1 // <format> Formatting -*- C++ -*-
3 // Copyright The GNU Toolchain Authors.
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)
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.
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 #define __glibcxx_want_format_uchar
39 #include <bits/version.h>
41 #ifdef __cpp_lib_format // C++ >= 20 && HOSTED
50 #include <string_view>
52 #include <variant> // monostate (TODO: move to bits/utility.h?)
53 #include <bits/ranges_base.h> // input_range, range_reference_t
54 #include <bits/ranges_util.h> // subrange
55 #include <bits/ranges_algobase.h> // ranges::copy
56 #include <bits/stl_iterator.h> // back_insert_iterator
57 #include <bits/stl_pair.h> // __is_pair
58 #include <bits/unicode.h> // __is_scalar_value, _Utf_view, etc.
59 #include <bits/utility.h> // tuple_size_v
60 #include <ext/numeric_traits.h> // __int_traits
62 #if !__has_builtin(__builtin_toupper)
66 namespace std _GLIBCXX_VISIBILITY(default)
68 _GLIBCXX_BEGIN_NAMESPACE_VERSION
70 // [format.context], class template basic_format_context
71 template<typename _Out, typename _CharT> class basic_format_context;
73 /// @cond undocumented
76 // Type-erased character sink.
77 template<typename _CharT> class _Sink;
78 // Output iterator that writes to a type-erase character sink.
79 template<typename _CharT>
82 template<typename _CharT>
83 using __format_context = basic_format_context<_Sink_iter<_CharT>, _CharT>;
85 template<typename _CharT>
86 struct _Runtime_format_string { basic_string_view<_CharT> _M_str; };
87 } // namespace __format
90 using format_context = __format::__format_context<char>;
91 #ifdef _GLIBCXX_USE_WCHAR_T
92 using wformat_context = __format::__format_context<wchar_t>;
95 // [format.args], class template basic_format_args
96 template<typename _Context> class basic_format_args;
97 using format_args = basic_format_args<format_context>;
98 #ifdef _GLIBCXX_USE_WCHAR_T
99 using wformat_args = basic_format_args<wformat_context>;
102 // [format.arguments], arguments
103 // [format.arg], class template basic_format_arg
104 template<typename _Context>
105 class basic_format_arg;
107 // [format.fmt.string], class template basic_format_string
109 /** A compile-time checked format string for the specified argument types.
111 * @since C++23 but available as an extension in C++20.
113 template<typename _CharT, typename... _Args>
114 struct basic_format_string
116 template<typename _Tp>
117 requires convertible_to<const _Tp&, basic_string_view<_CharT>>
119 basic_format_string(const _Tp& __s);
121 [[__gnu__::__always_inline__]]
122 basic_format_string(__format::_Runtime_format_string<_CharT>&& __s)
126 [[__gnu__::__always_inline__]]
127 constexpr basic_string_view<_CharT>
132 basic_string_view<_CharT> _M_str;
135 template<typename... _Args>
136 using format_string = basic_format_string<char, type_identity_t<_Args>...>;
138 #ifdef _GLIBCXX_USE_WCHAR_T
139 template<typename... _Args>
141 = basic_format_string<wchar_t, type_identity_t<_Args>...>;
144 #if __cplusplus > 202302L
145 [[__gnu__::__always_inline__]]
146 inline __format::_Runtime_format_string<char>
147 runtime_format(string_view __fmt)
150 #ifdef _GLIBCXX_USE_WCHAR_T
151 [[__gnu__::__always_inline__]]
152 inline __format::_Runtime_format_string<wchar_t>
153 runtime_format(wstring_view __fmt)
158 // [format.formatter], formatter
160 /// The primary template of std::formatter is disabled.
161 template<typename _Tp, typename _CharT = char>
164 formatter() = delete; // No std::formatter specialization for this type.
165 formatter(const formatter&) = delete;
166 formatter& operator=(const formatter&) = delete;
169 // [format.error], class format_error
170 class format_error : public runtime_error
173 explicit format_error(const string& __what) : runtime_error(__what) { }
174 explicit format_error(const char* __what) : runtime_error(__what) { }
177 /// @cond undocumented
180 __throw_format_error(const char* __what)
181 { _GLIBCXX_THROW_OR_ABORT(format_error(__what)); }
185 // XXX use named functions for each constexpr error?
