| blob | 8ec1c8a0b9a75548d3900e2c4258e5fb698b7778 |
1 // <format> Formatting -*- C++ -*-
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.
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.
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.
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/>.
25 /** @file include/format
26 * This is a Standard C++ Library header.
27 */
29 #ifndef _GLIBCXX_FORMAT
30 #define _GLIBCXX_FORMAT 1
32 #pragma GCC system_header
34 #include <bits/requires_hosted.h> // for std::string
36 #define __glibcxx_want_format
37 #define __glibcxx_want_format_ranges
38 #include <bits/version.h>
40 #ifdef __cpp_lib_format // C++ >= 20 && HOSTED
42 #include <array>
43 #include <charconv>
44 #include <concepts>
45 #include <limits>
46 #include <locale>
47 #include <optional>
48 #include <span>
49 #include <string_view>
50 #include <string>
51 #include <variant> // monostate (TODO: move to bits/utility.h?)
52 #include <bits/ranges_base.h> // input_range, range_reference_t
53 #include <bits/ranges_algobase.h> // ranges::copy
54 #include <bits/stl_iterator.h> // back_insert_iterator
55 #include <bits/stl_pair.h> // __is_pair
56 #include <bits/utility.h> // tuple_size_v
57 #include <ext/numeric_traits.h> // __int_traits
59 #if !__has_builtin(__builtin_toupper)
60 # include <cctype>
61 #endif
63 namespace std _GLIBCXX_VISIBILITY(default)
64 {
65 _GLIBCXX_BEGIN_NAMESPACE_VERSION
67 // [format.context], class template basic_format_context
68 template<typename _Out, typename _CharT> class basic_format_context;
70 /// @cond undocumented
71 namespace __format
72 {
73 // Type-erased character sink.
74 template<typename _CharT> class _Sink;
75 // Output iterator that writes to a type-erase character sink.
76 template<typename _CharT>
77 class _Sink_iter;
79 template<typename _CharT>
80 using __format_context = basic_format_context<_Sink_iter<_CharT>, _CharT>;
81 } // namespace __format
82 /// @endcond
84 using format_context = __format::__format_context<char>;
85 #ifdef _GLIBCXX_USE_WCHAR_T
86 using wformat_context = __format::__format_context<wchar_t>;
87 #endif
89 // [format.args], class template basic_format_args
90 template<typename _Context> class basic_format_args;
91 using format_args = basic_format_args<format_context>;
92 #ifdef _GLIBCXX_USE_WCHAR_T
93 using wformat_args = basic_format_args<wformat_context>;
94 #endif
96 // [format.arguments], arguments
97 // [format.arg], class template basic_format_arg
98 template<typename _Context>
99 class basic_format_arg;
101 // [format.fmt.string], class template basic_format_string
103 /** A compile-time checked format string for the specified argument types.
104 *
105 * @since C++23 but available as an extension in C++20.
106 */
107 template<typename _CharT, typename... _Args>
108 struct basic_format_string
109 {
110 template<typename _Tp>
111 requires convertible_to<const _Tp&, basic_string_view<_CharT>>
112 consteval
113 basic_format_string(const _Tp& __s);
115 [[__gnu__::__always_inline__]]
116 constexpr basic_string_view<_CharT>
117 get() const noexcept
118 { return _M_str; }
120 private:
121 basic_string_view<_CharT> _M_str;
122 };
124 template<typename... _Args>
125 using format_string = basic_format_string<char, type_identity_t<_Args>...>;
127 #ifdef _GLIBCXX_USE_WCHAR_T
128 template<typename... _Args>
129 using wformat_string
130 = basic_format_string<wchar_t, type_identity_t<_Args>...>;
131 #endif
133 // [format.formatter], formatter
135 /// The primary template of std::formatter is disabled.
136 template<typename _Tp, typename _CharT = char>
137 struct formatter
138 {
139 formatter() = delete; // No std::formatter specialization for this type.
140 formatter(const formatter&) = delete;
141 formatter& operator=(const formatter&) = delete;
142 };
144 // [format.error], class format_error
145 class format_error : public runtime_error
146 {
147 public:
148 explicit format_error(const string& __what) : runtime_error(__what) { }
149 explicit format_error(const char* __what) : runtime_error(__what) { }
150 };
152 /// @cond undocumented
153 [[noreturn]]
154 inline void
155 __throw_format_error(const char* __what)
156 { _GLIBCXX_THROW_OR_ABORT(format_error(__what)); }
158 namespace __format
159 {
160 // XXX use named functions for each constexpr error?
162 [[noreturn]]
163 inline void
164 __unmatched_left_brace_in_format_string()
165 { __throw_format_error("format error: unmatched '{' in format string"); }
167 [[noreturn]]
168 inline void
169 __unmatched_right_brace_in_format_string()
170 { __throw_format_error("format error: unmatched '}' in format string"); }
172 [[noreturn]]
173 inline void
174 __conflicting_indexing_in_format_string()
175 { __throw_format_error("format error: conflicting indexing style in format string"); }
177 [[noreturn]]
178 inline void
179 __invalid_arg_id_in_format_string()
180 { __throw_format_error("format error: invalid arg-id in format string"); }
182 [[noreturn]]
183 inline void
184 __failed_to_parse_format_spec()
185 { __throw_format_error("format error: failed to parse format-spec"); }
186 } // namespace __format
187 /// @endcond
189 // [format.parse.ctx], class template basic_format_parse_context
190 template<typename _CharT> class basic_format_parse_context;
191 using format_parse_context = basic_format_parse_context<char>;
192 #ifdef _GLIBCXX_USE_WCHAR_T
193 using wformat_parse_context = basic_format_parse_context<wchar_t>;
194 #endif
196 template<typename _CharT>
197 class basic_format_parse_context
198 {
199 public:
200 using char_type = _CharT;
201 using const_iterator = typename basic_string_view<_CharT>::const_iterator;
202 using iterator = const_iterator;
204 constexpr explicit
205 basic_format_parse_context(basic_string_view<_CharT> __fmt,
206 size_t __num_args = 0) noexcept
207 : _M_begin(__fmt.begin()), _M_end(__fmt.end()), _M_num_args(__num_args)
208 { }
210 basic_format_parse_context(const basic_format_parse_context&) = delete;
211 void operator=(const basic_format_parse_context&) = delete;
213 constexpr const_iterator begin() const noexcept { return _M_begin; }
214 constexpr const_iterator end() const noexcept { return _M_end; }
216 constexpr void
217 advance_to(const_iterator __it) noexcept
218 { _M_begin = __it; }
220 constexpr size_t
221 next_arg_id()
222 {
223 if (_M_indexing == _Manual)
224 __format::__conflicting_indexing_in_format_string();
225 _M_indexing = _Auto;
227 // _GLIBCXX_RESOLVE_LIB_DEFECTS
228 // 3825. Missing compile-time argument id check in next_arg_id
229 if (std::is_constant_evaluated())
230 if (_M_next_arg_id == _M_num_args)
231 __format::__invalid_arg_id_in_format_string();
232 return _M_next_arg_id++;
233 }
235 constexpr void
236 check_arg_id(size_t __id)
237 {
238 if (_M_indexing == _Auto)
239 __format::__conflicting_indexing_in_format_string();
240 _M_indexing = _Manual;
242 if (std::is_constant_evaluated())
243 if (__id >= _M_num_args)
244 __format::__invalid_arg_id_in_format_string();
245 }
247 private:
248 iterator _M_begin;
249 iterator _M_end;
250 enum _Indexing { _Unknown, _Manual, _Auto };
251 _Indexing _M_indexing = _Unknown;
252 size_t _M_next_arg_id = 0;
253 size_t _M_num_args;
254 };
256 /// @cond undocumented
257 template<typename _Tp, template<typename...> class _Class>
258 static constexpr bool __is_specialization_of = false;
259 template<template<typename...> class _Class, typename... _Args>
260 static constexpr bool __is_specialization_of<_Class<_Args...>, _Class>
261 = true;
263 namespace __format
264 {
265 // pre: first != last
266 template<typename _CharT>
267 constexpr pair<unsigned short, const _CharT*>
268 __parse_integer(const _CharT* __first, const _CharT* __last)
269 {
270 if (__first == __last)
271 __builtin_unreachable();
273 if constexpr (is_same_v<_CharT, char>)
274 {
275 const auto __start = __first;
276 unsigned short __val = 0;
277 // N.B. std::from_chars is not constexpr in C++20.
278 if (__detail::__from_chars_alnum<true>(__first, __last, __val, 10)
279 && __first != __start) [[likely]]
280 return {__val, __first};
281 }
282 else
283 {
284 constexpr int __n = 32;
285 char __buf[__n]{};
286 for (int __i = 0; __i < __n && (__first + __i) != __last; ++__i)
287 __buf[__i] = __first[__i];
288 auto [__v, __ptr] = __format::__parse_integer(__buf, __buf + __n);
289 if (__ptr) [[likely]]
290 return {__v, __first + (__ptr - __buf)};
291 }
292 return {0, nullptr};
293 }
295 template<typename _CharT>
296 constexpr pair<unsigned short, const _CharT*>
297 __parse_arg_id(const _CharT* __first, const _CharT* __last)
298 {
299 if (__first == __last)
300 __builtin_unreachable();
302 if (*__first == '0')
303 return {0, __first + 1}; // No leading zeros allowed, so '0...' == 0
305 if ('1' <= *__first && *__first <= '9')
306 {
307 const unsigned short __id = *__first - '0';
308 const auto __next = __first + 1;
309 // Optimize for most likely case of single digit arg-id.
310 if (__next == __last || !('0' <= *__next && *__next <= '9'))
311 return {__id, __next};
312 else
313 return __format::__parse_integer(__first, __last);
314 }
315 return {0, nullptr};
316 }
318 enum _Pres_type {
319 _Pres_none = 0, // Default type (not valid for integer presentation types).
320 // Presentation types for integral types (including bool and charT).
321 _Pres_d = 1, _Pres_b, _Pres_B, _Pres_o, _Pres_x, _Pres_X, _Pres_c,
322 // Presentation types for floating-point types.
323 _Pres_a = 1, _Pres_A, _Pres_e, _Pres_E, _Pres_f, _Pres_F, _Pres_g, _Pres_G,
324 _Pres_p = 0, _Pres_P, // For pointers.
325 _Pres_s = 0, // For strings and bool.
326 _Pres_esc = 0xf, // For strings and charT.
327 };
329 enum _Align {
330 _Align_default,
331 _Align_left,
332 _Align_right,
333 _Align_centre,
334 };
336 enum _Sign {
337 _Sign_default,
338 _Sign_plus,
339 _Sign_minus, // XXX does this need to be distinct from _Sign_default?
340 _Sign_space,
341 };
343 enum _WidthPrec {
344 _WP_none, // No width/prec specified.
345 _WP_value, // Fixed width/prec specified.
346 _WP_from_arg // Use a formatting argument for width/prec.
347 };
349 template<typename _Context>
350 size_t
351 __int_from_arg(const basic_format_arg<_Context>& __arg);
353 constexpr bool __is_digit(char __c)
354 { return std::__detail::__from_chars_alnum_to_val(__c) < 10; }
356 constexpr bool __is_xdigit(char __c)
357 { return std::__detail::__from_chars_alnum_to_val(__c) < 16; }
359 template<typename _CharT>
360 struct _Spec
361 {
362 _Align _M_align : 2;
363 _Sign _M_sign : 2;
364 unsigned _M_alt : 1;
365 unsigned _M_localized : 1;
366 unsigned _M_zero_fill : 1;
367 _WidthPrec _M_width_kind : 2;
368 _WidthPrec _M_prec_kind : 2;
369 _Pres_type _M_type : 4;
370 unsigned short _M_width;
371 unsigned short _M_prec;
372 _CharT _M_fill = ' ';
374 using iterator = typename basic_string_view<_CharT>::iterator;
376 static constexpr _Align
377 _S_align(_CharT __c) noexcept
378 {
379 switch (__c)
380 {
381 case '<': return _Align_left;
382 case '>': return _Align_right;
383 case '^': return _Align_centre;
384 default: return _Align_default;
385 }
386 }
388 // pre: __first != __last
389 constexpr iterator
390 _M_parse_fill_and_align(iterator __first, iterator __last) noexcept
391 {
392 if (*__first != '{')
393 {
394 // TODO: accept any UCS scalar value as fill character.
395 // If narrow source encoding is UTF-8 then accept multibyte char.
396 if (__last - __first >= 2)
397 {
398 if (_Align __align = _S_align(__first[1]))
399 {
400 _M_fill = *__first;
401 _M_align = __align;
402 return __first + 2;
403 }
404 }
406 if (_Align __align = _S_align(__first[0]))
407 {
408 _M_fill = ' ';
409 _M_align = __align;
410 return __first + 1;
411 }
412 }
413 return __first;
414 }
416 static constexpr _Sign
417 _S_sign(_CharT __c) noexcept
418 {
419 switch (__c)
420 {
421 case '+': return _Sign_plus;
422 case '-': return _Sign_minus;
423 case ' ': return _Sign_space;
424 default: return _Sign_default;
425 }
426 }
428 // pre: __first != __last
429 constexpr iterator
430 _M_parse_sign(iterator __first, iterator) noexcept
431 {
432 if (_Sign __sign = _S_sign(*__first))
433 {
434 _M_sign = __sign;
435 return __first + 1;
436 }
437 return __first;
438 }
440 // pre: *__first is valid
441 constexpr iterator
442 _M_parse_alternate_form(iterator __first, iterator) noexcept
443 {
444 if (*__first == '#')
445 {
446 _M_alt = true;
447 ++__first;
448 }
449 return __first;
450 }
452 // pre: __first != __last
453 constexpr iterator
454 _M_parse_zero_fill(iterator __first, iterator /* __last */) noexcept
455 {
456 if (*__first == '0')
457 {
458 _M_zero_fill = true;
459 ++__first;
460 }
461 return __first;
462 }
464 // pre: __first != __last
465 static constexpr iterator
466 _S_parse_width_or_precision(iterator __first, iterator __last,
467 unsigned short& __val, bool& __arg_id,
468 basic_format_parse_context<_CharT>& __pc)
469 {
470 if (__format::__is_digit(*__first))
471 {
472 auto [__v, __ptr] = __format::__parse_integer(__first, __last);
473 if (!__ptr)
474 __throw_format_error("format error: invalid width or precision "
475 "in format-spec");
476 __first = __ptr;
477 __val = __v;
478 }
479 else if (*__first == '{')
480 {
481 __arg_id = true;
482 ++__first;
483 if (__first == __last)
484 __format::__unmatched_left_brace_in_format_string();
485 if (*__first == '}')
486 __val = __pc.next_arg_id();
487 else
488 {
489 auto [__v, __ptr] = __format::__parse_arg_id(__first, __last);
490 if (__ptr == nullptr || __ptr == __last || *__ptr != '}')
491 __format::__invalid_arg_id_in_format_string();
492 __first = __ptr;
493 __pc.check_arg_id(__v);
494 __val = __v;
495 }
496 ++__first; // past the '}'
497 }
498 return __first;
499 }
501 // pre: __first != __last
502 constexpr iterator
503 _M_parse_width(iterator __first, iterator __last,
504 basic_format_parse_context<_CharT>& __pc)
505 {
506 bool __arg_id = false;
507 if (*__first == '0')
508 __throw_format_error("format error: width must be non-zero in "
509 "format string");
510 auto __next = _S_parse_width_or_precision(__first, __last, _M_width,
511 __arg_id, __pc);
512 if (__next != __first)
513 _M_width_kind = __arg_id ? _WP_from_arg : _WP_value;
514 return __next;
515 }
517 // pre: __first != __last
518 constexpr iterator
519 _M_parse_precision(iterator __first, iterator __last,
520 basic_format_parse_context<_CharT>& __pc)
521 {
522 if (__first[0] != '.')
523 return __first;
525 iterator __next = ++__first;
526 bool __arg_id = false;
527 if (__next != __last)
528 __next = _S_parse_width_or_precision(__first, __last, _M_prec,
529 __arg_id, __pc);
530 if (__next == __first)
531 __throw_format_error("format error: missing precision after '.' in "
532 "format string");
533 _M_prec_kind = __arg_id ? _WP_from_arg : _WP_value;
534 return __next;
535 }
537 // pre: __first != __last
538 constexpr iterator
539 _M_parse_locale(iterator __first, iterator /* __last */) noexcept
540 {
541 if (*__first == 'L')
542 {
543 _M_localized = true;
544 ++__first;
545 }
546 return __first;
547 }
549 template<typename _Context>
550 size_t
551 _M_get_width(_Context& __ctx) const
552 {
553 size_t __width = 0;
554 if (_M_width_kind == _WP_value)
555 __width = _M_width;
556 else if (_M_width_kind == _WP_from_arg)
557 __width = __format::__int_from_arg(__ctx.arg(_M_width));
558 return __width;
559 }
561 template<typename _Context>
562 size_t
563 _M_get_precision(_Context& __ctx) const
564 {
565 size_t __prec = -1;
566 if (_M_prec_kind == _WP_value)
567 __prec = _M_prec;
568 else if (_M_prec_kind == _WP_from_arg)
569 __prec = __format::__int_from_arg(__ctx.arg(_M_prec));
570 return __prec;
571 }
572 };
574 template<typename _Int>
575 inline char*
576 __put_sign(_Int __i, _Sign __sign, char* __dest) noexcept
577 {
578 if (__i < 0)
579 *__dest = '-';
580 else if (__sign == _Sign_plus)
581 *__dest = '+';
582 else if (__sign == _Sign_space)
583 *__dest = ' ';
584 else
585 ++__dest;
586 return __dest;
587 }
589 // Write STR to OUT (and do so efficiently if OUT is a _Sink_iter).
590 template<typename _Out, typename _CharT>
591 requires output_iterator<_Out, const _CharT&>
592 inline _Out
593 __write(_Out __out, basic_string_view<_CharT> __str)
594 {
595 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
596 {
597 if (__str.size())
598 __out = __str;
599 }
600 else
601 for (_CharT __c : __str)
602 *__out++ = __c;
603 return __out;
604 }
606 // Write STR to OUT with NFILL copies of FILL_CHAR specified by ALIGN.
