out, _Esc::_S_quote().substr(1, 2));
1110 case _Esc::_S_apos()[0]:
1111 return __format::__write(__out, _Esc::_S_apos().substr(1, 2));
1112 default:
1113 return __format::__write_escape_seq(
1114 __out, static_cast<_UChar>(__c), _Esc::_S_u());
1115 }
1116 }
1117
1118 template<typename _CharT, typename _Out>
1119 _Out
1120 __write_escaped_ascii(_Out __out,
1121 basic_string_view<_CharT> __str,
1122 _Term_char __term)
1123 {
1124 using _Str_view = basic_string_view<_CharT>;
1125 auto __first = __str.begin();
1126 auto const __last = __str.end();
1127 while (__first != __last)
1128 {
1129 auto __print = __first;
1130 // assume anything outside ASCII is printable
1131 while (__print != __last
1132 && !__format::__should_escape_ascii(*__print, __term))
1133 ++__print;
1134
1135 if (__print != __first)
1136 __out = __format::__write(__out, _Str_view(__first, __print));
1137
1138 if (__print == __last)
1139 return __out;
1140
1141 __first = __print;
1142 __out = __format::__write_escaped_char(__out, *__first);
1143 ++__first;
1144 }
1145 return __out;
1146 }
1147
1148 template<typename _CharT, typename _Out>
1149 _Out
1150 __write_escaped_unicode_part(_Out __out, basic_string_view<_CharT>& __str,
1151 bool& __prev_esc, _Term_char __term)
1152 {
1153 using _Str_view = basic_string_view<_CharT>;
1154 using _Esc = _Escapes<_CharT>;
1155
1156 static constexpr char32_t __replace = U'\uFFFD';
1157 static constexpr _Str_view __replace_rep = []
1158 {
1159 // N.B. "\uFFFD" is ill-formed if encoding is not unicode.
1160 if constexpr (is_same_v<char, _CharT>)
1161 return "\xEF\xBF\xBD";
1162 else
1163 return L"\xFFFD";
1164 }();
1165
1166 __unicode::_Utf_view<char32_t, _Str_view> __v(std::move(__str));
1167 __str = {};
1168
1169 auto __first = __v.begin();
1170 auto const __last = __v.end();
1171 while (__first != __last)
1172 {
1173 bool __esc_ascii = false;
1174 bool __esc_unicode = false;
1175 bool __esc_replace = false;
1176 auto __should_escape = [&](auto const& __it)
1177 {
1178 if (*__it <= 0x7f)
1179 return __esc_ascii
1180 = __format::__should_escape_ascii(*__it.base(), __term);
1181 if (__format::__should_escape_unicode(c: *__it, __prev_esc))
1182 return __esc_unicode = true;
1183 if (*__it == __replace)
1184 {
1185 _Str_view __units(__it.base(), __it._M_units());
1186 return __esc_replace = (__units != __replace_rep);
1187 }
1188 return false;
1189 };
1190
1191 auto __print = __first;
1192 while (__print != __last && !__should_escape(__print))
1193 {
1194 __prev_esc = false;
1195 ++__print;
1196 }
1197
1198 if (__print != __first)
1199 __out = __format::__write(__out, _Str_view(__first.base(), __print.base()));
1200
1201 if (__print == __last)
1202 return __out;
1203
1204 __first = __print;
1205 if (__esc_ascii)
1206 __out = __format::__write_escaped_char(__out, *__first.base());
1207 else if (__esc_unicode)
1208 __out = __format::__write_escape_seq(__out, *__first, _Esc::_S_u());
1209 // __esc_replace
1210 else if (_Str_view __units(__first.base(), __first._M_units());
1211 __units.end() != __last.base())
1212 __out = __format::__write_escape_seqs(__out, __units);
1213 else
1214 {
1215 __str = __units;
1216 return __out;
1217 }
1218
1219 __prev_esc = true;
1220 ++__first;
1221 }
1222
1223 return __out;
1224 }
1225
1226 template<typename _CharT, typename _Out>
1227 _Out
1228 __write_escaped_unicode(_Out __out, basic_string_view<_CharT> __str,
1229 _Term_char __term)
1230 {
1231 bool __prev_escape = true;
1232 __out = __format::__write_escaped_unicode_part(__out, __str,
1233 __prev_escape, __term);
1234 __out = __format::__write_escape_seqs(__out, __str);
1235 return __out;
1236 }
1237
1238 template<typename _CharT, typename _Out>
1239 _Out
1240 __write_escaped(_Out __out, basic_string_view<_CharT> __str, _Term_char __term)
1241 {
1242 __out = __format::__write(__out, _Escapes<_CharT>::_S_term(__term));
1243
1244 if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
1245 __out = __format::__write_escaped_unicode(__out, __str, __term);
1246 else if constexpr (is_same_v<char, _CharT>
1247 && __unicode::__literal_encoding_is_extended_ascii())
1248 __out = __format::__write_escaped_ascii(__out, __str, __term);
1249 else
1250 // TODO Handle non-ascii extended encoding
1251 __out = __format::__write_escaped_ascii(__out, __str, __term);
1252
1253 return __format::__write(__out, _Escapes<_CharT>::_S_term(__term));
1254 }
1255
1256 // A lightweight optional<locale>.
1257 struct _Optional_locale
1258 {
1259 [[__gnu__::__always_inline__]]
1260 _Optional_locale() : _M_dummy(), _M_hasval(false) { }
1261
1262 _Optional_locale(const locale& __loc) noexcept
1263 : _M_loc(__loc), _M_hasval(true)
1264 { }
1265
1266 _Optional_locale(const _Optional_locale& __l) noexcept
1267 : _M_dummy(), _M_hasval(__l._M_hasval)
1268 {
1269 if (_M_hasval)
1270 std::construct_at(location: &_M_loc, args: __l._M_loc);
1271 }
1272
1273 _Optional_locale&
1274 operator=(const _Optional_locale& __l) noexcept
1275 {
1276 if (_M_hasval)
1277 {
1278 if (__l._M_hasval)
1279 _M_loc = __l._M_loc;
1280 else
1281 {
1282 _M_loc.~locale();
1283 _M_hasval = false;
1284 }
1285 }
1286 else if (__l._M_hasval)
1287 {
1288 std::construct_at(location: &_M_loc, args: __l._M_loc);
1289 _M_hasval = true;
1290 }
1291 return *this;
1292 }
1293
1294 ~_Optional_locale() { if (_M_hasval) _M_loc.~locale(); }
1295
1296 _Optional_locale&
1297 operator=(locale&& __loc) noexcept
1298 {
1299 if (_M_hasval)
1300 _M_loc = std::move(__loc);
1301 else
1302 {
1303 std::construct_at(location: &_M_loc, args: std::move(__loc));
1304 _M_hasval = true;
1305 }
1306 return *this;
1307 }
1308
1309 const locale&
1310 value() noexcept
1311 {
1312 if (!_M_hasval)
1313 {
1314 std::construct_at(location: &_M_loc);
1315 _M_hasval = true;
1316 }
1317 return _M_loc;
1318 }
1319
1320 bool has_value() const noexcept { return _M_hasval; }
1321
1322 union {
1323 char _M_dummy = '\0';
1324 std::locale _M_loc;
1325 };
1326 bool _M_hasval = false;
1327 };
1328
1329 template<__char _CharT>
1330 struct __formatter_str
1331 {
1332 __formatter_str() = default;
1333
1334 constexpr
1335 __formatter_str(_Spec<_CharT> __spec) noexcept
1336 : _M_spec(__spec)
1337 { }
1338
1339 constexpr typename basic_format_parse_context<_CharT>::iterator
1340 parse(basic_format_parse_context<_CharT>& __pc)
1341 {
1342 auto __first = __pc.begin();
1343 const auto __last = __pc.end();
1344 _Spec<_CharT> __spec{};
1345
1346 auto __finalize = [this, &__spec] {
1347 _M_spec = __spec;
1348 };
1349
1350 auto __finished = [&] {
1351 if (__first == __last || *__first == '}')
1352 {
1353 __finalize();
1354 return true;
1355 }
1356 return false;
1357 };
1358
1359 if (__finished())
1360 return __first;
1361
1362 __first = __spec._M_parse_fill_and_align(__first, __last);
1363 if (__finished())
1364 return __first;
1365
1366 __first = __spec._M_parse_width(__first, __last, __pc);
1367 if (__finished())
1368 return __first;
1369
1370 __first = __spec._M_parse_precision(__first, __last, __pc);
1371 if (__finished())
1372 return __first;
1373
1374 if (*__first == 's')
1375 {
1376 __spec._M_type = _Pres_s;
1377 ++__first;
1378 }
1379#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
1380 else if (*__first == '?')
1381 {
1382 __spec._M_debug = true;
1383 ++__first;
1384 }
1385#endif
1386
1387 if (__finished())
1388 return __first;
1389
1390 __format::__failed_to_parse_format_spec();
1391 }
1392
1393 template<typename _Out>
1394 _Out
1395 format(basic_string_view<_CharT> __s,
1396 basic_format_context<_Out, _CharT>& __fc) const
1397 {
1398 if (_M_spec._M_debug)
1399 return _M_format_escaped(__s, __fc);
1400
1401 if (_M_spec._M_width_kind == _WP_none
1402 && _M_spec._M_prec_kind == _WP_none)
1403 return __format::__write(__fc.out(), __s);
1404
1405 const size_t __maxwidth = _M_spec._M_get_precision(__fc);
1406 const size_t __width = __format::__truncate(__s, __maxwidth);
1407 return __format::__write_padded_as_spec(__s, __width, __fc, _M_spec);
1408 }
1409
1410 template<typename _Out>
1411 _Out
1412 _M_format_escaped(basic_string_view<_CharT> __s,
1413 basic_format_context<_Out, _CharT>& __fc) const
1414 {
1415 const size_t __padwidth = _M_spec._M_get_width(__fc);
1416 if (__padwidth == 0 && _M_spec._M_prec_kind == _WP_none)
1417 return __format::__write_escaped(__fc.out(), __s, _Term_quote);
1418
1419 const size_t __maxwidth = _M_spec._M_get_precision(__fc);
1420 const size_t __width = __truncate(__s, __maxwidth);
1421 // N.B. Escaping only increases width
1422 if (__padwidth <= __width && _M_spec._M_prec_kind == _WP_none)
1423 return __format::__write_escaped(__fc.out(), __s, _Term_quote);
1424
1425 // N.B. [tab:format.type.string] defines '?' as
1426 // Copies the escaped string ([format.string.escaped]) to the output,
1427 // so precision seem to appy to escaped string.
1428 _Padding_sink<_Out, _CharT> __sink(__fc.out(), __padwidth, __maxwidth);
1429 __format::__write_escaped(__sink.out(), __s, _Term_quote);
1430 return __sink._M_finish(_M_spec._M_align, _M_spec._M_fill);
1431 }
1432
1433#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
1434 template<ranges::input_range _Rg, typename _Out>
1435 requires same_as<remove_cvref_t<ranges::range_reference_t<_Rg>>, _CharT>
1436 _Out
1437 _M_format_range(_Rg&& __rg, basic_format_context<_Out, _CharT>& __fc) const
1438 {
1439 using _Range = remove_reference_t<_Rg>;
1440 using _String_view = basic_string_view<_CharT>;
1441 if constexpr (!is_lvalue_reference_v<_Rg>)
1442 return _M_format_range<_Range&>(__rg, __fc);
1443 else if constexpr (!is_const_v<_Range>
1444 && __simply_formattable_range<_Range, _CharT>)
1445 return _M_format_range<const _Range&>(__rg, __fc);
1446 else if constexpr (ranges::contiguous_range<_Rg>)
1447 {
1448 _String_view __str(ranges::data(__rg),
1449 size_t(ranges::distance(__rg)));
1450 return format(__str, __fc);
1451 }
1452 else
1453 {
1454 auto __handle_debug = [this, &__rg]<typename _NOut>(_NOut __nout)
1455 {
1456 if (!_M_spec._M_debug)
1457 return ranges::copy(__rg, std::move(__nout)).out;
1458
1459 _Escaping_sink<_NOut, _CharT>
1460 __sink(std::move(__nout), _Term_quote);
1461 ranges::copy(__rg, __sink.out());
1462 return __sink._M_finish();
1463 };
1464
1465 const size_t __padwidth = _M_spec._M_get_width(__fc);
1466 if (__padwidth == 0 && _M_spec._M_prec_kind == _WP_none)
1467 return __handle_debug(__fc.out());
1468
1469 _Padding_sink<_Out, _CharT>
1470 __sink(__fc.out(), __padwidth, _M_spec._M_get_precision(__fc));
1471 __handle_debug(__sink.out());
1472 return __sink._M_finish(_M_spec._M_align, _M_spec._M_fill);
1473 }
1474 }
1475
1476 constexpr void
1477 set_debug_format() noexcept
1478 { _M_spec._M_debug = true; }
1479#endif
1480
1481 private:
1482 _Spec<_CharT> _M_spec{};
1483 };
1484
1485 template<__char _CharT>
1486 struct __formatter_int
1487 {
1488 // If no presentation type is specified, meaning of "none" depends
1489 // whether we are formatting an integer or a char or a bool.
1490 static constexpr _Pres_type _AsInteger = _Pres_d;
1491 static constexpr _Pres_type _AsBool = _Pres_s;
1492 static constexpr _Pres_type _AsChar = _Pres_c;
1493
1494 __formatter_int() = default;
1495
1496 constexpr
1497 __formatter_int(_Spec<_CharT> __spec) noexcept
1498 : _M_spec(__spec)
1499 {
1500 if (_M_spec._M_type == _Pres_none)
1501 _M_spec._M_type = _Pres_d;
1502 }
1503
1504 constexpr typename basic_format_parse_context<_CharT>::iterator
1505 _M_do_parse(basic_format_parse_context<_CharT>& __pc, _Pres_type __type)
1506 {
1507 _Spec<_CharT> __spec{};
1508 __spec._M_type = __type;
1509
1510 const auto __last = __pc.end();
1511 auto __first = __pc.begin();
1512
1513 auto __finalize = [this, &__spec] {
1514 _M_spec = __spec;
1515 };
1516
1517 auto __finished = [&] {
1518 if (__first == __last || *__first == '}')
1519 {
1520 __finalize();
1521 return true;
1522 }
1523 return false;
1524 };
1525
1526 if (__finished())
1527 return __first;
1528
1529 __first = __spec._M_parse_fill_and_align(__first, __last);
1530 if (__finished())
1531 return __first;
1532
1533 __first = __spec._M_parse_sign(__first, __last);
1534 if (__finished())
1535 return __first;
1536
1537 __first = __spec._M_parse_alternate_form(__first, __last);
1538 if (__finished())
1539 return __first;
1540
1541 __first = __spec._M_parse_zero_fill(__first, __last);
1542 if (__finished())
1543 return __first;
1544
1545 __first = __spec._M_parse_width(__first, __last, __pc);
1546 if (__finished())
1547 return __first;
1548
1549 __first = __spec._M_parse_locale(__first, __last);
1550 if (__finished())
1551 return __first;
1552
1553 switch (*__first)
1554 {
1555 case 'b':
1556 __spec._M_type = _Pres_b;
1557 ++__first;
1558 break;
1559 case 'B':
1560 __spec._M_type = _Pres_B;
1561 ++__first;
1562 break;
1563 case 'c':
1564 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1565 // 3586. format should not print bool with 'c'
1566 if (__type != _AsBool)
1567 {
1568 __spec._M_type = _Pres_c;
1569 ++__first;
1570 }
1571 break;
1572 case 'd':
1573 __spec._M_type = _Pres_d;
1574 ++__first;
1575 break;
1576 case 'o':
1577 __spec._M_type = _Pres_o;
1578 ++__first;
1579 break;
1580 case 'x':
1581 __spec._M_type = _Pres_x;
1582 ++__first;
1583 break;
1584 case 'X':
1585 __spec._M_type = _Pres_X;
1586 ++__first;
1587 break;
1588 case 's':
1589 if (__type == _AsBool)
1590 {
1591 __spec._M_type = _Pres_s; // same meaning as "none" for bool
1592 ++__first;
1593 }
1594 break;
1595#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
1596 case '?':
1597 if (__type == _AsChar)
1598 {
1599 __spec._M_debug = true;
1600 ++__first;
1601 }
1602#endif
1603 break;
1604 }
1605
1606 if (__finished())
1607 return __first;
1608
1609 __format::__failed_to_parse_format_spec();
1610 }
1611
1612 template<typename _Tp>
1613 constexpr typename basic_format_parse_context<_CharT>::iterator
1614 _M_parse(basic_format_parse_context<_CharT>& __pc)
1615 {
1616 if constexpr (is_same_v<_Tp, bool>)
1617 {
1618 auto __end = _M_do_parse(__pc, type: _AsBool);
1619 if (_M_spec._M_type == _Pres_s)
1620 if (_M_spec._M_sign != _Sign_default || _M_spec._M_alt
1621 || _M_spec._M_zero_fill)
1622 __throw_format_error(what: "format error: format-spec contains "
1623 "invalid formatting options for "
1624 "'bool'");
1625 return __end;
1626 }
1627 else if constexpr (__char<_Tp>)
1628 {
1629 auto __end = _M_do_parse(__pc, type: _AsChar);
1630 if (_M_spec._M_type == _Pres_c)
1631 if (_M_spec._M_sign != _Sign_default || _M_spec._M_alt
1632 || _M_spec._M_zero_fill
1633 /* XXX should be invalid? || _M_spec._M_localized */)
1634 __throw_format_error(what: "format error: format-spec contains "
1635 "invalid formatting options for "
1636 "'charT'");
1637 return __end;
1638 }
1639 else
1640 return _M_do_parse(__pc, type: _AsInteger);
1641 }
1642
1643 template<typename _Int, typename _Out>
1644 typename basic_format_context<_Out, _CharT>::iterator
1645 format(_Int __i, basic_format_context<_Out, _CharT>& __fc) const
1646 {
1647 if (_M_spec._M_type == _Pres_c)
1648 return _M_format_character(_S_to_character(__i), __fc);
1649
1650 constexpr size_t __buf_size = sizeof(_Int) * __CHAR_BIT__ + 3;
1651 char __buf[__buf_size];
1652 to_chars_result __res{};
1653
1654 string_view __base_prefix;
1655 make_unsigned_t<_Int> __u;
1656 if (__i < 0)
1657 __u = -static_cast<make_unsigned_t<_Int>>(__i);
1658 else
1659 __u = __i;
1660
1661 char* __start = __buf + 3;
1662 char* const __end = __buf + sizeof(__buf);
1663 char* const __start_digits = __start;
1664
1665 switch (_M_spec._M_type)
1666 {
1667 case _Pres_b:
1668 case _Pres_B:
1669 __base_prefix = _M_spec._M_type == _Pres_b ? "0b" : "0B";
1670 __res = to_chars(__start, __end, __u, 2);
1671 break;
1672#if 0
1673 case _Pres_c:
1674 return _M_format_character(_S_to_character(__i), __fc);
1675#endif
1676 case _Pres_none:
1677 // Should not reach here with _Pres_none for bool or charT, so:
1678 [[fallthrough]];
1679 case _Pres_d:
1680 __res = to_chars(__start, __end, __u, 10);
1681 break;
1682 case _Pres_o:
1683 if (__i != 0)
1684 __base_prefix = "0";
1685 __res = to_chars(__start, __end, __u, 8);
1686 break;
1687 case _Pres_x:
1688 case _Pres_X:
1689 __base_prefix = _M_spec._M_type == _Pres_x ? "0x" : "0X";
1690 __res = to_chars(__start, __end, __u, 16);
1691 if (_M_spec._M_type == _Pres_X)
1692 for (auto __p = __start; __p != __res.ptr; ++__p)
1693#if __has_builtin(__builtin_toupper)
1694 *__p = __builtin_toupper(*__p);
1695#else
1696 *__p = std::toupper(c: *__p);
1697#endif
1698 break;
1699 default:
1700 __builtin_unreachable();
1701 }
1702
1703 if (_M_spec._M_alt && __base_prefix.size())
1704 {
1705 __start -= __base_prefix.size();
1706 __builtin_memcpy(__start, __base_prefix.data(),
1707 __base_prefix.size());
1708 }
1709 __start = __format::__put_sign(__i, _M_spec._M_sign, __start - 1);
1710
1711
1712 string_view __narrow_str(__start, __res.ptr - __start);
1713 size_t __prefix_len = __start_digits - __start;
1714 if constexpr (is_same_v<char, _CharT>)
1715 return _M_format_int(__narrow_str, __prefix_len, __fc);
1716#ifdef _GLIBCXX_USE_WCHAR_T
1717 else
1718 {
1719 _CharT __wbuf[__buf_size];
1720 size_t __n = __narrow_str.size();
1721 // _GLIBCXX_RESOLVE_LIB_DEFECTS
1722 // 4522. Clarify that `std::format` transcodes for `std::wformat_strings`
1723 std::__to_wstring_numeric(__narrow_str.data(), __n, __wbuf);
1724 return _M_format_int(basic_string_view<_CharT>(__wbuf, __n),
1725 __prefix_len, __fc);
1726 }
1727#endif
1728 }
1729
1730 template<typename _Out>
1731 typename basic_format_context<_Out, _CharT>::iterator
1732 format(bool __i, basic_format_context<_Out, _CharT>& __fc) const
1733 {
1734 if (_M_spec._M_type == _Pres_c)
1735 return _M_format_character(static_cast<unsigned char>(__i), __fc);
1736 if (_M_spec._M_type != _Pres_s)
1737 return format(static_cast<unsigned char>(__i), __fc);
1738
1739 basic_string<_CharT> __s;
1740 size_t __est_width;
1741 if (_M_spec._M_localized) [[unlikely]]
1742 {
1743 auto& __np = std::use_facet<numpunct<_CharT>>(__fc.locale());
1744 __s = __i ? __np.truename() : __np.falsename();
1745 __est_width = __s.size(); // TODO Unicode-aware estimate
1746 }
1747 else
1748 {
1749 if constexpr (is_same_v<char, _CharT>)
1750 __s = __i ? "true" : "false";
1751 else
1752 __s = __i ? L"true" : L"false";
1753 __est_width = __s.size();
1754 }
1755
1756 return __format::__write_padded_as_spec(__s, __est_width, __fc,
1757 _M_spec);
1758 }
1759
1760 template<typename _Out>
1761 typename basic_format_context<_Out, _CharT>::iterator
1762 _M_format_character(_CharT __c,
1763 basic_format_context<_Out, _CharT>& __fc) const
1764 {
1765 basic_string_view<_CharT> __in(&__c, 1u);
1766 size_t __width = 1u;
1767 // N.B. single byte cannot encode character of width greater than 1
1768 if constexpr (sizeof(_CharT) > 1u &&
1769 __unicode::__literal_encoding_is_unicode<_CharT>())
1770 __width = __unicode::__field_width(__c);
1771
1772 if (!_M_spec._M_debug)
1773 return __format::__write_padded_as_spec(__in, __width,
1774 __fc, _M_spec);
1775
1776 __width += 2;
1777 if (_M_spec._M_get_width(__fc) <= __width)
1778 return __format::__write_escaped(__fc.out(), __in, _Term_apos);
1779
1780 _CharT __buf[12];
1781 _Fixedbuf_sink<_CharT> __sink(__buf);
1782 __format::__write_escaped(__sink.out(), __in, _Term_apos);
1783
1784 __in = __sink.view();
1785 if (__in[1] == _Escapes<_CharT>::_S_bslash()[0]) // escape sequence
1786 __width = __in.size();
1787 return __format::__write_padded_as_spec(__in, __width,
1788 __fc, _M_spec);
1789 }
1790
1791 template<typename _Int>
1792 static _CharT
1793 _S_to_character(_Int __i)
1794 {
1795 using _Traits = __gnu_cxx::__int_traits<_CharT>;
1796 if constexpr (is_signed_v<_Int> == is_signed_v<_CharT>)
1797 {
1798 if (_Traits::__min <= __i && __i <= _Traits::__max)
1799 return static_cast<_CharT>(__i);
1800 }
1801 else if constexpr (is_signed_v<_Int>)
1802 {
1803 if (__i >= 0 && make_unsigned_t<_Int>(__i) <= _Traits::__max)
1804 return static_cast<_CharT>(__i);
1805 }
1806 else if (__i <= make_unsigned_t<_CharT>(_Traits::__max))
1807 return static_cast<_CharT>(__i);
1808 __throw_format_error(what: "format error: integer not representable as "
1809 "character");
1810 }
1811
1812 template<typename _Out>
1813 typename basic_format_context<_Out, _CharT>::iterator
1814 _M_format_int(basic_string_view<_CharT> __str, size_t __prefix_len,
1815 basic_format_context<_Out, _CharT>& __fc) const
1816 {
1817 size_t __width = _M_spec._M_get_width(__fc);
1818 if (_M_spec._M_localized)
1819 {
1820 const auto& __l = __fc.locale();
1821 if (__l.name() != "C")
1822 {
1823 auto& __np = use_facet<numpunct<_CharT>>(__l);
1824 string __grp = __np.grouping();
1825 if (!__grp.empty())
1826 {
1827 size_t __n = __str.size() - __prefix_len;
1828 auto __p = (_CharT*)__builtin_alloca(2 * __n
1829 * sizeof(_CharT)
1830 + __prefix_len);
1831 auto __s = __str.data();
1832 char_traits<_CharT>::copy(__p, __s, __prefix_len);
1833 __s += __prefix_len;
1834 auto __end = std::__add_grouping(__p + __prefix_len,
1835 __np.thousands_sep(),
1836 __grp.data(),
1837 __grp.size(),
1838 __s, __s + __n);
1839 __str = {__p, size_t(__end - __p)};
1840 }
1841 }
1842 }
1843
1844 if (__width <= __str.size())
1845 return __format::__write(__fc.out(), __str);
1846
1847 char32_t __fill_char = _M_spec._M_fill;
1848 _Align __align = _M_spec._M_align;
1849
1850 size_t __nfill = __width - __str.size();
1851 auto __out = __fc.out();
1852 if (__align == _Align_default)
1853 {
1854 __align = _Align_right;
1855 if (_M_spec._M_zero_fill)
1856 {
1857 __fill_char = _CharT('0');
1858 // Write sign and base prefix before zero filling.