189 __unmatched_left_brace_in_format_string()
190 { __throw_format_error("format error: unmatched '{' in format string"); }
194 __unmatched_right_brace_in_format_string()
195 { __throw_format_error("format error: unmatched '}' in format string"); }
199 __conflicting_indexing_in_format_string()
200 { __throw_format_error("format error: conflicting indexing style in format string"); }
204 __invalid_arg_id_in_format_string()
205 { __throw_format_error("format error: invalid arg-id in format string"); }
209 __failed_to_parse_format_spec()
210 { __throw_format_error("format error: failed to parse format-spec"); }
211 } // namespace __format
214 // [format.parse.ctx], class template basic_format_parse_context
215 template<typename _CharT> class basic_format_parse_context;
216 using format_parse_context = basic_format_parse_context<char>;
217 #ifdef _GLIBCXX_USE_WCHAR_T
218 using wformat_parse_context = basic_format_parse_context<wchar_t>;
221 template<typename _CharT>
222 class basic_format_parse_context
225 using char_type = _CharT;
226 using const_iterator = typename basic_string_view<_CharT>::const_iterator;
227 using iterator = const_iterator;
230 basic_format_parse_context(basic_string_view<_CharT> __fmt,
231 size_t __num_args = 0) noexcept
232 : _M_begin(__fmt.begin()), _M_end(__fmt.end()), _M_num_args(__num_args)
235 basic_format_parse_context(const basic_format_parse_context&) = delete;
236 void operator=(const basic_format_parse_context&) = delete;
238 constexpr const_iterator begin() const noexcept { return _M_begin; }
239 constexpr const_iterator end() const noexcept { return _M_end; }
242 advance_to(const_iterator __it) noexcept
248 if (_M_indexing == _Manual)
249 __format::__conflicting_indexing_in_format_string();
252 // _GLIBCXX_RESOLVE_LIB_DEFECTS
253 // 3825. Missing compile-time argument id check in next_arg_id
254 if (std::is_constant_evaluated())
255 if (_M_next_arg_id == _M_num_args)
256 __format::__invalid_arg_id_in_format_string();
257 return _M_next_arg_id++;
261 check_arg_id(size_t __id)
263 if (_M_indexing == _Auto)
264 __format::__conflicting_indexing_in_format_string();
265 _M_indexing = _Manual;
267 if (std::is_constant_evaluated())
268 if (__id >= _M_num_args)
269 __format::__invalid_arg_id_in_format_string();
275 enum _Indexing { _Unknown, _Manual, _Auto };
276 _Indexing _M_indexing = _Unknown;
277 size_t _M_next_arg_id = 0;
281 /// @cond undocumented
282 template<typename _Tp, template<typename...> class _Class>
283 static constexpr bool __is_specialization_of = false;
284 template<template<typename...> class _Class, typename... _Args>
285 static constexpr bool __is_specialization_of<_Class<_Args...>, _Class>
290 // pre: first != last
291 template<typename _CharT>
292 constexpr pair<unsigned short, const _CharT*>
293 __parse_integer(const _CharT* __first, const _CharT* __last)
295 if (__first == __last)
296 __builtin_unreachable();
298 if constexpr (is_same_v<_CharT, char>)
300 const auto __start = __first;
301 unsigned short __val = 0;
302 // N.B. std::from_chars is not constexpr in C++20.
303 if (__detail::__from_chars_alnum<true>(__first, __last, __val, 10)
304 && __first != __start) [[likely]]
305 return {__val, __first};
309 constexpr int __n = 32;
311 for (int __i = 0; __i < __n && (__first + __i) != __last; ++__i)
312 __buf[__i] = __first[__i];
313 auto [__v, __ptr] = __format::__parse_integer(__buf, __buf + __n);
314 if (__ptr) [[likely]]
315 return {__v, __first + (__ptr - __buf)};
320 template<typename _CharT>
321 constexpr pair<unsigned short, const _CharT*>
322 __parse_arg_id(const _CharT* __first, const _CharT* __last)
324 if (__first == __last)
325 __builtin_unreachable();
328 return {0, __first + 1}; // No leading zeros allowed, so '0...' == 0
330 if ('1' <= *__first && *__first <= '9')
332 const unsigned short __id = *__first - '0';
333 const auto __next = __first + 1;
334 // Optimize for most likely case of single digit arg-id.
335 if (__next == __last || !('0' <= *__next && *__next <= '9'))
336 return {__id, __next};
338 return __format::__parse_integer(__first, __last);
344 _Pres_none = 0, // Default type (not valid for integer presentation types).
345 // Presentation types for integral types (including bool and charT).