607 // pre: __align != _Align_default
608 template<typename _Out, typename _CharT>
609 _Out
610 __write_padded(_Out __out, basic_string_view<_CharT> __str,
611 _Align __align, size_t __nfill, _CharT __fill_char)
612 {
613 const size_t __buflen = 0x20;
614 _CharT __padding_chars[__buflen];
615 __padding_chars[0] = _CharT();
616 basic_string_view<_CharT> __padding{__padding_chars, __buflen};
618 auto __pad = [&__padding] (size_t __n, _Out& __o) {
619 if (__n == 0)
620 return;
621 while (__n > __padding.size())
622 {
623 __o = __format::__write(std::move(__o), __padding);
624 __n -= __padding.size();
625 }
626 if (__n != 0)
627 __o = __format::__write(std::move(__o), __padding.substr(0, __n));
628 };
630 size_t __l, __r, __max;
631 if (__align == _Align_centre)
632 {
633 __l = __nfill / 2;
634 __r = __l + (__nfill & 1);
635 __max = __r;
636 }
637 else if (__align == _Align_right)
638 {
639 __l = __nfill;
640 __r = 0;
641 __max = __l;
642 }
643 else
644 {
645 __l = 0;
646 __r = __nfill;
647 __max = __r;
648 }
649 if (__max < __buflen)
650 __padding.remove_suffix(__buflen - __max);
651 else
652 __max = __buflen;
653 char_traits<_CharT>::assign(__padding_chars, __max, __fill_char);
655 __pad(__l, __out);
656 __out = __format::__write(std::move(__out), __str);
657 __pad(__r, __out);
659 return __out;
660 }
662 // Write STR to OUT, with alignment and padding as determined by SPEC.
663 // pre: __spec._M_align != _Align_default || __align != _Align_default
664 template<typename _CharT, typename _Out>
665 _Out
666 __write_padded_as_spec(basic_string_view<type_identity_t<_CharT>> __str,
667 size_t __estimated_width,
668 basic_format_context<_Out, _CharT>& __fc,
669 const _Spec<_CharT>& __spec,
670 _Align __align = _Align_left)
671 {
672 size_t __width = __spec._M_get_width(__fc);
674 if (__width <= __estimated_width)
675 return __format::__write(__fc.out(), __str);
677 const size_t __nfill = __width - __estimated_width;
679 if (__spec._M_align)
680 __align = __spec._M_align;
682 return __format::__write_padded(__fc.out(), __str, __align, __nfill,
683 __spec._M_fill);
684 }
686 // A lightweight optional<locale>.
687 struct _Optional_locale
688 {
689 [[__gnu__::__always_inline__]]
690 _Optional_locale() : _M_dummy(), _M_hasval(false) { }
692 _Optional_locale(const locale& __loc) noexcept
693 : _M_loc(__loc), _M_hasval(true)
694 { }
696 _Optional_locale(const _Optional_locale& __l) noexcept
697 : _M_dummy(), _M_hasval(__l._M_hasval)
698 {
699 if (_M_hasval)
700 std::construct_at(&_M_loc, __l._M_loc);
701 }
703 _Optional_locale&
704 operator=(const _Optional_locale& __l) noexcept
705 {
706 if (_M_hasval)
707 {
708 if (__l._M_hasval)
709 _M_loc = __l._M_loc;
710 else
711 {
712 _M_loc.~locale();
713 _M_hasval = false;
714 }
715 }
716 else if (__l._M_hasval)
717 {
718 std::construct_at(&_M_loc, __l._M_loc);
719 _M_hasval = true;
720 }
721 return *this;
722 }
724 ~_Optional_locale() { if (_M_hasval) _M_loc.~locale(); }
726 _Optional_locale&
727 operator=(locale&& __loc) noexcept
728 {
729 if (_M_hasval)
730 _M_loc = std::move(__loc);
731 else
732 {
733 std::construct_at(&_M_loc, std::move(__loc));
734 _M_hasval = true;
735 }
736 return *this;
737 }
739 const locale&
740 value() noexcept
741 {
742 if (!_M_hasval)
743 {
744 std::construct_at(&_M_loc);
745 _M_hasval = true;
746 }
747 return _M_loc;
748 }
750 bool has_value() const noexcept { return _M_hasval; }
752 union {
753 char _M_dummy = '\0';
754 std::locale _M_loc;
755 };
756 bool _M_hasval = false;
757 };
759 #ifdef _GLIBCXX_USE_WCHAR_T
760 template<typename _CharT>
761 concept __char = same_as<_CharT, char> || same_as<_CharT, wchar_t>;
762 #else
763 template<typename _CharT>
764 concept __char = same_as<_CharT, char>;
765 #endif
767 template<__char _CharT>
768 struct __formatter_str
769 {
770 constexpr typename basic_format_parse_context<_CharT>::iterator
771 parse(basic_format_parse_context<_CharT>& __pc)
772 {
773 auto __first = __pc.begin();
774 const auto __last = __pc.end();
775 _Spec<_CharT> __spec{};
777 auto __finalize = [this, &__spec] {
778 _M_spec = __spec;
779 };
781 auto __finished = [&] {
782 if (__first == __last || *__first == '}')
783 {
784 __finalize();
785 return true;
786 }
787 return false;
788 };
790 if (__finished())
791 return __first;
793 __first = __spec._M_parse_fill_and_align(__first, __last);
794 if (__finished())
795 return __first;
797 __first = __spec._M_parse_width(__first, __last, __pc);
798 if (__finished())
799 return __first;
801 __first = __spec._M_parse_precision(__first, __last, __pc);
802 if (__finished())
803 return __first;
805 if (*__first == 's')
806 ++__first;
807 #if __cpp_lib_format_ranges
808 else if (*__first == '?')
809 {
810 __spec._M_type = _Pres_esc;
811 ++__first;
812 }
813 #endif
815 if (__finished())
816 return __first;
818 __format::__failed_to_parse_format_spec();
819 }
821 template<typename _Out>
822 _Out
823 format(basic_string_view<_CharT> __s,
824 basic_format_context<_Out, _CharT>& __fc) const
825 {
826 if (_M_spec._M_type == _Pres_esc)
827 {
828 // TODO: C++23 escaped string presentation
829 }
831 if (_M_spec._M_width_kind == _WP_none
832 && _M_spec._M_prec_kind == _WP_none)
833 return __format::__write(__fc.out(), __s);
835 size_t __estimated_width = __s.size(); // TODO: Unicode-aware estim.
837 if (_M_spec._M_prec_kind != _WP_none)
838 {
839 size_t __prec = _M_spec._M_get_precision(__fc);
840 if (__estimated_width > __prec)
841 {
842 __s = __s.substr(0, __prec); // TODO: do not split code points
843 __estimated_width = __prec;
844 }
845 }
847 return __format::__write_padded_as_spec(__s, __estimated_width,
848 __fc, _M_spec);
849 }
851 #if __cpp_lib_format_ranges
852 constexpr void
853 set_debug_format() noexcept
854 { _M_spec._M_type = _Pres_esc; }
855 #endif
857 private:
858 _Spec<_CharT> _M_spec{};
859 };
861 template<__char _CharT>
862 struct __formatter_int
863 {
864 // If no presentation type is specified, meaning of "none" depends
865 // whether we are formatting an integer or a char or a bool.
866 static constexpr _Pres_type _AsInteger = _Pres_d;
867 static constexpr _Pres_type _AsBool = _Pres_s;
868 static constexpr _Pres_type _AsChar = _Pres_c;
870 constexpr typename basic_format_parse_context<_CharT>::iterator
871 _M_do_parse(basic_format_parse_context<_CharT>& __pc, _Pres_type __type)
872 {
873 _Spec<_CharT> __spec{};
874 __spec._M_type = __type;
876 const auto __last = __pc.end();
877 auto __first = __pc.begin();
879 auto __finalize = [this, &__spec] {
880 _M_spec = __spec;
881 };
883 auto __finished = [&] {
884 if (__first == __last || *__first == '}')
885 {
886 __finalize();
887 return true;
888 }
889 return false;
890 };
892 if (__finished())
893 return __first;
895 __first = __spec._M_parse_fill_and_align(__first, __last);
896 if (__finished())
897 return __first;
899 __first = __spec._M_parse_sign(__first, __last);
900 if (__finished())
901 return __first;
903 __first = __spec._M_parse_alternate_form(__first, __last);
904 if (__finished())
905 return __first;
907 __first = __spec._M_parse_zero_fill(__first, __last);
908 if (__finished())
909 return __first;
911 __first = __spec._M_parse_width(__first, __last, __pc);
912 if (__finished())
913 return __first;
915 __first = __spec._M_parse_locale(__first, __last);
916 if (__finished())
917 return __first;
919 switch (*__first)
920 {
921 case 'b':
922 __spec._M_type = _Pres_b;
923 ++__first;
924 break;
925 case 'B':
926 __spec._M_type = _Pres_B;
927 ++__first;
928 break;
929 case 'c':
930 // _GLIBCXX_RESOLVE_LIB_DEFECTS
931 // 3586. format should not print bool with 'c'
932 if (__type != _AsBool)
933 {
934 __spec._M_type = _Pres_c;
935 ++__first;
936 }
937 break;
938 case 'd':
939 __spec._M_type = _Pres_d;
940 ++__first;
941 break;
942 case 'o':
943 __spec._M_type = _Pres_o;
944 ++__first;
945 break;
946 case 'x':
947 __spec._M_type = _Pres_x;
948 ++__first;
949 break;
950 case 'X':
951 __spec._M_type = _Pres_X;
952 ++__first;
953 break;
954 case 's':
955 if (__type == _AsBool)
956 {
957 __spec._M_type = _Pres_s; // same value (and meaning) as "none"
958 ++__first;
959 }
960 break;
961 #if __cpp_lib_format_ranges
962 case '?':
963 if (__type == _AsChar)
964 {
965 __spec._M_type = _Pres_esc;
966 ++__first;
967 }
968 #endif
969 break;
970 }
972 if (__finished())
973 return __first;
975 __format::__failed_to_parse_format_spec();
976 }
978 template<typename _Tp>
979 constexpr typename basic_format_parse_context<_CharT>::iterator
980 _M_parse(basic_format_parse_context<_CharT>& __pc)
981 {
982 if constexpr (is_same_v<_Tp, bool>)
983 {
984 auto __end = _M_do_parse(__pc, _AsBool);
985 if (_M_spec._M_type == _Pres_s)
986 if (_M_spec._M_sign || _M_spec._M_alt || _M_spec._M_zero_fill)
987 __throw_format_error("format error: format-spec contains "
988 "invalid formatting options for "
989 "'bool'");
990 return __end;
991 }
992 else if constexpr (__char<_Tp>)
993 {
994 auto __end = _M_do_parse(__pc, _AsChar);
995 if (_M_spec._M_type == _Pres_c || _M_spec._M_type == _Pres_esc)
996 if (_M_spec._M_sign || _M_spec._M_alt || _M_spec._M_zero_fill
997 /* XXX should be invalid? || _M_spec._M_localized */)
998 __throw_format_error("format error: format-spec contains "
999 "invalid formatting options for "
1000 "'charT'");
1001 return __end;
1002 }
1003 else
1004 return _M_do_parse(__pc, _AsInteger);
1005 }
1007 template<typename _Int, typename _Out>
1008 typename basic_format_context<_Out, _CharT>::iterator
1009 format(_Int __i, basic_format_context<_Out, _CharT>& __fc) const
1010 {
1011 if (_M_spec._M_type == _Pres_c)
1012 return _M_format_character(_S_to_character(__i), __fc);
1014 char __buf[sizeof(_Int) * __CHAR_BIT__ + 3];
1015 to_chars_result __res{};
1017 string_view __base_prefix;
1018 make_unsigned_t<_Int> __u;
1019 if (__i < 0)
1020 __u = -static_cast<make_unsigned_t<_Int>>(__i);
1021 else
1022 __u = __i;
1024 char* __start = __buf + 3;
1025 char* const __end = __buf + sizeof(__buf);
1026 char* const __start_digits = __start;
1028 switch (_M_spec._M_type)
1029 {
1030 case _Pres_b:
1031 case _Pres_B:
1032 __base_prefix = _M_spec._M_type == _Pres_b ? "0b" : "0B";
1033 __res = to_chars(__start, __end, __u, 2);
1034 break;
1035 #if 0
1036 case _Pres_c:
1037 return _M_format_character(_S_to_character(__i), __fc);
1038 #endif
1039 case _Pres_none:
1040 // Should not reach here with _Pres_none for bool or charT, so:
1041 [[fallthrough]];
1042 case _Pres_d:
1043 __res = to_chars(__start, __end, __u, 10);
1044 break;
1045 case _Pres_o:
1046 if (__i != 0)
1047 __base_prefix = "0";
1048 __res = to_chars(__start, __end, __u, 8);
1049 break;
1050 case _Pres_x:
1051 case _Pres_X:
1052 __base_prefix = _M_spec._M_type == _Pres_x ? "0x" : "0X";
1053 __res = to_chars(__start, __end, __u, 16);
1054 if (_M_spec._M_type == _Pres_X)
1055 for (auto __p = __start; __p != __res.ptr; ++__p)
1056 #if __has_builtin(__builtin_toupper)
1057 *__p = __builtin_toupper(*__p);
1058 #else
1059 *__p = std::toupper(*__p);
1060 #endif
1061 break;
1062 default:
1063 __builtin_unreachable();
1064 }
1066 if (_M_spec._M_alt && __base_prefix.size())
1067 {
1068 __start -= __base_prefix.size();
1069 __builtin_memcpy(__start, __base_prefix.data(),
1070 __base_prefix.size());
1071 }
1072 __start = __format::__put_sign(__i, _M_spec._M_sign, __start - 1);
1074 return _M_format_int(string_view(__start, __res.ptr - __start),
1075 __start_digits - __start, __fc);
1076 }
1078 template<typename _Out>
1079 typename basic_format_context<_Out, _CharT>::iterator
1080 format(bool __i, basic_format_context<_Out, _CharT>& __fc) const
1081 {
1082 if (_M_spec._M_type == _Pres_c)
1083 return _M_format_character(static_cast<unsigned char>(__i), __fc);
1084 if (_M_spec._M_type != _Pres_s)
1085 return format(static_cast<unsigned char>(__i), __fc);
1087 basic_string<_CharT> __s;
1088 size_t __est_width;
1089 if (_M_spec._M_localized) [[unlikely]]
1090 {
1091 auto& __np = std::use_facet<numpunct<_CharT>>(__fc.locale());
1092 __s = __i ? __np.truename() : __np.falsename();
1093 __est_width = __s.size(); // TODO Unicode-aware estimate
1094 }
1095 else
1096 {
1097 if constexpr (is_same_v<char, _CharT>)
1098 __s = __i ? "true" : "false";
1099 else
1100 __s = __i ? L"true" : L"false";
1101 __est_width = __s.size();
1102 }
1104 return __format::__write_padded_as_spec(__s, __est_width, __fc,
1105 _M_spec);
1106 }
1108 template<typename _Out>
1109 typename basic_format_context<_Out, _CharT>::iterator
1110 _M_format_character(_CharT __c,
1111 basic_format_context<_Out, _CharT>& __fc) const
1112 {
1113 return __format::__write_padded_as_spec({&__c, 1u}, 1, __fc, _M_spec);
1114 }
1116 template<typename _Int>
1117 static _CharT
1118 _S_to_character(_Int __i)
1119 {
1120 using _Traits = __gnu_cxx::__int_traits<_CharT>;
1121 if constexpr (is_signed_v<_Int> == is_signed_v<_CharT>)
1122 {
1123 if (_Traits::__min <= __i && __i <= _Traits::__max)
1124 return static_cast<_CharT>(__i);
1125 }
1126 else if constexpr (is_signed_v<_Int>)
1127 {
1128 if (__i >= 0 && make_unsigned_t<_Int>(__i) <= _Traits::__max)
1129 return static_cast<_CharT>(__i);
1130 }
1131 else if (__i <= make_unsigned_t<_CharT>(_Traits::__max))
1132 return static_cast<_CharT>(__i);
1133 __throw_format_error("format error: integer not representable as "
1134 "character");
1135 }
1137 template<typename _Out>
1138 typename basic_format_context<_Out, _CharT>::iterator
1139 _M_format_int(string_view __narrow_str, size_t __prefix_len,
1140 basic_format_context<_Out, _CharT>& __fc) const
1141 {
1142 size_t __width = _M_spec._M_get_width(__fc);
1144 basic_string_view<_CharT> __str;
1145 if constexpr (is_same_v<char, _CharT>)
1146 __str = __narrow_str;
1147 #ifdef _GLIBCXX_USE_WCHAR_T
1148 else
1149 {
1150 size_t __n = __narrow_str.size();
1151 auto __p = (_CharT*)__builtin_alloca(__n * sizeof(_CharT));
1152 std::__to_wstring_numeric(__narrow_str.data(), __n, __p);
1153 __str = {__p, __n};
1154 }
1155 #endif
1157 if (_M_spec._M_localized)
1158 {
1159 const auto& __l = __fc.locale();
1160 if (__l.name() != "C")
1161 {
1162 auto& __np = use_facet<numpunct<_CharT>>(__l);
1163 string __grp = __np.grouping();
1164 if (!__grp.empty())
1165 {
1166 size_t __n = __str.size() - __prefix_len;
1167 auto __p = (_CharT*)__builtin_alloca(2 * __n
1168 * sizeof(_CharT)
1169 + __prefix_len);
1170 auto __s = __str.data();
1171 char_traits<_CharT>::copy(__p, __s, __prefix_len);
1172 __s += __prefix_len;
1173 auto __end = std::__add_grouping(__p + __prefix_len,
1174 __np.thousands_sep(),
1175 __grp.data(),
1176 __grp.size(),
1177 __s, __s + __n);
1178 __str = {__p, size_t(__end - __p)};
1179 }
1180 }
1181 }
1183 if (__width <= __str.size())
1184 return __format::__write(__fc.out(), __str);
1186 _CharT __fill_char = _M_spec._M_fill;
1187 _Align __align = _M_spec._M_align;
1189 size_t __nfill = __width - __str.size();
1190 auto __out = __fc.out();
1191 if (__align == _Align_default)
1192 {
1193 __align = _Align_right;
1194 if (_M_spec._M_zero_fill)
1195 {
1196 __fill_char = _CharT('0');
1197 // Write sign and base prefix before zero filling.