1859 if (__prefix_len != 0)
1860 {
1861 __out = __format::__write(std::move(__out),
1862 __str.substr(0, __prefix_len));
1863 __str.remove_prefix(__prefix_len);
1864 }
1865 }
1866 else
1867 __fill_char = _CharT(' ');
1868 }
1869 return __format::__write_padded(std::move(__out), __str,
1870 __align, __nfill, __fill_char);
1871 }
1872
1873 _Spec<_CharT> _M_spec{};
1874 };
1875
1876#ifdef __BFLT16_DIG__
1877 using __bflt16_t = decltype(0.0bf16);
1878#endif
1879
1880 // Decide how 128-bit floating-point types should be formatted (or not).
1881 // When supported, the typedef __format::__flt128_t is the type that format
1882 // arguments should be converted to before passing them to __formatter_fp.
1883 // Define the macro _GLIBCXX_FORMAT_F128 to say they're supported.
1884 // The __float128, _Float128 will be formatted by converting them to:
1885 // __ieee128 (same as __float128) when _GLIBCXX_FORMAT_F128=1,
1886 // long double when _GLIBCXX_FORMAT_F128=2,
1887 // _Float128 when _GLIBCXX_FORMAT_F128=3.
1888#undef _GLIBCXX_FORMAT_F128
1889
1890#ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
1891
1892 // Format 128-bit floating-point types using __ieee128.
1893 using __flt128_t = __ieee128;
1894# define _GLIBCXX_FORMAT_F128 1
1895
1896#ifdef __LONG_DOUBLE_IEEE128__
1897 // These overloads exist in the library, but are not declared.
1898 // Make them available as std::__format::to_chars.
1899 to_chars_result
1900 to_chars(char*, char*, __ibm128) noexcept
1901 __asm("_ZSt8to_charsPcS_e");
1902
1903 to_chars_result
1904 to_chars(char*, char*, __ibm128, chars_format) noexcept
1905 __asm("_ZSt8to_charsPcS_eSt12chars_format");
1906
1907 to_chars_result
1908 to_chars(char*, char*, __ibm128, chars_format, int) noexcept
1909 __asm("_ZSt8to_charsPcS_eSt12chars_formati");
1910#elif __cplusplus == 202002L
1911 to_chars_result
1912 to_chars(char*, char*, __ieee128) noexcept
1913 __asm("_ZSt8to_charsPcS_u9__ieee128");
1914
1915 to_chars_result
1916 to_chars(char*, char*, __ieee128, chars_format) noexcept
1917 __asm("_ZSt8to_charsPcS_u9__ieee128St12chars_format");
1918
1919 to_chars_result
1920 to_chars(char*, char*, __ieee128, chars_format, int) noexcept
1921 __asm("_ZSt8to_charsPcS_u9__ieee128St12chars_formati");
1922#endif
1923
1924#elif defined _GLIBCXX_LDOUBLE_IS_IEEE_BINARY128
1925
1926 // Format 128-bit floating-point types using long double.
1927 using __flt128_t = long double;
1928# define _GLIBCXX_FORMAT_F128 2
1929
1930#elif __FLT128_DIG__ && defined(_GLIBCXX_HAVE_FLOAT128_MATH)
1931
1932 // Format 128-bit floating-point types using _Float128.
1933 using __flt128_t = _Float128;
1934# define _GLIBCXX_FORMAT_F128 3
1935
1936# if __cplusplus == 202002L
1937 // These overloads exist in the library, but are not declared for C++20.
1938 // Make them available as std::__format::to_chars.
1939 to_chars_result
1940 to_chars(char*, char*, _Float128) noexcept
1941# if _GLIBCXX_INLINE_VERSION
1942 __asm("_ZNSt3__88to_charsEPcS0_DF128_");
1943# else
1944 __asm("_ZSt8to_charsPcS_DF128_");
1945# endif
1946
1947 to_chars_result
1948 to_chars(char*, char*, _Float128, chars_format) noexcept
1949# if _GLIBCXX_INLINE_VERSION
1950 __asm("_ZNSt3__88to_charsEPcS0_DF128_NS_12chars_formatE");
1951# else
1952 __asm("_ZSt8to_charsPcS_DF128_St12chars_format");
1953# endif
1954
1955 to_chars_result
1956 to_chars(char*, char*, _Float128, chars_format, int) noexcept
1957# if _GLIBCXX_INLINE_VERSION
1958 __asm("_ZNSt3__88to_charsEPcS0_DF128_NS_12chars_formatEi");
1959# else
1960 __asm("_ZSt8to_charsPcS_DF128_St12chars_formati");
1961# endif
1962# endif
1963#endif
1964
1965 using std::to_chars;
1966
1967 // We can format a floating-point type iff it is usable with to_chars.
1968 template<typename _Tp>
1969 concept __formattable_float
1970 = is_same_v<remove_cv_t<_Tp>, _Tp> && requires (_Tp __t, char* __p)
1971 { __format::to_chars(__p, __p, __t, chars_format::scientific, 6); };
1972
1973 template<__char _CharT>
1974 struct __formatter_fp
1975 {
1976 constexpr typename basic_format_parse_context<_CharT>::iterator
1977 parse(basic_format_parse_context<_CharT>& __pc)
1978 {
1979 _Spec<_CharT> __spec{};
1980 const auto __last = __pc.end();
1981 auto __first = __pc.begin();
1982
1983 auto __finalize = [this, &__spec] {
1984 _M_spec = __spec;
1985 };
1986
1987 auto __finished = [&] {
1988 if (__first == __last || *__first == '}')
1989 {
1990 __finalize();
1991 return true;
1992 }
1993 return false;
1994 };
1995
1996 if (__finished())
1997 return __first;
1998
1999 __first = __spec._M_parse_fill_and_align(__first, __last);
2000 if (__finished())
2001 return __first;
2002
2003 __first = __spec._M_parse_sign(__first, __last);
2004 if (__finished())
2005 return __first;
2006
2007 __first = __spec._M_parse_alternate_form(__first, __last);
2008 if (__finished())
2009 return __first;
2010
2011 __first = __spec._M_parse_zero_fill(__first, __last);
2012 if (__finished())
2013 return __first;
2014
2015 if (__first[0] != '.')
2016 {
2017 __first = __spec._M_parse_width(__first, __last, __pc);
2018 if (__finished())
2019 return __first;
2020 }
2021
2022 __first = __spec._M_parse_precision(__first, __last, __pc);
2023 if (__finished())
2024 return __first;
2025
2026 __first = __spec._M_parse_locale(__first, __last);
2027 if (__finished())
2028 return __first;
2029
2030 switch (*__first)
2031 {
2032 case 'a':
2033 __spec._M_type = _Pres_a;
2034 ++__first;
2035 break;
2036 case 'A':
2037 __spec._M_type = _Pres_A;
2038 ++__first;
2039 break;
2040 case 'e':
2041 __spec._M_type = _Pres_e;
2042 ++__first;
2043 break;
2044 case 'E':
2045 __spec._M_type = _Pres_E;
2046 ++__first;
2047 break;
2048 case 'f':
2049 __spec._M_type = _Pres_f;
2050 ++__first;
2051 break;
2052 case 'F':
2053 __spec._M_type = _Pres_F;
2054 ++__first;
2055 break;
2056 case 'g':
2057 __spec._M_type = _Pres_g;
2058 ++__first;
2059 break;
2060 case 'G':
2061 __spec._M_type = _Pres_G;
2062 ++__first;
2063 break;
2064 }
2065
2066 if (__finished())
2067 return __first;
2068
2069 __format::__failed_to_parse_format_spec();
2070 }
2071
2072 template<typename _Fp, typename _Out>
2073 typename basic_format_context<_Out, _CharT>::iterator
2074 format(_Fp __v, basic_format_context<_Out, _CharT>& __fc) const
2075 {
2076 std::string __dynbuf;
2077 char __buf[128];
2078 to_chars_result __res{};
2079
2080 size_t __prec = 6;
2081 bool __use_prec = _M_spec._M_prec_kind != _WP_none;
2082 if (__use_prec)
2083 __prec = _M_spec._M_get_precision(__fc);
2084
2085 char* __start = __buf + 1; // reserve space for sign
2086 char* __end = __buf + sizeof(__buf);
2087
2088 chars_format __fmt{};
2089 bool __upper = false;
2090 bool __trailing_zeros = false;
2091 char __expc = 'e';
2092
2093 switch (_M_spec._M_type)
2094 {
2095 case _Pres_A:
2096 __upper = true;
2097 __expc = 'P';
2098 [[fallthrough]];
2099 case _Pres_a:
2100 if (_M_spec._M_type != _Pres_A)
2101 __expc = 'p';
2102 __fmt = chars_format::hex;
2103 break;
2104 case _Pres_E:
2105 __upper = true;
2106 __expc = 'E';
2107 [[fallthrough]];
2108 case _Pres_e:
2109 __use_prec = true;
2110 __fmt = chars_format::scientific;
2111 break;
2112 case _Pres_F:
2113 __upper = true;
2114 [[fallthrough]];
2115 case _Pres_f:
2116 __use_prec = true;
2117 __fmt = chars_format::fixed;
2118 break;
2119 case _Pres_G:
2120 __upper = true;
2121 __expc = 'E';
2122 [[fallthrough]];
2123 case _Pres_g:
2124 __trailing_zeros = true;
2125 __use_prec = true;
2126 __fmt = chars_format::general;
2127 break;
2128 case _Pres_none:
2129 if (__use_prec)
2130 __fmt = chars_format::general;
2131 break;
2132 default:
2133 __builtin_unreachable();
2134 }
2135
2136 // Write value into buffer using std::to_chars.
2137 auto __to_chars = [&](char* __b, char* __e) {
2138 if (__use_prec)
2139 return __format::to_chars(__b, __e, __v, __fmt, __prec);
2140 else if (__fmt != chars_format{})
2141 return __format::to_chars(__b, __e, __v, __fmt);
2142 else
2143 return __format::to_chars(__b, __e, __v);
2144 };
2145
2146 // First try using stack buffer.
2147 __res = __to_chars(__start, __end);
2148
2149 if (__builtin_expect(__res.ec == errc::value_too_large, 0))
2150 {
2151 // If the buffer is too small it's probably because of a large
2152 // precision, or a very large value in fixed format.
2153 size_t __guess = 8 + __prec;
2154 if (__fmt == chars_format::fixed) // +ddd.prec
2155 {
2156 if constexpr (is_same_v<_Fp, float> || is_same_v<_Fp, double>
2157 || is_same_v<_Fp, long double>)
2158 {
2159 // The number of digits to the left of the decimal point
2160 // is floor(log10(max(abs(__v),1)))+1
2161 int __exp{};
2162 if constexpr (is_same_v<_Fp, float>)
2163 __builtin_frexpf(__v, &__exp);
2164 else if constexpr (is_same_v<_Fp, double>)
2165 __builtin_frexp(__v, &__exp);
2166 else if constexpr (is_same_v<_Fp, long double>)
2167 __builtin_frexpl(__v, &__exp);
2168 if (__exp > 0)
2169 __guess += 1U + __exp * 4004U / 13301U; // log10(2) approx.
2170 }
2171 else
2172 __guess += numeric_limits<_Fp>::max_exponent10;
2173 }
2174 if (__guess <= sizeof(__buf)) [[unlikely]]
2175 __guess = sizeof(__buf) * 2;
2176 __dynbuf.reserve(res: __guess);
2177
2178 do
2179 {
2180 // Mangling of this lambda, and thus resize_and_overwrite
2181 // instantiated with it, was fixed in ABI 18 (G++ 13). Since
2182 // <format> was new in G++ 13, and is experimental, that
2183 // isn't a problem.
2184 auto __overwrite = [&__to_chars, &__res] (char* __p, size_t __n)
2185 {
2186 __res = __to_chars(__p + 1, __p + __n - 1);
2187 return __res.ec == errc{} ? __res.ptr - __p : 0;
2188 };
2189
2190 __dynbuf.__resize_and_overwrite(__dynbuf.capacity() * 2,
2191 __overwrite);
2192 __start = __dynbuf.data() + 1; // reserve space for sign
2193 __end = __dynbuf.data() + __dynbuf.size();
2194 }
2195 while (__builtin_expect(__res.ec == errc::value_too_large, 0));
2196 }
2197
2198 // Use uppercase for 'A', 'E', and 'G' formats.
2199 if (__upper)
2200 {
2201 for (char* __p = __start; __p != __res.ptr; ++__p)
2202 *__p = std::toupper(c: *__p);
2203 }
2204
2205 bool __have_sign = true;
2206 // Add sign for non-negative values.
2207 if (!__builtin_signbit(__v))
2208 {
2209 if (_M_spec._M_sign == _Sign_plus)
2210 *--__start = '+';
2211 else if (_M_spec._M_sign == _Sign_space)
2212 *--__start = ' ';
2213 else
2214 __have_sign = false;
2215 }
2216
2217 string_view __narrow_str(__start, __res.ptr - __start);
2218
2219 // Use alternate form. Ensure decimal point is always present,
2220 // and add trailing zeros (up to precision) for g and G forms.
2221 if (_M_spec._M_alt && __builtin_isfinite(__v))
2222 {
2223 string_view __s = __narrow_str;
2224 size_t __sigfigs; // Number of significant figures.
2225 size_t __z = 0; // Number of trailing zeros to add.
2226 size_t __p; // Position of the exponent character (if any).
2227 size_t __d = __s.find(c: '.'); // Position of decimal point.
2228 if (__d != __s.npos) // Found decimal point.
2229 {
2230 __p = __s.find(c: __expc, pos: __d + 1);
2231 if (__p == __s.npos)
2232 __p = __s.size();
2233
2234 // If presentation type is g or G we might need to add zeros.
2235 if (__trailing_zeros)
2236 {
2237 // Find number of digits after first significant figure.
2238 if (__s[__have_sign] != '0')
2239 // A string like "D.D" or "-D.DDD"
2240 __sigfigs = __p - __have_sign - 1;
2241 else
2242 // A string like "0.D" or "-0.0DD".
2243 // Safe to assume there is a non-zero digit, because
2244 // otherwise there would be no decimal point.
2245 __sigfigs = __p - __s.find_first_not_of(c: '0', pos: __d + 1);
2246 }
2247 }
2248 else // No decimal point, we need to insert one.
2249 {
2250 __p = __s.find(c: __expc); // Find the exponent, if present.
2251 if (__p == __s.npos)
2252 __p = __s.size();
2253 __d = __p; // Position where '.' should be inserted.
2254 __sigfigs = __d - __have_sign;
2255 }
2256
2257 if (__trailing_zeros && __prec != 0)
2258 {
2259 // For g and G presentation types std::to_chars produces
2260 // no more than prec significant figures. Insert this many
2261 // zeros so the result has exactly prec significant figures.
2262 __z = __prec - __sigfigs;
2263 }
2264
2265 if (size_t __extras = int(__d == __p) + __z) // How many to add.
2266 {
2267 if (__dynbuf.empty() && __extras <= size_t(__end - __res.ptr))
2268 {
2269 // The stack buffer is large enough for the result.
2270 // Move exponent to make space for extra chars.
2271 __builtin_memmove(__start + __p + __extras,
2272 __start + __p,
2273 __s.size() - __p);
2274 if (__d == __p)
2275 __start[__p++] = '.';
2276 __builtin_memset(__start + __p, '0', __z);
2277 __narrow_str = {__s.data(), __s.size() + __extras};
2278 }
2279 else // Need to switch to the dynamic buffer.
2280 {
2281 __dynbuf.reserve(res: __s.size() + __extras);
2282 if (__dynbuf.empty())
2283 {
2284 __dynbuf = __s.substr(pos: 0, n: __p);
2285 if (__d == __p)
2286 __dynbuf += '.';
2287 if (__z)
2288 __dynbuf.append(n: __z, c: '0');
2289 __dynbuf.append(svt: __s.substr(pos: __p));
2290 }
2291 else
2292 {
2293 __dynbuf.insert(pos: __p, n: __extras, c: '0');
2294 if (__d == __p)
2295 __dynbuf[__p] = '.';
2296 }
2297 __narrow_str = __dynbuf;
2298 }
2299 }
2300 }
2301
2302 basic_string<_CharT> __wstr;
2303 basic_string_view<_CharT> __str;
2304 if constexpr (is_same_v<_CharT, char>)
2305 __str = __narrow_str;
2306#ifdef _GLIBCXX_USE_WCHAR_T
2307 else
2308 {
2309 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2310 // 4522. Clarify that `std::format` transcodes for `std::wformat_strings`
2311 __wstr = std::__to_wstring_numeric(s: __narrow_str);
2312 __str = __wstr;
2313 }
2314#endif
2315
2316 if (_M_spec._M_localized && __builtin_isfinite(__v))
2317 {
2318 auto __s = _M_localize(__str, __expc, loc: __fc.locale());
2319 if (!__s.empty())
2320 __str = __wstr = std::move(__s);
2321 }
2322
2323 size_t __width = _M_spec._M_get_width(__fc);
2324
2325 if (__width <= __str.size())
2326 return __format::__write(__fc.out(), __str);
2327
2328 char32_t __fill_char = _M_spec._M_fill;
2329 _Align __align = _M_spec._M_align;
2330
2331 size_t __nfill = __width - __str.size();
2332 auto __out = __fc.out();
2333 if (__align == _Align_default)
2334 {
2335 __align = _Align_right;
2336 if (_M_spec._M_zero_fill && __builtin_isfinite(__v))
2337 {
2338 __fill_char = _CharT('0');
2339 // Write sign before zero filling.
2340 if (!__format::__is_xdigit(c: __narrow_str[0]))
2341 {
2342 *__out++ = __str[0];
2343 __str.remove_prefix(1);
2344 }
2345 }
2346 else
2347 __fill_char = _CharT(' ');
2348 }
2349 return __format::__write_padded(std::move(__out), __str,
2350 __align, __nfill, __fill_char);
2351 }
2352
2353 // Locale-specific format.
2354 basic_string<_CharT>
2355 _M_localize(basic_string_view<_CharT> __str, char __expc,
2356 const locale& __loc) const
2357 {
2358 basic_string<_CharT> __lstr;
2359
2360 if (__loc == locale::classic())
2361 return __lstr; // Nothing to do.
2362
2363 const auto& __np = use_facet<numpunct<_CharT>>(__loc);
2364 const _CharT __point = __np.decimal_point();
2365 const string __grp = __np.grouping();
2366
2367 _CharT __dot, __exp;
2368 if constexpr (is_same_v<_CharT, char>)
2369 {
2370 __dot = '.';
2371 __exp = __expc;
2372 }
2373 else
2374 {
2375 __dot = L'.';
2376 switch (__expc)
2377 {
2378 case 'e':
2379 __exp = L'e';
2380 break;
2381 case 'E':
2382 __exp = L'E';
2383 break;
2384 case 'p':
2385 __exp = L'p';
2386 break;
2387 case 'P':
2388 __exp = L'P';
2389 break;
2390 default:
2391 __builtin_unreachable();
2392 }
2393 }
2394
2395 if (__grp.empty() && __point == __dot)
2396 return __lstr; // Locale uses '.' and no grouping.
2397
2398 size_t __d = __str.find(__dot); // Index of radix character (if any).
2399 size_t __e = min(__d, __str.find(__exp)); // First of radix or exponent
2400 if (__e == __str.npos)
2401 __e = __str.size();
2402 const size_t __r = __str.size() - __e; // Length of remainder.
2403 auto __overwrite = [&](_CharT* __p, size_t) {
2404 // Apply grouping to the digits before the radix or exponent.
2405 int __off = 0;
2406 if (auto __c = __str.front(); __c == '-' || __c == '+' || __c == ' ')
2407 {
2408 *__p = __c;
2409 __off = 1;
2410 }
2411 auto __end = std::__add_grouping(__p + __off, __np.thousands_sep(),
2412 __grp.data(), __grp.size(),
2413 __str.data() + __off,
2414 __str.data() + __e);
2415 if (__r) // If there's a fractional part or exponent
2416 {
2417 if (__d != __str.npos)
2418 {
2419 *__end = __point; // Add the locale's radix character.