346 _Pres_d = 1, _Pres_b, _Pres_B, _Pres_o, _Pres_x, _Pres_X, _Pres_c,
347 // Presentation types for floating-point types.
348 _Pres_a = 1, _Pres_A, _Pres_e, _Pres_E, _Pres_f, _Pres_F, _Pres_g, _Pres_G,
349 _Pres_p = 0, _Pres_P, // For pointers.
350 _Pres_s = 0, // For strings and bool.
351 _Pres_esc = 0xf, // For strings and charT.
364 _Sign_minus, // XXX does this need to be distinct from _Sign_default?
369 _WP_none, // No width/prec specified.
370 _WP_value, // Fixed width/prec specified.
371 _WP_from_arg // Use a formatting argument for width/prec.
374 template<typename _Context>
376 __int_from_arg(const basic_format_arg<_Context>& __arg);
378 constexpr bool __is_digit(char __c)
379 { return std::__detail::__from_chars_alnum_to_val(__c) < 10; }
381 constexpr bool __is_xdigit(char __c)
382 { return std::__detail::__from_chars_alnum_to_val(__c) < 16; }
384 template<typename _CharT>
390 unsigned _M_localized : 1;
391 unsigned _M_zero_fill : 1;
392 _WidthPrec _M_width_kind : 2;
393 _WidthPrec _M_prec_kind : 2;
394 _Pres_type _M_type : 4;
395 unsigned short _M_width;
396 unsigned short _M_prec;
397 char32_t _M_fill = ' ';
399 using iterator = typename basic_string_view<_CharT>::iterator;
401 static constexpr _Align
402 _S_align(_CharT __c) noexcept
406 case '<': return _Align_left;
407 case '>': return _Align_right;
408 case '^': return _Align_centre;
409 default: return _Align_default;
413 // pre: __first != __last
415 _M_parse_fill_and_align(iterator __first, iterator __last) noexcept
419 using namespace __unicode;
420 if constexpr (__literal_encoding_is_unicode<_CharT>())
422 // Accept any UCS scalar value as fill character.
423 _Utf32_view __uv(ranges::subrange(__first, __last));
426 auto __beg = __uv.begin();
427 char32_t __c = *__beg++;
428 if (__is_scalar_value(__c))
429 if (auto __next = __beg.base(); __next != __last)
430 if (_Align __align = _S_align(*__next))
438 else if (__last - __first >= 2)
439 if (_Align __align = _S_align(__first[1]))
446 if (_Align __align = _S_align(__first[0]))
456 static constexpr _Sign
457 _S_sign(_CharT __c) noexcept
461 case '+': return _Sign_plus;
462 case '-': return _Sign_minus;
463 case ' ': return _Sign_space;
464 default: return _Sign_default;
468 // pre: __first != __last
470 _M_parse_sign(iterator __first, iterator) noexcept
472 if (_Sign __sign = _S_sign(*__first))
480 // pre: *__first is valid
482 _M_parse_alternate_form(iterator __first, iterator) noexcept
492 // pre: __first != __last
494 _M_parse_zero_fill(iterator __first, iterator /* __last */) noexcept
504 // pre: __first != __last
505 static constexpr iterator
506 _S_parse_width_or_precision(iterator __first, iterator __last,
507 unsigned short& __val, bool& __arg_id,
508 basic_format_parse_context<_CharT>& __pc)
510 if (__format::__is_digit(*__first))
512 auto [__v, __ptr] = __format::__parse_integer(__first, __last);
514 __throw_format_error("format error: invalid width or precision "
519 else if (*__first == '{')
523 if (__first == __last)
524 __format::__unmatched_left_brace_in_format_string();
526 __val = __pc.next_arg_id();
529 auto [__v, __ptr] = __format::__parse_arg_id(__first, __last);
530 if (__ptr == nullptr || __ptr == __last || *__ptr != '}')
531 __format::__invalid_arg_id_in_format_string();
533 __pc.check_arg_id(__v);
536 ++__first; // past the '}'
541 // pre: __first != __last
543 _M_parse_width(iterator __first, iterator __last,
544 basic_format_parse_context<_CharT>& __pc)
546 bool __arg_id = false;
548 __throw_format_error("format error: width must be non-zero in "
550 auto __next = _S_parse_width_or_precision(__first, __last, _M_width,
552 if (__next != __first)
553 _M_width_kind = __arg_id ? _WP_from_arg : _WP_value;
557 // pre: __first != __last
559 _M_parse_precision(iterator __first, iterator __last,
560 basic_format_parse_context<_CharT>& __pc)
562 if (__first[0] != '.')