1198 if (__prefix_len != 0)
1199 {
1200 __out = __format::__write(std::move(__out),
1201 __str.substr(0, __prefix_len));
1202 __str.remove_prefix(__prefix_len);
1203 }
1204 }
1205 else
1206 __fill_char = _CharT(' ');
1207 }
1208 return __format::__write_padded(std::move(__out), __str,
1209 __align, __nfill, __fill_char);
1210 }
1212 #if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
1213 template<typename _Tp>
1214 using make_unsigned_t
1215 = typename __conditional_t<(sizeof(_Tp) <= sizeof(long long)),
1216 std::make_unsigned<_Tp>,
1217 type_identity<unsigned __int128>>::type;
1219 // std::to_chars is not overloaded for int128 in strict mode.
1220 template<typename _Int>
1221 static to_chars_result
1222 to_chars(char* __first, char* __last, _Int __value, int __base)
1223 { return std::__to_chars_i<_Int>(__first, __last, __value, __base); }
1224 #endif
1226 _Spec<_CharT> _M_spec{};
1227 };
1229 // Decide how 128-bit floating-point types should be formatted (or not).
1230 // When supported, the typedef __format::__float128_t is the type that
1231 // format arguments should be converted to for storage in basic_format_arg.
1232 // Define the macro _GLIBCXX_FORMAT_F128 to say they're supported.
1233 // _GLIBCXX_FORMAT_F128=1 means __float128, _Float128 etc. will be formatted
1234 // by converting them to long double (or __ieee128 for powerpc64le).
1235 // _GLIBCXX_FORMAT_F128=2 means basic_format_arg needs to enable explicit
1236 // support for _Float128, rather than formatting it as another type.
1237 #undef _GLIBCXX_FORMAT_F128
1239 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
1241 // Format 128-bit floating-point types using __ieee128.
1242 using __float128_t = __ieee128;
1243 # define _GLIBCXX_FORMAT_F128 1
1245 #ifdef __LONG_DOUBLE_IEEE128__
1246 // These overloads exist in the library, but are not declared.
1247 // Make them available as std::__format::to_chars.
1248 to_chars_result
1249 to_chars(char*, char*, __ibm128) noexcept
1250 __asm("_ZSt8to_charsPcS_e");
1252 to_chars_result
1253 to_chars(char*, char*, __ibm128, chars_format) noexcept
1254 __asm("_ZSt8to_charsPcS_eSt12chars_format");
1256 to_chars_result
1257 to_chars(char*, char*, __ibm128, chars_format, int) noexcept
1258 __asm("_ZSt8to_charsPcS_eSt12chars_formati");
1259 #elif __cplusplus == 202002L
1260 to_chars_result
1261 to_chars(char*, char*, __ieee128) noexcept
1262 __asm("_ZSt8to_charsPcS_u9__ieee128");
1264 to_chars_result
1265 to_chars(char*, char*, __ieee128, chars_format) noexcept
1266 __asm("_ZSt8to_charsPcS_u9__ieee128St12chars_format");
1268 to_chars_result
1269 to_chars(char*, char*, __ieee128, chars_format, int) noexcept
1270 __asm("_ZSt8to_charsPcS_u9__ieee128St12chars_formati");
1271 #endif
1273 #elif defined _GLIBCXX_LDOUBLE_IS_IEEE_BINARY128
1275 // Format 128-bit floating-point types using long double.
1276 using __float128_t = long double;
1277 # define _GLIBCXX_FORMAT_F128 1
1279 #elif __FLT128_DIG__ && defined(_GLIBCXX_HAVE_FLOAT128_MATH)
1281 // Format 128-bit floating-point types using _Float128.
1282 using __float128_t = _Float128;
1283 # define _GLIBCXX_FORMAT_F128 2
1285 # if __cplusplus == 202002L
1286 // These overloads exist in the library, but are not declared for C++20.
1287 // Make them available as std::__format::to_chars.
1288 to_chars_result
1289 to_chars(char*, char*, _Float128) noexcept
1290 # if _GLIBCXX_INLINE_VERSION
1291 __asm("_ZNSt3__88to_charsEPcS0_DF128_");
1292 # else
1293 __asm("_ZSt8to_charsPcS_DF128_");
1294 # endif
1296 to_chars_result
1297 to_chars(char*, char*, _Float128, chars_format) noexcept
1298 # if _GLIBCXX_INLINE_VERSION
1299 __asm("_ZNSt3__88to_charsEPcS0_DF128_NS_12chars_formatE");
1300 # else
1301 __asm("_ZSt8to_charsPcS_DF128_St12chars_format");
1302 # endif
1304 to_chars_result
1305 to_chars(char*, char*, _Float128, chars_format, int) noexcept
1306 # if _GLIBCXX_INLINE_VERSION
1307 __asm("_ZNSt3__88to_charsEPcS0_DF128_NS_12chars_formatEi");
1308 # else
1309 __asm("_ZSt8to_charsPcS_DF128_St12chars_formati");
1310 # endif
1311 # endif
1312 #endif
1314 using std::to_chars;
1316 // We can format a floating-point type iff it is usable with to_chars.
1317 template<typename _Tp>
1318 concept __formattable_float = requires (_Tp __t, char* __p)
1319 { __format::to_chars(__p, __p, __t, chars_format::scientific, 6); };
1321 template<__char _CharT>
1322 struct __formatter_fp
1323 {
1324 constexpr typename basic_format_parse_context<_CharT>::iterator
1325 parse(basic_format_parse_context<_CharT>& __pc)
1326 {
1327 _Spec<_CharT> __spec{};
1328 const auto __last = __pc.end();
1329 auto __first = __pc.begin();
1331 auto __finalize = [this, &__spec] {
1332 _M_spec = __spec;
1333 };
1335 auto __finished = [&] {
1336 if (__first == __last || *__first == '}')
1337 {
1338 __finalize();
1339 return true;
1340 }
1341 return false;
1342 };
1344 if (__finished())
1345 return __first;
1347 __first = __spec._M_parse_fill_and_align(__first, __last);
1348 if (__finished())
1349 return __first;
1351 __first = __spec._M_parse_sign(__first, __last);
1352 if (__finished())
1353 return __first;
1355 __first = __spec._M_parse_alternate_form(__first, __last);
1356 if (__finished())
1357 return __first;
1359 __first = __spec._M_parse_zero_fill(__first, __last);
1360 if (__finished())
1361 return __first;
1363 if (__first[0] != '.')
1364 {
1365 __first = __spec._M_parse_width(__first, __last, __pc);
1366 if (__finished())
1367 return __first;
1368 }
1370 __first = __spec._M_parse_precision(__first, __last, __pc);
1371 if (__finished())
1372 return __first;
1374 __first = __spec._M_parse_locale(__first, __last);
1375 if (__finished())
1376 return __first;
1378 switch (*__first)
1379 {
1380 case 'a':
1381 __spec._M_type = _Pres_a;
1382 ++__first;
1383 break;
1384 case 'A':
1385 __spec._M_type = _Pres_A;
1386 ++__first;
1387 break;
1388 case 'e':
1389 __spec._M_type = _Pres_e;
1390 ++__first;
1391 break;
1392 case 'E':
1393 __spec._M_type = _Pres_E;
1394 ++__first;
1395 break;
1396 case 'f':
1397 __spec._M_type = _Pres_f;
1398 ++__first;
1399 break;
1400 case 'F':
1401 __spec._M_type = _Pres_F;
1402 ++__first;
1403 break;
1404 case 'g':
1405 __spec._M_type = _Pres_g;
1406 ++__first;
1407 break;
1408 case 'G':
1409 __spec._M_type = _Pres_G;
1410 ++__first;
1411 break;
1412 }
1414 if (__finished())
1415 return __first;
1417 __format::__failed_to_parse_format_spec();
1418 }
1420 template<typename _Fp, typename _Out>
1421 typename basic_format_context<_Out, _CharT>::iterator
1422 format(_Fp __v, basic_format_context<_Out, _CharT>& __fc) const
1423 {
1424 std::string __dynbuf;
1425 char __buf[128];
1426 to_chars_result __res{};
1428 size_t __prec = 6;
1429 bool __use_prec = _M_spec._M_prec_kind != _WP_none;
1430 if (__use_prec)
1431 __prec = _M_spec._M_get_precision(__fc);
1433 char* __start = __buf + 1; // reserve space for sign
1434 char* __end = __buf + sizeof(__buf);
1436 chars_format __fmt{};
1437 bool __upper = false;
1438 bool __trailing_zeros = false;
1439 char __expc = 'e';
1441 switch (_M_spec._M_type)
1442 {
1443 case _Pres_A:
1444 __upper = true;
1445 __expc = 'P';
1446 [[fallthrough]];
1447 case _Pres_a:
1448 if (_M_spec._M_type != _Pres_A)
1449 __expc = 'p';
1450 __fmt = chars_format::hex;
1451 break;
1452 case _Pres_E:
1453 __upper = true;
1454 __expc = 'E';
1455 [[fallthrough]];
1456 case _Pres_e:
1457 __use_prec = true;
1458 __fmt = chars_format::scientific;
1459 break;
1460 case _Pres_F:
1461 __upper = true;
1462 [[fallthrough]];
1463 case _Pres_f:
1464 __use_prec = true;
1465 __fmt = chars_format::fixed;
1466 break;
1467 case _Pres_G:
1468 __upper = true;
1469 __expc = 'E';
1470 [[fallthrough]];
1471 case _Pres_g:
1472 __trailing_zeros = true;
1473 __use_prec = true;
1474 __fmt = chars_format::general;
1475 break;
1476 case _Pres_none:
1477 if (__use_prec)
1478 __fmt = chars_format::general;
1479 break;
1480 default:
1481 __builtin_unreachable();
1482 }
1484 // Write value into buffer using std::to_chars.
1485 auto __to_chars = [&](char* __b, char* __e) {
1486 if (__use_prec)
1487 return __format::to_chars(__b, __e, __v, __fmt, __prec);
1488 else if (__fmt != chars_format{})
1489 return __format::to_chars(__b, __e, __v, __fmt);
1490 else
1491 return __format::to_chars(__b, __e, __v);
1492 };
1494 // First try using stack buffer.
1495 __res = __to_chars(__start, __end);
1497 if (__builtin_expect(__res.ec == errc::value_too_large, 0))
1498 {
1499 // If the buffer is too small it's probably because of a large
1500 // precision, or a very large value in fixed format.
1501 size_t __guess = 8 + __prec;
1502 if (__fmt == chars_format::fixed) // +ddd.prec
1503 {
1504 if constexpr (is_same_v<_Fp, float> || is_same_v<_Fp, double>
1505 || is_same_v<_Fp, long double>)
1506 {
1507 // The number of digits to the left of the decimal point
1508 // is floor(log10(max(abs(__v),1)))+1
1509 int __exp{};
1510 if constexpr (is_same_v<_Fp, float>)
1511 __builtin_frexpf(__v, &__exp);
1512 else if constexpr (is_same_v<_Fp, double>)
1513 __builtin_frexp(__v, &__exp);
1514 else if constexpr (is_same_v<_Fp, long double>)
1515 __builtin_frexpl(__v, &__exp);
1516 if (__exp > 0)
1517 __guess += 1U + __exp * 4004U / 13301U; // log10(2) approx.
1518 }
1519 else
1520 __guess += numeric_limits<_Fp>::max_exponent10;
1521 }
1522 if (__guess <= sizeof(__buf)) [[unlikely]]
1523 __guess = sizeof(__buf) * 2;
1524 __dynbuf.reserve(__guess);
1526 do
1527 {
1528 auto __overwrite = [&__to_chars, &__res] (char* __p, size_t __n)
1529 {
1530 __res = __to_chars(__p + 1, __p + __n - 1);
1531 return __res.ec == errc{} ? __res.ptr - __p : 0;
1532 };
1534 __dynbuf.__resize_and_overwrite(__dynbuf.capacity() * 2,
1535 __overwrite);
1536 __start = __dynbuf.data() + 1; // reserve space for sign
1537 __end = __dynbuf.data() + __dynbuf.size();
1538 }
1539 while (__builtin_expect(__res.ec == errc::value_too_large, 0));
1540 }
1542 // Use uppercase for 'A', 'E', and 'G' formats.
1543 if (__upper)
1544 {
1545 for (char* __p = __start; __p != __res.ptr; ++__p)
1546 *__p = std::toupper(*__p);
1547 }
1549 // Add sign for non-negative values.
1550 if (!__builtin_signbit(__v))
1551 {
1552 if (_M_spec._M_sign == _Sign_plus)
1553 *--__start = '+';
1554 else if (_M_spec._M_sign == _Sign_space)
1555 *--__start = ' ';
1556 }
1558 string_view __narrow_str(__start, __res.ptr - __start);
1560 // Use alternate form.
1561 if (_M_spec._M_alt && __builtin_isfinite(__v))
1562 {
1563 string_view __s = __narrow_str;
1564 size_t __z = 0;
1565 size_t __p;
1566 size_t __d = __s.find('.');
1567 size_t __sigfigs;
1568 if (__d != __s.npos)
1569 {
1570 __p = __s.find(__expc, __d + 1);
1571 if (__p == __s.npos)
1572 __p = __s.size();
1573 __sigfigs = __p - 1;
1574 }
1575 else
1576 {
1577 __p = __s.find(__expc);
1578 if (__p == __s.npos)
1579 __p = __s.size();
1580 __d = __p; // Position where '.' should be inserted.
1581 __sigfigs = __d;
1582 }
1584 if (__trailing_zeros && __prec != 0)
1585 {
1586 if (!__format::__is_xdigit(__s[0]))
1587 --__sigfigs;
1588 __z = __prec - __sigfigs; // Number of zeros to insert.
1589 }
1591 if (size_t __extras = int(__d == __p) + __z)
1592 {
1593 if (__dynbuf.empty() && __extras <= size_t(__end - __res.ptr))
1594 {
1595 // Move exponent to make space for extra chars.
1596 __builtin_memmove(__start + __p + __extras,
1597 __start + __p,
1598 __s.size() - __p);
1600 if (__d == __p)
1601 __start[__p++] = '.';
1602 __builtin_memset(__start + __p, '0', __z);
1603 __narrow_str = {__s.data(), __s.size() + __extras};
1604 }
1605 else
1606 {
1607 __dynbuf.reserve(__s.size() + __extras);
1608 if (__dynbuf.empty())
1609 {
1610 __dynbuf = __s.substr(0, __p);
1611 if (__d == __p)
1612 __dynbuf += '.';
1613 if (__z)
1614 __dynbuf.append(__z, '0');
1615 }
1616 else
1617 {
1618 __dynbuf.insert(__p, __extras, '0');
1619 if (__d == __p)
1620 __dynbuf[__p] = '.';
1621 }
1622 __narrow_str = __dynbuf;
1623 }
1624 }
1625 }
1627 basic_string<_CharT> __wstr;
1628 basic_string_view<_CharT> __str;
1629 if constexpr (is_same_v<_CharT, char>)
1630 __str = __narrow_str;
1631 #ifdef _GLIBCXX_USE_WCHAR_T
1632 else
1633 {
1634 __wstr = std::__to_wstring_numeric(__narrow_str);
1635 __str = __wstr;
1636 }
1637 #endif
1639 if (_M_spec._M_localized)
1640 {
1641 __wstr = _M_localize(__str, __expc, __fc.locale());
1642 if (!__wstr.empty())
1643 __str = __wstr;
1644 }
1646 size_t __width = _M_spec._M_get_width(__fc);
1648 if (__width <= __str.size())
1649 return __format::__write(__fc.out(), __str);
1651 _CharT __fill_char = _M_spec._M_fill;
1652 _Align __align = _M_spec._M_align;
1654 size_t __nfill = __width - __str.size();
1655 auto __out = __fc.out();
1656 if (__align == _Align_default)
1657 {
1658 __align = _Align_right;
1659 if (_M_spec._M_zero_fill && __builtin_isfinite(__v))
1660 {
1661 __fill_char = _CharT('0');
1662 // Write sign before zero filling.
1663 if (!__format::__is_xdigit(__narrow_str[0]))
1664 {
1665 *__out++ = __str[0];
1666 __str.remove_prefix(1);
1667 }
1668 }
1669 else
1670 __fill_char = _CharT(' ');
1671 }
1672 return __format::__write_padded(std::move(__out), __str,
1673 __align, __nfill, __fill_char);
1674 }
1676 // Locale-specific format.
1677 basic_string<_CharT>
1678 _M_localize(basic_string_view<_CharT> __str, char __expc,
1679 const locale& __loc) const
1680 {
1681 basic_string<_CharT> __lstr;
1683 if (__loc == locale::classic())
1684 return __lstr; // Nothing to do.
1686 const auto& __np = use_facet<numpunct<_CharT>>(__loc);
1687 const _CharT __point = __np.decimal_point();
1688 const string __grp = __np.grouping();
1690 _CharT __dot, __exp;
1691 if constexpr (is_same_v<_CharT, char>)
1692 {
1693 __dot = '.';
1694 __exp = __expc;
1695 }
1696 else
1697 {
1698 __dot = L'.';
1699 switch (__expc)
1700 {
1701 case 'e':
1702 __exp = L'e';
1703 break;
1704 case 'E':
1705 __exp = L'E';
1706 break;
1707 case 'p':
1708 __exp = L'p';
1709 break;
1710 case 'P':
1711 __exp = L'P';
1712 break;
1713 default:
1714 __builtin_unreachable();
1715 }
1716 }
1718 if (__grp.empty() && __point == __dot)
1719 return __lstr; // Locale uses '.' and no grouping.