2420 ++__end;
2421 ++__e;
2422 }
2423 const size_t __rlen = __str.size() - __e;
2424 // Append fractional digits and/or exponent:
2425 char_traits<_CharT>::copy(__end, __str.data() + __e, __rlen);
2426 __end += __rlen;
2427 }
2428 return (__end - __p);
2429 };
2430 __lstr.__resize_and_overwrite(__e * 2 + __r, __overwrite);
2431 return __lstr;
2432 }
2433
2434 _Spec<_CharT> _M_spec{};
2435 };
2436
2437 template<__format::__char _CharT>
2438 struct __formatter_ptr
2439 {
2440 constexpr
2441 __formatter_ptr() noexcept
2442 : _M_spec()
2443 {
2444 _M_spec._M_type = _Pres_p;
2445 _M_spec._M_alt = true;
2446 }
2447
2448 constexpr
2449 __formatter_ptr(_Spec<_CharT> __spec) noexcept
2450 : _M_spec(__spec)
2451 { _M_set_default(type: _Pres_p); }
2452
2453 constexpr typename basic_format_parse_context<_CharT>::iterator
2454 parse(basic_format_parse_context<_CharT>& __pc, _Pres_type __type = _Pres_p)
2455 {
2456 __format::_Spec<_CharT> __spec{};
2457 const auto __last = __pc.end();
2458 auto __first = __pc.begin();
2459
2460 auto __finalize = [this, &__spec, __type] {
2461 _M_spec = __spec;
2462 _M_set_default(__type);
2463 };
2464
2465 auto __finished = [&] {
2466 if (__first == __last || *__first == '}')
2467 {
2468 __finalize();
2469 return true;
2470 }
2471 return false;
2472 };
2473
2474 if (__finished())
2475 return __first;
2476
2477 __first = __spec._M_parse_fill_and_align(__first, __last);
2478 if (__finished())
2479 return __first;
2480
2481// _GLIBCXX_RESOLVE_LIB_DEFECTS
2482// P2510R3 Formatting pointers
2483#if __glibcxx_format >= 202304L
2484 __first = __spec._M_parse_zero_fill(__first, __last);
2485 if (__finished())
2486 return __first;
2487#endif
2488
2489 __first = __spec._M_parse_width(__first, __last, __pc);
2490 if (__finished())
2491 return __first;
2492
2493 if (*__first == 'p')
2494 {
2495 __spec._M_type = _Pres_p;
2496 __spec._M_alt = !__spec._M_alt;
2497 ++__first;
2498 }
2499#if __glibcxx_format >= 202304L
2500 else if (*__first == 'P')
2501 {
2502 __spec._M_type = _Pres_P;
2503 __spec._M_alt = !__spec._M_alt;
2504 ++__first;
2505 }
2506#endif
2507
2508 if (__finished())
2509 return __first;
2510
2511 __format::__failed_to_parse_format_spec();
2512 }
2513
2514 template<typename _Out>
2515 typename basic_format_context<_Out, _CharT>::iterator
2516 format(const void* __v, basic_format_context<_Out, _CharT>& __fc) const
2517 {
2518 auto __u = reinterpret_cast<__UINTPTR_TYPE__>(__v);
2519 return __formatter_int<_CharT>(_M_spec).format(__u, __fc);
2520 }
2521
2522 private:
2523 [[__gnu__::__always_inline__]]
2524 constexpr void
2525 _M_set_default(_Pres_type __type)
2526 {
2527 if (_M_spec._M_type == _Pres_none && __type != _Pres_none)
2528 {
2529 _M_spec._M_type = __type;
2530 _M_spec._M_alt = !_M_spec._M_alt;
2531 }
2532 }
2533
2534 __format::_Spec<_CharT> _M_spec;
2535 };
2536
2537} // namespace __format
2538/// @endcond
2539
2540 /// Format a character.
2541 template<__format::__char _CharT>
2542 struct formatter<_CharT, _CharT>
2543 {
2544 formatter() = default;
2545
2546 constexpr typename basic_format_parse_context<_CharT>::iterator
2547 parse(basic_format_parse_context<_CharT>& __pc)
2548 {
2549 return _M_f.template _M_parse<_CharT>(__pc);
2550 }
2551
2552 template<typename _Out>
2553 typename basic_format_context<_Out, _CharT>::iterator
2554 format(_CharT __u, basic_format_context<_Out, _CharT>& __fc) const
2555 {
2556 if (_M_f._M_spec._M_type == __format::_Pres_c)
2557 return _M_f._M_format_character(__u, __fc);
2558 else
2559 return _M_f.format(static_cast<make_unsigned_t<_CharT>>(__u), __fc);
2560 }
2561
2562#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2563 constexpr void
2564 set_debug_format() noexcept
2565 { _M_f._M_spec._M_debug = true; }
2566#endif
2567
2568 private:
2569 __format::__formatter_int<_CharT> _M_f;
2570 };
2571
2572#if __glibcxx_print >= 202403L
2573 template<__format::__char _CharT>
2574 constexpr bool enable_nonlocking_formatter_optimization<_CharT> = true;
2575#endif
2576
2577#ifdef _GLIBCXX_USE_WCHAR_T
2578 /// Format a char value for wide character output.
2579 template<>
2580 struct formatter<char, wchar_t>
2581 {
2582 formatter() = default;
2583
2584 constexpr typename basic_format_parse_context<wchar_t>::iterator
2585 parse(basic_format_parse_context<wchar_t>& __pc)
2586 {
2587 return _M_f._M_parse<char>(__pc);
2588 }
2589
2590 template<typename _Out>
2591 typename basic_format_context<_Out, wchar_t>::iterator
2592 format(char __u, basic_format_context<_Out, wchar_t>& __fc) const
2593 {
2594 if (_M_f._M_spec._M_type == __format::_Pres_c)
2595 return _M_f._M_format_character(__u, __fc);
2596 else
2597 return _M_f.format(static_cast<unsigned char>(__u), __fc);
2598 }
2599
2600#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2601 constexpr void
2602 set_debug_format() noexcept
2603 { _M_f._M_spec._M_debug = true; }
2604#endif
2605
2606 private:
2607 __format::__formatter_int<wchar_t> _M_f;
2608 };
2609#endif // USE_WCHAR_T
2610
2611 /** Format a string.
2612 * @{
2613 */
2614 template<__format::__char _CharT>
2615 struct formatter<_CharT*, _CharT>
2616 {
2617 formatter() = default;
2618
2619 [[__gnu__::__always_inline__]]
2620 constexpr typename basic_format_parse_context<_CharT>::iterator
2621 parse(basic_format_parse_context<_CharT>& __pc)
2622 { return _M_f.parse(__pc); }
2623
2624 template<typename _Out>
2625 [[__gnu__::__nonnull__]]
2626 typename basic_format_context<_Out, _CharT>::iterator
2627 format(_CharT* __u, basic_format_context<_Out, _CharT>& __fc) const
2628 { return _M_f.format(__u, __fc); }
2629
2630#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2631 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2632#endif
2633
2634 private:
2635 __format::__formatter_str<_CharT> _M_f;
2636 };
2637
2638#if __glibcxx_print >= 202403L
2639 template<__format::__char _CharT>
2640 constexpr bool enable_nonlocking_formatter_optimization<_CharT*> = true;
2641#endif
2642
2643 template<__format::__char _CharT>
2644 struct formatter<const _CharT*, _CharT>
2645 {
2646 formatter() = default;
2647
2648 [[__gnu__::__always_inline__]]
2649 constexpr typename basic_format_parse_context<_CharT>::iterator
2650 parse(basic_format_parse_context<_CharT>& __pc)
2651 { return _M_f.parse(__pc); }
2652
2653 template<typename _Out>
2654 [[__gnu__::__nonnull__]]
2655 typename basic_format_context<_Out, _CharT>::iterator
2656 format(const _CharT* __u,
2657 basic_format_context<_Out, _CharT>& __fc) const
2658 { return _M_f.format(__u, __fc); }
2659
2660#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2661 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2662#endif
2663
2664 private:
2665 __format::__formatter_str<_CharT> _M_f;
2666 };
2667
2668#if __glibcxx_print >= 202403L
2669 template<__format::__char _CharT>
2670 constexpr bool
2671 enable_nonlocking_formatter_optimization<const _CharT*> = true;
2672#endif
2673
2674 template<__format::__char _CharT, size_t _Nm>
2675 struct formatter<_CharT[_Nm], _CharT>
2676 {
2677 formatter() = default;
2678
2679 [[__gnu__::__always_inline__]]
2680 constexpr typename basic_format_parse_context<_CharT>::iterator
2681 parse(basic_format_parse_context<_CharT>& __pc)
2682 { return _M_f.parse(__pc); }
2683
2684 template<typename _Out>
2685 typename basic_format_context<_Out, _CharT>::iterator
2686 format(const _CharT (&__u)[_Nm],
2687 basic_format_context<_Out, _CharT>& __fc) const
2688 { return _M_f.format({__u, _Nm}, __fc); }
2689
2690#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2691 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2692#endif
2693
2694 private:
2695 __format::__formatter_str<_CharT> _M_f;
2696 };
2697
2698#if __glibcxx_print >= 202403L
2699 template<__format::__char _CharT, size_t _Nm>
2700 constexpr bool enable_nonlocking_formatter_optimization<_CharT[_Nm]> = true;
2701#endif
2702
2703 template<typename _Traits, typename _Alloc>
2704 struct formatter<basic_string<char, _Traits, _Alloc>, char>
2705 {
2706 formatter() = default;
2707
2708 [[__gnu__::__always_inline__]]
2709 constexpr typename basic_format_parse_context<char>::iterator
2710 parse(basic_format_parse_context<char>& __pc)
2711 { return _M_f.parse(__pc); }
2712
2713 template<typename _Out>
2714 typename basic_format_context<_Out, char>::iterator
2715 format(const basic_string<char, _Traits, _Alloc>& __u,
2716 basic_format_context<_Out, char>& __fc) const
2717 { return _M_f.format(__u, __fc); }
2718
2719#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2720 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2721#endif
2722
2723 private:
2724 __format::__formatter_str<char> _M_f;
2725 };
2726
2727#if __glibcxx_print >= 202403L
2728 template<typename _Tr, typename _Alloc>
2729 constexpr bool
2730 enable_nonlocking_formatter_optimization<basic_string<char, _Tr, _Alloc>>
2731 = true;
2732#endif
2733
2734#ifdef _GLIBCXX_USE_WCHAR_T
2735 template<typename _Traits, typename _Alloc>
2736 struct formatter<basic_string<wchar_t, _Traits, _Alloc>, wchar_t>
2737 {
2738 formatter() = default;
2739
2740 [[__gnu__::__always_inline__]]
2741 constexpr typename basic_format_parse_context<wchar_t>::iterator
2742 parse(basic_format_parse_context<wchar_t>& __pc)
2743 { return _M_f.parse(__pc); }
2744
2745 template<typename _Out>
2746 typename basic_format_context<_Out, wchar_t>::iterator
2747 format(const basic_string<wchar_t, _Traits, _Alloc>& __u,
2748 basic_format_context<_Out, wchar_t>& __fc) const
2749 { return _M_f.format(__u, __fc); }
2750
2751#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2752 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2753#endif
2754
2755 private:
2756 __format::__formatter_str<wchar_t> _M_f;
2757 };
2758
2759#if __glibcxx_print >= 202403L
2760 template<typename _Tr, typename _Alloc>
2761 constexpr bool
2762 enable_nonlocking_formatter_optimization<basic_string<wchar_t, _Tr, _Alloc>>
2763 = true;
2764#endif
2765
2766#endif // USE_WCHAR_T
2767
2768 template<typename _Traits>
2769 struct formatter<basic_string_view<char, _Traits>, char>
2770 {
2771 formatter() = default;
2772
2773 [[__gnu__::__always_inline__]]
2774 constexpr typename basic_format_parse_context<char>::iterator
2775 parse(basic_format_parse_context<char>& __pc)
2776 { return _M_f.parse(__pc); }
2777
2778 template<typename _Out>
2779 typename basic_format_context<_Out, char>::iterator
2780 format(basic_string_view<char, _Traits> __u,
2781 basic_format_context<_Out, char>& __fc) const
2782 { return _M_f.format(__u, __fc); }
2783
2784#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2785 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2786#endif
2787
2788 private:
2789 __format::__formatter_str<char> _M_f;
2790 };
2791
2792#if __glibcxx_print >= 202403L
2793 template<typename _Tr>
2794 constexpr bool
2795 enable_nonlocking_formatter_optimization<basic_string_view<char, _Tr>>
2796 = true;
2797#endif
2798
2799#ifdef _GLIBCXX_USE_WCHAR_T
2800 template<typename _Traits>
2801 struct formatter<basic_string_view<wchar_t, _Traits>, wchar_t>
2802 {
2803 formatter() = default;
2804
2805 [[__gnu__::__always_inline__]]
2806 constexpr typename basic_format_parse_context<wchar_t>::iterator
2807 parse(basic_format_parse_context<wchar_t>& __pc)
2808 { return _M_f.parse(__pc); }
2809
2810 template<typename _Out>
2811 typename basic_format_context<_Out, wchar_t>::iterator
2812 format(basic_string_view<wchar_t, _Traits> __u,
2813 basic_format_context<_Out, wchar_t>& __fc) const
2814 { return _M_f.format(__u, __fc); }
2815
2816#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
2817 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2818#endif
2819
2820 private:
2821 __format::__formatter_str<wchar_t> _M_f;
2822 };
2823
2824#if __glibcxx_print >= 202403L
2825 template<typename _Tr>
2826 constexpr bool
2827 enable_nonlocking_formatter_optimization<basic_string_view<wchar_t, _Tr>>
2828 = true;
2829#endif
2830#endif // USE_WCHAR_T
2831 /// @}
2832
2833/// @cond undocumented
2834namespace __format
2835{
2836 // each cv-unqualified arithmetic type ArithmeticT other than
2837 // char, wchar_t, char8_t, char16_t, or char32_t
2838 template<typename _Tp>
2839 constexpr bool __is_formattable_integer = __is_integer<_Tp>::__value;
2840
2841#if defined __SIZEOF_INT128__
2842 template<> inline constexpr bool __is_formattable_integer<__int128> = true;
2843 template<> inline constexpr bool __is_formattable_integer<unsigned __int128>
2844 = true;
2845#endif
2846
2847 template<> inline constexpr bool __is_formattable_integer<char> = false;
2848 template<> inline constexpr bool __is_formattable_integer<wchar_t> = false;
2849#ifdef _GLIBCXX_USE_CHAR8_T
2850 template<> inline constexpr bool __is_formattable_integer<char8_t> = false;
2851#endif
2852 template<> inline constexpr bool __is_formattable_integer<char16_t> = false;
2853 template<> inline constexpr bool __is_formattable_integer<char32_t> = false;
2854
2855 template<typename _Tp>
2856 concept __formattable_integer = __is_formattable_integer<_Tp>;
2857}
2858/// @endcond
2859
2860 /// Format an integer.
2861 template<__format::__formattable_integer _Tp, __format::__char _CharT>
2862 struct formatter<_Tp, _CharT>
2863 {
2864 formatter() = default;
2865
2866 [[__gnu__::__always_inline__]]
2867 constexpr typename basic_format_parse_context<_CharT>::iterator
2868 parse(basic_format_parse_context<_CharT>& __pc)
2869 {
2870 return _M_f.template _M_parse<_Tp>(__pc);
2871 }
2872
2873 template<typename _Out>
2874 typename basic_format_context<_Out, _CharT>::iterator
2875 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2876 { return _M_f.format(__u, __fc); }
2877
2878 private:
2879 __format::__formatter_int<_CharT> _M_f;
2880 };
2881
2882#if __glibcxx_print >= 202403L
2883 template<__format::__formattable_integer _Tp>
2884 constexpr bool
2885 enable_nonlocking_formatter_optimization<_Tp> = true;
2886#endif
2887
2888#if defined __glibcxx_to_chars
2889 /// Format a floating-point value.
2890 template<__format::__formattable_float _Tp, __format::__char _CharT>
2891 struct formatter<_Tp, _CharT>
2892 {
2893 formatter() = default;
2894
2895 [[__gnu__::__always_inline__]]
2896 constexpr typename basic_format_parse_context<_CharT>::iterator
2897 parse(basic_format_parse_context<_CharT>& __pc)
2898 { return _M_f.parse(__pc); }
2899
2900 template<typename _Out>
2901 typename basic_format_context<_Out, _CharT>::iterator
2902 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2903 { return _M_f.format(__u, __fc); }
2904
2905 private:
2906 __format::__formatter_fp<_CharT> _M_f;
2907 };
2908
2909#if __glibcxx_print >= 202403L
2910 template<__format::__formattable_float _Tp>
2911 constexpr bool
2912 enable_nonlocking_formatter_optimization<_Tp> = true;
2913#endif
2914
2915#if __LDBL_MANT_DIG__ == __DBL_MANT_DIG__
2916 // Reuse __formatter_fp<C>::format<double, Out> for long double.
2917 template<__format::__char _CharT>
2918 struct formatter<long double, _CharT>
2919 {
2920 formatter() = default;
2921
2922 [[__gnu__::__always_inline__]]
2923 constexpr typename basic_format_parse_context<_CharT>::iterator
2924 parse(basic_format_parse_context<_CharT>& __pc)
2925 { return _M_f.parse(__pc); }
2926
2927 template<typename _Out>
2928 typename basic_format_context<_Out, _CharT>::iterator
2929 format(long double __u, basic_format_context<_Out, _CharT>& __fc) const
2930 { return _M_f.format((double)__u, __fc); }
2931
2932 private:
2933 __format::__formatter_fp<_CharT> _M_f;
2934 };
2935#endif
2936
2937#if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
2938 // Reuse __formatter_fp<C>::format<float, Out> for _Float16.
2939 template<__format::__char _CharT>
2940 struct formatter<_Float16, _CharT>
2941 {
2942 formatter() = default;
2943
2944 [[__gnu__::__always_inline__]]
2945 constexpr typename basic_format_parse_context<_CharT>::iterator
2946 parse(basic_format_parse_context<_CharT>& __pc)
2947 { return _M_f.parse(__pc); }
2948
2949 template<typename _Out>
2950 typename basic_format_context<_Out, _CharT>::iterator
2951 format(_Float16 __u, basic_format_context<_Out, _CharT>& __fc) const
2952 { return _M_f.format((float)__u, __fc); }
2953
2954 private:
2955 __format::__formatter_fp<_CharT> _M_f;
2956 };
2957#endif
2958
2959#if defined(__FLT32_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
2960 // Reuse __formatter_fp<C>::format<float, Out> for _Float32.
2961 template<__format::__char _CharT>
2962 struct formatter<_Float32, _CharT>
2963 {
2964 formatter() = default;
2965
2966 [[__gnu__::__always_inline__]]
2967 constexpr typename basic_format_parse_context<_CharT>::iterator
2968 parse(basic_format_parse_context<_CharT>& __pc)
2969 { return _M_f.parse(__pc); }
2970
2971 template<typename _Out>
2972 typename basic_format_context<_Out, _CharT>::iterator
2973 format(_Float32 __u, basic_format_context<_Out, _CharT>& __fc) const
2974 { return _M_f.format((float)__u, __fc); }
2975
2976 private:
2977 __format::__formatter_fp<_CharT> _M_f;
2978 };
2979#endif
2980
2981#if defined(__FLT64_DIG__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
2982 // Reuse __formatter_fp<C>::format<double, Out> for _Float64.
2983 template<__format::__char _CharT>
2984 struct formatter<_Float64, _CharT>
2985 {
2986 formatter() = default;
2987
2988 [[__gnu__::__always_inline__]]
2989 constexpr typename basic_format_parse_context<_CharT>::iterator
2990 parse(basic_format_parse_context<_CharT>& __pc)
2991 { return _M_f.parse(__pc); }
2992
2993 template<typename _Out>
2994 typename basic_format_context<_Out, _CharT>::iterator
2995 format(_Float64 __u, basic_format_context<_Out, _CharT>& __fc) const
2996 { return _M_f.format((double)__u, __fc); }
2997
2998 private:
2999 __format::__formatter_fp<_CharT> _M_f;
3000 };
3001#endif
3002
3003#if defined(__FLT128_DIG__) && _GLIBCXX_FORMAT_F128
3004 // Use __formatter_fp<C>::format<__format::__flt128_t, Out> for _Float128.
3005 template<__format::__char _CharT>
3006 struct formatter<_Float128, _CharT>
3007 {
3008 formatter() = default;
3009
3010 [[__gnu__::__always_inline__]]
3011 constexpr typename basic_format_parse_context<_CharT>::iterator
3012 parse(basic_format_parse_context<_CharT>& __pc)
3013 { return _M_f.parse(__pc); }
3014
3015 template<typename _Out>
3016 typename basic_format_context<_Out, _CharT>::iterator
3017 format(_Float128 __u, basic_format_context<_Out, _CharT>& __fc) const
3018 { return _M_f.format((__format::__flt128_t)__u, __fc); }
3019
3020 private:
3021 __format::__formatter_fp<_CharT> _M_f;
3022 };
3023#endif
3024
3025#if defined(__SIZEOF_FLOAT128__) && _GLIBCXX_FORMAT_F128 == 2
3026 // Use __formatter_fp<C>::format<__format::__flt128_t, Out> for __float128,
3027 // when long double is not 128bit IEEE type.
3028 template<__format::__char _CharT>
3029 struct formatter<__float128, _CharT>
3030 {
3031 formatter() = default;
3032
3033 [[__gnu__::__always_inline__]]
3034 constexpr typename basic_format_parse_context<_CharT>::iterator
3035 parse(basic_format_parse_context<_CharT>& __pc)
3036 { return _M_f.parse(__pc); }
3037
3038 template<typename _Out>
3039 typename basic_format_context<_Out, _CharT>::iterator
3040 format(__float128 __u, basic_format_context<_Out, _CharT>& __fc) const
3041 { return _M_f.format((__format::__flt128_t)__u, __fc); }
3042
3043 private:
3044 __format::__formatter_fp<_CharT> _M_f;
3045 };
3046#endif
3047
3048#if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
3049 // Reuse __formatter_fp<C>::format<float, Out> for bfloat16_t.
3050 template<__format::__char _CharT>
3051 struct formatter<__format::__bflt16_t, _CharT>
3052 {
3053 formatter() = default;
3054
3055 [[__gnu__::__always_inline__]]
3056 constexpr typename basic_format_parse_context<_CharT>::iterator
3057 parse(basic_format_parse_context<_CharT>& __pc)
3058 { return _M_f.parse(__pc); }
3059
3060 template<typename _Out>
3061 typename basic_format_context<_Out, _CharT>::iterator
3062 format(__gnu_cxx::__bfloat16_t __u,
3063 basic_format_context<_Out, _CharT>& __fc) const
3064 { return _M_f.format((float)__u, __fc); }
3065
3066 private:
3067 __format::__formatter_fp<_CharT> _M_f;
3068 };
3069#endif
3070#endif // __cpp_lib_to_chars
3071
3072 /** Format a pointer.
3073 * @{
3074 */
3075 template<__format::__char _CharT>
3076 struct formatter<const void*, _CharT>
3077 {
3078 formatter() = default;
3079
3080 constexpr typename basic_format_parse_context<_CharT>::iterator
3081 parse(basic_format_parse_context<_CharT>& __pc)
3082 { return _M_f.parse(__pc); }
3083
3084 template<typename _Out>
3085 typename basic_format_context<_Out, _CharT>::iterator
3086 format(const void* __v, basic_format_context<_Out, _CharT>& __fc) const
3087 { return _M_f.format(__v, __fc); }
3088
3089 private:
3090 __format::__formatter_ptr<_CharT> _M_f;
3091 };
3092
3093#if __glibcxx_print >= 202403L
3094 template<>
3095 inline constexpr bool
3096 enable_nonlocking_formatter_optimization<const void*> = true;
3097#endif
3098
3099 template<__format::__char _CharT>
3100 struct formatter<void*, _CharT>
3101 {
3102 formatter() = default;
3103
3104 [[__gnu__::__always_inline__]]
3105 constexpr typename basic_format_parse_context<_CharT>::iterator
3106 parse(basic_format_parse_context<_CharT>& __pc)
3107 { return _M_f.parse(__pc); }
3108
3109 template<typename _Out>
3110 typename basic_format_context<_Out, _CharT>::iterator
3111 format(void* __v, basic_format_context<_Out, _CharT>& __fc) const
3112 { return _M_f.format(__v, __fc); }
3113
3114 private:
3115 __format::__formatter_ptr<_CharT> _M_f;
3116 };
3117
3118#if __glibcxx_print >= 202403l
3119 template<>
3120 inline constexpr bool
3121 enable_nonlocking_formatter_optimization<void*> = true;
3122#endif
3123
3124 template<__format::__char _CharT>
3125 struct formatter<nullptr_t, _CharT>
3126 {
3127 formatter() = default;
3128
3129 [[__gnu__::__always_inline__]]
3130 constexpr typename basic_format_parse_context<_CharT>::iterator
3131 parse(basic_format_parse_context<_CharT>& __pc)
3132 { return _M_f.parse(__pc); }
3133
3134 template<typename _Out>
3135 typename basic_format_context<_Out, _CharT>::iterator
3136 format(nullptr_t, basic_format_context<_Out, _CharT>& __fc) const
3137 { return _M_f.format(nullptr, __fc); }
3138
3139 private:
3140 __format::__formatter_ptr<_CharT> _M_f;
3141 };
3142 /// @}
3143
3144#if __glibcxx_print >= 202403L
3145 template<>
3146 inline constexpr bool
3147 enable_nonlocking_formatter_optimization<nullptr_t> = true;
3148#endif
3149
3150#if defined _GLIBCXX_USE_WCHAR_T && __glibcxx_format_ranges
3151 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3152 // 3944. Formatters converting sequences of char to sequences of wchar_t
3153
3154 struct __formatter_disabled
3155 {
3156 __formatter_disabled() = delete; // Cannot format char sequence to wchar_t
3157 __formatter_disabled(const __formatter_disabled&) = delete;
3158 __formatter_disabled& operator=(const __formatter_disabled&) = delete;
3159 };
3160
3161 template<>
3162 struct formatter<char*, wchar_t>
3163 : private __formatter_disabled { };
3164 template<>
3165 struct formatter<const char*, wchar_t>
3166 : private __formatter_disabled { };
3167 template<size_t _Nm>
3168 struct formatter<char[_Nm], wchar_t>
3169 : private __formatter_disabled { };
3170 template<class _Traits, class _Allocator>
3171 struct formatter<basic_string<char, _Traits, _Allocator>, wchar_t>
3172 : private __formatter_disabled { };
3173 template<class _Traits>
3174 struct formatter<basic_string_view<char, _Traits>, wchar_t>
3175 : private __formatter_disabled { };
3176#endif
3177
3178 /// An iterator after the last character written, and the number of
3179 /// characters that would have been written.