565 iterator __next = ++__first;
566 bool __arg_id = false;
567 if (__next != __last)
568 __next = _S_parse_width_or_precision(__first, __last, _M_prec,
570 if (__next == __first)
571 __throw_format_error("format error: missing precision after '.' in "
573 _M_prec_kind = __arg_id ? _WP_from_arg : _WP_value;
577 // pre: __first != __last
579 _M_parse_locale(iterator __first, iterator /* __last */) noexcept
589 template<typename _Context>
591 _M_get_width(_Context& __ctx) const
594 if (_M_width_kind == _WP_value)
596 else if (_M_width_kind == _WP_from_arg)
597 __width = __format::__int_from_arg(__ctx.arg(_M_width));
601 template<typename _Context>
603 _M_get_precision(_Context& __ctx) const
606 if (_M_prec_kind == _WP_value)
608 else if (_M_prec_kind == _WP_from_arg)
609 __prec = __format::__int_from_arg(__ctx.arg(_M_prec));
614 template<typename _Int>
616 __put_sign(_Int __i, _Sign __sign, char* __dest) noexcept
620 else if (__sign == _Sign_plus)
622 else if (__sign == _Sign_space)
629 // Write STR to OUT (and do so efficiently if OUT is a _Sink_iter).
630 template<typename _Out, typename _CharT>
631 requires output_iterator<_Out, const _CharT&>
633 __write(_Out __out, basic_string_view<_CharT> __str)
635 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
641 for (_CharT __c : __str)
646 // Write STR to OUT with NFILL copies of FILL_CHAR specified by ALIGN.
647 // pre: __align != _Align_default
648 template<typename _Out, typename _CharT>
650 __write_padded(_Out __out, basic_string_view<_CharT> __str,
651 _Align __align, size_t __nfill, char32_t __fill_char)
653 const size_t __buflen = 0x20;
654 _CharT __padding_chars[__buflen];
655 __padding_chars[0] = _CharT();
656 basic_string_view<_CharT> __padding{__padding_chars, __buflen};
658 auto __pad = [&__padding] (size_t __n, _Out& __o) {
661 while (__n > __padding.size())
663 __o = __format::__write(std::move(__o), __padding);
664 __n -= __padding.size();
667 __o = __format::__write(std::move(__o), __padding.substr(0, __n));
670 size_t __l, __r, __max;
671 if (__align == _Align_centre)
674 __r = __l + (__nfill & 1);
677 else if (__align == _Align_right)
690 using namespace __unicode;
691 if constexpr (__literal_encoding_is_unicode<_CharT>())
692 if (!__is_single_code_unit<_CharT>(__fill_char)) [[unlikely]]
694 // Encode fill char as multiple code units of type _CharT.
695 const char32_t __arr[1]{ __fill_char };
696 _Utf_view<_CharT, const char32_t(&)[1]> __v(__arr);
697 basic_string<_CharT> __padstr(__v.begin(), __v.end());
698 __padding = __padstr;
700 __out = __format::__write(std::move(__out), __padding);
701 __out = __format::__write(std::move(__out), __str);
703 __out = __format::__write(std::move(__out), __padding);
707 if (__max < __buflen)
708 __padding.remove_suffix(__buflen - __max);
712 char_traits<_CharT>::assign(__padding_chars, __max, __fill_char);
714 __out = __format::__write(std::move(__out), __str);
720 // Write STR to OUT, with alignment and padding as determined by SPEC.
721 // pre: __spec._M_align != _Align_default || __align != _Align_default
722 template<typename _CharT, typename _Out>
724 __write_padded_as_spec(basic_string_view<type_identity_t<_CharT>> __str,
725 size_t __estimated_width,
726 basic_format_context<_Out, _CharT>& __fc,
727 const _Spec<_CharT>& __spec,
728 _Align __align = _Align_left)
730 size_t __width = __spec._M_get_width(__fc);
732 if (__width <= __estimated_width)
733 return __format::__write(__fc.out(), __str);
735 const size_t __nfill = __width - __estimated_width;
738 __align = __spec._M_align;
740 return __format::__write_padded(__fc.out(), __str, __align, __nfill,
744 // A lightweight optional<locale>.