1721 size_t __d = __str.find(__dot);
1722 size_t __e = min(__d, __str.find(__exp));
1723 if (__e == __str.npos)
1724 __e = __str.size();
1725 const size_t __r = __str.size() - __e;
1726 auto __overwrite = [&](_CharT* __p, size_t) {
1727 auto __end = std::__add_grouping(__p, __np.thousands_sep(),
1728 __grp.data(), __grp.size(),
1729 __str.data(), __str.data() + __e);
1730 if (__r)
1731 {
1732 if (__d != __str.npos)
1733 {
1734 *__end = __point;
1735 ++__end;
1736 ++__e;
1737 }
1738 if (__r > 1)
1739 __end += __str.copy(__end, __str.npos, __e);
1740 }
1741 return (__end - __p);
1742 };
1743 __lstr.__resize_and_overwrite(__e * 2 + __r, __overwrite);
1744 return __lstr;
1745 }
1747 _Spec<_CharT> _M_spec{};
1748 };
1750 } // namespace __format
1751 /// @endcond
1753 /// Format a character.
1754 template<__format::__char _CharT>
1755 struct formatter<_CharT, _CharT>
1756 {
1757 formatter() = default;
1759 constexpr typename basic_format_parse_context<_CharT>::iterator
1760 parse(basic_format_parse_context<_CharT>& __pc)
1761 {
1762 return _M_f.template _M_parse<_CharT>(__pc);
1763 }
1765 template<typename _Out>
1766 typename basic_format_context<_Out, _CharT>::iterator
1767 format(_CharT __u, basic_format_context<_Out, _CharT>& __fc) const
1768 {
1769 if (_M_f._M_spec._M_type == __format::_Pres_none)
1770 return _M_f._M_format_character(__u, __fc);
1771 else if (_M_f._M_spec._M_type == __format::_Pres_esc)
1772 {
1773 // TODO
1774 return __fc.out();
1775 }
1776 else
1777 return _M_f.format(__u, __fc);
1778 }
1780 #if __cpp_lib_format_ranges
1781 constexpr void
1782 set_debug_format() noexcept
1783 { _M_f._M_spec._M_type = __format::_Pres_esc; }
1784 #endif
1786 private:
1787 __format::__formatter_int<_CharT> _M_f;
1788 };
1790 #ifdef _GLIBCXX_USE_WCHAR_T
1791 /// Format a char value for wide character output.
1792 template<>
1793 struct formatter<char, wchar_t>
1794 {
1795 formatter() = default;
1797 constexpr typename basic_format_parse_context<wchar_t>::iterator
1798 parse(basic_format_parse_context<wchar_t>& __pc)
1799 {
1800 return _M_f._M_parse<char>(__pc);
1801 }
1803 template<typename _Out>
1804 typename basic_format_context<_Out, wchar_t>::iterator
1805 format(char __u, basic_format_context<_Out, wchar_t>& __fc) const
1806 {
1807 if (_M_f._M_spec._M_type == __format::_Pres_none)
1808 return _M_f._M_format_character(__u, __fc);
1809 else if (_M_f._M_spec._M_type == __format::_Pres_esc)
1810 {
1811 // TODO
1812 return __fc.out();
1813 }
1814 else
1815 return _M_f.format(__u, __fc);
1816 }
1818 constexpr void
1819 set_debug_format() noexcept
1820 { _M_f._M_spec._M_type = __format::_Pres_esc; }
1822 private:
1823 __format::__formatter_int<wchar_t> _M_f;
1824 };
1825 #endif // USE_WCHAR_T
1827 /** Format a string.
1828 * @{
1829 */
1830 template<__format::__char _CharT>
1831 struct formatter<_CharT*, _CharT>
1832 {
1833 formatter() = default;
1835 [[__gnu__::__always_inline__]]
1836 constexpr typename basic_format_parse_context<_CharT>::iterator
1837 parse(basic_format_parse_context<_CharT>& __pc)
1838 { return _M_f.parse(__pc); }
1840 template<typename _Out>
1841 [[__gnu__::__nonnull__]]
1842 typename basic_format_context<_Out, _CharT>::iterator
1843 format(_CharT* __u, basic_format_context<_Out, _CharT>& __fc) const
1844 { return _M_f.format(__u, __fc); }
1846 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1848 private:
1849 __format::__formatter_str<_CharT> _M_f;
1850 };
1852 template<__format::__char _CharT>
1853 struct formatter<const _CharT*, _CharT>
1854 {
1855 formatter() = default;
1857 [[__gnu__::__always_inline__]]
1858 constexpr typename basic_format_parse_context<_CharT>::iterator
1859 parse(basic_format_parse_context<_CharT>& __pc)
1860 { return _M_f.parse(__pc); }
1862 template<typename _Out>
1863 [[__gnu__::__nonnull__]]
1864 typename basic_format_context<_Out, _CharT>::iterator
1865 format(const _CharT* __u,
1866 basic_format_context<_Out, _CharT>& __fc) const
1867 { return _M_f.format(__u, __fc); }
1869 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1871 private:
1872 __format::__formatter_str<_CharT> _M_f;
1873 };
1875 template<__format::__char _CharT, size_t _Nm>
1876 struct formatter<_CharT[_Nm], _CharT>
1877 {
1878 formatter() = default;
1880 [[__gnu__::__always_inline__]]
1881 constexpr typename basic_format_parse_context<_CharT>::iterator
1882 parse(basic_format_parse_context<_CharT>& __pc)
1883 { return _M_f.parse(__pc); }
1885 template<typename _Out>
1886 typename basic_format_context<_Out, _CharT>::iterator
1887 format(const _CharT (&__u)[_Nm],
1888 basic_format_context<_Out, _CharT>& __fc) const
1889 { return _M_f.format({__u, _Nm}, __fc); }
1891 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1893 private:
1894 __format::__formatter_str<_CharT> _M_f;
1895 };
1897 template<typename _Traits, typename _Alloc>
1898 struct formatter<basic_string<char, _Traits, _Alloc>, char>
1899 {
1900 formatter() = default;
1902 [[__gnu__::__always_inline__]]
1903 constexpr typename basic_format_parse_context<char>::iterator
1904 parse(basic_format_parse_context<char>& __pc)
1905 { return _M_f.parse(__pc); }
1907 template<typename _Out>
1908 typename basic_format_context<_Out, char>::iterator
1909 format(const basic_string<char, _Traits, _Alloc>& __u,
1910 basic_format_context<_Out, char>& __fc) const
1911 { return _M_f.format(__u, __fc); }
1913 #if __cpp_lib_format_ranges
1914 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1915 #endif
1917 private:
1918 __format::__formatter_str<char> _M_f;
1919 };
1921 #ifdef _GLIBCXX_USE_WCHAR_T
1922 template<typename _Traits, typename _Alloc>
1923 struct formatter<basic_string<wchar_t, _Traits, _Alloc>, wchar_t>
1924 {
1925 formatter() = default;
1927 [[__gnu__::__always_inline__]]
1928 constexpr typename basic_format_parse_context<wchar_t>::iterator
1929 parse(basic_format_parse_context<wchar_t>& __pc)
1930 { return _M_f.parse(__pc); }
1932 template<typename _Out>
1933 typename basic_format_context<_Out, wchar_t>::iterator
1934 format(const basic_string<wchar_t, _Traits, _Alloc>& __u,
1935 basic_format_context<_Out, wchar_t>& __fc) const
1936 { return _M_f.format(__u, __fc); }
1938 #if __cpp_lib_format_ranges
1939 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1940 #endif
1942 private:
1943 __format::__formatter_str<wchar_t> _M_f;
1944 };
1945 #endif // USE_WCHAR_T
1947 template<typename _Traits>
1948 struct formatter<basic_string_view<char, _Traits>, char>
1949 {
1950 formatter() = default;
1952 [[__gnu__::__always_inline__]]
1953 constexpr typename basic_format_parse_context<char>::iterator
1954 parse(basic_format_parse_context<char>& __pc)
1955 { return _M_f.parse(__pc); }
1957 template<typename _Out>
1958 typename basic_format_context<_Out, char>::iterator
1959 format(basic_string_view<char, _Traits> __u,
1960 basic_format_context<_Out, char>& __fc) const
1961 { return _M_f.format(__u, __fc); }
1963 #if __cpp_lib_format_ranges
1964 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1965 #endif
1967 private:
1968 __format::__formatter_str<char> _M_f;
1969 };
1971 #ifdef _GLIBCXX_USE_WCHAR_T
1972 template<typename _Traits>
1973 struct formatter<basic_string_view<wchar_t, _Traits>, wchar_t>
1974 {
1975 formatter() = default;
1977 [[__gnu__::__always_inline__]]
1978 constexpr typename basic_format_parse_context<wchar_t>::iterator
1979 parse(basic_format_parse_context<wchar_t>& __pc)
1980 { return _M_f.parse(__pc); }
1982 template<typename _Out>
1983 typename basic_format_context<_Out, wchar_t>::iterator
1984 format(basic_string_view<wchar_t, _Traits> __u,
1985 basic_format_context<_Out, wchar_t>& __fc) const
1986 { return _M_f.format(__u, __fc); }
1988 #if __cpp_lib_format_ranges
1989 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1990 #endif
1992 private:
1993 __format::__formatter_str<wchar_t> _M_f;
1994 };
1995 #endif // USE_WCHAR_T
1996 /// @}
1998 /// Format an integer.
1999 template<integral _Tp, __format::__char _CharT>
2000 requires (!__is_one_of<_Tp, char, wchar_t, char16_t, char32_t>::value)
2001 struct formatter<_Tp, _CharT>
2002 {
2003 formatter() = default;
2005 [[__gnu__::__always_inline__]]
2006 constexpr typename basic_format_parse_context<_CharT>::iterator
2007 parse(basic_format_parse_context<_CharT>& __pc)
2008 {
2009 return _M_f.template _M_parse<_Tp>(__pc);
2010 }
2012 template<typename _Out>
2013 typename basic_format_context<_Out, _CharT>::iterator
2014 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2015 { return _M_f.format(__u, __fc); }
2017 private:
2018 __format::__formatter_int<_CharT> _M_f;
2019 };
2021 #if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
2022 template<typename _Tp, __format::__char _CharT>
2023 requires (__is_one_of<_Tp, __int128, unsigned __int128>::value)
2024 struct formatter<_Tp, _CharT>
2025 {
2026 formatter() = default;
2028 [[__gnu__::__always_inline__]]
2029 constexpr typename basic_format_parse_context<_CharT>::iterator
2030 parse(basic_format_parse_context<_CharT>& __pc)
2031 {
2032 return _M_f.template _M_parse<_Tp>(__pc);
2033 }
2035 template<typename _Out>
2036 typename basic_format_context<_Out, _CharT>::iterator
2037 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2038 { return _M_f.format(__u, __fc); }
2040 private:
2041 __format::__formatter_int<_CharT> _M_f;
2042 };
2043 #endif
2045 #if defined __glibcxx_to_chars
2046 /// Format a floating-point value.
2047 template<__format::__formattable_float _Tp, __format::__char _CharT>
2048 struct formatter<_Tp, _CharT>
2049 {
2050 formatter() = default;
2052 [[__gnu__::__always_inline__]]
2053 constexpr typename basic_format_parse_context<_CharT>::iterator
2054 parse(basic_format_parse_context<_CharT>& __pc)
2055 { return _M_f.parse(__pc); }
2057 template<typename _Out>
2058 typename basic_format_context<_Out, _CharT>::iterator
2059 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2060 { return _M_f.format(__u, __fc); }
2062 private:
2063 __format::__formatter_fp<_CharT> _M_f;
2064 };
2066 #if __LDBL_MANT_DIG__ == __DBL_MANT_DIG__
2067 // Reuse __formatter_fp<C>::format<double, Out> for long double.
2068 template<__format::__char _CharT>
2069 struct formatter<long double, _CharT>
2070 {
2071 formatter() = default;
2073 [[__gnu__::__always_inline__]]
2074 constexpr typename basic_format_parse_context<_CharT>::iterator
2075 parse(basic_format_parse_context<_CharT>& __pc)
2076 { return _M_f.parse(__pc); }
2078 template<typename _Out>
2079 typename basic_format_context<_Out, _CharT>::iterator
2080 format(long double __u, basic_format_context<_Out, _CharT>& __fc) const
2081 { return _M_f.format((double)__u, __fc); }
2083 private:
2084 __format::__formatter_fp<_CharT> _M_f;
2085 };
2086 #endif
2088 #ifdef __STDCPP_FLOAT16_T__
2089 // Reuse __formatter_fp<C>::format<float, Out> for _Float16.
2090 template<__format::__char _CharT>
2091 struct formatter<_Float16, _CharT>
2092 {
2093 formatter() = default;
2095 [[__gnu__::__always_inline__]]
2096 constexpr typename basic_format_parse_context<_CharT>::iterator
2097 parse(basic_format_parse_context<_CharT>& __pc)
2098 { return _M_f.parse(__pc); }
2100 template<typename _Out>
2101 typename basic_format_context<_Out, _CharT>::iterator
2102 format(_Float16 __u, basic_format_context<_Out, _CharT>& __fc) const
2103 { return _M_f.format((float)__u, __fc); }
2105 private:
2106 __format::__formatter_fp<_CharT> _M_f;
2107 };
2108 #endif
2110 #if defined(__FLT32_DIG__)
2111 // Reuse __formatter_fp<C>::format<float, Out> for _Float32.
2112 template<__format::__char _CharT>
2113 struct formatter<_Float32, _CharT>
2114 {
2115 formatter() = default;
2117 [[__gnu__::__always_inline__]]
2118 constexpr typename basic_format_parse_context<_CharT>::iterator
2119 parse(basic_format_parse_context<_CharT>& __pc)
2120 { return _M_f.parse(__pc); }
2122 template<typename _Out>
2123 typename basic_format_context<_Out, _CharT>::iterator
2124 format(_Float32 __u, basic_format_context<_Out, _CharT>& __fc) const
2125 { return _M_f.format((float)__u, __fc); }
2127 private:
2128 __format::__formatter_fp<_CharT> _M_f;
2129 };
2130 #endif
2132 #if defined(__FLT64_DIG__)
2133 // Reuse __formatter_fp<C>::format<double, Out> for _Float64.
2134 template<__format::__char _CharT>
2135 struct formatter<_Float64, _CharT>
2136 {
2137 formatter() = default;
2139 [[__gnu__::__always_inline__]]
2140 constexpr typename basic_format_parse_context<_CharT>::iterator
2141 parse(basic_format_parse_context<_CharT>& __pc)
2142 { return _M_f.parse(__pc); }
2144 template<typename _Out>
2145 typename basic_format_context<_Out, _CharT>::iterator
2146 format(_Float64 __u, basic_format_context<_Out, _CharT>& __fc) const
2147 { return _M_f.format((double)__u, __fc); }
2149 private:
2150 __format::__formatter_fp<_CharT> _M_f;
2151 };
2152 #endif
2154 #if defined(__FLT128_DIG__) && _GLIBCXX_FORMAT_F128 == 1
2155 // Reuse __formatter_fp<C>::format<__float128_t, Out> for _Float128.
2156 template<__format::__char _CharT>
2157 struct formatter<_Float128, _CharT>
2158 {
2159 formatter() = default;
2161 [[__gnu__::__always_inline__]]
2162 constexpr typename basic_format_parse_context<_CharT>::iterator
2163 parse(basic_format_parse_context<_CharT>& __pc)
2164 { return _M_f.parse(__pc); }
2166 template<typename _Out>
2167 typename basic_format_context<_Out, _CharT>::iterator
2168 format(_Float128 __u, basic_format_context<_Out, _CharT>& __fc) const
2169 { return _M_f.format((__format::__float128_t)__u, __fc); }
2171 private:
2172 __format::__formatter_fp<_CharT> _M_f;
2173 };
2174 #endif
2176 #ifdef __STDCPP_BFLOAT16_T__
2177 // Reuse __formatter_fp<C>::format<float, Out> for bfloat16_t.
2178 template<__format::__char _CharT>
2179 struct formatter<__gnu_cxx::__bfloat16_t, _CharT>
2180 {
2181 formatter() = default;
2183 [[__gnu__::__always_inline__]]
2184 constexpr typename basic_format_parse_context<_CharT>::iterator
2185 parse(basic_format_parse_context<_CharT>& __pc)
2186 { return _M_f.parse(__pc); }
2188 template<typename _Out>
2189 typename basic_format_context<_Out, _CharT>::iterator
2190 format(__gnu_cxx::__bfloat16_t __u,
2191 basic_format_context<_Out, _CharT>& __fc) const
2192 { return _M_f.format((float)__u, __fc); }
2194 private:
2195 __format::__formatter_fp<_CharT> _M_f;
2196 };
2197 #endif
2198 #endif // __cpp_lib_to_chars
2200 /** Format a pointer.