3180 template<typename _Out>
3181 struct format_to_n_result
3182 {
3183 _Out out;
3184 iter_difference_t<_Out> size;
3185 };
3186
3187_GLIBCXX_BEGIN_NAMESPACE_CONTAINER
3188template<typename, typename> class vector;
3189_GLIBCXX_END_NAMESPACE_CONTAINER
3190
3191/// @cond undocumented
3192namespace __format
3193{
3194 template<typename _CharT>
3195 class _Drop_iter
3196 {
3197 public:
3198 using iterator_category = output_iterator_tag;
3199 using value_type = void;
3200 using difference_type = ptrdiff_t;
3201 using pointer = void;
3202 using reference = void;
3203
3204 _Drop_iter() = default;
3205 _Drop_iter(const _Drop_iter&) = default;
3206 _Drop_iter& operator=(const _Drop_iter&) = default;
3207
3208 [[__gnu__::__always_inline__]]
3209 constexpr _Drop_iter&
3210 operator=(_CharT __c)
3211 { return *this; }
3212
3213 [[__gnu__::__always_inline__]]
3214 constexpr _Drop_iter&
3215 operator=(basic_string_view<_CharT> __s)
3216 { return *this; }
3217
3218 [[__gnu__::__always_inline__]]
3219 constexpr _Drop_iter&
3220 operator*() { return *this; }
3221
3222 [[__gnu__::__always_inline__]]
3223 constexpr _Drop_iter&
3224 operator++() { return *this; }
3225
3226 [[__gnu__::__always_inline__]]
3227 constexpr _Drop_iter
3228 operator++(int) { return *this; }
3229 };
3230
3231 template<typename _CharT>
3232 class _Sink_iter
3233 {
3234 _Sink<_CharT>* _M_sink = nullptr;
3235
3236 public:
3237 using iterator_category = output_iterator_tag;
3238 using value_type = void;
3239 using difference_type = ptrdiff_t;
3240 using pointer = void;
3241 using reference = void;
3242
3243 _Sink_iter() = default;
3244 _Sink_iter(const _Sink_iter&) = default;
3245 _Sink_iter& operator=(const _Sink_iter&) = default;
3246
3247 [[__gnu__::__always_inline__]]
3248 explicit constexpr
3249 _Sink_iter(_Sink<_CharT>& __sink) : _M_sink(std::addressof(__sink)) { }
3250
3251 [[__gnu__::__always_inline__]]
3252 constexpr _Sink_iter&
3253 operator=(_CharT __c)
3254 {
3255 _M_sink->_M_write(__c);
3256 return *this;
3257 }
3258
3259 [[__gnu__::__always_inline__]]
3260 constexpr _Sink_iter&
3261 operator=(basic_string_view<_CharT> __s)
3262 {
3263 _M_sink->_M_write(__s);
3264 return *this;
3265 }
3266
3267 [[__gnu__::__always_inline__]]
3268 constexpr _Sink_iter&
3269 operator*() { return *this; }
3270
3271 [[__gnu__::__always_inline__]]
3272 constexpr _Sink_iter&
3273 operator++() { return *this; }
3274
3275 [[__gnu__::__always_inline__]]
3276 constexpr _Sink_iter
3277 operator++(int) { return *this; }
3278
3279 auto
3280 _M_reserve(size_t __n) const
3281 { return _M_sink->_M_reserve(__n); }
3282
3283 bool
3284 _M_discarding() const
3285 { return _M_sink->_M_discarding(); }
3286 };
3287
3288 // Abstract base class for type-erased character sinks.
3289 // All formatting and output is done via this type's iterator,
3290 // to reduce the number of different template instantiations.
3291 template<typename _CharT>
3292 class _Sink
3293 {
3294 friend class _Sink_iter<_CharT>;
3295
3296 span<_CharT> _M_span;
3297 typename span<_CharT>::iterator _M_next;
3298
3299 // Called when the span is full, to make more space available.
3300 // Precondition: _M_next != _M_span.begin()
3301 // Postcondition: _M_next != _M_span.end()
3302 // TODO: remove the precondition? could make overflow handle it.
3303 virtual void _M_overflow() = 0;
3304
3305 protected:
3306 // Precondition: __span.size() != 0
3307 [[__gnu__::__always_inline__]]
3308 explicit constexpr
3309 _Sink(span<_CharT> __span) noexcept
3310 : _M_span(__span), _M_next(__span.begin())
3311 { }
3312
3313 // The portion of the span that has been written to.
3314 [[__gnu__::__always_inline__]]
3315 span<_CharT>
3316 _M_used() const noexcept
3317 { return _M_span.first(_M_next - _M_span.begin()); }
3318
3319 // The portion of the span that has not been written to.
3320 [[__gnu__::__always_inline__]]
3321 constexpr span<_CharT>
3322 _M_unused() const noexcept
3323 { return _M_span.subspan(_M_next - _M_span.begin()); }
3324
3325 // Use the start of the span as the next write position.
3326 [[__gnu__::__always_inline__]]
3327 constexpr void
3328 _M_rewind() noexcept
3329 { _M_next = _M_span.begin(); }
3330
3331 // Replace the current output range.
3332 void
3333 _M_reset(span<_CharT> __s, size_t __pos = 0) noexcept
3334 {
3335 _M_span = __s;
3336 _M_next = __s.begin() + __pos;
3337 }
3338
3339 // Called by the iterator for *it++ = c
3340 constexpr void
3341 _M_write(_CharT __c)
3342 {
3343 *_M_next++ = __c;
3344 if (_M_next - _M_span.begin() == std::ssize(_M_span)) [[unlikely]]
3345 _M_overflow();
3346 }
3347
3348 constexpr void
3349 _M_write(basic_string_view<_CharT> __s)
3350 {
3351 span __to = _M_unused();
3352 while (__to.size() <= __s.size())
3353 {
3354 __s.copy(__to.data(), __to.size());
3355 _M_next += __to.size();
3356 __s.remove_prefix(__to.size());
3357 _M_overflow();
3358 __to = _M_unused();
3359 }
3360 if (__s.size())
3361 {
3362 __s.copy(__to.data(), __s.size());
3363 _M_next += __s.size();
3364 }
3365 }
3366
3367 // A successful _Reservation can be used to directly write
3368 // up to N characters to the sink to avoid unwanted buffering.
3369 struct _Reservation
3370 {
3371 // True if the reservation was successful, false otherwise.
3372 explicit operator bool() const noexcept { return _M_sink; }
3373 // A pointer to write directly to the sink.
3374 _CharT* get() const noexcept { return _M_sink->_M_next.operator->(); }
3375 // Add n to the _M_next iterator for the sink.
3376 void _M_bump(size_t __n) { _M_sink->_M_bump(__n); }
3377 _Sink* _M_sink;
3378 };
3379
3380 // Attempt to reserve space to write n characters to the sink.
3381 // If anything is written to the reservation then there must be a call
3382 // to _M_bump(N2) before any call to another member function of *this,
3383 // where N2 is the number of characters written.
3384 virtual _Reservation
3385 _M_reserve(size_t __n)
3386 {
3387 if (__n <= _M_unused().size())
3388 return { this };
3389
3390 if (__n <= _M_span.size()) // Cannot meet the request.
3391 {
3392 _M_overflow(); // Make more space available.
3393 if (__n <= _M_unused().size())
3394 return { this };
3395 }
3396 return { nullptr };
3397 }
3398
3399 // Update the next output position after writing directly to the sink.
3400 // pre: no calls to _M_write or _M_overflow since _M_reserve.
3401 virtual void
3402 _M_bump(size_t __n)
3403 { _M_next += __n; }
3404
3405 // Returns true if the _Sink is discarding incoming characters.
3406 virtual bool
3407 _M_discarding() const
3408 { return false; }
3409
3410 public:
3411 _Sink(const _Sink&) = delete;
3412 _Sink& operator=(const _Sink&) = delete;
3413
3414 [[__gnu__::__always_inline__]]
3415 constexpr _Sink_iter<_CharT>
3416 out() noexcept
3417 { return _Sink_iter<_CharT>(*this); }
3418 };
3419
3420
3421 template<typename _CharT>
3422 class _Fixedbuf_sink final : public _Sink<_CharT>
3423 {
3424 void
3425 _M_overflow() override
3426 {
3427 __glibcxx_assert(false);
3428 this->_M_rewind();
3429 }
3430
3431 public:
3432 [[__gnu__::__always_inline__]]
3433 constexpr explicit
3434 _Fixedbuf_sink(span<_CharT> __buf)
3435 : _Sink<_CharT>(__buf)
3436 { }
3437
3438 constexpr basic_string_view<_CharT>
3439 view() const
3440 {
3441 auto __s = this->_M_used();
3442 return basic_string_view<_CharT>(__s.data(), __s.size());
3443 }
3444 };
3445
3446 // A sink with an internal buffer. This is used to implement concrete sinks.
3447 template<typename _CharT>
3448 class _Buf_sink : public _Sink<_CharT>
3449 {
3450 protected:
3451 _CharT _M_buf[__stackbuf_size<_CharT>];
3452
3453 [[__gnu__::__always_inline__]]
3454 constexpr
3455 _Buf_sink() noexcept
3456 : _Sink<_CharT>(_M_buf)
3457 { }
3458 };
3459
3460 using _GLIBCXX_STD_C::vector;
3461
3462 // A sink that fills a sequence (e.g. std::string, std::vector, std::deque).
3463 // Writes to a buffer then appends that to the sequence when it fills up.
3464 template<typename _Seq>
3465 class _Seq_sink : public _Buf_sink<typename _Seq::value_type>
3466 {
3467 using _CharT = typename _Seq::value_type;
3468
3469 _Seq _M_seq;
3470 protected:
3471 // Transfer buffer contents to the sequence, so buffer can be refilled.
3472 void
3473 _M_overflow() override
3474 {
3475 auto __s = this->_M_used();
3476 if (__s.empty()) [[unlikely]]
3477 return; // Nothing in the buffer to transfer to _M_seq.
3478
3479 // If _M_reserve was called then _M_bump must have been called too.
3480 _GLIBCXX_DEBUG_ASSERT(__s.data() != _M_seq.data());
3481
3482 if constexpr (__is_specialization_of<_Seq, basic_string>)
3483 _M_seq.append(__s.data(), __s.size());
3484 else
3485 _M_seq.insert(_M_seq.end(), __s.begin(), __s.end());
3486
3487 // Make the whole of _M_buf available for the next write:
3488 this->_M_rewind();
3489 }
3490
3491 typename _Sink<_CharT>::_Reservation
3492 _M_reserve(size_t __n) override
3493 {
3494 // We might already have n characters available in this->_M_unused(),
3495 // but the whole point of this function is to be an optimization for
3496 // the std::format("{}", x) case. We want to avoid writing to _M_buf
3497 // and then copying that into a basic_string if possible, so this
3498 // function prefers to create space directly in _M_seq rather than
3499 // using _M_buf.
3500
3501 if constexpr (__is_specialization_of<_Seq, basic_string>
3502 || __is_specialization_of<_Seq, vector>)
3503 {
3504 // Flush the buffer to _M_seq first (should not be needed).
3505 if (this->_M_used().size()) [[unlikely]]
3506 _Seq_sink::_M_overflow();
3507
3508 // Expand _M_seq to make __n new characters available:
3509 const auto __sz = _M_seq.size();
3510 if constexpr (is_same_v<string, _Seq> || is_same_v<wstring, _Seq>)
3511 _M_seq.__resize_and_overwrite(__sz + __n,
3512 [](auto, auto __n2) {
3513 return __n2;
3514 });
3515 else
3516 _M_seq.resize(__sz + __n);
3517
3518 // Set _M_used() to be a span over the original part of _M_seq
3519 // and _M_unused() to be the extra capacity we just created:
3520 this->_M_reset(_M_seq, __sz);
3521 return { this };
3522 }
3523 else // Try to use the base class' buffer.
3524 return _Sink<_CharT>::_M_reserve(__n);
3525 }
3526
3527 void
3528 _M_bump(size_t __n) override
3529 {
3530 if constexpr (__is_specialization_of<_Seq, basic_string>
3531 || __is_specialization_of<_Seq, vector>)
3532 {
3533 auto __s = this->_M_used();
3534 _GLIBCXX_DEBUG_ASSERT(__s.data() == _M_seq.data());
3535 // Truncate the sequence to the part that was actually written to:
3536 _M_seq.resize(__s.size() + __n);
3537 // Switch back to using buffer:
3538 this->_M_reset(this->_M_buf);
3539 }
3540 }
3541
3542 void _M_trim(span<const _CharT> __s)
3543 requires __is_specialization_of<_Seq, basic_string>
3544 {
3545 _GLIBCXX_DEBUG_ASSERT(__s.data() == this->_M_buf
3546 || __s.data() == _M_seq.data());
3547 if (__s.data() == _M_seq.data())
3548 _M_seq.resize(__s.size());
3549 else
3550 this->_M_reset(this->_M_buf, __s.size());
3551 }
3552
3553 public:
3554 // TODO: for SSO string, use SSO buffer as initial span, then switch
3555 // to _M_buf if it overflows? Or even do that for all unused capacity?
3556
3557 [[__gnu__::__always_inline__]]
3558 _Seq_sink() noexcept(is_nothrow_default_constructible_v<_Seq>)
3559 { }
3560
3561 _Seq_sink(_Seq&& __s) noexcept(is_nothrow_move_constructible_v<_Seq>)
3562 : _M_seq(std::move(__s))
3563 { }
3564
3565 using _Sink<_CharT>::out;
3566
3567 _Seq
3568 get() &&
3569 {
3570 if (this->_M_used().size() != 0)
3571 _Seq_sink::_M_overflow();
3572 return std::move(_M_seq);
3573 }
3574
3575 // A writable span that views everything written to the sink.
3576 // Will be either a view over _M_seq or the used part of _M_buf.
3577 span<_CharT>
3578 _M_span()
3579 {
3580 auto __s = this->_M_used();
3581 if (_M_seq.size())
3582 {
3583 if (__s.size() != 0)
3584 _Seq_sink::_M_overflow();
3585 return _M_seq;
3586 }
3587 return __s;
3588 }
3589
3590 basic_string_view<_CharT>
3591 view()
3592 {
3593 auto __span = _M_span();
3594 return basic_string_view<_CharT>(__span.data(), __span.size());
3595 }
3596 };
3597
3598 template<typename _CharT, typename _Alloc = allocator<_CharT>>
3599 using _Str_sink
3600 = _Seq_sink<basic_string<_CharT, char_traits<_CharT>, _Alloc>>;
3601
3602 // template<typename _CharT, typename _Alloc = allocator<_CharT>>
3603 // using _Vec_sink = _Seq_sink<vector<_CharTthis-> sink that writes to an output iterator.
3604 // Writes to a fixed-size buffer and then flushes to the output iterator
3605 // when the buffer fills up.
3606 template<typename _CharT, typename _OutIter>
3607 class _Iter_sink : public _Buf_sink<_CharT>
3608 {
3609 _OutIter _M_out;
3610 iter_difference_t<_OutIter> _M_max;
3611
3612 protected:
3613 size_t _M_count = 0;
3614
3615 void
3616 _M_overflow() override
3617 {
3618 auto __s = this->_M_used();
3619 if (_M_max < 0) // No maximum.
3620 _M_out = ranges::copy(__s, std::move(_M_out)).out;
3621 else if (_M_count < static_cast<size_t>(_M_max))
3622 {
3623 auto __max = _M_max - _M_count;
3624 span<_CharT> __first;
3625 if (__max < __s.size())
3626 __first = __s.first(static_cast<size_t>(__max));
3627 else
3628 __first = __s;
3629 _M_out = ranges::copy(__first, std::move(_M_out)).out;
3630 }
3631 this->_M_rewind();
3632 _M_count += __s.size();
3633 }
3634
3635 bool
3636 _M_discarding() const override
3637 {
3638 // format_to_n return total number of characters, that would be written,
3639 // see C++20 [format.functions] p20
3640 return false;
3641 }
3642
3643 public:
3644 [[__gnu__::__always_inline__]]
3645 explicit
3646 _Iter_sink(_OutIter __out, iter_difference_t<_OutIter> __max = -1)
3647 : _M_out(std::move(__out)), _M_max(__max)
3648 { }
3649
3650 using _Sink<_CharT>::out;
3651
3652 format_to_n_result<_OutIter>
3653 _M_finish() &&
3654 {
3655 if (this->_M_used().size() != 0)
3656 _Iter_sink::_M_overflow();
3657 iter_difference_t<_OutIter> __count(_M_count);
3658 return { std::move(_M_out), __count };
3659 }
3660 };
3661
3662 // Used for contiguous iterators.
3663 // No buffer is used, characters are written straight to the iterator.
3664 // We do not know the size of the output range, so the span size just grows
3665 // as needed. The end of the span might be an invalid pointer outside the
3666 // valid range, but we never actually call _M_span.end(). This class does
3667 // not introduce any invalid pointer arithmetic or overflows that would not
3668 // have happened anyway.
3669 template<typename _CharT>
3670 class _Ptr_sink : public _Sink<_CharT>
3671 {
3672 static constexpr size_t _S_no_limit = size_t(-1);
3673
3674 size_t _M_max;
3675 protected:
3676 size_t _M_count = 0;
3677 private:
3678 _CharT _M_buf[64]; // Write here after outputting _M_max characters.
3679
3680 protected:
3681 void
3682 _M_overflow() override
3683 {
3684 if (this->_M_unused().size() != 0)
3685 return; // No need to switch to internal buffer yet.
3686
3687 auto __s = this->_M_used();
3688
3689 if (_M_max != _S_no_limit)
3690 {
3691 _M_count += __s.size();
3692 // Span was already sized for the maximum character count,
3693 // if it overflows then any further output must go to the
3694 // internal buffer, to be discarded.
3695 this->_M_reset(this->_M_buf);
3696 }
3697 else
3698 {
3699 // No maximum character count. Just extend the span to allow
3700 // writing more characters to it.
3701 _M_rebuf(ptr: __s.data(), total: __s.size() + 1024, inuse: __s.size());
3702 }
3703 }
3704
3705 bool
3706 _M_discarding() const override
3707 {
3708 // format_to_n return total number of characters, that would be written,
3709 // see C++20 [format.functions] p20
3710 return false;
3711 }
3712
3713 typename _Sink<_CharT>::_Reservation
3714 _M_reserve(size_t __n) final
3715 {
3716 auto __avail = this->_M_unused();
3717 if (__n > __avail.size())
3718 {
3719 if (_M_max != _S_no_limit)
3720 return {}; // cannot grow
3721
3722 auto __s = this->_M_used();
3723 _M_rebuf(ptr: __s.data(), total: __s.size() + __n, inuse: __s.size());
3724 }
3725 return { this };
3726 }
3727
3728 private:
3729 template<typename _IterDifference>
3730 static size_t
3731 _S_trim_max(_IterDifference __max)
3732 {
3733 if (__max < 0)
3734 return _S_no_limit;
3735 if constexpr (!is_integral_v<_IterDifference> || sizeof(__max) > sizeof(size_t))
3736 // __int128 or __detail::__max_diff_type
3737 if (_IterDifference((size_t)-1) < __max)
3738 return _S_no_limit;
3739 return size_t(__max);
3740 }
3741
3742 [[__gnu__::__always_inline__]]
3743 void
3744 _M_rebuf(_CharT* __ptr, size_t __total, size_t __inuse = 0)
3745 {
3746 std::span<_CharT> __span(__ptr, __total);
3747 this->_M_reset(__span, __inuse);
3748 }
3749
3750 public:
3751 explicit
3752 _Ptr_sink(_CharT* __ptr, size_t __n = _S_no_limit) noexcept
3753 : _Sink<_CharT>(_M_buf), _M_max(__n)
3754 {
3755 if (__n == 0)
3756 return; // Only write to the internal buffer.
3757 else if (__n != _S_no_limit)
3758 _M_rebuf(__ptr, total: __n);
3759#if __has_builtin(__builtin_dynamic_object_size)
3760 else if (size_t __bytes = __builtin_dynamic_object_size(__ptr, 2))
3761 _M_rebuf(__ptr, total: __bytes / sizeof(_CharT));
3762#endif
3763 else
3764 {
3765 // Avoid forming a pointer to a different memory page.
3766 const auto __off = reinterpret_cast<__UINTPTR_TYPE__>(__ptr) % 1024;
3767 __n = (1024 - __off) / sizeof(_CharT);
3768 if (__n > 0) [[likely]]
3769 _M_rebuf(__ptr, total: __n);
3770 else // Misaligned/packed buffer of wchar_t?
3771 _M_rebuf(__ptr, total: 1);
3772 }
3773 }
3774
3775 template<contiguous_iterator _OutIter>
3776 explicit
3777 _Ptr_sink(_OutIter __out, iter_difference_t<_OutIter> __n = -1)
3778 : _Ptr_sink(std::to_address(__out), _S_trim_max(__n))
3779 { }
3780
3781 template<contiguous_iterator _OutIter>
3782 format_to_n_result<_OutIter>
3783 _M_finish(_OutIter __first) const
3784 {
3785 auto __s = this->_M_used();
3786 if (__s.data() == _M_buf)
3787 {
3788 // Switched to internal buffer, so must have written _M_max.
3789 iter_difference_t<_OutIter> __m(_M_max);
3790 iter_difference_t<_OutIter> __count(_M_count + __s.size());
3791 return { __first + __m, __count };
3792 }
3793 else // Not using internal buffer yet
3794 {
3795 iter_difference_t<_OutIter> __count(__s.size());
3796 return { __first + __count, __count };
3797 }
3798 }
3799 };
3800
3801 template<typename _CharT, typename _OutIter>
3802 concept __contiguous_char_iter
3803 = contiguous_iterator<_OutIter>
3804 && same_as<iter_value_t<_OutIter>, _CharT>;
3805
3806 // A sink for handling the padded outputs (_M_padwidth) or truncated
3807 // (_M_maxwidth). The handling is done by writting to buffer (_Str_strink)
3808 // until sufficient number of characters is written. After that if sequence
3809 // is longer than _M_padwidth it's written to _M_out, and further writes are
3810 // either:
3811 // * buffered and forwarded to _M_out, if below _M_maxwidth,
3812 // * ignored otherwise
3813 // If field width of written sequence is no greater than _M_padwidth, the
3814 // sequence is written during _M_finish call.