745 struct _Optional_locale
747 [[__gnu__::__always_inline__]]
748 _Optional_locale() : _M_dummy(), _M_hasval(false) { }
750 _Optional_locale(const locale& __loc) noexcept
751 : _M_loc(__loc), _M_hasval(true)
754 _Optional_locale(const _Optional_locale& __l) noexcept
755 : _M_dummy(), _M_hasval(__l._M_hasval)
758 std::construct_at(&_M_loc, __l._M_loc);
762 operator=(const _Optional_locale& __l) noexcept
774 else if (__l._M_hasval)
776 std::construct_at(&_M_loc, __l._M_loc);
782 ~_Optional_locale() { if (_M_hasval) _M_loc.~locale(); }
785 operator=(locale&& __loc) noexcept
788 _M_loc = std::move(__loc);
791 std::construct_at(&_M_loc, std::move(__loc));
802 std::construct_at(&_M_loc);
808 bool has_value() const noexcept { return _M_hasval; }
811 char _M_dummy = '\0';
814 bool _M_hasval = false;
817 #ifdef _GLIBCXX_USE_WCHAR_T
818 template<typename _CharT>
819 concept __char = same_as<_CharT, char> || same_as<_CharT, wchar_t>;
821 template<typename _CharT>
822 concept __char = same_as<_CharT, char>;
825 template<__char _CharT>
826 struct __formatter_str
828 constexpr typename basic_format_parse_context<_CharT>::iterator
829 parse(basic_format_parse_context<_CharT>& __pc)
831 auto __first = __pc.begin();
832 const auto __last = __pc.end();
833 _Spec<_CharT> __spec{};
835 auto __finalize = [this, &__spec] {
839 auto __finished = [&] {
840 if (__first == __last || *__first == '}')
851 __first = __spec._M_parse_fill_and_align(__first, __last);
855 __first = __spec._M_parse_width(__first, __last, __pc);
859 __first = __spec._M_parse_precision(__first, __last, __pc);
865 #if __cpp_lib_format_ranges
866 else if (*__first == '?')
868 __spec._M_type = _Pres_esc;
876 __format::__failed_to_parse_format_spec();
879 template<typename _Out>
881 format(basic_string_view<_CharT> __s,
882 basic_format_context<_Out, _CharT>& __fc) const
884 if (_M_spec._M_type == _Pres_esc)
886 // TODO: C++23 escaped string presentation
889 if (_M_spec._M_width_kind == _WP_none
890 && _M_spec._M_prec_kind == _WP_none)
891 return __format::__write(__fc.out(), __s);
893 size_t __estimated_width;
894 if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
896 if (_M_spec._M_prec_kind != _WP_none)
898 size_t __prec = _M_spec._M_get_precision(__fc);
899 __estimated_width = __unicode::__truncate(__s, __prec);
902 __estimated_width = __unicode::__field_width(__s);
906 __s = __s.substr(0, _M_spec._M_get_precision(__fc));
907 __estimated_width = __s.size();
910 return __format::__write_padded_as_spec(__s, __estimated_width,
914 #if __cpp_lib_format_ranges
916 set_debug_format() noexcept
917 { _M_spec._M_type = _Pres_esc; }
921 _Spec<_CharT> _M_spec{};
924 template<__char _CharT>
925 struct __formatter_int
927 // If no presentation type is specified, meaning of "none" depends
928 // whether we are formatting an integer or a char or a bool.
929 static constexpr _Pres_type _AsInteger = _Pres_d;
930 static constexpr _Pres_type _AsBool = _Pres_s;
931 static constexpr _Pres_type _AsChar = _Pres_c;
933 constexpr typename basic_format_parse_context<_CharT>::iterator
934 _M_do_parse(basic_format_parse_context<_CharT>& __pc, _Pres_type __type)
936 _Spec<_CharT> __spec{};
937 __spec._M_type = __type;
939 const auto __last = __pc.end();
940 auto __first = __pc.begin();
942 auto __finalize = [this, &__spec] {
946 auto __finished = [&] {
947 if (__first == __last || *__first == '}')
958 __first = __spec._M_parse_fill_and_align(__first, __last);
962 __first = __spec._M_parse_sign(__first, __last);
966 __first = __spec._M_parse_alternate_form(__first, __last);
970 __first = __spec._M_parse_zero_fill(__first, __last);
974 __first = __spec._M_parse_width(__first, __last, __pc);
978 __first = __spec._M_parse_locale(__first, __last);
985 __spec._M_type = _Pres_b;