2201 * @{
2202 */
2203 template<__format::__char _CharT>
2204 struct formatter<const void*, _CharT>
2205 {
2206 formatter() = default;
2208 constexpr typename basic_format_parse_context<_CharT>::iterator
2209 parse(basic_format_parse_context<_CharT>& __pc)
2210 {
2211 __format::_Spec<_CharT> __spec{};
2212 const auto __last = __pc.end();
2213 auto __first = __pc.begin();
2215 auto __finalize = [this, &__spec] {
2216 _M_spec = __spec;
2217 };
2219 auto __finished = [&] {
2220 if (__first == __last || *__first == '}')
2221 {
2222 __finalize();
2223 return true;
2224 }
2225 return false;
2226 };
2228 if (__finished())
2229 return __first;
2231 __first = __spec._M_parse_fill_and_align(__first, __last);
2232 if (__finished())
2233 return __first;
2235 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2236 // P2510R3 Formatting pointers
2237 #if __cplusplus > 202302L || ! defined __STRICT_ANSI__
2238 #define _GLIBCXX_P2518R3 1
2239 #else
2240 #define _GLIBCXX_P2518R3 0
2241 #endif
2243 #if _GLIBCXX_P2518R3
2244 __first = __spec._M_parse_zero_fill(__first, __last);
2245 if (__finished())
2246 return __first;
2247 #endif
2249 __first = __spec._M_parse_width(__first, __last, __pc);
2251 if (__first != __last)
2252 {
2253 if (*__first == 'p')
2254 ++__first;
2255 #if _GLIBCXX_P2518R3
2256 else if (*__first == 'P')
2257 {
2258 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2259 // P2510R3 Formatting pointers
2260 __spec._M_type = __format::_Pres_P;
2261 ++__first;
2262 }
2263 #endif
2264 }
2266 if (__finished())
2267 return __first;
2269 __format::__failed_to_parse_format_spec();
2270 }
2272 template<typename _Out>
2273 typename basic_format_context<_Out, _CharT>::iterator
2274 format(const void* __v, basic_format_context<_Out, _CharT>& __fc) const
2275 {
2276 auto __u = reinterpret_cast<__UINTPTR_TYPE__>(__v);
2277 char __buf[2 + sizeof(__v) * 2];
2278 auto [__ptr, __ec] = std::to_chars(__buf + 2, std::end(__buf),
2279 __u, 16);
2280 int __n = __ptr - __buf;
2281 __buf[0] = '0';
2282 __buf[1] = 'x';
2283 #if _GLIBCXX_P2518R3
2284 if (_M_spec._M_type == __format::_Pres_P)
2285 {
2286 __buf[1] = 'X';
2287 for (auto __p = __buf + 2; __p != __ptr; ++__p)
2288 #if __has_builtin(__builtin_toupper)
2289 *__p = __builtin_toupper(*__p);
2290 #else
2291 *__p = std::toupper(*__p);
2292 #endif
2293 }
2294 #endif
2296 basic_string_view<_CharT> __str;
2297 if constexpr (is_same_v<_CharT, char>)
2298 __str = string_view(__buf, __n);
2299 #ifdef _GLIBCXX_USE_WCHAR_T
2300 else
2301 {
2302 auto __p = (_CharT*)__builtin_alloca(__n * sizeof(_CharT));
2303 std::__to_wstring_numeric(__buf, __n, __p);
2304 __str = wstring_view(__p, __n);
2305 }
2306 #endif
2308 #if _GLIBCXX_P2518R3
2309 if (_M_spec._M_zero_fill)
2310 {
2311 size_t __width = _M_spec._M_get_width(__fc);
2312 if (__width <= __str.size())
2313 return __format::__write(__fc.out(), __str);
2315 auto __out = __fc.out();
2316 // Write "0x" or "0X" prefix before zero-filling.
2317 __out = __format::__write(std::move(__out), __str.substr(0, 2));
2318 __str.remove_prefix(2);
2319 size_t __nfill = __width - __n;
2320 return __format::__write_padded(std::move(__out), __str,
2321 __format::_Align_right,
2322 __nfill, _CharT('0'));
2323 }
2324 #endif
2326 return __format::__write_padded_as_spec(__str, __n, __fc, _M_spec,
2327 __format::_Align_right);
2328 }
2330 private:
2331 __format::_Spec<_CharT> _M_spec{};
2332 };
2334 template<__format::__char _CharT>
2335 struct formatter<void*, _CharT>
2336 {
2337 formatter() = default;
2339 [[__gnu__::__always_inline__]]
2340 constexpr typename basic_format_parse_context<_CharT>::iterator
2341 parse(basic_format_parse_context<_CharT>& __pc)
2342 { return _M_f.parse(__pc); }
2344 template<typename _Out>
2345 typename basic_format_context<_Out, _CharT>::iterator
2346 format(void* __v, basic_format_context<_Out, _CharT>& __fc) const
2347 { return _M_f.format(__v, __fc); }
2349 private:
2350 formatter<const void*, _CharT> _M_f;
2351 };
2353 template<__format::__char _CharT>
2354 struct formatter<nullptr_t, _CharT>
2355 {
2356 formatter() = default;
2358 [[__gnu__::__always_inline__]]
2359 constexpr typename basic_format_parse_context<_CharT>::iterator
2360 parse(basic_format_parse_context<_CharT>& __pc)
2361 { return _M_f.parse(__pc); }
2363 template<typename _Out>
2364 typename basic_format_context<_Out, _CharT>::iterator
2365 format(nullptr_t, basic_format_context<_Out, _CharT>& __fc) const
2366 { return _M_f.format(nullptr, __fc); }
2368 private:
2369 formatter<const void*, _CharT> _M_f;
2370 };
2371 /// @}
2374 /// @cond undocumented
2375 namespace __format
2376 {
2377 template<typename _Tp, typename _Context,
2378 typename _Formatter
2379 = typename _Context::template formatter_type<remove_const_t<_Tp>>,
2380 typename _ParseContext
2381 = basic_format_parse_context<typename _Context::char_type>>
2382 concept __parsable_with
2383 = semiregular<_Formatter>
2384 && requires (_Formatter __f, _ParseContext __pc)
2385 {
2386 { __f.parse(__pc) } -> same_as<typename _ParseContext::iterator>;
2387 };
2389 template<typename _Tp, typename _Context,
2390 typename _Formatter
2391 = typename _Context::template formatter_type<remove_const_t<_Tp>>,
2392 typename _ParseContext
2393 = basic_format_parse_context<typename _Context::char_type>>
2394 concept __formattable_with
2395 = semiregular<_Formatter>
2396 && requires (const _Formatter __cf, _Tp&& __t, _Context __fc)
2397 {
2398 { __cf.format(__t, __fc) } -> same_as<typename _Context::iterator>;
2399 };
2401 // An unspecified output iterator type used in the `formattable` concept.
2402 template<typename _CharT>
2403 using _Iter_for = back_insert_iterator<basic_string<_CharT>>;
2405 template<typename _Tp, typename _CharT,
2406 typename _Context = basic_format_context<_Iter_for<_CharT>, _CharT>>
2407 concept __formattable_impl
2408 = __parsable_with<_Tp, _Context> && __formattable_with<_Tp, _Context>;
2410 } // namespace __format
2411 /// @endcond
2413 #if __cplusplus > 202002L
2414 // [format.formattable], concept formattable
2415 template<typename _Tp, typename _CharT>
2416 concept formattable
2417 = __format::__formattable_impl<remove_reference_t<_Tp>, _CharT>;
2418 #endif
2420 #if __cpp_lib_format_ranges
2421 /// @cond undocumented
2422 namespace __format
2423 {
2424 template<typename _Rg, typename _CharT>
2425 concept __const_formattable_range
2426 = ranges::input_range<const _Rg>
2427 && formattable<ranges::range_reference_t<const _Rg>, _CharT>;
2429 template<typename _Rg, typename _CharT>
2430 using __maybe_const_range
2431 = conditional_t<__const_formattable_range<_Rg, _CharT>, const _Rg, _Rg>;
2432 } // namespace __format
2433 /// @endcond
2434 #endif // format_ranges
2436 /// An iterator after the last character written, and the number of
2437 /// characters that would have been written.
2438 template<typename _Out>
2439 struct format_to_n_result
2440 {
2441 _Out out;
2442 iter_difference_t<_Out> size;
2443 };
2445 /// @cond undocumented
2446 namespace __format
2447 {
2448 template<typename _CharT>
2449 class _Sink_iter
2450 {
2451 _Sink<_CharT>* _M_sink = nullptr;
2453 public:
2454 using iterator_category = output_iterator_tag;
2455 using value_type = void;
2456 using difference_type = ptrdiff_t;
2457 using pointer = void;
2458 using reference = void;
2460 _Sink_iter() = default;
2461 _Sink_iter(const _Sink_iter&) = default;
2462 _Sink_iter& operator=(const _Sink_iter&) = default;
2464 [[__gnu__::__always_inline__]]
2465 explicit constexpr
2466 _Sink_iter(_Sink<_CharT>& __sink) : _M_sink(std::addressof(__sink)) { }
2468 [[__gnu__::__always_inline__]]
2469 constexpr _Sink_iter&
2470 operator=(_CharT __c)
2471 {
2472 _M_sink->_M_write(__c);
2473 return *this;
2474 }
2476 [[__gnu__::__always_inline__]]
2477 constexpr _Sink_iter&
2478 operator=(basic_string_view<_CharT> __s)
2479 {
2480 _M_sink->_M_write(__s);
2481 return *this;
2482 }
2484 [[__gnu__::__always_inline__]]
2485 constexpr _Sink_iter&
2486 operator*() { return *this; }
2488 [[__gnu__::__always_inline__]]
2489 constexpr _Sink_iter&
2490 operator++() { return *this; }
2492 [[__gnu__::__always_inline__]]
2493 constexpr _Sink_iter
2494 operator++(int) { return *this; }
2495 };
2497 // Abstract base class for type-erased character sinks.
2498 // All formatting and output is done via this type's iterator,
2499 // to reduce the number of different template instantiations.
2500 template<typename _CharT>
2501 class _Sink
2502 {
2503 friend class _Sink_iter<_CharT>;
2505 span<_CharT> _M_span;
2506 typename span<_CharT>::iterator _M_next;
2508 // Called when the span is full, to make more space available.
2509 // Precondition: _M_next != _M_span.begin()
2510 // Postcondition: _M_next != _M_span.end()
2511 virtual void _M_overflow() = 0;
2513 protected:
2514 // Precondition: __span.size() != 0
2515 [[__gnu__::__always_inline__]]
2516 explicit constexpr
2517 _Sink(span<_CharT> __span) noexcept
2518 : _M_span(__span), _M_next(__span.begin())
2519 { }
2521 // The portion of the span that has been written to.
2522 [[__gnu__::__always_inline__]]
2523 span<_CharT>
2524 _M_used() const noexcept
2525 { return _M_span.first(_M_next - _M_span.begin()); }
2527 // The portion of the span that has not been written to.
2528 [[__gnu__::__always_inline__]]
2529 constexpr span<_CharT>
2530 _M_unused() const noexcept
2531 { return _M_span.subspan(_M_next - _M_span.begin()); }
2533 // Use the start of the span as the next write position.
2534 [[__gnu__::__always_inline__]]
2535 constexpr void
2536 _M_rewind() noexcept
2537 { _M_next = _M_span.begin(); }
2539 // Replace the current output range.
2540 void
2541 _M_reset(span<_CharT> __s, size_t __pos = 0) noexcept
2542 {
2543 _M_span = __s;
2544 _M_next = __s.begin() + __pos;
2545 }
2547 // Called by the iterator for *it++ = c
2548 constexpr void
2549 _M_write(_CharT __c)
2550 {
2551 *_M_next++ = __c;
2552 if (_M_next - _M_span.begin() == std::ssize(_M_span)) [[unlikely]]
2553 _M_overflow();
2554 }
2556 constexpr void
2557 _M_write(basic_string_view<_CharT> __s)
2558 {
2559 span __to = _M_unused();
2560 while (__to.size() <= __s.size())
2561 {
2562 __s.copy(__to.data(), __to.size());
2563 _M_next += __to.size();
2564 __s.remove_prefix(__to.size());
2565 _M_overflow();
2566 __to = _M_unused();
2567 }
2568 if (__s.size())
2569 {
2570 __s.copy(__to.data(), __s.size());
2571 _M_next += __s.size();
2572 }
2573 }
2575 public:
2576 _Sink(const _Sink&) = delete;
2577 _Sink& operator=(const _Sink&) = delete;
2579 [[__gnu__::__always_inline__]]
2580 constexpr _Sink_iter<_CharT>
2581 out() noexcept
2582 { return _Sink_iter<_CharT>(*this); }
2583 };
2585 // A sink with an internal buffer. This is used to implement concrete sinks.
2586 template<typename _CharT>
2587 class _Buf_sink : public _Sink<_CharT>
2588 {
2589 protected:
2590 _CharT _M_buf[32 * sizeof(void*) / sizeof(_CharT)];
2592 [[__gnu__::__always_inline__]]
2593 constexpr
2594 _Buf_sink() noexcept
2595 : _Sink<_CharT>(_M_buf)
2596 { }
2597 };
2599 // A sink that fills a sequence (e.g. std::string, std::vector, std::deque).
2600 // Writes to a buffer then appends that to the sequence when it fills up.
2601 template<typename _Seq>
2602 class _Seq_sink final : public _Buf_sink<typename _Seq::value_type>
2603 {
2604 using _CharT = typename _Seq::value_type;
2606 _Seq _M_seq;
2608 // Transfer buffer contents to the sequence, so buffer can be refilled.
2609 void
2610 _M_overflow() override
2611 {
2612 auto __s = this->_M_used();
2613 if (__s.empty())
2614 return;
2615 if constexpr (__is_specialization_of<_Seq, basic_string>)
2616 _M_seq.append(__s.data(), __s.size());
2617 else
2618 _M_seq.insert(_M_seq.end(), __s.begin(), __s.end());
2619 this->_M_rewind();
2620 }
2622 public:
2623 // TODO: for SSO string, use SSO buffer as initial span, then switch
2624 // to _M_buf if it overflows? Or even do that for all unused capacity?
2626 [[__gnu__::__always_inline__]]
2627 _Seq_sink() noexcept(is_nothrow_default_constructible_v<_Seq>)
2628 { }
2630 _Seq_sink(_Seq&& __s) noexcept(is_nothrow_move_constructible_v<_Seq>)
2631 : _M_seq(std::move(__s))
2632 { }
2634 using _Sink<_CharT>::out;
2636 _Seq
2637 get() &&
2638 {
2639 if (this->_M_used().size() != 0)
2640 _Seq_sink::_M_overflow();
2641 return std::move(_M_seq);
2642 }
2643 };
2645 template<typename _CharT, typename _Alloc = allocator<_CharT>>
2646 using _Str_sink
2647 = _Seq_sink<basic_string<_CharT, char_traits<_CharT>, _Alloc>>;
2649 // template<typename _CharT, typename _Alloc = allocator<_CharT>>
2650 // using _Vec_sink = _Seq_sink<vector<_CharT, _Alloc>>;
2652 // A sink that writes to an output iterator.
2653 // Writes to a fixed-size buffer and then flushes to the output iterator
2654 // when the buffer fills up.
2655 template<typename _CharT, typename _OutIter>
2656 class _Iter_sink : public _Buf_sink<_CharT>
2657 {
2658 _OutIter _M_out;
2659 iter_difference_t<_OutIter> _M_max;
2661 protected:
2662 size_t _M_count = 0;
2664 void
2665 _M_overflow() override
2666 {
2667 auto __s = this->_M_used();
2668 if (_M_max < 0) // No maximum.
2669 _M_out = ranges::copy(__s, std::move(_M_out)).out;
2670 else if (_M_count < static_cast<size_t>(_M_max))
2671 {
2672 auto __max = _M_max - _M_count;
2673 span<_CharT> __first;
2674 if (__max < __s.size())
2675 __first = __s.first(static_cast<size_t>(__max));
2676 else
2677 __first = __s;
2678 _M_out = ranges::copy(__first, std::move(_M_out)).out;
2679 }
2680 this->_M_rewind();
2681 _M_count += __s.size();
2682 }
2684 public:
2685 [[__gnu__::__always_inline__]]
2686 explicit
2687 _Iter_sink(_OutIter __out, iter_difference_t<_OutIter> __max = -1)
2688 : _M_out(std::move(__out)), _M_max(__max)
2689 { }
2691 using _Sink<_CharT>::out;
2693 format_to_n_result<_OutIter>
2694 _M_finish() &&
2695 {
2696 if (this->_M_used().size() != 0)
2697 _Iter_sink::_M_overflow();
2698 iter_difference_t<_OutIter> __count(_M_count);
2699 return { std::move(_M_out), __count };
2700 }
2701 };
2703 // Partial specialization for contiguous iterators.
2704 // No buffer is used, characters are written straight to the iterator.
2705 // We do not know the size of the output range, so the span size just grows
2706 // as needed. The end of the span might be an invalid pointer outside the
2707 // valid range, but we never actually call _M_span.end(). This class does
2708 // not introduce any invalid pointer arithmetic or overflows that would not
2709 // have happened anyway.
2710 template<typename _CharT, contiguous_iterator _OutIter>
2711 requires same_as<iter_value_t<_OutIter>, _CharT>
2712 class _Iter_sink<_CharT, _OutIter> : public _Sink<_CharT>
2713 {
2714 using uint64_t = __UINTPTR_TYPE__;
2715 _OutIter _M_first;
2716 iter_difference_t<_OutIter> _M_max = -1;
2717 protected:
2718 size_t _M_count = 0;
2719 private:
2720 _CharT _M_buf[64]; // Write here after outputting _M_max characters.
2722 protected:
2723 void
2724 _M_overflow() override
2725 {
2726 if (this->_M_unused().size() != 0)
2727 return; // No need to switch to internal buffer yet.
2729 auto __s = this->_M_used();
2731 if (_M_max >= 0)
2732 {
2733 _M_count += __s.size();
2734 // Span was already sized for the maximum character count,
2735 // if it overflows then any further output must go to the
2736 // internal buffer, to be discarded.
2737 this->_M_reset(this->_M_buf);
2738 }
2739 else
2740 {
2741 // No maximum character count. Just extend the span to allow
2742 // writing more characters to it.
2743 this->_M_reset({__s.data(), __s.size() + 1024}, __s.size());
2744 }
2745 }
2747 private:
2748 static span<_CharT>
2749 _S_make_span(_CharT* __ptr, iter_difference_t<_OutIter> __n,
2750 span<_CharT> __buf) noexcept
2751 {
2752 if (__n == 0)
2753 return __buf; // Only write to the internal buffer.
2755 if (__n > 0)
2756 {
2757 if constexpr (!is_integral_v<iter_difference_t<_OutIter>>
2758 || sizeof(__n) > sizeof(size_t))
2759 {
2760 // __int128 or __detail::__max_diff_type
2761 auto __m = iter_difference_t<_OutIter>((size_t)-1);
2762 if (__n > __m)
2763 __n = __m;
2764 }
2765 return {__ptr, (size_t)__n};
2766 }
2768 #if __has_builtin(__builtin_dynamic_object_size)
2769 if (size_t __bytes = __builtin_dynamic_object_size(__ptr, 2))
2770 return {__ptr, __bytes / sizeof(_CharT)};
2771 #endif
2772 // Avoid forming a pointer to a different memory page.
2773 uint64_t __off = reinterpret_cast<uint64_t>(__ptr) % 1024;
2774 __n = (1024 - __off) / sizeof(_CharT);
2775 if (__n > 0) [[likely]]
2776 return {__ptr, static_cast<size_t>(__n)};
2777 else // Misaligned/packed buffer of wchar_t?