3815 template<typename _Out, typename _CharT>
3816 class _Padding_sink : public _Str_sink<_CharT>
3817 {
3818 size_t _M_padwidth;
3819 size_t _M_maxwidth;
3820 _Out _M_out;
3821 size_t _M_printwidth;
3822
3823 [[__gnu__::__always_inline__]]
3824 bool
3825 _M_ignoring() const
3826 { return _M_printwidth >= _M_maxwidth; }
3827
3828 [[__gnu__::__always_inline__]]
3829 bool
3830 _M_buffering() const
3831 {
3832 if (_M_printwidth < _M_padwidth)
3833 return true;
3834 if (_M_maxwidth != (size_t)-1)
3835 return _M_printwidth < _M_maxwidth;
3836 return false;
3837 }
3838
3839 void
3840 _M_sync_discarding()
3841 {
3842 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
3843 if (_M_out._M_discarding())
3844 _M_maxwidth = _M_printwidth;
3845 }
3846
3847 void
3848 _M_flush()
3849 {
3850 span<_CharT> __new = this->_M_used();
3851 basic_string_view<_CharT> __str(__new.data(), __new.size());
3852 _M_out = __format::__write(std::move(_M_out), __str);
3853 _M_sync_discarding();
3854 this->_M_rewind();
3855 }
3856
3857 bool
3858 _M_force_update()
3859 {
3860 auto __str = this->view();
3861 // Compute actual field width, possibly truncated.
3862 _M_printwidth = __format::__truncate(__str, _M_maxwidth);
3863 if (_M_ignoring())
3864 this->_M_trim(__str);
3865 if (_M_buffering())
3866 return true;
3867
3868 // We have more characters than padidng, no padding is needed,
3869 // write direclty to _M_out.
3870 if (_M_printwidth >= _M_padwidth)
3871 {
3872 _M_out = __format::__write(std::move(_M_out), __str);
3873 _M_sync_discarding();
3874 }
3875 // We reached _M_maxwidth that is smaller than _M_padwidth.
3876 // Store the prefix sequence in _M_seq, and free _M_buf.
3877 else
3878 _Str_sink<_CharT>::_M_overflow();
3879
3880 // Use internal buffer for writes to _M_out.
3881 this->_M_reset(this->_M_buf);
3882 return false;
3883 }
3884
3885 bool
3886 _M_update(size_t __new)
3887 {
3888 _M_printwidth += __new;
3889 // Compute estimated width, to see if is not reduced.
3890 if (_M_printwidth >= _M_padwidth || _M_printwidth >= _M_maxwidth)
3891 return _M_force_update();
3892 return true;
3893 }
3894
3895 void
3896 _M_overflow() override
3897 {
3898 // Ignore characters in buffer, and override it.
3899 if (_M_ignoring())
3900 this->_M_rewind();
3901 // Write buffer to _M_out, and override it.
3902 else if (!_M_buffering())
3903 _M_flush();
3904 // Update written count, and if input still should be buffered,
3905 // flush the to _M_seq.
3906 else if (_M_update(new: this->_M_used().size()))
3907 _Str_sink<_CharT>::_M_overflow();
3908 }
3909
3910 bool
3911 _M_discarding() const override
3912 { return _M_ignoring(); }
3913
3914 typename _Sink<_CharT>::_Reservation
3915 _M_reserve(size_t __n) override
3916 {
3917 // Ignore characters in buffer, if any.
3918 if (_M_ignoring())
3919 this->_M_rewind();
3920 else if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
3921 if (!_M_buffering())
3922 {
3923 // Write pending characters if any
3924 if (!this->_M_used().empty())
3925 _M_flush();
3926 // Try to reserve from _M_out sink.
3927 if (auto __reserved = _M_out._M_reserve(__n))
3928 return __reserved;
3929 }
3930 return _Sink<_CharT>::_M_reserve(__n);
3931 }
3932
3933 void
3934 _M_bump(size_t __n) override
3935 {
3936 // Ignore the written characters.
3937 if (_M_ignoring())
3938 return;
3939 // If reservation was made directy sink associated _M_out,
3940 // _M_bump will be called on that sink.
3941 _Sink<_CharT>::_M_bump(__n);
3942 if (_M_buffering())
3943 _M_update(new: __n);
3944 }
3945
3946 public:
3947 [[__gnu__::__always_inline__]]
3948 explicit
3949 _Padding_sink(_Out __out, size_t __padwidth, size_t __maxwidth)
3950 : _M_padwidth(__padwidth), _M_maxwidth(__maxwidth),
3951 _M_out(std::move(__out)), _M_printwidth(0)
3952 { _M_sync_discarding(); }
3953
3954 [[__gnu__::__always_inline__]]
3955 explicit
3956 _Padding_sink(_Out __out, size_t __padwidth)
3957 : _Padding_sink(std::move(__out), __padwidth, (size_t)-1)
3958 { }
3959
3960 _Out
3961 _M_finish(_Align __align, char32_t __fill_char)
3962 {
3963 // Handle any characters in the buffer.
3964 if (auto __rem = this->_M_used().size())
3965 {
3966 if (_M_ignoring())
3967 this->_M_rewind();
3968 else if (!_M_buffering())
3969 _M_flush();
3970 else
3971 _M_update(new: __rem);
3972 }
3973
3974 if (!_M_buffering() || !_M_force_update())
3975 // Characters were already written to _M_out.
3976 if (_M_printwidth >= _M_padwidth)
3977 return std::move(_M_out);
3978
3979 const auto __str = this->view();
3980 if (_M_printwidth >= _M_padwidth)
3981 return __format::__write(std::move(_M_out), __str);
3982
3983 const size_t __nfill = _M_padwidth - _M_printwidth;
3984 return __format::__write_padded(std::move(_M_out), __str,
3985 __align, __nfill, __fill_char);
3986 }
3987 };
3988
3989 template<typename _Out, typename _CharT>
3990 class _Escaping_sink : public _Buf_sink<_CharT>
3991 {
3992 using _Esc = _Escapes<_CharT>;
3993
3994 _Out _M_out;
3995 _Term_char _M_term : 2;
3996 unsigned _M_prev_escape : 1;
3997 unsigned _M_out_discards : 1;
3998
3999 void
4000 _M_sync_discarding()
4001 {
4002 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
4003 _M_out_discards = _M_out._M_discarding();
4004 }
4005
4006 void
4007 _M_write()
4008 {
4009 span<_CharT> __bytes = this->_M_used();
4010 basic_string_view<_CharT> __str(__bytes.data(), __bytes.size());
4011
4012 size_t __rem = 0;
4013 if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
4014 {
4015 bool __prev_escape = _M_prev_escape;
4016 _M_out = __format::__write_escaped_unicode_part(
4017 std::move(_M_out), __str, __prev_escape, _M_term);
4018 _M_prev_escape = __prev_escape;
4019
4020 __rem = __str.size();
4021 if (__rem > 0 && __str.data() != this->_M_buf) [[unlikely]]
4022 ranges::move(__str, this->_M_buf);
4023 }
4024 else
4025 _M_out = __format::__write_escaped_ascii(
4026 std::move(_M_out), __str, _M_term);
4027
4028 this->_M_reset(this->_M_buf, __rem);
4029 _M_sync_discarding();
4030 }
4031
4032 void
4033 _M_overflow() override
4034 {
4035 if (_M_out_discards)
4036 this->_M_rewind();
4037 else
4038 _M_write();
4039 }
4040
4041 bool
4042 _M_discarding() const override
4043 { return _M_out_discards; }
4044
4045 public:
4046 [[__gnu__::__always_inline__]]
4047 explicit
4048 _Escaping_sink(_Out __out, _Term_char __term)
4049 : _M_out(std::move(__out)), _M_term(__term),
4050 _M_prev_escape(true), _M_out_discards(false)
4051 {
4052 _M_out = __format::__write(std::move(_M_out), _Esc::_S_term(_M_term));
4053 _M_sync_discarding();
4054 }
4055
4056 _Out
4057 _M_finish()
4058 {
4059 if (_M_out_discards)
4060 return std::move(_M_out);
4061
4062 if (!this->_M_used().empty())
4063 {
4064 _M_write();
4065 if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
4066 if (auto __rem = this->_M_used(); !__rem.empty())
4067 {
4068 basic_string_view<_CharT> __str(__rem.data(), __rem.size());
4069 _M_out = __format::__write_escape_seqs(std::move(_M_out), __str);
4070 }
4071 }
4072 return __format::__write(std::move(_M_out), _Esc::_S_term(_M_term));
4073 }
4074 };
4075
4076 enum class _Arg_t : unsigned char {
4077 _Arg_none, _Arg_bool, _Arg_c, _Arg_i, _Arg_u, _Arg_ll, _Arg_ull,
4078 _Arg_flt, _Arg_dbl, _Arg_ldbl, _Arg_str, _Arg_sv, _Arg_ptr, _Arg_handle,
4079 _Arg_i128, _Arg_u128, _Arg_float128,
4080 _Arg_bf16, _Arg_f16, _Arg_f32, _Arg_f64,
4081 _Arg_max_,
4082
4083#ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
4084 _Arg_ibm128 = _Arg_ldbl,
4085 _Arg_ieee128 = _Arg_float128,
4086#endif
4087 };
4088 using enum _Arg_t;
4089
4090 template<typename _Context>
4091 struct _Arg_value
4092 {
4093 using _CharT = typename _Context::char_type;
4094
4095 class handle
4096 {
4097 using _CharT = typename _Context::char_type;
4098 using _Func = void(*)(basic_format_parse_context<_CharT>&,
4099 _Context&, const void*);
4100
4101 // Format as const if possible, to reduce instantiations.
4102 template<typename _Tp>
4103 using __maybe_const_t
4104 = __conditional_t<__formattable_with<const _Tp, _Context>,
4105 const _Tp, _Tp>;
4106
4107 template<typename _Tq>
4108 static void
4109 _S_format(basic_format_parse_context<_CharT>& __parse_ctx,
4110 _Context& __format_ctx, const void* __ptr)
4111 {
4112 using _Td = remove_const_t<_Tq>;
4113 typename _Context::template formatter_type<_Td> __f;
4114 __parse_ctx.advance_to(__f.parse(__parse_ctx));
4115 _Tq& __val = *const_cast<_Tq*>(static_cast<const _Td*>(__ptr));
4116 __format_ctx.advance_to(__f.format(__val, __format_ctx));
4117 }
4118
4119 template<typename _Tp>
4120 requires (!is_same_v<remove_cv_t<_Tp>, handle>)
4121 explicit
4122 handle(_Tp& __val) noexcept
4123 : _M_ptr(__builtin_addressof(__val))
4124 , _M_func(&_S_format<__maybe_const_t<_Tp>>)
4125 { }
4126
4127 friend class basic_format_arg<_Context>;
4128
4129 public:
4130 handle(const handle&) = default;
4131 handle& operator=(const handle&) = default;
4132
4133 [[__gnu__::__always_inline__]]
4134 void
4135 format(basic_format_parse_context<_CharT>& __pc, _Context& __fc) const
4136 { _M_func(__pc, __fc, this->_M_ptr); }
4137
4138 private:
4139 const void* _M_ptr;
4140 _Func _M_func;
4141 };
4142
4143 union
4144 {
4145 monostate _M_none;
4146 bool _M_bool;
4147 _CharT _M_c;
4148 int _M_i;
4149 unsigned _M_u;
4150 long long _M_ll;
4151 unsigned long long _M_ull;
4152 float _M_flt;
4153 double _M_dbl;
4154#ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT // No long double if it's ambiguous.
4155 long double _M_ldbl;
4156#else
4157 __ibm128 _M_ibm128;
4158 __ieee128 _M_ieee128;
4159#endif
4160#ifdef __SIZEOF_FLOAT128__
4161 __float128 _M_float128;
4162#endif
4163 const _CharT* _M_str;
4164 basic_string_view<_CharT> _M_sv;
4165 const void* _M_ptr;
4166 handle _M_handle;
4167#ifdef __SIZEOF_INT128__
4168 __int128 _M_i128;
4169 unsigned __int128 _M_u128;
4170#endif
4171#ifdef __BFLT16_DIG__
4172 __bflt16_t _M_bf16;
4173#endif
4174#ifdef __FLT16_DIG__
4175 _Float16 _M_f16;
4176#endif
4177#ifdef __FLT32_DIG__
4178 _Float32 _M_f32;
4179#endif
4180#ifdef __FLT64_DIG__
4181 _Float64 _M_f64;
4182#endif
4183 };
4184
4185 [[__gnu__::__always_inline__]]
4186 _Arg_value() : _M_none() { }
4187
4188#if 0
4189 template<typename _Tp>
4190 _Arg_value(in_place_type_t<_Tp>, _Tp __val)
4191 { _S_get<_Tp>() = __val; }
4192#endif
4193
4194 // Returns reference to the _Arg_value member with the type _Tp.
4195 // Value of second argument (if provided), is assigned to that member.
4196 template<typename _Tp, typename _Self, typename... _Value>
4197 [[__gnu__::__always_inline__]]
4198 static auto&
4199 _S_access(_Self& __u, _Value... __value) noexcept
4200 {
4201 static_assert(sizeof...(_Value) <= 1);
4202 if constexpr (is_same_v<_Tp, bool>)
4203 return (__u._M_bool = ... = __value);
4204 else if constexpr (is_same_v<_Tp, _CharT>)
4205 return (__u._M_c = ... = __value);
4206 else if constexpr (is_same_v<_Tp, int>)
4207 return (__u._M_i = ... = __value);
4208 else if constexpr (is_same_v<_Tp, unsigned>)
4209 return (__u._M_u = ... = __value);
4210 else if constexpr (is_same_v<_Tp, long long>)
4211 return (__u._M_ll = ... = __value);
4212 else if constexpr (is_same_v<_Tp, unsigned long long>)
4213 return (__u._M_ull = ... = __value);
4214 else if constexpr (is_same_v<_Tp, float>)
4215 return (__u._M_flt = ... = __value);
4216 else if constexpr (is_same_v<_Tp, double>)
4217 return (__u._M_dbl = ... = __value);
4218#ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
4219 else if constexpr (is_same_v<_Tp, long double>)
4220 return (__u._M_ldbl = ... = __value);
4221#else
4222 else if constexpr (is_same_v<_Tp, __ibm128>)
4223 return (__u._M_ibm128 = ... = __value);
4224 else if constexpr (is_same_v<_Tp, __ieee128>)
4225 return (__u._M_ieee128 = ... = __value);
4226#endif
4227#ifdef __SIZEOF_FLOAT128__
4228 else if constexpr (is_same_v<_Tp, __float128>)
4229 return (__u._M_float128 = ... = __value);
4230#endif
4231 else if constexpr (is_same_v<_Tp, const _CharT*>)
4232 return (__u._M_str = ... = __value);
4233 else if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
4234 return (__u._M_sv = ... = __value);
4235 else if constexpr (is_same_v<_Tp, const void*>)
4236 return (__u._M_ptr = ... = __value);
4237#ifdef __SIZEOF_INT128__
4238 else if constexpr (is_same_v<_Tp, __int128>)
4239 return (__u._M_i128 = ... = __value);
4240 else if constexpr (is_same_v<_Tp, unsigned __int128>)
4241 return (__u._M_u128 = ... = __value);
4242#endif
4243#ifdef __BFLT16_DIG__
4244 else if constexpr (is_same_v<_Tp, __bflt16_t>)
4245 return (__u._M_bf16 = ... = __value);
4246#endif
4247#ifdef __FLT16_DIG__
4248 else if constexpr (is_same_v<_Tp, _Float16>)
4249 return (__u._M_f16 = ... = __value);
4250#endif
4251#ifdef __FLT32_DIG__
4252 else if constexpr (is_same_v<_Tp, _Float32>)
4253 return (__u._M_f32 = ... = __value);
4254#endif
4255#ifdef __FLT64_DIG__
4256 else if constexpr (is_same_v<_Tp, _Float64>)
4257 return (__u._M_f64 = ... = __value);
4258#endif
4259 else if constexpr (is_same_v<_Tp, handle>)
4260 return __u._M_handle;
4261 // Otherwise, ill-formed.
4262 }
4263
4264 template<typename _Tp>
4265 [[__gnu__::__always_inline__]]
4266 auto&
4267 _M_get() noexcept
4268 { return _S_access<_Tp>(*this); }
4269
4270 template<typename _Tp>
4271 [[__gnu__::__always_inline__]]
4272 const auto&
4273 _M_get() const noexcept
4274 { return _S_access<_Tp>(*this); }
4275
4276 template<typename _Tp>
4277 [[__gnu__::__always_inline__]]
4278 void
4279 _M_set(_Tp __v) noexcept
4280 {
4281 // Explicitly construct types without trivial default constructor.
4282 if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
4283 std::construct_at(&_M_sv, __v);
4284 else if constexpr (is_same_v<_Tp, handle>)
4285 std::construct_at(&_M_handle, __v);
4286 else
4287 // Builtin types are trivially default constructible, and assignment
4288 // changes active member per N5032 [class.union.general] p5.
4289 _S_access<_Tp>(*this, __v);
4290 }
4291 };
4292
4293 // [format.arg.store], class template format-arg-store
4294 template<typename _Context, typename... _Args>
4295 class _Arg_store;
4296
4297 template<typename _Visitor, typename _Ctx>
4298 decltype(auto) __visit_format_arg(_Visitor&&, basic_format_arg<_Ctx>);
4299
4300 template<typename _Ch, typename _Tp>
4301 consteval _Arg_t
4302 __to_arg_t_enum() noexcept;
4303} // namespace __format
4304/// @endcond
4305
4306 template<typename _Context>
4307 class basic_format_arg
4308 {
4309 using _CharT = typename _Context::char_type;
4310
4311 public:
4312 using handle = __format::_Arg_value<_Context>::handle;
4313
4314 [[__gnu__::__always_inline__]]
4315 basic_format_arg() noexcept : _M_type(__format::_Arg_none) { }
4316
4317 [[nodiscard,__gnu__::__always_inline__]]
4318 explicit operator bool() const noexcept
4319 { return _M_type != __format::_Arg_none; }
4320
4321#if __cpp_lib_format >= 202306L // >= C++26
4322 template<typename _Visitor>
4323 decltype(auto)
4324 visit(this basic_format_arg __arg, _Visitor&& __vis)
4325 { return __arg._M_visit_user(std::forward<_Visitor>(__vis), __arg._M_type); }
4326
4327 template<typename _Res, typename _Visitor>
4328 _Res
4329 visit(this basic_format_arg __arg, _Visitor&& __vis)
4330 { return __arg._M_visit_user(std::forward<_Visitor>(__vis), __arg._M_type); }
4331#endif
4332
4333 private:
4334 template<typename _Ctx>
4335 friend class basic_format_args;
4336
4337 template<typename _Ctx, typename... _Args>
4338 friend class __format::_Arg_store;
4339
4340 static_assert(is_trivially_copyable_v<__format::_Arg_value<_Context>>);
4341
4342 __format::_Arg_value<_Context> _M_val;
4343 __format::_Arg_t _M_type;
4344
4345 // Transform incoming argument type to the type stored in _Arg_value.
4346 // e.g. short -> int, std::string -> std::string_view,
4347 // char[3] -> const char*.
4348 template<typename _Tp>
4349 static consteval auto
4350 _S_to_arg_type()
4351 {
4352 using _Td = remove_const_t<_Tp>;
4353 if constexpr (is_same_v<_Td, bool>)
4354 return type_identity<bool>();
4355 else if constexpr (is_same_v<_Td, _CharT>)
4356 return type_identity<_CharT>();
4357 else if constexpr (is_same_v<_Td, char> && is_same_v<_CharT, wchar_t>)
4358 return type_identity<_CharT>();
4359#ifdef __SIZEOF_INT128__ // Check before signed/unsigned integer
4360 else if constexpr (is_same_v<_Td, __int128>)
4361 return type_identity<__int128>();
4362 else if constexpr (is_same_v<_Td, unsigned __int128>)
4363 return type_identity<unsigned __int128>();
4364#endif
4365 else if constexpr (__is_signed_integer<_Td>::value)
4366 {
4367 if constexpr (sizeof(_Td) <= sizeof(int))
4368 return type_identity<int>();
4369 else if constexpr (sizeof(_Td) <= sizeof(long long))
4370 return type_identity<long long>();
4371 }
4372 else if constexpr (__is_unsigned_integer<_Td>::value)
4373 {
4374 if constexpr (sizeof(_Td) <= sizeof(unsigned))
4375 return type_identity<unsigned>();
4376 else if constexpr (sizeof(_Td) <= sizeof(unsigned long long))
4377 return type_identity<unsigned long long>();
4378 }
4379 else if constexpr (is_same_v<_Td, float>)
4380 return type_identity<float>();
4381 else if constexpr (is_same_v<_Td, double>)
4382 return type_identity<double>();
4383#ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
4384 else if constexpr (is_same_v<_Td, long double>)
4385 return type_identity<long double>();
4386#else
4387 else if constexpr (is_same_v<_Td, __ibm128>)
4388 return type_identity<__ibm128>();
4389 else if constexpr (is_same_v<_Td, __ieee128>)
4390 return type_identity<__ieee128>();
4391#endif
4392#if defined(__SIZEOF_FLOAT128__) && _GLIBCXX_FORMAT_F128
4393 else if constexpr (is_same_v<_Td, __float128>)
4394 return type_identity<__float128>();
4395#endif
4396#if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4397 else if constexpr (is_same_v<_Td, __format::__bflt16_t>)
4398 return type_identity<__format::__bflt16_t>();
4399#endif
4400#if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4401 else if constexpr (is_same_v<_Td, _Float16>)
4402 return type_identity<_Float16>();
4403#endif
4404#if defined(__FLT32_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4405 else if constexpr (is_same_v<_Td, _Float32>)
4406 return type_identity<_Float32>();
4407#endif
4408#if defined(__FLT64_DIG__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
4409 else if constexpr (is_same_v<_Td, _Float64>)
4410 return type_identity<_Float64>();
4411#endif
4412 else if constexpr (__is_specialization_of<_Td, basic_string_view>
4413 || __is_specialization_of<_Td, basic_string>)
4414 {
4415 if constexpr (is_same_v<typename _Td::value_type, _CharT>)
4416 return type_identity<basic_string_view<_CharT>>();
4417 else
4418 return type_identity<handle>();
4419 }
4420 else if constexpr (is_same_v<decay_t<_Td>, const _CharT*>)
4421 return type_identity<const _CharT*>();
4422 else if constexpr (is_same_v<decay_t<_Td>, _CharT*>)
4423 return type_identity<const _CharT*>();
4424 else if constexpr (is_void_v<remove_pointer_t<_Td>>)
4425 return type_identity<const void*>();
4426 else if constexpr (is_same_v<_Td, nullptr_t>)
4427 return type_identity<const void*>();
4428 else
4429 return type_identity<handle>();
4430 }
4431
4432 // Transform a formattable type to the appropriate storage type.
4433 template<typename _Tp>
4434 using _Normalize = typename decltype(_S_to_arg_type<_Tp>())::type;
4435
4436 // Get the _Arg_t value corresponding to a normalized type.
4437 template<typename _Tp>
4438 static consteval __format::_Arg_t
4439 _S_to_enum()
4440 {
4441 using namespace __format;
4442 if constexpr (is_same_v<_Tp, bool>)
4443 return _Arg_bool;
4444 else if constexpr (is_same_v<_Tp, _CharT>)
4445 return _Arg_c;
4446 else if constexpr (is_same_v<_Tp, int>)
4447 return _Arg_i;
4448 else if constexpr (is_same_v<_Tp, unsigned>)
4449 return _Arg_u;
4450 else if constexpr (is_same_v<_Tp, long long>)
4451 return _Arg_ll;
4452 else if constexpr (is_same_v<_Tp, unsigned long long>)
4453 return _Arg_ull;
4454 else if constexpr (is_same_v<_Tp, float>)
4455 return _Arg_flt;
4456 else if constexpr (is_same_v<_Tp, double>)
4457 return _Arg_dbl;
4458#ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
4459 else if constexpr (is_same_v<_Tp, long double>)
4460 return _Arg_ldbl;
4461#else
4462 // Don't use _Arg_ldbl for this target, it's ambiguous.
4463 else if constexpr (is_same_v<_Tp, __ibm128>)
4464 return _Arg_ibm128;
4465 else if constexpr (is_same_v<_Tp, __ieee128>)
4466 return _Arg_ieee128;
4467#endif
4468#if defined(__SIZEOF_FLOAT128__) && _GLIBCXX_FORMAT_F128
4469 else if constexpr (is_same_v<_Tp, __float128>)
4470 return _Arg_float128;
4471#endif
4472#if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4473 else if constexpr (is_same_v<_Tp, __format::__bflt16_t>)
4474 return _Arg_bf16;
4475#endif
4476#if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4477 else if constexpr (is_same_v<_Tp, _Float16>)
4478 return _Arg_f16;
4479#endif
4480#if defined(__FLT32_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4481 else if constexpr (is_same_v<_Tp, _Float32>)
4482 return _Arg_f32;
4483#endif
4484#if defined(__FLT64_DIG__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
4485 else if constexpr (is_same_v<_Tp, _Float64>)
4486 return _Arg_f64;
4487#endif
4488 else if constexpr (is_same_v<_Tp, const _CharT*>)
4489 return _Arg_str;
4490 else if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
4491 return _Arg_sv;
4492 else if constexpr (is_same_v<_Tp, const void*>)
4493 return _Arg_ptr;
4494#ifdef __SIZEOF_INT128__
4495 else if constexpr (is_same_v<_Tp, __int128>)
4496 return _Arg_i128;
4497 else if constexpr (is_same_v<_Tp, unsigned __int128>)
4498 return _Arg_u128;
4499#endif
4500 else if constexpr (is_same_v<_Tp, handle>)
4501 return _Arg_handle;
4502 }
4503
4504 template<typename _Tp>
4505 void
4506 _M_set(_Tp __v) noexcept
4507 {
4508 _M_type = _S_to_enum<_Tp>();
4509 _M_val._M_set(__v);
4510 }
4511
4512 template<typename _Tp>
4513 requires __format::__formattable_with<_Tp, _Context>
4514 explicit
4515 basic_format_arg(_Tp& __v) noexcept
4516 {
4517 using _Td = _Normalize<_Tp>;
4518 if constexpr (is_same_v<_Td, basic_string_view<_CharT>>)
4519 _M_set(_Td{__v.data(), __v.size()});
4520 else if constexpr (is_same_v<remove_const_t<_Tp>, char>
4521 && is_same_v<_CharT, wchar_t>)
4522 _M_set(static_cast<_Td>(static_cast<unsigned char>(__v)));
4523 else
4524 _M_set(static_cast<_Td>(__v));
4525 }
4526
4527 template<typename _Ctx, typename... _Argz>
4528 friend auto
4529 make_format_args(_Argz&...) noexcept;
4530
4531 template<typename _Visitor, typename _Ctx>
4532 friend decltype(auto)
4533 visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx>);
4534
4535 template<typename _Visitor, typename _Ctx>
4536 friend decltype(auto)
4537 __format::__visit_format_arg(_Visitor&&, basic_format_arg<_Ctx>);
4538
4539 template<typename _Ch, typename _Tp>
4540 friend consteval __format::_Arg_t
4541 __format::__to_arg_t_enum() noexcept;
4542
4543 template<typename _Visitor>
4544 decltype(auto)
4545 _M_visit(_Visitor&& __vis, __format::_Arg_t __type)
4546 {
4547 using namespace __format;
4548 switch (__type)
4549 {
4550 case _Arg_none:
4551 return std::forward<_Visitor>(__vis)(_M_val._M_none);
4552 case _Arg_bool:
4553 return std::forward<_Visitor>(__vis)(_M_val._M_bool);
4554 case _Arg_c:
4555 return std::forward<_Visitor>(__vis)(_M_val._M_c);
4556 case _Arg_i:
4557 return std::forward<_Visitor>(__vis)(_M_val._M_i);
4558 case _Arg_u:
4559 return std::forward<_Visitor>(__vis)(_M_val._M_u);
4560 case _Arg_ll:
4561 return std::forward<_Visitor>(__vis)(_M_val._M_ll);
4562 case _Arg_ull:
4563 return std::forward<_Visitor>(__vis)(_M_val._M_ull);
4564#if __glibcxx_to_chars // FIXME: need to be able to format these types!
4565 case _Arg_flt:
4566 return std::forward<_Visitor>(__vis)(_M_val._M_flt);
4567 case _Arg_dbl:
4568 return std::forward<_Visitor>(__vis)(_M_val._M_dbl);
4569#ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
4570 case _Arg_ldbl:
4571 return std::forward<_Visitor>(__vis)(_M_val._M_ldbl);
4572#if defined(__SIZEOF_FLOAT128__) && _GLIBCXX_FORMAT_F128
4573 case _Arg_float128:
4574 return std::forward<_Visitor>(__vis)(_M_val._M_float128);
4575#endif
4576#else
4577 case _Arg_ibm128:
4578 return std::forward<_Visitor>(__vis)(_M_val._M_ibm128);
4579 case _Arg_ieee128:
4580 return std::forward<_Visitor>(__vis)(_M_val._M_ieee128);
4581#endif
4582#if defined(__STDCPP_BFLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4583 case _Arg_bf16:
4584 return std::forward<_Visitor>(__vis)(_M_val._M_bf16);
4585#endif
4586#if defined(__STDCPP_FLOAT16_T__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4587 case _Arg_f16:
4588 return std::forward<_Visitor>(__vis)(_M_val._M_f16);
4589#endif
4590#if defined(__FLT32_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
4591 case _Arg_f32:
4592 return std::forward<_Visitor>(__vis)(_M_val._M_f32);
4593#endif
4594#if defined(__FLT64_DIG__) && defined(_GLIBCXX_DOUBLE_IS_IEEE_BINARY64)
4595 case _Arg_f64:
4596 return std::forward<_Visitor>(__vis)(_M_val._M_f64);
4597#endif
4598#endif // __glibcxx_to_chars
4599 case _Arg_str:
4600 return std::forward<_Visitor>(__vis)(_M_val._M_str);
4601 case _Arg_sv:
4602 return std::forward<_Visitor>(__vis)(_M_val._M_sv);
4603 case _Arg_ptr:
4604 return std::forward<_Visitor>(__vis)(_M_val._M_ptr);
4605 case _Arg_handle:
4606 return std::forward<_Visitor>(__vis)(_M_val._M_handle);
4607#ifdef __SIZEOF_INT128__
4608 case _Arg_i128:
4609 return std::forward<_Visitor>(__vis)(_M_val._M_i128);
4610 case _Arg_u128:
4611 return std::forward<_Visitor>(__vis)(_M_val._M_u128);
4612#endif
4613 default:
4614 __builtin_unreachable();
4615 }
4616 }
4617
4618 template<typename _Visitor>
4619 decltype(auto)
4620 _M_visit_user(_Visitor&& __vis, __format::_Arg_t __type)
4621 {
4622 return _M_visit([&__vis]<typename _Tp>(_Tp& __val) -> decltype(auto)
4623 {
4624 constexpr bool __user_facing = __is_one_of<_Tp,
4625 monostate, bool, _CharT,
4626 int, unsigned int, long long int, unsigned long long int,
4627 float, double, long double,
4628 const _CharT*, basic_string_view<_CharT>,
4629 const void*, handle>::value;
4630 if constexpr (__user_facing)
4631 return std::forward<_Visitor>(__vis)(__val);
4632 else
4633 {
4634 handle __h(__val);
4635 return std::forward<_Visitor>(__vis)(__h);
4636 }
4637 }, __type);
4638 }
4639 };
4640
4641 template<typename _Visitor, typename _Context>
4642 _GLIBCXX26_DEPRECATED_SUGGEST("std::basic_format_arg::visit")
4643 inline decltype(auto)
4644 visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg)
4645 {
4646 return __arg._M_visit_user(std::forward<_Visitor>(__vis), __arg._M_type);
4647 }
4648
4649/// @cond undocumented
4650namespace __format
4651{
4652 template<typename _Visitor, typename _Ctx>
4653 inline decltype(auto)
4654 __visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx> __arg)
4655 {
4656 return __arg._M_visit(std::forward<_Visitor>(__vis), __arg._M_type);
4657 }
4658
4659 struct _WidthPrecVisitor
4660 {
4661 template<typename _Tp>
4662 size_t
4663 operator()(_Tp& __arg) const
4664 {
4665 if constexpr (is_same_v<_Tp, monostate>)
4666 __format::__invalid_arg_id_in_format_string();
4667 // _GLIBCXX_RESOLVE_LIB_DEFECTS
4668 // 3720. Restrict the valid types of arg-id for width and precision
4669 // 3721. Allow an arg-id with a value of zero for width
4670 else if constexpr (sizeof(_Tp) <= sizeof(long long))
4671 {
4672 // _GLIBCXX_RESOLVE_LIB_DEFECTS
4673 // 3720. Restrict the valid types of arg-id for width and precision
4674 if constexpr (__is_unsigned_integer<_Tp>::value)
4675 return __arg;
4676 else if constexpr (__is_signed_integer<_Tp>::value)
4677 if (__arg >= 0)
4678 return __arg;
4679 }
4680 __throw_format_error(what: "format error: argument used for width or "
4681 "precision must be a non-negative integer");
4682 }
4683 };
4684
4685#pragma GCC diagnostic push
4686#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
4687 template<typename _Context>
4688 inline size_t
4689 __int_from_arg(const basic_format_arg<_Context>& __arg)
4690 { return __format::__visit_format_arg(_WidthPrecVisitor(), __arg); }
4691
4692 // Pack _Arg_t enum values into a single 60-bit integer.
4693 template<int _Bits, size_t _Nm>
4694 constexpr auto
4695 __pack_arg_types(const array<_Arg_t, _Nm>& __types)
4696 {
4697 __UINT64_TYPE__ __packed_types = 0;
4698 for (auto __i = __types.rbegin(); __i != __types.rend(); ++__i)
4699 __packed_types = (__packed_types << _Bits) | (unsigned)*__i;
4700 return __packed_types;
4701 }
4702} // namespace __format
4703/// @endcond
4704
4705 template<typename _Context>
4706 class basic_format_args
4707 {
4708 static constexpr int _S_packed_type_bits = 5; // _Arg_t values [0,20]
4709 static constexpr int _S_packed_type_mask = 0b11111;
4710 static constexpr int _S_max_packed_args = 12;
4711
4712 static_assert( (unsigned)__format::_Arg_max_ <= (1u << _S_packed_type_bits) );
4713
4714 template<typename... _Args>
4715 using _Store = __format::_Arg_store<_Context, _Args...>;
4716
4717 template<typename _Ctx, typename... _Args>
4718 friend class __format::_Arg_store;
4719
4720 using uint64_t = __UINT64_TYPE__;
4721 using _Format_arg = basic_format_arg<_Context>;
4722 using _Format_arg_val = __format::_Arg_value<_Context>;
4723
4724 // If args are packed then the number of args is in _M_packed_size and
4725 // the packed types are in _M_unpacked_size, accessed via _M_type(i).
4726 // If args are not packed then the number of args is in _M_unpacked_size
4727 // and _M_packed_size is zero.
4728 uint64_t _M_packed_size : 4;
4729 uint64_t _M_unpacked_size : 60;
4730
4731 union {
4732 const _Format_arg_val* _M_values; // Active when _M_packed_size != 0
4733 const _Format_arg* _M_args; // Active when _M_packed_size == 0
4734 };
4735
4736 size_t
4737 _M_size() const noexcept
4738 { return _M_packed_size ? _M_packed_size : _M_unpacked_size; }
4739
4740 typename __format::_Arg_t
4741 _M_type(size_t __i) const noexcept
4742 {
4743 uint64_t __t = _M_unpacked_size >> (__i * _S_packed_type_bits);
4744 return static_cast<__format::_Arg_t>(__t & _S_packed_type_mask);
4745 }
4746
4747 template<typename _Ctx, typename... _Args>
4748 friend auto
4749 make_format_args(_Args&...) noexcept;
4750
4751 // An array of _Arg_t enums corresponding to _Args...
4752 template<typename... _Args>
4753 static consteval array<__format::_Arg_t, sizeof...(_Args)>
4754 _S_types_to_pack()
4755 { return {_Format_arg::template _S_to_enum<_Args>()...}; }
4756
4757 public:
4758 template<typename... _Args>
4759 basic_format_args(const _Store<_Args...>& __store) noexcept;
4760
4761 [[nodiscard,__gnu__::__always_inline__]]
4762 basic_format_arg<_Context>
4763 get(size_t __i) const noexcept
4764 {
4765 basic_format_arg<_Context> __arg;
4766 if (__i < _M_packed_size)
4767 {
4768 __arg._M_type = _M_type(__i);
4769 __arg._M_val = _M_values[__i];
4770 }
4771 else if (_M_packed_size == 0 && __i < _M_unpacked_size)
4772 __arg = _M_args[__i];
4773 return __arg;
4774 }
4775 };
4776
4777 // _GLIBCXX_RESOLVE_LIB_DEFECTS
4778 // 3810. CTAD for std::basic_format_args
4779 template<typename _Context, typename... _Args>
4780 basic_format_args(__format::_Arg_store<_Context, _Args...>)
4781 -> basic_format_args<_Context>;
4782
4783 template<typename _Context, typename... _Args>
4784 auto
4785 make_format_args(_Args&... __fmt_args) noexcept;
4786
4787 // An array of type-erased formatting arguments.
4788 template<typename _Context, typename... _Args>
4789 class __format::_Arg_store
4790 {
4791 friend std::basic_format_args<_Context>;
4792
4793 template<typename _Ctx, typename... _Argz>
4794 friend auto std::
4795#if _GLIBCXX_INLINE_VERSION
4796 __8:: // Needed for PR c++/59256
4797#endif
4798 make_format_args(_Argz&...) noexcept;
4799
4800 // For a sufficiently small number of arguments we only store values.
4801 // basic_format_args can get the types from the _Args pack.
4802 static constexpr bool _S_values_only
4803 = sizeof...(_Args) <= basic_format_args<_Context>::_S_max_packed_args;
4804
4805 using _Element_t
4806 = __conditional_t<_S_values_only,
4807 __format::_Arg_value<_Context>,
4808 basic_format_arg<_Context>>;
4809
4810 _Element_t _M_args[sizeof...(_Args)];
4811
4812 template<typename _Tp>
4813 static _Element_t
4814 _S_make_elt(_Tp& __v)
4815 {
4816 using _Tq = remove_const_t<_Tp>;
4817 using _CharT = typename _Context::char_type;
4818 static_assert(is_default_constructible_v<formatter<_Tq, _CharT>>,
4819 "std::formatter must be specialized for the type "
4820 "of each format arg");
4821 using __format::__formattable_with;
4822 if constexpr (is_const_v<_Tp>)
4823 if constexpr (!__formattable_with<_Tp, _Context>)
4824 if constexpr (__formattable_with<_Tq, _Context>)
4825 static_assert(__formattable_with<_Tp, _Context>,
4826 "format arg must be non-const because its "
4827 "std::formatter specialization has a "
4828 "non-const reference parameter");
4829 basic_format_arg<_Context> __arg(__v);
4830 if constexpr (_S_values_only)
4831 return __arg._M_val;
4832 else
4833 return __arg;
4834 }
4835
4836 template<typename... _Tp>
4837 requires (sizeof...(_Tp) == sizeof...(_Args))
4838 [[__gnu__::__always_inline__]]
4839 _Arg_store(_Tp&... __a) noexcept
4840 : _M_args{_S_make_elt(__a)...}
4841 { }
4842 };
4843
4844 template<typename _Context>
4845 class __format::_Arg_store<_Context>
4846 { };
4847
4848 template<typename _Context>
4849 template<typename... _Args>
4850 inline
4851 basic_format_args<_Context>::
4852 basic_format_args(const _Store<_Args...>& __store) noexcept
4853 {
4854 if constexpr (sizeof...(_Args) == 0)
4855 {
4856 _M_packed_size = 0;
4857 _M_unpacked_size = 0;
4858 _M_args = nullptr;
4859 }
4860 else if constexpr (sizeof...(_Args) <= _S_max_packed_args)
4861 {
4862 // The number of packed arguments:
4863 _M_packed_size = sizeof...(_Args);
4864 // The packed type enums:
4865 _M_unpacked_size
4866 = __format::__pack_arg_types<_S_packed_type_bits>(_S_types_to_pack<_Args...>());
4867 // The _Arg_value objects.
4868 _M_values = __store._M_args;
4869 }
4870 else
4871 {
4872 // No packed arguments:
4873 _M_packed_size = 0;
4874 // The number of unpacked arguments:
4875 _M_unpacked_size = sizeof...(_Args);
4876 // The basic_format_arg objects:
4877 _M_args = __store._M_args;
4878 }
4879 }
4880
4881 /// Capture formatting arguments for use by `std::vformat`.
4882 template<typename _Context = format_context, typename... _Args>
4883 [[nodiscard,__gnu__::__always_inline__]]
4884 inline auto
4885 make_format_args(_Args&... __fmt_args) noexcept
4886 {
4887 using _Fmt_arg = basic_format_arg<_Context>;
4888 using _Store = __format::_Arg_store<_Context, typename _Fmt_arg::template
4889 _Normalize<_Args>...>;
4890 return _Store(__fmt_args...);
4891 }
4892
4893#ifdef _GLIBCXX_USE_WCHAR_T
4894 /// Capture formatting arguments for use by `std::vformat` (for wide output).
4895 template<typename... _Args>
4896 [[nodiscard,__gnu__::__always_inline__]]
4897 inline auto
4898 make_wformat_args(_Args&... __args) noexcept
4899 { return std::make_format_args<wformat_context>(__args...); }
4900#endif
4901
4902/// @cond undocumented
4903namespace __format
4904{
4905 template<typename _Out, typename _CharT, typename _Context>
4906 _Out
4907 __do_vformat_to(_Out, basic_string_view<_CharT>,
4908 const basic_format_args<_Context>&,
4909 const locale* = nullptr);
4910
4911 template<typename _CharT> struct __formatter_chrono;
4912
4913} // namespace __format
4914/// @endcond
4915
4916 /** Context for std::format and similar functions.
4917 *
4918 * A formatting context contains an output iterator and locale to use
4919 * for the formatting operations. Most programs will never need to use
4920 * this class template explicitly. For typical uses of `std::format` the
4921 * library will use the specializations `std::format_context` (for `char`)
4922 * and `std::wformat_context` (for `wchar_t`).
4923 *
4924 * You are not allowed to define partial or explicit specializations of
4925 * this class template.
4926 *
4927 * @since C++20
4928 */
4929 template<typename _Out, typename _CharT>
4930 class basic_format_context
4931 {
4932 static_assert( output_iterator<_Out, const _CharT&> );
4933
4934 basic_format_args<basic_format_context> _M_args;
4935 _Out _M_out;
4936 __format::_Optional_locale _M_loc;
4937
4938 basic_format_context(basic_format_args<basic_format_context> __args,
4939 _Out __out)
4940 : _M_args(__args), _M_out(std::move(__out))
4941 { }
4942
4943 basic_format_context(basic_format_args<basic_format_context> __args,
4944 _Out __out, const std::locale& __loc)
4945 : _M_args(__args), _M_out(std::move(__out)), _M_loc(__loc)
4946 { }
4947
4948 // _GLIBCXX_RESOLVE_LIB_DEFECTS
4949 // 4061. Should std::basic_format_context be
4950 // default-constructible/copyable/movable?
4951 basic_format_context(const basic_format_context&) = delete;
4952 basic_format_context& operator=(const basic_format_context&) = delete;
4953
4954 template<typename _Out2, typename _CharT2, typename _Context2>
4955 friend _Out2
4956 __format::__do_vformat_to(_Out2, basic_string_view<_CharT2>,
4957 const basic_format_args<_Context2>&,
4958 const locale*);
4959
4960 friend __format::__formatter_chrono<_CharT>;
4961
4962 public:
4963 ~basic_format_context() = default;
4964
4965 using iterator = _Out;
4966 using char_type = _CharT;
4967 template<typename _Tp>
4968 using formatter_type = formatter<_Tp, _CharT>;
4969
4970 [[nodiscard]]
4971 basic_format_arg<basic_format_context>
4972 arg(size_t __id) const noexcept
4973 { return _M_args.get(__id); }
4974
4975 [[nodiscard]]
4976 std::locale locale() { return _M_loc.value(); }
4977
4978 [[nodiscard]]
4979 iterator out() { return std::move(_M_out); }
4980
4981 void advance_to(iterator __it) { _M_out = std::move(__it); }
4982 };
4983
4984
4985/// @cond undocumented
4986namespace __format
4987{
4988 // Abstract base class defining an interface for scanning format strings.
4989 // Scan the characters in a format string, dividing it up into strings of
4990 // ordinary characters, escape sequences, and replacement fields.
4991 // Call virtual functions for derived classes to parse format-specifiers
4992 // or write formatted output.
4993 template<typename _CharT>
4994 struct _Scanner
4995 {
4996 using iterator = typename basic_format_parse_context<_CharT>::iterator;
4997
4998 struct _Parse_context : basic_format_parse_context<_CharT>
4999 {
5000 using basic_format_parse_context<_CharT>::basic_format_parse_context;
5001 const _Arg_t* _M_types = nullptr;
5002 } _M_pc;
5003
5004 constexpr explicit
5005 _Scanner(basic_string_view<_CharT> __str, size_t __nargs = (size_t)-1)
5006 : _M_pc(__str, __nargs)
5007 { }
5008
5009 constexpr iterator begin() const noexcept { return _M_pc.begin(); }
5010 constexpr iterator end() const noexcept { return _M_pc.end(); }
5011
5012 constexpr void
5013 _M_scan()
5014 {
5015 basic_string_view<_CharT> __fmt = _M_fmt_str();
5016
5017 if (__fmt.size() == 2 && __fmt[0] == '{' && __fmt[1] == '}')
5018 {
5019 _M_pc.advance_to(begin() + 1);
5020 _M_format_arg(id: _M_pc.next_arg_id());
5021 return;
5022 }
5023
5024 size_t __lbr = __fmt.find('{');
5025 size_t __rbr = __fmt.find('}');
5026
5027 while (__fmt.size())
5028 {
5029 auto __cmp = __lbr <=> __rbr;
5030 if (__cmp == 0)
5031 {
5032 _M_on_chars(end());
5033 _M_pc.advance_to(end());
5034 return;
5035 }
5036 else if (__cmp < 0)
5037 {
5038 if (__lbr + 1 == __fmt.size()
5039 || (__rbr == __fmt.npos && __fmt[__lbr + 1] != '{'))
5040 __format::__unmatched_left_brace_in_format_string();
5041 const bool __is_escape = __fmt[__lbr + 1] == '{';
5042 iterator __last = begin() + __lbr + int(__is_escape);
5043 _M_on_chars(__last);
5044 _M_pc.advance_to(__last + 1);
5045 __fmt = _M_fmt_str();
5046 if (__is_escape)
5047 {
5048 if (__rbr != __fmt.npos)
5049 __rbr -= __lbr + 2;
5050 __lbr = __fmt.find('{');
5051 }
5052 else
5053 {
5054 _M_on_replacement_field();
5055 __fmt = _M_fmt_str();
5056 __lbr = __fmt.find('{');
5057 __rbr = __fmt.find('}');
5058 }
5059 }
5060 else
5061 {
5062 if (++__rbr == __fmt.size() || __fmt[__rbr] != '}')
5063 __format::__unmatched_right_brace_in_format_string();
5064 iterator __last = begin() + __rbr;
5065 _M_on_chars(__last);
5066 _M_pc.advance_to(__last + 1);
5067 __fmt = _M_fmt_str();
5068 if (__lbr != __fmt.npos)
5069 __lbr -= __rbr + 1;
5070 __rbr = __fmt.find('}');
5071 }
5072 }
5073 }
5074
5075 constexpr basic_string_view<_CharT>
5076 _M_fmt_str() const noexcept
5077 { return {begin(), end()}; }
5078
5079 constexpr virtual void _M_on_chars(iterator) { }
5080
5081 constexpr void _M_on_replacement_field()
5082 {
5083 auto __next = begin();
5084
5085 size_t __id;
5086 if (*__next == '}')
5087 __id = _M_pc.next_arg_id();
5088 else if (*__next == ':')
5089 {
5090 __id = _M_pc.next_arg_id();
5091 _M_pc.advance_to(++__next);
5092 }
5093 else
5094 {
5095 auto [__i, __ptr] = __format::__parse_arg_id(begin(), end());
5096 if (!__ptr || !(*__ptr == '}' || *__ptr == ':'))
5097 __format::__invalid_arg_id_in_format_string();
5098 _M_pc.check_arg_id(__id = __i);
5099 if (*__ptr == ':')
5100 {
5101 _M_pc.advance_to(++__ptr);
5102 }
5103 else
5104 _M_pc.advance_to(__ptr);
5105 }
5106 _M_format_arg(__id);
5107 if (begin() == end() || *begin() != '}')
5108 __format::__unmatched_left_brace_in_format_string();
5109 _M_pc.advance_to(begin() + 1); // Move past '}'
5110 }
5111
5112 constexpr virtual void _M_format_arg(size_t __id) = 0;
5113 };
5114
5115 // Process a format string and format the arguments in the context.