2778 return {__ptr, 1};
2779 }
2781 public:
2782 explicit
2783 _Iter_sink(_OutIter __out, iter_difference_t<_OutIter> __n = -1) noexcept
2784 : _Sink<_CharT>(_S_make_span(std::to_address(__out), __n, _M_buf)),
2785 _M_first(__out), _M_max(__n)
2786 { }
2788 format_to_n_result<_OutIter>
2789 _M_finish() &&
2790 {
2791 auto __s = this->_M_used();
2792 if (__s.data() == _M_buf)
2793 {
2794 // Switched to internal buffer, so must have written _M_max.
2795 iter_difference_t<_OutIter> __count(_M_count + __s.size());
2796 return { _M_first + _M_max, __count };
2797 }
2798 else // Not using internal buffer yet
2799 {
2800 iter_difference_t<_OutIter> __count(__s.size());
2801 return { _M_first + __count, __count };
2802 }
2803 }
2804 };
2806 enum _Arg_t : unsigned char {
2807 _Arg_none, _Arg_bool, _Arg_c, _Arg_i, _Arg_u, _Arg_ll, _Arg_ull,
2808 _Arg_flt, _Arg_dbl, _Arg_ldbl, _Arg_str, _Arg_sv, _Arg_ptr, _Arg_handle,
2809 _Arg_i128, _Arg_u128,
2810 _Arg_bf16, _Arg_f16, _Arg_f32, _Arg_f64, // These are unused.
2811 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
2812 _Arg_next_value_,
2813 _Arg_f128 = _Arg_ldbl,
2814 _Arg_ibm128 = _Arg_next_value_,
2815 #else
2816 _Arg_f128,
2817 #endif
2818 _Arg_max_
2819 };
2821 template<typename _Context>
2822 struct _Arg_value
2823 {
2824 using _CharT = typename _Context::char_type;
2826 struct _HandleBase
2827 {
2828 const void* _M_ptr;
2829 void (*_M_func)();
2830 };
2832 union
2833 {
2834 monostate _M_none;
2835 bool _M_bool;
2836 _CharT _M_c;
2837 int _M_i;
2838 unsigned _M_u;
2839 long long _M_ll;
2840 unsigned long long _M_ull;
2841 float _M_flt;
2842 double _M_dbl;
2843 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT // No long double if it's ambiguous.
2844 long double _M_ldbl;
2845 #endif
2846 const _CharT* _M_str;
2847 basic_string_view<_CharT> _M_sv;
2848 const void* _M_ptr;
2849 _HandleBase _M_handle;
2850 #ifdef __SIZEOF_INT128__
2851 __int128 _M_i128;
2852 unsigned __int128 _M_u128;
2853 #endif
2854 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
2855 __ieee128 _M_f128;
2856 __ibm128 _M_ibm128;
2857 #elif _GLIBCXX_FORMAT_F128 == 2
2858 __float128_t _M_f128;
2859 #endif
2860 };
2862 [[__gnu__::__always_inline__]]
2863 _Arg_value() : _M_none() { }
2865 #if 0
2866 template<typename _Tp>
2867 _Arg_value(in_place_type_t<_Tp>, _Tp __val)
2868 { _S_get<_Tp>() = __val; }
2869 #endif
2871 template<typename _Tp, typename _Self>
2872 [[__gnu__::__always_inline__]]
2873 static auto&
2874 _S_get(_Self& __u) noexcept
2875 {
2876 if constexpr (is_same_v<_Tp, bool>)
2877 return __u._M_bool;
2878 else if constexpr (is_same_v<_Tp, _CharT>)
2879 return __u._M_c;
2880 else if constexpr (is_same_v<_Tp, int>)
2881 return __u._M_i;
2882 else if constexpr (is_same_v<_Tp, unsigned>)
2883 return __u._M_u;
2884 else if constexpr (is_same_v<_Tp, long long>)
2885 return __u._M_ll;
2886 else if constexpr (is_same_v<_Tp, unsigned long long>)
2887 return __u._M_ull;
2888 else if constexpr (is_same_v<_Tp, float>)
2889 return __u._M_flt;
2890 else if constexpr (is_same_v<_Tp, double>)
2891 return __u._M_dbl;
2892 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
2893 else if constexpr (is_same_v<_Tp, long double>)
2894 return __u._M_ldbl;
2895 #else
2896 else if constexpr (is_same_v<_Tp, __ieee128>)
2897 return __u._M_f128;
2898 else if constexpr (is_same_v<_Tp, __ibm128>)
2899 return __u._M_ibm128;
2900 #endif
2901 else if constexpr (is_same_v<_Tp, const _CharT*>)
2902 return __u._M_str;
2903 else if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
2904 return __u._M_sv;
2905 else if constexpr (is_same_v<_Tp, const void*>)
2906 return __u._M_ptr;
2907 #ifdef __SIZEOF_INT128__
2908 else if constexpr (is_same_v<_Tp, __int128>)
2909 return __u._M_i128;
2910 else if constexpr (is_same_v<_Tp, unsigned __int128>)
2911 return __u._M_u128;
2912 #endif
2913 #if _GLIBCXX_FORMAT_F128 == 2
2914 else if constexpr (is_same_v<_Tp, __float128_t>)
2915 return __u._M_f128;
2916 #endif
2917 else if constexpr (derived_from<_Tp, _HandleBase>)
2918 return static_cast<_Tp&>(__u._M_handle);
2919 // Otherwise, ill-formed.
2920 }
2922 template<typename _Tp>
2923 [[__gnu__::__always_inline__]]
2924 auto&
2925 _M_get() noexcept
2926 { return _S_get<_Tp>(*this); }
2928 template<typename _Tp>
2929 [[__gnu__::__always_inline__]]
2930 const auto&
2931 _M_get() const noexcept
2932 { return _S_get<_Tp>(*this); }
2934 template<typename _Tp>
2935 [[__gnu__::__always_inline__]]
2936 void
2937 _M_set(_Tp __v) noexcept
2938 {
2939 if constexpr (derived_from<_Tp, _HandleBase>)
2940 std::construct_at(&_M_handle, __v);
2941 else
2942 _S_get<_Tp>(*this) = __v;
2943 }
2944 };
2946 // [format.arg.store], class template format-arg-store
2947 template<typename _Context, typename... _Args>
2948 class _Arg_store;
2950 } // namespace __format
2951 /// @endcond
2953 template<typename _Context>
2954 class basic_format_arg
2955 {
2956 using _CharT = typename _Context::char_type;
2958 template<typename _Tp>
2959 static constexpr bool __formattable
2960 = __format::__formattable_with<_Tp, _Context>;
2962 public:
2963 class handle : public __format::_Arg_value<_Context>::_HandleBase
2964 {
2965 using _Base = typename __format::_Arg_value<_Context>::_HandleBase;
2967 // Format as const if possible, to reduce instantiations.
2968 template<typename _Tp>
2969 using __maybe_const_t
2970 = __conditional_t<__format::__formattable_with<_Tp, _Context>,
2971 const _Tp, _Tp>;
2973 template<typename _Tq>
2974 static void
2975 _S_format(basic_format_parse_context<_CharT>& __parse_ctx,
2976 _Context& __format_ctx, const void* __ptr)
2977 {
2978 using _Td = remove_const_t<_Tq>;
2979 typename _Context::template formatter_type<_Td> __f;
2980 __parse_ctx.advance_to(__f.parse(__parse_ctx));
2981 _Tq& __val = *const_cast<_Tq*>(static_cast<const _Td*>(__ptr));
2982 __format_ctx.advance_to(__f.format(__val, __format_ctx));
2983 }
2985 template<typename _Tp>
2986 explicit
2987 handle(_Tp& __val) noexcept
2988 {
2989 if constexpr (!__format::__formattable_with<const _Tp, _Context>)
2990 static_assert(!is_const_v<_Tp>, "std::format argument must be "
2991 "non-const for this type");
2993 this->_M_ptr = __builtin_addressof(__val);
2994 auto __func = _S_format<__maybe_const_t<_Tp>>;
2995 this->_M_func = reinterpret_cast<void(*)()>(__func);
2996 }
2998 friend class basic_format_arg<_Context>;
3000 public:
3001 handle(const handle&) = default;
3002 handle& operator=(const handle&) = default;
3004 [[__gnu__::__always_inline__]]
3005 void
3006 format(basic_format_parse_context<_CharT>& __pc, _Context& __fc) const
3007 {
3008 using _Func = void(*)(basic_format_parse_context<_CharT>&,
3009 _Context&, const void*);
3010 auto __f = reinterpret_cast<_Func>(this->_M_func);
3011 __f(__pc, __fc, this->_M_ptr);
3012 }
3013 };
3015 [[__gnu__::__always_inline__]]
3016 basic_format_arg() noexcept : _M_type(__format::_Arg_none) { }
3018 [[nodiscard,__gnu__::__always_inline__]]
3019 explicit operator bool() const noexcept
3020 { return _M_type != __format::_Arg_none; }
3022 private:
3023 template<typename _Ctx>
3024 friend class basic_format_args;
3026 template<typename _Ctx, typename... _Args>
3027 friend class __format::_Arg_store;
3029 static_assert(is_trivially_copyable_v<__format::_Arg_value<_Context>>);
3031 __format::_Arg_value<_Context> _M_val;
3032 __format::_Arg_t _M_type;
3034 // Transform incoming argument type to the type stored in _Arg_value.
3035 // e.g. short -> int, std::string -> std::string_view,
3036 // char[3] -> const char*.
3037 template<typename _Tp>
3038 static consteval auto
3039 _S_to_arg_type()
3040 {
3041 using _Td = remove_const_t<_Tp>;
3042 if constexpr (is_same_v<_Td, bool>)
3043 return type_identity<bool>();
3044 else if constexpr (is_same_v<_Td, _CharT>)
3045 return type_identity<_CharT>();
3046 else if constexpr (is_same_v<_Td, char> && is_same_v<_CharT, wchar_t>)
3047 return type_identity<_CharT>();
3048 #ifdef __SIZEOF_INT128__ // Check before signed/unsigned integer
3049 else if constexpr (is_same_v<_Td, __int128>)
3050 return type_identity<__int128>();
3051 else if constexpr (is_same_v<_Td, unsigned __int128>)
3052 return type_identity<unsigned __int128>();
3053 #endif
3054 else if constexpr (__is_signed_integer<_Td>::value)
3055 {
3056 if constexpr (sizeof(_Td) <= sizeof(int))
3057 return type_identity<int>();
3058 else if constexpr (sizeof(_Td) <= sizeof(long long))
3059 return type_identity<long long>();
3060 }
3061 else if constexpr (__is_unsigned_integer<_Td>::value)
3062 {
3063 if constexpr (sizeof(_Td) <= sizeof(unsigned))
3064 return type_identity<unsigned>();
3065 else if constexpr (sizeof(_Td) <= sizeof(unsigned long long))
3066 return type_identity<unsigned long long>();
3067 }
3068 else if constexpr (is_same_v<_Td, float>)
3069 return type_identity<float>();
3070 else if constexpr (is_same_v<_Td, double>)
3071 return type_identity<double>();
3072 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3073 else if constexpr (is_same_v<_Td, long double>)
3074 return type_identity<long double>();
3075 #else
3076 else if constexpr (is_same_v<_Td, __ibm128>)
3077 return type_identity<__ibm128>();
3078 else if constexpr (is_same_v<_Td, __ieee128>)
3079 return type_identity<__ieee128>();
3080 #endif
3082 #if defined(__FLT16_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
3083 else if constexpr (is_same_v<_Td, _Float16>)
3084 return type_identity<float>();
3085 #endif
3087 #if defined(__BFLT16_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
3088 else if constexpr (is_same_v<_Td, decltype(0.0bf16)>)
3089 return type_identity<float>();
3090 #endif
3092 #ifdef __FLT32_DIG__
3093 else if constexpr (is_same_v<_Td, _Float32>)
3094 # ifdef _GLIBCXX_FLOAT_IS_IEEE_BINARY32
3095 return type_identity<float>();
3096 # else
3097 return type_identity<_Float32>();
3098 # endif
3099 #endif
3100 #ifdef __FLT64_DIG__
3101 else if constexpr (is_same_v<_Td, _Float64>)
3102 # ifdef _GLIBCXX_DOUBLE_IS_IEEE_BINARY64
3103 return type_identity<double>();
3104 # else
3105 return type_identity<_Float64>();
3106 # endif
3107 #endif
3108 #if _GLIBCXX_FORMAT_F128
3109 # if __FLT128_DIG__
3110 else if constexpr (is_same_v<_Td, _Float128>)
3111 return type_identity<__format::__float128_t>();
3112 # endif
3113 # if __SIZEOF_FLOAT128__
3114 else if constexpr (is_same_v<_Td, __float128>)
3115 return type_identity<__format::__float128_t>();
3116 # endif
3117 #endif
3118 else if constexpr (__is_specialization_of<_Td, basic_string_view>)
3119 return type_identity<basic_string_view<_CharT>>();
3120 else if constexpr (__is_specialization_of<_Td, basic_string>)
3121 return type_identity<basic_string_view<_CharT>>();
3122 else if constexpr (is_same_v<decay_t<_Td>, const _CharT*>)
3123 return type_identity<const _CharT*>();
3124 else if constexpr (is_same_v<decay_t<_Td>, _CharT*>)
3125 return type_identity<const _CharT*>();
3126 else if constexpr (is_void_v<remove_pointer_t<_Td>>)
3127 return type_identity<const void*>();
3128 else if constexpr (is_same_v<_Td, nullptr_t>)
3129 return type_identity<const void*>();
3130 else
3131 return type_identity<handle>();
3132 }
3134 // Transform a formattable type to the appropriate storage type.
3135 template<typename _Tp>
3136 using _Normalize = typename decltype(_S_to_arg_type<_Tp>())::type;
3138 // Get the _Arg_t value corresponding to a normalized type.
3139 template<typename _Tp>
3140 static consteval __format::_Arg_t
3141 _S_to_enum()
3142 {
3143 using namespace __format;
3144 if constexpr (is_same_v<_Tp, bool>)
3145 return _Arg_bool;
3146 else if constexpr (is_same_v<_Tp, _CharT>)
3147 return _Arg_c;
3148 else if constexpr (is_same_v<_Tp, int>)
3149 return _Arg_i;
3150 else if constexpr (is_same_v<_Tp, unsigned>)
3151 return _Arg_u;
3152 else if constexpr (is_same_v<_Tp, long long>)
3153 return _Arg_ll;
3154 else if constexpr (is_same_v<_Tp, unsigned long long>)
3155 return _Arg_ull;
3156 else if constexpr (is_same_v<_Tp, float>)
3157 return _Arg_flt;
3158 else if constexpr (is_same_v<_Tp, double>)
3159 return _Arg_dbl;
3160 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3161 else if constexpr (is_same_v<_Tp, long double>)
3162 return _Arg_ldbl;
3163 #else
3164 // Don't use _Arg_ldbl for this target, it's ambiguous.
3165 else if constexpr (is_same_v<_Tp, __ibm128>)
3166 return _Arg_ibm128;
3167 else if constexpr (is_same_v<_Tp, __ieee128>)
3168 return _Arg_f128;
3169 #endif
3170 else if constexpr (is_same_v<_Tp, const _CharT*>)
3171 return _Arg_str;
3172 else if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
3173 return _Arg_sv;
3174 else if constexpr (is_same_v<_Tp, const void*>)
3175 return _Arg_ptr;
3176 #ifdef __SIZEOF_INT128__
3177 else if constexpr (is_same_v<_Tp, __int128>)
3178 return _Arg_i128;
3179 else if constexpr (is_same_v<_Tp, unsigned __int128>)
3180 return _Arg_u128;
3181 #endif
3183 // N.B. some of these types will never actually be used here,
3184 // because they get normalized to a standard floating-point type.
3185 #if defined __FLT32_DIG__ && ! _GLIBCXX_FLOAT_IS_IEEE_BINARY32
3186 else if constexpr (is_same_v<_Tp, _Float32>)
3187 return _Arg_f32;
3188 #endif
3189 #if defined __FLT64_DIG__ && ! _GLIBCXX_DOUBLE_IS_IEEE_BINARY64
3190 else if constexpr (is_same_v<_Tp, _Float64>)
3191 return _Arg_f64;
3192 #endif
3193 #if _GLIBCXX_FORMAT_F128 == 2
3194 else if constexpr (is_same_v<_Tp, __format::__float128_t>)
3195 return _Arg_f128;
3196 #endif
3197 else if constexpr (is_same_v<_Tp, handle>)
3198 return _Arg_handle;
3199 }
3201 template<typename _Tp>
3202 void
3203 _M_set(_Tp __v) noexcept
3204 {
3205 _M_type = _S_to_enum<_Tp>();
3206 _M_val._M_set(__v);
3207 }
3209 template<typename _Tp>
3210 requires __format::__formattable_with<_Tp, _Context>
3211 explicit
3212 basic_format_arg(_Tp& __v) noexcept
3213 {
3214 using _Td = _Normalize<_Tp>;
3215 if constexpr (is_same_v<_Td, basic_string_view<_CharT>>)
3216 _M_set(_Td{__v.data(), __v.size()});
3217 else
3218 _M_set(static_cast<_Td>(__v));
3219 }
3221 template<typename _Ctx, typename... _Argz>
3222 friend auto
3223 make_format_args(_Argz&&...) noexcept;
3225 template<typename _Visitor, typename _Ctx>
3226 friend decltype(auto)
3227 visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx>);
3229 template<typename _Visitor>
3230 decltype(auto)
3231 _M_visit(_Visitor&& __vis, __format::_Arg_t __type)
3232 {
3233 using namespace __format;
3234 switch (__type)
3235 {
3236 case _Arg_none:
3237 return std::forward<_Visitor>(__vis)(_M_val._M_none);
3238 case _Arg_bool:
3239 return std::forward<_Visitor>(__vis)(_M_val._M_bool);
3240 case _Arg_c:
3241 return std::forward<_Visitor>(__vis)(_M_val._M_c);
3242 case _Arg_i:
3243 return std::forward<_Visitor>(__vis)(_M_val._M_i);
3244 case _Arg_u:
3245 return std::forward<_Visitor>(__vis)(_M_val._M_u);
3246 case _Arg_ll:
3247 return std::forward<_Visitor>(__vis)(_M_val._M_ll);
3248 case _Arg_ull:
3249 return std::forward<_Visitor>(__vis)(_M_val._M_ull);
3250 #if __glibcxx_to_chars // FIXME: need to be able to format these types!