5116 template<typename _Out, typename _CharT>
5117 class _Formatting_scanner : public _Scanner<_CharT>
5118 {
5119 public:
5120 _Formatting_scanner(basic_format_context<_Out, _CharT>& __fc,
5121 basic_string_view<_CharT> __str)
5122 : _Scanner<_CharT>(__str), _M_fc(__fc)
5123 { }
5124
5125 private:
5126 basic_format_context<_Out, _CharT>& _M_fc;
5127
5128 using iterator = typename _Scanner<_CharT>::iterator;
5129
5130 constexpr void
5131 _M_on_chars(iterator __last) override
5132 {
5133 basic_string_view<_CharT> __str(this->begin(), __last);
5134 _M_fc.advance_to(__format::__write(_M_fc.out(), __str));
5135 }
5136
5137 constexpr void
5138 _M_format_arg(size_t __id) override
5139 {
5140 using _Context = basic_format_context<_Out, _CharT>;
5141 using handle = typename basic_format_arg<_Context>::handle;
5142
5143 __format::__visit_format_arg([this](auto& __arg) {
5144 using _Type = remove_reference_t<decltype(__arg)>;
5145 using _Formatter = typename _Context::template formatter_type<_Type>;
5146 if constexpr (is_same_v<_Type, monostate>)
5147 __format::__invalid_arg_id_in_format_string();
5148 else if constexpr (is_same_v<_Type, handle>)
5149 __arg.format(this->_M_pc, this->_M_fc);
5150 else if constexpr (is_default_constructible_v<_Formatter>)
5151 {
5152 _Formatter __f;
5153 this->_M_pc.advance_to(__f.parse(this->_M_pc));
5154 this->_M_fc.advance_to(__f.format(__arg, this->_M_fc));
5155 }
5156 else
5157 static_assert(__format::__formattable_with<_Type, _Context>);
5158 }, _M_fc.arg(__id));
5159 }
5160 };
5161
5162 template<typename _CharT, typename _Tp>
5163 consteval _Arg_t
5164 __to_arg_t_enum() noexcept
5165 {
5166 using _Context = __format::__format_context<_CharT>;
5167 using _Fmt_arg = basic_format_arg<_Context>;
5168 using _NormalizedTp = typename _Fmt_arg::template _Normalize<_Tp>;
5169 return _Fmt_arg::template _S_to_enum<_NormalizedTp>();
5170 }
5171
5172 // Validate a format string for Args.
5173 template<typename _CharT, typename... _Args>
5174 class _Checking_scanner : public _Scanner<_CharT>
5175 {
5176 static_assert(
5177 (is_default_constructible_v<formatter<_Args, _CharT>> && ...),
5178 "std::formatter must be specialized for each type being formatted");
5179
5180 public:
5181 consteval
5182 _Checking_scanner(basic_string_view<_CharT> __str)
5183 : _Scanner<_CharT>(__str, sizeof...(_Args))
5184 {
5185#if __cpp_lib_format >= 202305L
5186 this->_M_pc._M_types = _M_types.data();
5187#endif
5188 }
5189
5190 private:
5191 constexpr void
5192 _M_format_arg(size_t __id) override
5193 {
5194 if constexpr (sizeof...(_Args) != 0)
5195 {
5196 if (__id < sizeof...(_Args))
5197 {
5198 _M_parse_format_spec<_Args...>(__id);
5199 return;
5200 }
5201 }
5202 __builtin_unreachable();
5203 }
5204
5205 template<typename _Tp, typename... _OtherArgs>
5206 constexpr void
5207 _M_parse_format_spec(size_t __id)
5208 {
5209 if (__id == 0)
5210 {
5211 formatter<_Tp, _CharT> __f;
5212 this->_M_pc.advance_to(__f.parse(this->_M_pc));
5213 }
5214 else if constexpr (sizeof...(_OtherArgs) != 0)
5215 _M_parse_format_spec<_OtherArgs...>(__id - 1);
5216 else
5217 __builtin_unreachable();
5218 }
5219
5220#if __cpp_lib_format >= 202305L
5221 array<_Arg_t, sizeof...(_Args)>
5222 _M_types{ { __format::__to_arg_t_enum<_CharT, _Args>()... } };
5223#endif
5224 };
5225
5226 template<typename _CharT, unsigned = __unicode::__literal_encoding_is_unicode<_CharT>()>
5227 _Sink_iter<_CharT>
5228 __do_vformat_to(_Sink_iter<_CharT> __out, basic_string_view<_CharT> __fmt,
5229 __format_context<_CharT>& __ctx)
5230 {
5231 if constexpr (is_same_v<_CharT, char>)
5232 // Fast path for "{}" format strings and simple format arg types.
5233 if (__fmt.size() == 2 && __fmt[0] == '{' && __fmt[1] == '}')
5234 {
5235 bool __done = false;
5236 __format::__visit_format_arg([&](auto& __arg) {
5237 using _Tp = remove_cvref_t<decltype(__arg)>;
5238 if constexpr (is_same_v<_Tp, bool>)
5239 {
5240 size_t __len = 4 + !__arg;
5241 const char* __chars[] = { "false", "true" };
5242 if (auto __res = __out._M_reserve(__len))
5243 {
5244 __builtin_memcpy(__res.get(), __chars[__arg], __len);
5245 __res._M_bump(__len);
5246 __done = true;
5247 }
5248 }
5249 else if constexpr (is_same_v<_Tp, char>)
5250 {
5251 if (auto __res = __out._M_reserve(1))
5252 {
5253 *__res.get() = __arg;
5254 __res._M_bump(1);
5255 __done = true;
5256 }
5257 }
5258 else if constexpr (is_integral_v<_Tp>)
5259 {
5260 make_unsigned_t<_Tp> __uval;
5261 const bool __neg = __arg < 0;
5262 if (__neg)
5263 __uval = make_unsigned_t<_Tp>(~__arg) + 1u;
5264 else
5265 __uval = __arg;
5266 const auto __n = __detail::__to_chars_len(__uval);
5267 if (auto __res = __out._M_reserve(__n + __neg))
5268 {
5269 auto __ptr = __res.get();
5270 *__ptr = '-';
5271 __detail::__to_chars_10_impl(__ptr + (int)__neg, __n,
5272 __uval);
5273 __res._M_bump(__n + __neg);
5274 __done = true;
5275 }
5276 }
5277 else if constexpr (is_convertible_v<_Tp, string_view>)
5278 {
5279 string_view __sv = __arg;
5280 if (auto __res = __out._M_reserve(__sv.size()))
5281 {
5282 __builtin_memcpy(__res.get(), __sv.data(), __sv.size());
5283 __res._M_bump(__sv.size());
5284 __done = true;
5285 }
5286 }
5287 }, __ctx.arg(0));
5288
5289 if (__done)
5290 return __out;
5291 }
5292
5293 _Formatting_scanner<_Sink_iter<_CharT>, _CharT> __scanner(__ctx, __fmt);
5294 __scanner._M_scan();
5295 return __out;
5296 }
5297
5298// The behavior of the formatters (interpretation of fill character) depends
5299// on the literal encoding. As explicit instantiation of __do_vformat_to
5300// instantiates formatters for types stored in basic_format_arg, we can
5301// support only single encoding, in this case unicode. This should cover
5302// most common use cases.
5303#if __cplusplus <= 202002L && _GLIBCXX_EXTERN_TEMPLATE > 0
5304 extern template _Sink_iter<char>
5305 __do_vformat_to<char, 1>(_Sink_iter<char>, string_view,
5306 format_context&);
5307# ifdef _GLIBCXX_USE_WCHAR_T
5308 extern template _Sink_iter<wchar_t>
5309 __do_vformat_to<wchar_t, 1>(_Sink_iter<wchar_t>, wstring_view,
5310 wformat_context&);
5311# endif
5312#endif
5313
5314 template<typename _Out, typename _CharT, typename _Context>
5315 inline _Out
5316 __do_vformat_to(_Out __out, basic_string_view<_CharT> __fmt,
5317 const basic_format_args<_Context>& __args,
5318 const locale* __loc)
5319 {
5320 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
5321 {
5322 auto __ctx = __loc == nullptr
5323 ? _Context(__args, __out)
5324 : _Context(__args, __out, *__loc);
5325 return __format::__do_vformat_to(__out, __fmt, __ctx);
5326 }
5327 else if constexpr (__contiguous_char_iter<_CharT, _Out>)
5328 {
5329 _Ptr_sink<_CharT> __sink(__out);
5330 __format::__do_vformat_to(__sink.out(), __fmt, __args, __loc);
5331 return std::move(__sink)._M_finish(__out).out;
5332 }
5333 else
5334 {
5335 _Iter_sink<_CharT, _Out> __sink(std::move(__out));
5336 __format::__do_vformat_to(__sink.out(), __fmt, __args, __loc);
5337 return std::move(__sink)._M_finish().out;
5338 }
5339 }
5340
5341 template<typename _Out, typename _CharT>
5342 inline format_to_n_result<_Out>
5343 __do_vformat_to_n(_Out __out, iter_difference_t<_Out> __n,
5344 basic_string_view<_CharT> __fmt,
5345 const type_identity_t<
5346 basic_format_args<__format_context<_CharT>>>& __args,
5347 const locale* __loc = nullptr)
5348 {
5349 if constexpr (__contiguous_char_iter<_CharT, _Out>)
5350 {
5351 _Ptr_sink<_CharT> __sink(__out, __n);
5352 __format::__do_vformat_to(__sink.out(), __fmt, __args, __loc);
5353 return std::move(__sink)._M_finish(__out);
5354 }
5355 else
5356 {
5357 _Iter_sink<_CharT, _Out> __sink(std::move(__out), __n);
5358 __format::__do_vformat_to(__sink.out(), __fmt, __args, __loc);
5359 return std::move(__sink)._M_finish();
5360 }
5361 }
5362
5363#pragma GCC diagnostic pop
5364
5365} // namespace __format
5366/// @endcond
5367
5368#if __cpp_lib_format >= 202305L // >= C++26
5369 /// @cond undocumented
5370 // Common implementation of check_dynamic_spec{,_string,_integral}
5371 template<typename _CharT>
5372 template<typename... _Ts>
5373 consteval void
5374 basic_format_parse_context<_CharT>::
5375 __check_dynamic_spec(size_t __id) noexcept
5376 {
5377 if (__id >= _M_num_args)
5378 __format::__invalid_arg_id_in_format_string();
5379 if constexpr (sizeof...(_Ts) != 0)
5380 {
5381 using _Parse_ctx = __format::_Scanner<_CharT>::_Parse_context;
5382 auto __arg = static_cast<_Parse_ctx*>(this)->_M_types[__id];
5383 __format::_Arg_t __types[] = {
5384 __format::__to_arg_t_enum<_CharT, _Ts>()...
5385 };
5386 for (auto __t : __types)
5387 if (__arg == __t)
5388 return;
5389 }
5390 __invalid_dynamic_spec("arg(id) type does not match");
5391 }
5392 /// @endcond
5393#endif
5394
5395 template<typename _CharT, typename... _Args>
5396 template<typename _Tp>
5397 requires convertible_to<const _Tp&, basic_string_view<_CharT>>
5398 consteval
5399 basic_format_string<_CharT, _Args...>::
5400 basic_format_string(const _Tp& __s)
5401 : _M_str(__s)
5402 {
5403 __format::_Checking_scanner<_CharT, remove_cvref_t<_Args>...>
5404 __scanner(_M_str);
5405 __scanner._M_scan();
5406 }
5407
5408 // [format.functions], formatting functions
5409
5410 template<typename _Out> requires output_iterator<_Out, const char&>
5411 [[__gnu__::__always_inline__]]
5412 inline _Out
5413 vformat_to(_Out __out, string_view __fmt, format_args __args)
5414 { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
5415
5416#ifdef _GLIBCXX_USE_WCHAR_T
5417 template<typename _Out> requires output_iterator<_Out, const wchar_t&>
5418 [[__gnu__::__always_inline__]]
5419 inline _Out
5420 vformat_to(_Out __out, wstring_view __fmt, wformat_args __args)
5421 { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
5422#endif
5423
5424 template<typename _Out> requires output_iterator<_Out, const char&>
5425 [[__gnu__::__always_inline__]]
5426 inline _Out
5427 vformat_to(_Out __out, const locale& __loc, string_view __fmt,
5428 format_args __args)
5429 {
5430 return __format::__do_vformat_to(std::move(__out), __fmt, __args, &__loc);
5431 }
5432
5433#ifdef _GLIBCXX_USE_WCHAR_T
5434 template<typename _Out> requires output_iterator<_Out, const wchar_t&>
5435 [[__gnu__::__always_inline__]]
5436 inline _Out
5437 vformat_to(_Out __out, const locale& __loc, wstring_view __fmt,
5438 wformat_args __args)
5439 {
5440 return __format::__do_vformat_to(std::move(__out), __fmt, __args, &__loc);
5441 }
5442#endif
5443
5444 [[nodiscard]]
5445 inline string
5446 vformat(string_view __fmt, format_args __args)
5447 {
5448 __format::_Str_sink<char> __buf;
5449 std::vformat_to(out: __buf.out(), __fmt, __args);
5450 return std::move(__buf).get();
5451 }
5452
5453#ifdef _GLIBCXX_USE_WCHAR_T
5454 [[nodiscard]]
5455 inline wstring
5456 vformat(wstring_view __fmt, wformat_args __args)
5457 {
5458 __format::_Str_sink<wchar_t> __buf;
5459 std::vformat_to(out: __buf.out(), __fmt, __args);
5460 return std::move(__buf).get();
5461 }
5462#endif
5463
5464 [[nodiscard]]
5465 inline string
5466 vformat(const locale& __loc, string_view __fmt, format_args __args)
5467 {
5468 __format::_Str_sink<char> __buf;
5469 std::vformat_to(out: __buf.out(), __loc, __fmt, __args);
5470 return std::move(__buf).get();
5471 }
5472
5473#ifdef _GLIBCXX_USE_WCHAR_T
5474 [[nodiscard]]
5475 inline wstring
5476 vformat(const locale& __loc, wstring_view __fmt, wformat_args __args)
5477 {
5478 __format::_Str_sink<wchar_t> __buf;
5479 std::vformat_to(out: __buf.out(), __loc, __fmt, __args);
5480 return std::move(__buf).get();
5481 }
5482#endif
5483
5484 template<typename... _Args>
5485 [[nodiscard]]
5486 inline string
5487 format(format_string<_Args...> __fmt, _Args&&... __args)
5488 { return std::vformat(__fmt.get(), std::make_format_args(__args...)); }
5489
5490#ifdef _GLIBCXX_USE_WCHAR_T
5491 template<typename... _Args>
5492 [[nodiscard]]
5493 inline wstring
5494 format(wformat_string<_Args...> __fmt, _Args&&... __args)
5495 { return std::vformat(__fmt.get(), std::make_wformat_args(__args...)); }
5496#endif
5497
5498 template<typename... _Args>
5499 [[nodiscard]]
5500 inline string
5501 format(const locale& __loc, format_string<_Args...> __fmt,
5502 _Args&&... __args)
5503 {
5504 return std::vformat(__loc, __fmt.get(),
5505 std::make_format_args(__args...));
5506 }
5507
5508#ifdef _GLIBCXX_USE_WCHAR_T
5509 template<typename... _Args>
5510 [[nodiscard]]
5511 inline wstring
5512 format(const locale& __loc, wformat_string<_Args...> __fmt,
5513 _Args&&... __args)
5514 {
5515 return std::vformat(__loc, __fmt.get(),
5516 std::make_wformat_args(__args...));
5517 }
5518#endif
5519
5520 template<typename _Out, typename... _Args>
5521 requires output_iterator<_Out, const char&>
5522 inline _Out
5523 format_to(_Out __out, format_string<_Args...> __fmt, _Args&&... __args)
5524 {
5525 return std::vformat_to(std::move(__out), __fmt.get(),
5526 std::make_format_args(__args...));
5527 }
5528
5529#ifdef _GLIBCXX_USE_WCHAR_T
5530 template<typename _Out, typename... _Args>
5531 requires output_iterator<_Out, const wchar_t&>
5532 inline _Out
5533 format_to(_Out __out, wformat_string<_Args...> __fmt, _Args&&... __args)
5534 {
5535 return std::vformat_to(std::move(__out), __fmt.get(),
5536 std::make_wformat_args(__args...));
5537 }
5538#endif
5539
5540 template<typename _Out, typename... _Args>
5541 requires output_iterator<_Out, const char&>
5542 inline _Out
5543 format_to(_Out __out, const locale& __loc, format_string<_Args...> __fmt,
5544 _Args&&... __args)
5545 {
5546 return std::vformat_to(std::move(__out), __loc, __fmt.get(),
5547 std::make_format_args(__args...));
5548 }
5549
5550#ifdef _GLIBCXX_USE_WCHAR_T
5551 template<typename _Out, typename... _Args>
5552 requires output_iterator<_Out, const wchar_t&>
5553 inline _Out
5554 format_to(_Out __out, const locale& __loc, wformat_string<_Args...> __fmt,
5555 _Args&&... __args)
5556 {
5557 return std::vformat_to(std::move(__out), __loc, __fmt.get(),
5558 std::make_wformat_args(__args...));
5559 }
5560#endif
5561
5562 template<typename _Out, typename... _Args>
5563 requires output_iterator<_Out, const char&>
5564 inline format_to_n_result<_Out>
5565 format_to_n(_Out __out, iter_difference_t<_Out> __n,
5566 format_string<_Args...> __fmt, _Args&&... __args)
5567 {
5568 return __format::__do_vformat_to_n(
5569 std::move(__out), __n, __fmt.get(),
5570 std::make_format_args(__args...));
5571 }
5572
5573#ifdef _GLIBCXX_USE_WCHAR_T
5574 template<typename _Out, typename... _Args>
5575 requires output_iterator<_Out, const wchar_t&>
5576 inline format_to_n_result<_Out>
5577 format_to_n(_Out __out, iter_difference_t<_Out> __n,
5578 wformat_string<_Args...> __fmt, _Args&&... __args)
5579 {
5580 return __format::__do_vformat_to_n(
5581 std::move(__out), __n, __fmt.get(),
5582 std::make_wformat_args(__args...));
5583 }
5584#endif
5585
5586 template<typename _Out, typename... _Args>
5587 requires output_iterator<_Out, const char&>
5588 inline format_to_n_result<_Out>
5589 format_to_n(_Out __out, iter_difference_t<_Out> __n, const locale& __loc,
5590 format_string<_Args...> __fmt, _Args&&... __args)
5591 {
5592 return __format::__do_vformat_to_n(
5593 std::move(__out), __n, __fmt.get(),
5594 std::make_format_args(__args...), &__loc);
5595 }
5596
5597#ifdef _GLIBCXX_USE_WCHAR_T
5598 template<typename _Out, typename... _Args>
5599 requires output_iterator<_Out, const wchar_t&>
5600 inline format_to_n_result<_Out>
5601 format_to_n(_Out __out, iter_difference_t<_Out> __n, const locale& __loc,
5602 wformat_string<_Args...> __fmt, _Args&&... __args)
5603 {
5604 return __format::__do_vformat_to_n(
5605 std::move(__out), __n, __fmt.get(),
5606 std::make_wformat_args(__args...), &__loc);
5607 }
5608#endif
5609
5610/// @cond undocumented
5611namespace __format
5612{
5613#if 1
5614 template<typename _CharT>
5615 class _Counting_sink final : public _Ptr_sink<_CharT>
5616 {
5617 public:
5618 _Counting_sink() : _Ptr_sink<_CharT>(nullptr, 0) { }
5619
5620 [[__gnu__::__always_inline__]]
5621 size_t
5622 count() const
5623 { return this->_M_count + this->_M_used().size(); }
5624 };
5625#else
5626 template<typename _CharT>
5627 class _Counting_sink : public _Buf_sink<_CharT>
5628 {
5629 size_t _M_count = 0;
5630
5631 void
5632 _M_overflow() override
5633 {
5634 if (!std::is_constant_evaluated())
5635 _M_count += this->_M_used().size();
5636 this->_M_rewind();
5637 }
5638
5639 public:
5640 _Counting_sink() = default;
5641
5642 [[__gnu__::__always_inline__]]
5643 size_t
5644 count() noexcept
5645 {
5646 _Counting_sink::_M_overflow();
5647 return _M_count;
5648 }
5649 };
5650#endif
5651} // namespace __format
5652/// @endcond
5653
5654 template<typename... _Args>
5655 [[nodiscard]]
5656 inline size_t
5657 formatted_size(format_string<_Args...> __fmt, _Args&&... __args)
5658 {
5659 __format::_Counting_sink<char> __buf;
5660 std::vformat_to(__buf.out(), __fmt.get(),
5661 std::make_format_args(__args...));
5662 return __buf.count();
5663 }
5664
5665#ifdef _GLIBCXX_USE_WCHAR_T
5666 template<typename... _Args>
5667 [[nodiscard]]
5668 inline size_t
5669 formatted_size(wformat_string<_Args...> __fmt, _Args&&... __args)
5670 {
5671 __format::_Counting_sink<wchar_t> __buf;
5672 std::vformat_to(__buf.out(), __fmt.get(),
5673 std::make_wformat_args(__args...));
5674 return __buf.count();
5675 }
5676#endif
5677
5678 template<typename... _Args>
5679 [[nodiscard]]
5680 inline size_t
5681 formatted_size(const locale& __loc, format_string<_Args...> __fmt,
5682 _Args&&... __args)
5683 {
5684 __format::_Counting_sink<char> __buf;
5685 std::vformat_to(__buf.out(), __loc, __fmt.get(),
5686 std::make_format_args(__args...));
5687 return __buf.count();
5688 }
5689
5690#ifdef _GLIBCXX_USE_WCHAR_T
5691 template<typename... _Args>
5692 [[nodiscard]]
5693 inline size_t
5694 formatted_size(const locale& __loc, wformat_string<_Args...> __fmt,
5695 _Args&&... __args)
5696 {
5697 __format::_Counting_sink<wchar_t> __buf;
5698 std::vformat_to(__buf.out(), __loc, __fmt.get(),
5699 std::make_wformat_args(__args...));
5700 return __buf.count();
5701 }
5702#endif
5703
5704#if __glibcxx_format_ranges // C++ >= 23 && HOSTED
5705 /// @cond undocumented
5706 template<typename _Tp>
5707 consteval range_format
5708 __fmt_kind()
5709 {
5710 using _Ref = ranges::range_reference_t<_Tp>;
5711 if constexpr (is_same_v<remove_cvref_t<_Ref>, _Tp>)
5712 return range_format::disabled;
5713 else if constexpr (requires { typename _Tp::key_type; })
5714 {
5715 if constexpr (requires { typename _Tp::mapped_type; })
5716 {
5717 using _Up = remove_cvref_t<_Ref>;
5718 if constexpr (__is_pair<_Up>)
5719 return range_format::map;
5720 else if constexpr (__is_specialization_of<_Up, tuple>)
5721 if constexpr (tuple_size_v<_Up> == 2)
5722 return range_format::map;
5723 }
5724 return range_format::set;
5725 }
5726 else
5727 return range_format::sequence;
5728 }
5729 /// @endcond
5730
5731 /// A constant determining how a range should be formatted.
5732 template<ranges::input_range _Rg> requires same_as<_Rg, remove_cvref_t<_Rg>>
5733 constexpr range_format format_kind<_Rg> = __fmt_kind<_Rg>();
5734
5735/// @cond undocumented
5736namespace __format
5737{
5738 template<typename _CharT, typename _Out, typename _Callback>
5739 typename basic_format_context<_Out, _CharT>::iterator
5740 __format_padded(basic_format_context<_Out, _CharT>& __fc,
5741 const _Spec<_CharT>& __spec,
5742 _Callback&& __call)
5743 {
5744 if constexpr (is_same_v<_Out, _Drop_iter<_CharT>>)
5745 return __fc.out();
5746 else
5747 {
5748 // This is required to implement formatting with padding,
5749 // as we need to format to temporary buffer, using the same iterator.
5750 static_assert(is_same_v<_Out, _Sink_iter<_CharT>>);
5751
5752 const size_t __padwidth = __spec._M_get_width(__fc);
5753 if (__padwidth == 0)
5754 return __call(__fc);
5755
5756 struct _Restore_out
5757 {
5758 _Restore_out(basic_format_context<_Sink_iter<_CharT>, _CharT>& __fc)
5759 : _M_ctx(std::addressof(__fc)), _M_out(__fc.out())
5760 { }
5761
5762 void
5763 _M_disarm()
5764 { _M_ctx = nullptr; }
5765
5766 ~_Restore_out()
5767 {
5768 if (_M_ctx)
5769 _M_ctx->advance_to(_M_out);
5770 }
5771
5772 private:
5773 basic_format_context<_Sink_iter<_CharT>, _CharT>* _M_ctx;
5774 _Sink_iter<_CharT> _M_out;
5775 };
5776
5777 _Restore_out __restore(__fc);
5778 _Padding_sink<_Sink_iter<_CharT>, _CharT> __sink(__fc.out(), __padwidth);
5779 __fc.advance_to(__sink.out());
5780 __call(__fc);
5781 __fc.advance_to(__sink._M_finish(__spec._M_align, __spec._M_fill));
5782 __restore._M_disarm();
5783 return __fc.out();
5784 }
5785 }
5786
5787 template<size_t _Pos, typename _Tp, typename _CharT>
5788 struct __indexed_formatter_storage
5789 {
5790 constexpr void
5791 _M_parse()
5792 {
5793 basic_format_parse_context<_CharT> __pc({});
5794 if (_M_formatter.parse(__pc) != __pc.end())
5795 __format::__failed_to_parse_format_spec();
5796 }
5797
5798 template<typename _Out>
5799 void
5800 _M_format(__maybe_const<_Tp, _CharT>& __elem,
5801 basic_format_context<_Out, _CharT>& __fc,
5802 basic_string_view<_CharT> __sep) const
5803 {
5804 if constexpr (_Pos != 0)
5805 __fc.advance_to(__format::__write(__fc.out(), __sep));
5806 __fc.advance_to(_M_formatter.format(__elem, __fc));
5807 }
5808
5809 [[__gnu__::__always_inline__]]
5810 constexpr void
5811 set_debug_format()
5812 {
5813 if constexpr (__has_debug_format<formatter<_Tp, _CharT>>)
5814 _M_formatter.set_debug_format();
5815 }
5816
5817 private:
5818 formatter<_Tp, _CharT> _M_formatter;
5819 };
5820
5821 template<typename _CharT, typename... _Tps>
5822 class __tuple_formatter
5823 {
5824 using _String_view = basic_string_view<_CharT>;
5825 using _Seps = __format::_Separators<_CharT>;
5826
5827 public:
5828 constexpr void
5829 set_separator(basic_string_view<_CharT> __sep) noexcept
5830 { _M_sep = __sep; }
5831
5832 constexpr void
5833 set_brackets(basic_string_view<_CharT> __open,
5834 basic_string_view<_CharT> __close) noexcept
5835 {
5836 _M_open = __open;
5837 _M_close = __close;
5838 }
5839
5840 // We deviate from standard, that declares this as template accepting
5841 // unconstrained ParseContext type, which seems unimplementable.
5842 constexpr typename basic_format_parse_context<_CharT>::iterator
5843 parse(basic_format_parse_context<_CharT>& __pc)
5844 {
5845 auto __first = __pc.begin();
5846 const auto __last = __pc.end();
5847 __format::_Spec<_CharT> __spec{};
5848
5849 auto __finished = [&]
5850 {
5851 if (__first != __last && *__first != '}')
5852 return false;
5853
5854 _M_spec = __spec;
5855 _M_felems._M_parse();
5856 _M_felems.set_debug_format();
5857 return true;
5858 };
5859
5860 if (__finished())
5861 return __first;
5862
5863 __first = __spec._M_parse_fill_and_align(__first, __last, "{:");
5864 if (__finished())
5865 return __first;
5866
5867 __first = __spec._M_parse_width(__first, __last, __pc);
5868 if (__finished())
5869 return __first;
5870
5871 if (*__first == 'n')
5872 {
5873 ++__first;
5874 _M_open = _M_close = _String_view();
5875 }
5876 else if (*__first == 'm')
5877 {
5878 ++__first;
5879 if constexpr (sizeof...(_Tps) == 2)
5880 {
5881 _M_sep = _Seps::_S_colon();
5882 _M_open = _M_close = _String_view();
5883 }
5884 else
5885 __throw_format_error("format error: 'm' specifier requires range"
5886 " of pair or tuple of two elements");
5887 }
5888
5889 if (__finished())
5890 return __first;
5891
5892 __format::__failed_to_parse_format_spec();
5893 }
5894
5895 protected:
5896 template<typename _Tuple, typename _Out, size_t... _Ids>
5897 typename basic_format_context<_Out, _CharT>::iterator
5898 _M_format(_Tuple& __tuple, index_sequence<_Ids...>,
5899 basic_format_context<_Out, _CharT>& __fc) const
5900 { return _M_format_elems(std::get<_Ids>(__tuple)..., __fc); }
5901
5902 template<typename _Out>
5903 typename basic_format_context<_Out, _CharT>::iterator
5904 _M_format_elems(__maybe_const<_Tps, _CharT>&... __elems,
5905 basic_format_context<_Out, _CharT>& __fc) const
5906 {
5907 return __format::__format_padded(
5908 __fc, _M_spec,
5909 [this, &__elems...](basic_format_context<_Out, _CharT>& __nfc)
5910 {
5911 __nfc.advance_to(__format::__write(__nfc.out(), _M_open));
5912 _M_felems._M_format(__elems..., __nfc, _M_sep);
5913 return __format::__write(__nfc.out(), _M_close);
5914 });
5915 }
5916
5917 private:
5918 template<size_t... _Ids>
5919 struct __formatters_storage
5920 : __indexed_formatter_storage<_Ids, _Tps, _CharT>...
5921 {
5922 template<size_t _Id, typename _Up>
5923 using _Base = __indexed_formatter_storage<_Id, _Up, _CharT>;
5924
5925 constexpr void
5926 _M_parse()
5927 {
5928 (_Base<_Ids, _Tps>::_M_parse(), ...);
5929 }
5930
5931 template<typename _Out>
5932 void
5933 _M_format(__maybe_const<_Tps, _CharT>&... __elems,
5934 basic_format_context<_Out, _CharT>& __fc,
5935 _String_view __sep) const
5936 {
5937 (_Base<_Ids, _Tps>::_M_format(__elems, __fc, __sep), ...);
5938 }
5939
5940 constexpr void
5941 set_debug_format()
5942 {
5943 (_Base<_Ids, _Tps>::set_debug_format(), ...);
5944 }
5945 };
5946
5947 template<size_t... _Ids>
5948 static auto
5949 _S_create_storage(index_sequence<_Ids...>)
5950 -> __formatters_storage<_Ids...>;
5951 using _Formatters
5952 = decltype(_S_create_storage(index_sequence_for<_Tps...>()));
5953
5954 _Spec<_CharT> _M_spec{};
5955 _String_view _M_open = _Seps::_S_parens().substr(0, 1);
5956 _String_view _M_close = _Seps::_S_parens().substr(1, 1);
5957 _String_view _M_sep = _Seps::_S_comma();
5958 _Formatters _M_felems;
5959 };
5960
5961 template<typename _Tp>
5962 concept __is_map_formattable
5963 = __is_pair<_Tp> || (__is_tuple_v<_Tp> && tuple_size_v<_Tp> == 2);
5964
5965} // namespace __format
5966/// @endcond
5967
5968 // [format.tuple] Tuple formatter
5969 template<__format::__char _CharT, formattable<_CharT> _Fp,
5970 formattable<_CharT> _Sp>
5971 struct formatter<pair<_Fp, _Sp>, _CharT>
5972 : __format::__tuple_formatter<_CharT, remove_cvref_t<_Fp>,
5973 remove_cvref_t<_Sp>>
5974 {
5975 private:
5976 using __maybe_const_pair
5977 = __conditional_t<formattable<const _Fp, _CharT>
5978 && formattable<const _Sp, _CharT>,
5979 const pair<_Fp, _Sp>, pair<_Fp, _Sp>>;
5980 public:
5981 // We deviate from standard, that declares this as template accepting
5982 // unconstrained FormatContext type, which seems unimplementable.
5983 template<typename _Out>
5984 typename basic_format_context<_Out, _CharT>::iterator
5985 format(__maybe_const_pair& __p,
5986 basic_format_context<_Out, _CharT>& __fc) const
5987 { return this->_M_format_elems(__p.first, __p.second, __fc); }
5988 };
5989
5990#if __glibcxx_print >= 202406L
5991 // _GLIBCXX_RESOLVE_LIB_DEFECTS
5992 // 4399. enable_nonlocking_formatter_optimization for pair and tuple needs remove_cvref_t
5993 template<typename _Fp, typename _Sp>
5994 constexpr bool enable_nonlocking_formatter_optimization<pair<_Fp, _Sp>>
5995 = enable_nonlocking_formatter_optimization<remove_cvref_t<_Fp>>
5996 && enable_nonlocking_formatter_optimization<remove_cvref_t<_Sp>>;
5997#endif
5998
5999 template<__format::__char _CharT, formattable<_CharT>... _Tps>
6000 struct formatter<tuple<_Tps...>, _CharT>
6001 : __format::__tuple_formatter<_CharT, remove_cvref_t<_Tps>...>
6002 {
6003 private:
6004 using __maybe_const_tuple
6005 = __conditional_t<(formattable<const _Tps, _CharT> && ...),
6006 const tuple<_Tps...>, tuple<_Tps...>>;
6007 public:
6008 // We deviate from standard, that declares this as template accepting
6009 // unconstrained FormatContext type, which seems unimplementable.
6010 template<typename _Out>
6011 typename basic_format_context<_Out, _CharT>::iterator
6012 format(__maybe_const_tuple& __t,
6013 basic_format_context<_Out, _CharT>& __fc) const
6014 { return this->_M_format(__t, index_sequence_for<_Tps...>(), __fc); }
6015 };
6016
6017#if __glibcxx_print >= 202406L
6018 // _GLIBCXX_RESOLVE_LIB_DEFECTS
6019 // 4399. enable_nonlocking_formatter_optimization for pair and tuple needs remove_cvref_t
6020 template<typename... _Tps>
6021 constexpr bool enable_nonlocking_formatter_optimization<tuple<_Tps...>>
6022 = (enable_nonlocking_formatter_optimization<remove_cvref_t<_Tps>> && ...);
6023#endif
6024
6025 // [format.range.formatter], class template range_formatter
6026 template<typename _Tp, __format::__char _CharT>
6027 requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT>
6028 class range_formatter
6029 {
6030 using _String_view = basic_string_view<_CharT>;
6031 using _Seps = __format::_Separators<_CharT>;
6032
6033 public:
6034 constexpr void
6035 set_separator(basic_string_view<_CharT> __sep) noexcept
6036 { _M_sep = __sep; }
6037
6038 constexpr void
6039 set_brackets(basic_string_view<_CharT> __open,
6040 basic_string_view<_CharT> __close) noexcept
6041 {
6042 _M_open = __open;
6043 _M_close = __close;
6044 }
6045
6046 constexpr formatter<_Tp, _CharT>&
6047 underlying() noexcept
6048 { return _M_fval; }
6049
6050 constexpr const formatter<_Tp, _CharT>&
6051 underlying() const noexcept
6052 { return _M_fval; }
6053
6054 // We deviate from standard, that declares this as template accepting
6055 // unconstrained ParseContext type, which seems unimplementable.
6056 constexpr typename basic_format_parse_context<_CharT>::iterator
6057 parse(basic_format_parse_context<_CharT>& __pc)
6058 {
6059 auto __first = __pc.begin();
6060 const auto __last = __pc.end();
6061 __format::_Spec<_CharT> __spec{};
6062 bool __no_brace = false;
6063
6064 auto __finished = [&]
6065 { return __first == __last || *__first == '}'; };
6066
6067 auto __finalize = [&]
6068 {
6069 _M_spec = __spec;
6070 return __first;
6071 };
6072
6073 auto __parse_val = [&](_String_view __nfs = _String_view())
6074 {
6075 basic_format_parse_context<_CharT> __npc(__nfs);
6076 if (_M_fval.parse(__npc) != __npc.end())
6077 __format::__failed_to_parse_format_spec();
6078 if constexpr (__format::__has_debug_format<formatter<_Tp, _CharT>>)
6079 _M_fval.set_debug_format();
6080 return __finalize();
6081 };
6082
6083 if (__finished())
6084 return __parse_val();
6085
6086 __first = __spec._M_parse_fill_and_align(__first, __last, "{:");
6087 if (__finished())
6088 return __parse_val();
6089
6090 __first = __spec._M_parse_width(__first, __last, __pc);
6091 if (__finished())
6092 return __parse_val();
6093
6094 if (*__first == '?')
6095 {
6096 ++__first;
6097 __spec._M_debug = true;
6098 if (__finished() || *__first != 's')
6099 __throw_format_error("format error: '?' is allowed only in"
6100 " combination with 's'");
6101 }
6102
6103 if (*__first == 's')
6104 {
6105 ++__first;
6106 if constexpr (same_as<_Tp, _CharT>)
6107 {
6108 __spec._M_type = __format::_Pres_s;
6109 if (__finished())
6110 return __finalize();
6111 __throw_format_error("format error: element format specifier"
6112 " cannot be provided when 's' specifier is used");
6113 }
6114 else
6115 __throw_format_error("format error: 's' specifier requires"
6116 " range of character types");
6117 }
6118
6119 if (__finished())
6120 return __parse_val();
6121
6122 if (*__first == 'n')
6123 {
6124 ++__first;
6125 _M_open = _M_close = _String_view();
6126 __no_brace = true;
6127 }
6128
6129 if (__finished())
6130 return __parse_val();
6131
6132 if (*__first == 'm')
6133 {
6134 _String_view __m(__first, 1);
6135 ++__first;
6136 if constexpr (__format::__is_map_formattable<_Tp>)
6137 {
6138 _M_sep = _Seps::_S_comma();
6139 if (!__no_brace)
6140 {
6141 _M_open = _Seps::_S_braces().substr(0, 1);
6142 _M_close = _Seps::_S_braces().substr(1, 1);
6143 }
6144 if (__finished())
6145 return __parse_val(__m);
6146 __throw_format_error("format error: element format specifier"
6147 " cannot be provided when 'm' specifier is used");
6148 }
6149 else
6150 __throw_format_error("format error: 'm' specifier requires"
6151 " range of pairs or tuples of two elements");
6152 }
6153
6154 if (__finished())
6155 return __parse_val();
6156
6157 if (*__first == ':')
6158 {
6159 __pc.advance_to(++__first);
6160 __first = _M_fval.parse(__pc);
6161 }
6162
6163 if (__finished())
6164 return __finalize();
6165
6166 __format::__failed_to_parse_format_spec();
6167 }
6168
6169 // We deviate from standard, that declares this as template accepting
6170 // unconstrained FormatContext type, which seems unimplementable.
6171 template<ranges::input_range _Rg, typename _Out>
6172 requires formattable<ranges::range_reference_t<_Rg>, _CharT> &&
6173 same_as<remove_cvref_t<ranges::range_reference_t<_Rg>>, _Tp>
6174 typename basic_format_context<_Out, _CharT>::iterator
6175 format(_Rg&& __rg, basic_format_context<_Out, _CharT>& __fc) const
6176 {
6177 using _Range = remove_reference_t<_Rg>;
6178 if constexpr (__format::__simply_formattable_range<_Range, _CharT>)
6179 return _M_format<const _Range>(__rg, __fc);
6180 else
6181 return _M_format(__rg, __fc);
6182 }
6183
6184 private:
6185 template<ranges::input_range _Rg, typename _Out>
6186 typename basic_format_context<_Out, _CharT>::iterator
6187 _M_format(_Rg& __rg, basic_format_context<_Out, _CharT>& __fc) const
6188 {
6189 if constexpr (same_as<_Tp, _CharT>)
6190 if (_M_spec._M_type == __format::_Pres_s)
6191 {
6192 __format::__formatter_str __fstr(_M_spec);
6193 return __fstr._M_format_range(__rg, __fc);
6194 }
6195 return __format::__format_padded(
6196 __fc, _M_spec,
6197 [this, &__rg](basic_format_context<_Out, _CharT>& __nfc)
6198 { return _M_format_elems(__rg, __nfc); });
6199 }
6200
6201
6202 template<ranges::input_range _Rg, typename _Out>
6203 typename basic_format_context<_Out, _CharT>::iterator
6204 _M_format_elems(_Rg& __rg,
6205 basic_format_context<_Out, _CharT>& __fc) const
6206 {
6207 auto __out = __format::__write(__fc.out(), _M_open);
6208
6209 auto __first = ranges::begin(__rg);
6210 auto const __last = ranges::end(__rg);
6211 if (__first == __last)
6212 return __format::__write(__out, _M_close);
6213
6214 __fc.advance_to(__out);
6215 __out = _M_fval.format(*__first, __fc);
6216 for (++__first; __first != __last; ++__first)
6217 {
6218 __out = __format::__write(__out, _M_sep);
6219 __fc.advance_to(__out);
6220 __out = _M_fval.format(*__first, __fc);
6221 }
6222
6223 return __format::__write(__out, _M_close);
6224 }
6225
6226 __format::_Spec<_CharT> _M_spec{};
6227 _String_view _M_open = _Seps::_S_squares().substr(0, 1);
6228 _String_view _M_close = _Seps::_S_squares().substr(1, 1);
6229 _String_view _M_sep = _Seps::_S_comma();
6230 formatter<_Tp, _CharT> _M_fval;
6231 };
6232
6233 // In standard this is shown as inheriting from specialization of
6234 // exposition only specialization for range-default-formatter for
6235 // each range_format. We opt for simpler implementation.
6236 // [format.range.fmtmap], [format.range.fmtset], [format.range.fmtstr],
6237 // specializations for maps, sets, and strings
6238 template<ranges::input_range _Rg, __format::__char _CharT>
6239 requires (format_kind<_Rg> != range_format::disabled)
6240 && formattable<ranges::range_reference_t<_Rg>, _CharT>
6241 struct formatter<_Rg, _CharT>
6242 {
6243 private:
6244 static const bool _S_range_format_is_string =
6245 (format_kind<_Rg> == range_format::string)
6246 || (format_kind<_Rg> == range_format::debug_string);
6247 using _Vt = remove_cvref_t<
6248 ranges::range_reference_t<
6249 __format::__maybe_const_range<_Rg, _CharT>>>;
6250
6251 static consteval bool _S_is_correct()
6252 {
6253 if constexpr (_S_range_format_is_string)
6254 static_assert(same_as<_Vt, _CharT>);
6255 return true;
6256 }
6257
6258 static_assert(_S_is_correct());
6259
6260 public:
6261 constexpr formatter() noexcept
6262 {
6263 using _Seps = __format::_Separators<_CharT>;
6264 if constexpr (format_kind<_Rg> == range_format::map)
6265 {
6266 static_assert(__format::__is_map_formattable<_Vt>);
6267 _M_under.set_brackets(_Seps::_S_braces().substr(0, 1),
6268 _Seps::_S_braces().substr(1, 1));
6269 _M_under.underlying().set_brackets({}, {});
6270 _M_under.underlying().set_separator(_Seps::_S_colon());
6271 }
6272 else if constexpr (format_kind<_Rg> == range_format::set)
6273 _M_under.set_brackets(_Seps::_S_braces().substr(0, 1),
6274 _Seps::_S_braces().substr(1, 1));
6275 }
6276
6277 constexpr void
6278 set_separator(basic_string_view<_CharT> __sep) noexcept
6279 requires (format_kind<_Rg> == range_format::sequence)
6280 { _M_under.set_separator(__sep); }
6281
6282 constexpr void
6283 set_brackets(basic_string_view<_CharT> __open,
6284 basic_string_view<_CharT> __close) noexcept
6285 requires (format_kind<_Rg> == range_format::sequence)
6286 { _M_under.set_brackets(__open, __close); }
6287
6288 // We deviate from standard, that declares this as template accepting
6289 // unconstrained ParseContext type, which seems unimplementable.
6290 constexpr typename basic_format_parse_context<_CharT>::iterator
6291 parse(basic_format_parse_context<_CharT>& __pc)
6292 {
6293 auto __res = _M_under.parse(__pc);
6294 if constexpr (format_kind<_Rg> == range_format::debug_string)
6295 _M_under.set_debug_format();
6296 return __res;
6297 }
6298
6299 // We deviate from standard, that declares this as template accepting
6300 // unconstrained FormatContext type, which seems unimplementable.
6301 template<typename _Out>
6302 typename basic_format_context<_Out, _CharT>::iterator
6303 format(__format::__maybe_const_range<_Rg, _CharT>& __rg,
6304 basic_format_context<_Out, _CharT>& __fc) const
6305 {
6306 if constexpr (_S_range_format_is_string)
6307 return _M_under._M_format_range(__rg, __fc);
6308 else
6309 return _M_under.format(__rg, __fc);
6310 }
6311
6312 private:
6313 using _Formatter_under
6314 = __conditional_t<_S_range_format_is_string,
6315 __format::__formatter_str<_CharT>,
6316 range_formatter<_Vt, _CharT>>;
6317 _Formatter_under _M_under;
6318 };
6319
6320#if __glibcxx_print >= 202406L
6321 template<ranges::input_range _Rg>
6322 requires (format_kind<_Rg> != range_format::disabled)
6323 constexpr bool enable_nonlocking_formatter_optimization<_Rg> = false;
6324#endif
6325
6326#endif // C++23 formatting ranges
6327#undef _GLIBCXX_WIDEN
6328
6329_GLIBCXX_END_NAMESPACE_VERSION
6330} // namespace std
6331#endif // __cpp_lib_format
6332#pragma GCC diagnostic pop
6333#endif // _GLIBCXX_FORMAT
6334