3251 case _Arg_flt:
3252 return std::forward<_Visitor>(__vis)(_M_val._M_flt);
3253 case _Arg_dbl:
3254 return std::forward<_Visitor>(__vis)(_M_val._M_dbl);
3255 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3256 case _Arg_ldbl:
3257 return std::forward<_Visitor>(__vis)(_M_val._M_ldbl);
3258 #else
3259 case _Arg_f128:
3260 return std::forward<_Visitor>(__vis)(_M_val._M_f128);
3261 case _Arg_ibm128:
3262 return std::forward<_Visitor>(__vis)(_M_val._M_ibm128);
3263 #endif
3264 #endif
3265 case _Arg_str:
3266 return std::forward<_Visitor>(__vis)(_M_val._M_str);
3267 case _Arg_sv:
3268 return std::forward<_Visitor>(__vis)(_M_val._M_sv);
3269 case _Arg_ptr:
3270 return std::forward<_Visitor>(__vis)(_M_val._M_ptr);
3271 case _Arg_handle:
3272 {
3273 auto& __h = static_cast<handle&>(_M_val._M_handle);
3274 return std::forward<_Visitor>(__vis)(__h);
3275 }
3276 #ifdef __SIZEOF_INT128__
3277 case _Arg_i128:
3278 return std::forward<_Visitor>(__vis)(_M_val._M_i128);
3279 case _Arg_u128:
3280 return std::forward<_Visitor>(__vis)(_M_val._M_u128);
3281 #endif
3283 #if _GLIBCXX_FORMAT_F128 == 2
3284 case _Arg_f128:
3285 return std::forward<_Visitor>(__vis)(_M_val._M_f128);
3286 #endif
3288 default:
3289 // _Arg_f16 etc.
3290 __builtin_unreachable();
3291 }
3292 }
3293 };
3295 template<typename _Visitor, typename _Context>
3296 inline decltype(auto)
3297 visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg)
3298 {
3299 return __arg._M_visit(std::forward<_Visitor>(__vis), __arg._M_type);
3300 }
3302 /// @cond undocumented
3303 namespace __format
3304 {
3305 struct _WidthPrecVisitor
3306 {
3307 template<typename _Tp>
3308 size_t
3309 operator()(_Tp& __arg) const
3310 {
3311 if constexpr (is_same_v<_Tp, monostate>)
3312 __format::__invalid_arg_id_in_format_string();
3313 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3314 // 3720. Restrict the valid types of arg-id for width and precision
3315 // 3721. Allow an arg-id with a value of zero for width
3316 else if constexpr (sizeof(_Tp) <= sizeof(long long))
3317 {
3318 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3319 // 3720. Restrict the valid types of arg-id for width and precision
3320 if constexpr (__is_unsigned_integer<_Tp>::value)
3321 return __arg;
3322 else if constexpr (__is_signed_integer<_Tp>::value)
3323 if (__arg >= 0)
3324 return __arg;
3325 }
3326 __throw_format_error("format error: argument used for width or "
3327 "precision must be a non-negative integer");
3328 }
3329 };
3331 template<typename _Context>
3332 inline size_t
3333 __int_from_arg(const basic_format_arg<_Context>& __arg)
3334 { return std::visit_format_arg(_WidthPrecVisitor(), __arg); }
3336 // Pack _Arg_t enum values into a single 60-bit integer.
3337 template<int _Bits, size_t _Nm>
3338 constexpr auto
3339 __pack_arg_types(const array<_Arg_t, _Nm>& __types)
3340 {
3341 __UINT64_TYPE__ __packed_types = 0;
3342 for (auto __i = __types.rbegin(); __i != __types.rend(); ++__i)
3343 __packed_types = (__packed_types << _Bits) | *__i;
3344 return __packed_types;
3345 }
3346 } // namespace __format
3347 /// @endcond
3349 template<typename _Context>
3350 class basic_format_args
3351 {
3352 static constexpr int _S_packed_type_bits = 5; // _Arg_t values [0,20]
3353 static constexpr int _S_packed_type_mask = 0b11111;
3354 static constexpr int _S_max_packed_args = 12;
3356 static_assert( __format::_Arg_max_ <= (1 << _S_packed_type_bits) );
3358 template<typename... _Args>
3359 using _Store = __format::_Arg_store<_Context, _Args...>;
3361 template<typename _Ctx, typename... _Args>
3362 friend class __format::_Arg_store;
3364 using uint64_t = __UINT64_TYPE__;
3365 using _Format_arg = basic_format_arg<_Context>;
3366 using _Format_arg_val = __format::_Arg_value<_Context>;
3368 // If args are packed then the number of args is in _M_packed_size and
3369 // the packed types are in _M_unpacked_size, accessed via _M_type(i).
3370 // If args are not packed then the number of args is in _M_unpacked_size
3371 // and _M_packed_size is zero.
3372 uint64_t _M_packed_size : 4;
3373 uint64_t _M_unpacked_size : 60;
3375 union {
3376 const _Format_arg_val* _M_values; // Active when _M_packed_size != 0
3377 const _Format_arg* _M_args; // Active when _M_packed_size == 0
3378 };
3380 size_t
3381 _M_size() const noexcept
3382 { return _M_packed_size ? _M_packed_size : _M_unpacked_size; }
3384 typename __format::_Arg_t
3385 _M_type(size_t __i) const noexcept
3386 {
3387 uint64_t __t = _M_unpacked_size >> (__i * _S_packed_type_bits);
3388 return static_cast<__format::_Arg_t>(__t & _S_packed_type_mask);
3389 }
3391 template<typename _Ctx, typename... _Args>
3392 friend auto
3393 make_format_args(_Args&&...) noexcept;
3395 // An array of _Arg_t enums corresponding to _Args...
3396 template<typename... _Args>
3397 static consteval array<__format::_Arg_t, sizeof...(_Args)>
3398 _S_types_to_pack()
3399 { return {_Format_arg::template _S_to_enum<_Args>()...}; }
3401 public:
3402 basic_format_args() noexcept = default;
3404 template<typename... _Args>
3405 basic_format_args(const _Store<_Args...>& __store) noexcept;
3407 [[nodiscard,__gnu__::__always_inline__]]
3408 basic_format_arg<_Context>
3409 get(size_t __i) const noexcept
3410 {
3411 basic_format_arg<_Context> __arg;
3412 if (__i < _M_packed_size)
3413 {
3414 __arg._M_type = _M_type(__i);
3415 __arg._M_val = _M_values[__i];
3416 }
3417 else if (_M_packed_size == 0 && __i < _M_unpacked_size)
3418 __arg = _M_args[__i];
3419 return __arg;
3420 }
3421 };
3423 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3424 // 3810. CTAD for std::basic_format_args
3425 template<typename _Context, typename... _Args>
3426 basic_format_args(__format::_Arg_store<_Context, _Args...>)
3427 -> basic_format_args<_Context>;
3429 template<typename _Context, typename... _Args>
3430 auto
3431 make_format_args(_Args&&... __fmt_args) noexcept;
3433 // An array of type-erased formatting arguments.
3434 template<typename _Context, typename... _Args>
3435 class __format::_Arg_store
3436 {
3437 friend std::basic_format_args<_Context>;
3439 template<typename _Ctx, typename... _Argz>
3440 friend auto
3441 #if _GLIBCXX_INLINE_VERSION
3442 // Needed for PR c++/59526
3443 std::__8::
3444 #else
3445 std::
3446 #endif
3447 make_format_args(_Argz&&...) noexcept;
3449 // For a sufficiently small number of arguments we only store values.
3450 // basic_format_args can get the types from the _Args pack.
3451 static constexpr bool _S_values_only
3452 = sizeof...(_Args) <= basic_format_args<_Context>::_S_max_packed_args;
3454 using _Element_t
3455 = __conditional_t<_S_values_only,
3456 __format::_Arg_value<_Context>,
3457 basic_format_arg<_Context>>;
3459 _Element_t _M_args[sizeof...(_Args)];
3461 template<typename _Tp>
3462 static _Element_t
3463 _S_make_elt(_Tp& __v)
3464 {
3465 basic_format_arg<_Context> __arg(__v);
3466 if constexpr (_S_values_only)
3467 return __arg._M_val;
3468 else
3469 return __arg;
3470 }
3472 template<typename... _Tp>
3473 requires (sizeof...(_Tp) == sizeof...(_Args))
3474 [[__gnu__::__always_inline__]]
3475 _Arg_store(_Tp&... __a) noexcept
3476 : _M_args{_S_make_elt(__a)...}
3477 { }
3478 };
3480 template<typename _Context>
3481 class __format::_Arg_store<_Context>
3482 { };
3484 template<typename _Context>
3485 template<typename... _Args>
3486 inline
3487 basic_format_args<_Context>::
3488 basic_format_args(const _Store<_Args...>& __store) noexcept
3489 {
3490 if constexpr (sizeof...(_Args) == 0)
3491 {
3492 _M_packed_size = 0;
3493 _M_unpacked_size = 0;
3494 _M_args = nullptr;
3495 }
3496 else if constexpr (sizeof...(_Args) <= _S_max_packed_args)
3497 {
3498 // The number of packed arguments:
3499 _M_packed_size = sizeof...(_Args);
3500 // The packed type enums:
3501 _M_unpacked_size
3502 = __format::__pack_arg_types<_S_packed_type_bits>(_S_types_to_pack<_Args...>());
3503 // The _Arg_value objects.
3504 _M_values = __store._M_args;
3505 }
3506 else
3507 {
3508 // No packed arguments:
3509 _M_packed_size = 0;
3510 // The number of unpacked arguments:
3511 _M_unpacked_size = sizeof...(_Args);
3512 // The basic_format_arg objects:
3513 _M_args = __store._M_args;
3514 }
3515 }
3517 /// Capture formatting arguments for use by `std::vformat`.
3518 template<typename _Context = format_context, typename... _Args>
3519 [[nodiscard,__gnu__::__always_inline__]]
3520 inline auto
3521 make_format_args(_Args&&... __fmt_args) noexcept
3522 {
3523 using _Fmt_arg = basic_format_arg<_Context>;
3524 using _Store = __format::_Arg_store<_Context, typename _Fmt_arg::template
3525 _Normalize<remove_reference_t<_Args>>...>;
3526 return _Store(__fmt_args...);
3527 }
3529 #ifdef _GLIBCXX_USE_WCHAR_T
3530 /// Capture formatting arguments for use by `std::vformat` (for wide output).
3531 template<typename... _Args>
3532 [[nodiscard,__gnu__::__always_inline__]]
3533 inline auto
3534 make_wformat_args(_Args&&... __args) noexcept
3535 { return std::make_format_args<wformat_context>(__args...); }
3536 #endif
3538 /// @cond undocumented
3539 namespace __format
3540 {
3541 template<typename _Out, typename _CharT, typename _Context>
3542 _Out
3543 __do_vformat_to(_Out, basic_string_view<_CharT>,
3544 const basic_format_args<_Context>&,
3545 const locale* = nullptr);
3546 } // namespace __format
3547 /// @endcond
3549 /** Context for std::format and similar functions.
3550 *
3551 * A formatting context contains an output iterator and locale to use
3552 * for the formatting operations. Most programs will never need to use
3553 * this class template explicitly. For typical uses of `std::format` the
3554 * library will use the specializations `std::format_context` (for `char`)
3555 * and `std::wformat_context` (for `wchar_t`).
3556 */
3557 template<typename _Out, typename _CharT>
3558 class basic_format_context
3559 {
3560 static_assert( output_iterator<_Out, const _CharT&> );
3562 basic_format_args<basic_format_context> _M_args;
3563 _Out _M_out;
3564 __format::_Optional_locale _M_loc;
3566 basic_format_context(basic_format_args<basic_format_context> __args,
3567 _Out __out)
3568 : _M_args(__args), _M_out(std::move(__out))
3569 { }
3571 basic_format_context(basic_format_args<basic_format_context> __args,
3572 _Out __out, const std::locale& __loc)
3573 : _M_args(__args), _M_out(std::move(__out)), _M_loc(__loc)
3574 { }
3576 template<typename _Out2, typename _CharT2, typename _Context2>
3577 friend _Out2
3578 __format::__do_vformat_to(_Out2, basic_string_view<_CharT2>,
3579 const basic_format_args<_Context2>&,
3580 const locale*);
3582 public:
3583 basic_format_context() = default;
3584 ~basic_format_context() = default;
3586 using iterator = _Out;
3587 using char_type = _CharT;
3588 template<typename _Tp>
3589 using formatter_type = formatter<_Tp, _CharT>;
3591 [[nodiscard]]
3592 basic_format_arg<basic_format_context>
3593 arg(size_t __id) const noexcept
3594 { return _M_args.get(__id); }
3596 [[nodiscard]]
3597 std::locale locale() { return _M_loc.value(); }
3599 [[nodiscard]]
3600 iterator out() { return std::move(_M_out); }
3602 void advance_to(iterator __it) { _M_out = std::move(__it); }
3603 };
3606 /// @cond undocumented
3607 namespace __format
3608 {
3609 // Abstract base class defining an interface for scanning format strings.
3610 // Scan the characters in a format string, dividing it up into strings of
3611 // ordinary characters, escape sequences, and replacement fields.
3612 // Call virtual functions for derived classes to parse format-specifiers
3613 // or write formatted output.
3614 template<typename _CharT>
3615 struct _Scanner
3616 {
3617 using iterator = typename basic_format_parse_context<_CharT>::iterator;
3619 basic_format_parse_context<_CharT> _M_pc;
3621 constexpr explicit
3622 _Scanner(basic_string_view<_CharT> __str, size_t __nargs = -1)
3623 : _M_pc(__str, __nargs)
3624 { }
3626 constexpr iterator begin() const noexcept { return _M_pc.begin(); }
3627 constexpr iterator end() const noexcept { return _M_pc.end(); }
3629 constexpr void
3630 _M_scan()
3631 {
3632 basic_string_view<_CharT> __fmt = _M_fmt_str();
3634 if (__fmt.size() == 2 && __fmt[0] == '{' && __fmt[1] == '}')
3635 {
3636 _M_pc.advance_to(begin() + 1);
3637 _M_format_arg(_M_pc.next_arg_id());
3638 return;
3639 }
3641 size_t __lbr = __fmt.find('{');
3642 size_t __rbr = __fmt.find('}');
3644 while (__fmt.size())
3645 {
3646 auto __cmp = __lbr <=> __rbr;
3647 if (__cmp == 0)
3648 {
3649 _M_on_chars(end());
3650 _M_pc.advance_to(end());
3651 return;
3652 }
3653 else if (__cmp < 0)
3654 {
3655 if (__lbr + 1 == __fmt.size()
3656 || (__rbr == __fmt.npos && __fmt[__lbr + 1] != '{'))
3657 __format::__unmatched_left_brace_in_format_string();
3658 const bool __is_escape = __fmt[__lbr + 1] == '{';
3659 iterator __last = begin() + __lbr + int(__is_escape);
3660 _M_on_chars(__last);
3661 _M_pc.advance_to(__last + 1);
3662 __fmt = _M_fmt_str();
3663 if (__is_escape)
3664 {
3665 if (__rbr != __fmt.npos)
3666 __rbr -= __lbr + 2;
3667 __lbr = __fmt.find('{');
3668 }
3669 else
3670 {
3671 _M_on_replacement_field();
3672 __fmt = _M_fmt_str();
3673 __lbr = __fmt.find('{');
3674 __rbr = __fmt.find('}');
3675 }
3676 }
3677 else
3678 {
3679 if (++__rbr == __fmt.size() || __fmt[__rbr] != '}')
3680 __format::__unmatched_right_brace_in_format_string();
3681 iterator __last = begin() + __rbr;
3682 _M_on_chars(__last);
3683 _M_pc.advance_to(__last + 1);
3684 __fmt = _M_fmt_str();
3685 if (__lbr != __fmt.npos)
3686 __lbr -= __rbr + 1;
3687 __rbr = __fmt.find('}');
3688 }
3689 }
3690 }
3692 constexpr basic_string_view<_CharT>
3693 _M_fmt_str() const noexcept
3694 { return {begin(), end()}; }
3696 constexpr virtual void _M_on_chars(iterator) { }
3698 constexpr void _M_on_replacement_field()
3699 {
3700 auto __next = begin();
3702 size_t __id;
3703 if (*__next == '}')
3704 __id = _M_pc.next_arg_id();
3705 else if (*__next == ':')
3706 {
3707 __id = _M_pc.next_arg_id();
3708 _M_pc.advance_to(++__next);
3709 }
3710 else
3711 {
3712 auto [__i, __ptr] = __format::__parse_arg_id(begin(), end());
3713 if (!__ptr || !(*__ptr == '}' || *__ptr == ':'))
3714 __format::__invalid_arg_id_in_format_string();
3715 _M_pc.check_arg_id(__id = __i);
3716 if (*__ptr == ':')
3717 {
3718 _M_pc.advance_to(++__ptr);
3719 }
3720 else
3721 _M_pc.advance_to(__ptr);
3722 }
3723 _M_format_arg(__id);
3724 if (begin() == end() || *begin() != '}')
3725 __format::__unmatched_left_brace_in_format_string();
3726 _M_pc.advance_to(begin() + 1); // Move past '}'
3727 }
3729 constexpr virtual void _M_format_arg(size_t __id) = 0;
3730 };
3732 // Process a format string and format the arguments in the context.
3733 template<typename _Out, typename _CharT>
3734 class _Formatting_scanner : public _Scanner<_CharT>
3735 {
3736 public:
3737 _Formatting_scanner(basic_format_context<_Out, _CharT>& __fc,
3738 basic_string_view<_CharT> __str)
3739 : _Scanner<_CharT>(__str), _M_fc(__fc)
3740 { }
3742 private:
3743 basic_format_context<_Out, _CharT>& _M_fc;
3745 using iterator = typename _Scanner<_CharT>::iterator;
3747 constexpr void
3748 _M_on_chars(iterator __last) override
3749 {
3750 basic_string_view<_CharT> __str(this->begin(), __last);
3751 _M_fc.advance_to(__format::__write(_M_fc.out(), __str));
3752 }
3754 constexpr void
3755 _M_format_arg(size_t __id) override
3756 {
3757 using _Context = basic_format_context<_Out, _CharT>;
3758 using handle = typename basic_format_arg<_Context>::handle;
3760 std::visit_format_arg([this](auto& __arg) {
3761 using _Type = remove_reference_t<decltype(__arg)>;
3762 using _Formatter = typename _Context::template formatter_type<_Type>;
3763 if constexpr (is_same_v<_Type, monostate>)
3764 __format::__invalid_arg_id_in_format_string();
3765 else if constexpr (is_same_v<_Type, handle>)
3766 __arg.format(this->_M_pc, this->_M_fc);
3767 else if constexpr (is_default_constructible_v<_Formatter>)
3768 {
3769 _Formatter __f;
3770 this->_M_pc.advance_to(__f.parse(this->_M_pc));
3771 this->_M_fc.advance_to(__f.format(__arg, this->_M_fc));
3772 }
3773 else
3774 static_assert(__format::__formattable_with<_Type, _Context>);
3775 }, _M_fc.arg(__id));
3776 }
3777 };
3779 // Validate a format string for Args.
3780 template<typename _CharT, typename... _Args>
3781 class _Checking_scanner : public _Scanner<_CharT>
3782 {
3783 static_assert(
3784 (is_default_constructible_v<formatter<_Args, _CharT>> && ...),
3785 "std::formatter must be specialized for each type being formatted");
3787 public:
3788 constexpr
3789 _Checking_scanner(basic_string_view<_CharT> __str)
3790 : _Scanner<_CharT>(__str, sizeof...(_Args))
3791 { }
3793 private:
3794 constexpr void
3795 _M_format_arg(size_t __id) override
3796 {
3797 if constexpr (sizeof...(_Args) != 0)
3798 {
3799 if (__id < sizeof...(_Args))
3800 {
3801 _M_parse_format_spec<_Args...>(__id);
3802 return;
3803 }
3804 }
3805 __builtin_unreachable();
3806 }
3808 template<typename _Tp, typename... _OtherArgs>
3809 constexpr void
3810 _M_parse_format_spec(size_t __id)
3811 {
3812 if (__id == 0)
3813 {
3814 formatter<_Tp, _CharT> __f;
3815 this->_M_pc.advance_to(__f.parse(this->_M_pc));
3816 }
3817 else if constexpr (sizeof...(_OtherArgs) != 0)
3818 _M_parse_format_spec<_OtherArgs...>(__id - 1);
3819 else
3820 __builtin_unreachable();
3821 }
3822 };
3824 template<typename _Out, typename _CharT, typename _Context>
3825 inline _Out
3826 __do_vformat_to(_Out __out, basic_string_view<_CharT> __fmt,
3827 const basic_format_args<_Context>& __args,
3828 const locale* __loc)
3829 {
3830 _Iter_sink<_CharT, _Out> __sink(std::move(__out));
3831 _Sink_iter<_CharT> __sink_out;
3833 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
3834 __sink_out = __out; // Already a sink iterator, safe to use post-move.
3835 else
3836 __sink_out = __sink.out();
3838 auto __ctx = __loc == nullptr
3839 ? _Context(__args, __sink_out)
3840 : _Context(__args, __sink_out, *__loc);
3841 _Formatting_scanner<_Sink_iter<_CharT>, _CharT> __scanner(__ctx, __fmt);
3842 __scanner._M_scan();
3844 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
3845 return __ctx.out();
3846 else
3847 return std::move(__sink)._M_finish().out;
3848 }
3850 } // namespace __format
3851 /// @endcond
3853 template<typename _CharT, typename... _Args>
3854 template<typename _Tp>
3855 requires convertible_to<const _Tp&, basic_string_view<_CharT>>
3856 consteval
3857 basic_format_string<_CharT, _Args...>::
3858 basic_format_string(const _Tp& __s)
3859 : _M_str(__s)
3860 {
3861 __format::_Checking_scanner<_CharT, remove_cvref_t<_Args>...>
3862 __scanner(_M_str);
3863 __scanner._M_scan();
3864 }
3866 // [format.functions], formatting functions
3868 template<typename _Out> requires output_iterator<_Out, const char&>
3869 [[__gnu__::__always_inline__]]
3870 inline _Out
3871 vformat_to(_Out __out, string_view __fmt, format_args __args)
3872 { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
3874 #ifdef _GLIBCXX_USE_WCHAR_T
3875 template<typename _Out> requires output_iterator<_Out, const wchar_t&>
3876 [[__gnu__::__always_inline__]]
3877 inline _Out
3878 vformat_to(_Out __out, wstring_view __fmt, wformat_args __args)
3879 { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
3880 #endif
3882 template<typename _Out> requires output_iterator<_Out, const char&>
3883 [[__gnu__::__always_inline__]]
3884 inline _Out
3885 vformat_to(_Out __out, const locale& __loc, string_view __fmt,
3886 format_args __args)
3887 {
3888 return __format::__do_vformat_to(std::move(__out), __fmt, __args, &__loc);
3889 }
3891 #ifdef _GLIBCXX_USE_WCHAR_T
3892 template<typename _Out> requires output_iterator<_Out, const wchar_t&>
3893 [[__gnu__::__always_inline__]]
3894 inline _Out
3895 vformat_to(_Out __out, const locale& __loc, wstring_view __fmt,
3896 wformat_args __args)
3897 {
3898 return __format::__do_vformat_to(std::move(__out), __fmt, __args, &__loc);
3899 }
3900 #endif
3902 [[nodiscard]]
3903 inline string
3904 vformat(string_view __fmt, format_args __args)
3905 {
3906 __format::_Str_sink<char> __buf;
3907 std::vformat_to(__buf.out(), __fmt, __args);
3908 return std::move(__buf).get();
3909 }
3911 #ifdef _GLIBCXX_USE_WCHAR_T
3912 [[nodiscard]]
3913 inline wstring
3914 vformat(wstring_view __fmt, wformat_args __args)
3915 {
3916 __format::_Str_sink<wchar_t> __buf;
3917 std::vformat_to(__buf.out(), __fmt, __args);
3918 return std::move(__buf).get();
3919 }
3920 #endif
3922 [[nodiscard]]
3923 inline string
3924 vformat(const locale& __loc, string_view __fmt, format_args __args)
3925 {
3926 __format::_Str_sink<char> __buf;
3927 std::vformat_to(__buf.out(), __loc, __fmt, __args);
3928 return std::move(__buf).get();
3929 }
3931 #ifdef _GLIBCXX_USE_WCHAR_T
3932 [[nodiscard]]
3933 inline wstring
3934 vformat(const locale& __loc, wstring_view __fmt, wformat_args __args)
3935 {
3936 __format::_Str_sink<wchar_t> __buf;
3937 std::vformat_to(__buf.out(), __loc, __fmt, __args);
3938 return std::move(__buf).get();
3939 }
3940 #endif
3942 template<typename... _Args>
3943 [[nodiscard]]
3944 inline string
3945 format(format_string<_Args...> __fmt, _Args&&... __args)
3946 { return std::vformat(__fmt.get(), std::make_format_args(__args...)); }
3948 #ifdef _GLIBCXX_USE_WCHAR_T
3949 template<typename... _Args>
3950 [[nodiscard]]
3951 inline wstring
3952 format(wformat_string<_Args...> __fmt, _Args&&... __args)
3953 { return std::vformat(__fmt.get(), std::make_wformat_args(__args...)); }
3954 #endif
3956 template<typename... _Args>
3957 [[nodiscard]]
3958 inline string
3959 format(const locale& __loc, format_string<_Args...> __fmt,
3960 _Args&&... __args)
3961 {
3962 return std::vformat(__loc, __fmt.get(),
3963 std::make_format_args(__args...));
3964 }
3966 #ifdef _GLIBCXX_USE_WCHAR_T
3967 template<typename... _Args>
3968 [[nodiscard]]
3969 inline wstring
3970 format(const locale& __loc, wformat_string<_Args...> __fmt,
3971 _Args&&... __args)
3972 {
3973 return std::vformat(__loc, __fmt.get(),
3974 std::make_wformat_args(__args...));
3975 }
3976 #endif
3978 template<typename _Out, typename... _Args>
3979 requires output_iterator<_Out, const char&>
3980 inline _Out
3981 format_to(_Out __out, format_string<_Args...> __fmt, _Args&&... __args)
3982 {
3983 return std::vformat_to(std::move(__out), __fmt.get(),
3984 std::make_format_args(std::forward<_Args>(__args)...));
3985 }
3987 #ifdef _GLIBCXX_USE_WCHAR_T
3988 template<typename _Out, typename... _Args>
3989 requires output_iterator<_Out, const wchar_t&>
3990 inline _Out
3991 format_to(_Out __out, wformat_string<_Args...> __fmt, _Args&&... __args)
3992 {
3993 return std::vformat_to(std::move(__out), __fmt.get(),
3994 std::make_wformat_args(std::forward<_Args>(__args)...));
3995 }
3996 #endif
3998 template<typename _Out, typename... _Args>
3999 requires output_iterator<_Out, const char&>
4000 inline _Out
4001 format_to(_Out __out, const locale& __loc, format_string<_Args...> __fmt,
4002 _Args&&... __args)
4003 {
4004 return std::vformat_to(std::move(__out), __loc, __fmt.get(),
4005 std::make_format_args(std::forward<_Args>(__args)...));
4006 }
4008 #ifdef _GLIBCXX_USE_WCHAR_T
4009 template<typename _Out, typename... _Args>
4010 requires output_iterator<_Out, const wchar_t&>
4011 inline _Out
4012 format_to(_Out __out, const locale& __loc, wformat_string<_Args...> __fmt,
4013 _Args&&... __args)
4014 {
4015 return std::vformat_to(std::move(__out), __loc, __fmt.get(),
4016 std::make_wformat_args(std::forward<_Args>(__args)...));
4017 }
4018 #endif
4020 template<typename _Out, typename... _Args>
4021 requires output_iterator<_Out, const char&>
4022 inline format_to_n_result<_Out>
4023 format_to_n(_Out __out, iter_difference_t<_Out> __n,
4024 format_string<_Args...> __fmt, _Args&&... __args)
4025 {
4026 __format::_Iter_sink<char, _Out> __sink(std::move(__out), __n);
4027 std::vformat_to(__sink.out(), __fmt.get(),
4028 std::make_format_args(__args...));
4029 return std::move(__sink)._M_finish();
4030 }
4032 #ifdef _GLIBCXX_USE_WCHAR_T
4033 template<typename _Out, typename... _Args>
4034 requires output_iterator<_Out, const wchar_t&>
4035 inline format_to_n_result<_Out>
4036 format_to_n(_Out __out, iter_difference_t<_Out> __n,
4037 wformat_string<_Args...> __fmt, _Args&&... __args)
4038 {
4039 __format::_Iter_sink<wchar_t, _Out> __sink(std::move(__out), __n);
4040 std::vformat_to(__sink.out(), __fmt.get(),
4041 std::make_wformat_args(__args...));
4042 return std::move(__sink)._M_finish();
4043 }
4044 #endif
4046 template<typename _Out, typename... _Args>
4047 requires output_iterator<_Out, const char&>
4048 inline format_to_n_result<_Out>
4049 format_to_n(_Out __out, iter_difference_t<_Out> __n, const locale& __loc,
4050 format_string<_Args...> __fmt, _Args&&... __args)
4051 {
4052 __format::_Iter_sink<char, _Out> __sink(std::move(__out), __n);
4053 std::vformat_to(__sink.out(), __loc, __fmt.get(),
4054 std::make_format_args(__args...));
4055 return std::move(__sink)._M_finish();
4056 }
4058 #ifdef _GLIBCXX_USE_WCHAR_T
4059 template<typename _Out, typename... _Args>
4060 requires output_iterator<_Out, const wchar_t&>
4061 inline format_to_n_result<_Out>
4062 format_to_n(_Out __out, iter_difference_t<_Out> __n, const locale& __loc,
4063 wformat_string<_Args...> __fmt, _Args&&... __args)
4064 {
4065 __format::_Iter_sink<wchar_t, _Out> __sink(std::move(__out), __n);
4066 std::vformat_to(__sink.out(), __loc, __fmt.get(),
4067 std::make_wformat_args(__args...));
4068 return std::move(__sink)._M_finish();
4069 }
4070 #endif
4072 /// @cond undocumented
4073 namespace __format
4074 {
4075 #if 1
4076 template<typename _CharT>
4077 class _Counting_sink final : public _Iter_sink<_CharT, _CharT*>
4078 {
4079 public:
4080 _Counting_sink() : _Iter_sink<_CharT, _CharT*>(nullptr, 0) { }
4082 [[__gnu__::__always_inline__]]
4083 size_t
4084 count() const
4085 { return this->_M_count + this->_M_used().size(); }
4086 };
4087 #else
4088 template<typename _CharT>
4089 class _Counting_sink : public _Buf_sink<_CharT>
4090 {
4091 size_t _M_count = 0;
4093 void
4094 _M_overflow() override
4095 {
4096 if (!std::is_constant_evaluated())
4097 _M_count += this->_M_used().size();
4098 this->_M_rewind();
4099 }
4101 public:
4102 _Counting_sink() = default;
4104 [[__gnu__::__always_inline__]]
4105 size_t
4106 count() noexcept
4107 {
4108 _Counting_sink::_M_overflow();
4109 return _M_count;
4110 }
4111 };
4112 #endif
4113 } // namespace __format
4114 /// @endcond
4116 template<typename... _Args>
4117 [[nodiscard]]
4118 inline size_t
4119 formatted_size(format_string<_Args...> __fmt, _Args&&... __args)
4120 {
4121 __format::_Counting_sink<char> __buf;
4122 std::vformat_to(__buf.out(), __fmt.get(),
4123 std::make_format_args(std::forward<_Args>(__args)...));
4124 return __buf.count();
4125 }
4127 #ifdef _GLIBCXX_USE_WCHAR_T
4128 template<typename... _Args>
4129 [[nodiscard]]
4130 inline size_t
4131 formatted_size(wformat_string<_Args...> __fmt, _Args&&... __args)
4132 {
4133 __format::_Counting_sink<wchar_t> __buf;
4134 std::vformat_to(__buf.out(), __fmt.get(),
4135 std::make_wformat_args(std::forward<_Args>(__args)...));
4136 return __buf.count();
4137 }
4138 #endif
4140 template<typename... _Args>
4141 [[nodiscard]]
4142 inline size_t
4143 formatted_size(const locale& __loc, format_string<_Args...> __fmt,
4144 _Args&&... __args)
4145 {
4146 __format::_Counting_sink<char> __buf;
4147 std::vformat_to(__buf.out(), __loc, __fmt.get(),
4148 std::make_format_args(std::forward<_Args>(__args)...));
4149 return __buf.count();
4150 }
4152 #ifdef _GLIBCXX_USE_WCHAR_T
4153 template<typename... _Args>
4154 [[nodiscard]]
4155 inline size_t
4156 formatted_size(const locale& __loc, wformat_string<_Args...> __fmt,
4157 _Args&&... __args)
4158 {
4159 __format::_Counting_sink<wchar_t> __buf;
4160 std::vformat_to(__buf.out(), __loc, __fmt.get(),
4161 std::make_wformat_args(std::forward<_Args>(__args)...));
4162 return __buf.count();
4163 }
4164 #endif
4166 #if __cpp_lib_format_ranges
4167 // [format.range], formatting of ranges
4168 // [format.range.fmtkind], variable template format_kind
4169 enum class range_format {
4170 disabled,
4171 map,
4172 set,
4173 sequence,
4174 string,
4175 debug_string
4176 };
4178 /// @cond undocumented
4179 template<typename _Rg>
4180 constexpr auto format_kind = not defined(format_kind<_Rg>);
4182 template<typename _Tp>
4183 consteval range_format
4184 __fmt_kind()
4185 {
4186 using _Ref = ranges::range_reference_t<_Tp>;
4187 if constexpr (is_same_v<remove_cvref_t<_Ref>, _Tp>)
4188 return range_format::disabled;
4189 else if constexpr (requires { typename _Tp::key_type; })
4190 {
4191 if constexpr (requires { typename _Tp::mapped_type; })
4192 {
4193 using _Up = remove_cvref_t<_Ref>;
4194 if constexpr (__is_pair<_Up>)
4195 return range_format::map;
4196 else if constexpr (__is_specialization_of<_Up, tuple>)
4197 if constexpr (tuple_size_v<_Up> == 2)
4198 return range_format::map;
4199 }
4200 return range_format::set;
4201 }
4202 else
4203 return range_format::sequence;
4204 }
4205 /// @endcond
4207 /// A constant determining how a range should be formatted.
4208 template<ranges::input_range _Rg> requires same_as<_Rg, remove_cvref_t<_Rg>>
4209 constexpr range_format format_kind<_Rg> = __fmt_kind<_Rg>();
4211 // [format.range.formatter], class template range_formatter
4212 template<typename _Tp, typename _CharT = char>
4213 requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT>
4214 class range_formatter; // TODO
4216 /// @cond undocumented
4217 namespace __format
4218 {
4219 // [format.range.fmtdef], class template range-default-formatter
4220 template<range_format _Kind, ranges::input_range _Rg, typename _CharT>
4221 struct __range_default_formatter; // TODO
4222 } // namespace __format
4223 /// @endcond
4225 // [format.range.fmtmap], [format.range.fmtset], [format.range.fmtstr],
4226 // specializations for maps, sets, and strings
4227 template<ranges::input_range _Rg, typename _CharT>
4228 requires (format_kind<_Rg> != range_format::disabled)
4229 && formattable<ranges::range_reference_t<_Rg>, _CharT>
4230 struct formatter<_Rg, _CharT>
4231 : __format::__range_default_formatter<format_kind<_Rg>, _Rg, _CharT>
4232 { };
4233 #endif // C++23 formatting ranges
4235 _GLIBCXX_END_NAMESPACE_VERSION
4236 } // namespace std
4237 #endif // __cpp_lib_format
4238 #endif // _GLIBCXX_FORMAT