989 __spec._M_type = _Pres_B;
993 // _GLIBCXX_RESOLVE_LIB_DEFECTS
994 // 3586. format should not print bool with 'c'
995 if (__type != _AsBool)
997 __spec._M_type = _Pres_c;
1002 __spec._M_type = _Pres_d;
1006 __spec._M_type = _Pres_o;
1010 __spec._M_type = _Pres_x;
1014 __spec._M_type = _Pres_X;
1018 if (__type == _AsBool)
1020 __spec._M_type = _Pres_s; // same value (and meaning) as "none"
1024 #if __cpp_lib_format_ranges
1026 if (__type == _AsChar)
1028 __spec._M_type = _Pres_esc;
1038 __format::__failed_to_parse_format_spec();
1041 template<typename _Tp>
1042 constexpr typename basic_format_parse_context<_CharT>::iterator
1043 _M_parse(basic_format_parse_context<_CharT>& __pc)
1045 if constexpr (is_same_v<_Tp, bool>)
1047 auto __end = _M_do_parse(__pc, _AsBool);
1048 if (_M_spec._M_type == _Pres_s)
1049 if (_M_spec._M_sign || _M_spec._M_alt || _M_spec._M_zero_fill)
1050 __throw_format_error("format error: format-spec contains "
1051 "invalid formatting options for "
1055 else if constexpr (__char<_Tp>)
1057 auto __end = _M_do_parse(__pc, _AsChar);
1058 if (_M_spec._M_type == _Pres_c || _M_spec._M_type == _Pres_esc)
1059 if (_M_spec._M_sign || _M_spec._M_alt || _M_spec._M_zero_fill
1060 /* XXX should be invalid? || _M_spec._M_localized */)
1061 __throw_format_error("format error: format-spec contains "
1062 "invalid formatting options for "
1067 return _M_do_parse(__pc, _AsInteger);
1070 template<typename _Int, typename _Out>
1071 typename basic_format_context<_Out, _CharT>::iterator
1072 format(_Int __i, basic_format_context<_Out, _CharT>& __fc) const
1074 if (_M_spec._M_type == _Pres_c)
1075 return _M_format_character(_S_to_character(__i), __fc);
1077 char __buf[sizeof(_Int) * __CHAR_BIT__ + 3];
1078 to_chars_result __res{};
1080 string_view __base_prefix;
1081 make_unsigned_t<_Int> __u;
1083 __u = -static_cast<make_unsigned_t<_Int>>(__i);
1087 char* __start = __buf + 3;
1088 char* const __end = __buf + sizeof(__buf);
1089 char* const __start_digits = __start;
1091 switch (_M_spec._M_type)
1095 __base_prefix = _M_spec._M_type == _Pres_b ? "0b" : "0B";
1096 __res = to_chars(__start, __end, __u, 2);
1100 return _M_format_character(_S_to_character(__i), __fc);
1103 // Should not reach here with _Pres_none for bool or charT, so:
1106 __res = to_chars(__start, __end, __u, 10);
1110 __base_prefix = "0";
1111 __res = to_chars(__start, __end, __u, 8);
1115 __base_prefix = _M_spec._M_type == _Pres_x ? "0x" : "0X";
1116 __res = to_chars(__start, __end, __u, 16);
1117 if (_M_spec._M_type == _Pres_X)
1118 for (auto __p = __start; __p != __res.ptr; ++__p)
1119 #if __has_builtin(__builtin_toupper)
1120 *__p = __builtin_toupper(*__p);
1122 *__p = std::toupper(*__p);
1126 __builtin_unreachable();
1129 if (_M_spec._M_alt && __base_prefix.size())
1131 __start -= __base_prefix.size();
1132 __builtin_memcpy(__start, __base_prefix.data(),
1133 __base_prefix.size());
1135 __start = __format::__put_sign(__i, _M_spec._M_sign, __start - 1);
1137 return _M_format_int(string_view(__start, __res.ptr - __start),
1138 __start_digits - __start, __fc);
1141 template<typename _Out>
1142 typename basic_format_context<_Out, _CharT>::iterator
1143 format(bool __i, basic_format_context<_Out, _CharT>& __fc) const
1145 if (_M_spec._M_type == _Pres_c)
1146 return _M_format_character(static_cast<unsigned char>(__i), __fc);
1147 if (_M_spec._M_type != _Pres_s)
1148 return format(static_cast<unsigned char>(__i), __fc);
1150 basic_string<_CharT> __s;
1152 if (_M_spec._M_localized) [[unlikely]]
1154 auto& __np = std::use_facet<numpunct<_CharT>>(__fc.locale());
1155 __s = __i ? __np.truename() : __np.falsename();
1156 __est_width = __s.size(); // TODO Unicode-aware estimate
1160 if constexpr (is_same_v<char, _CharT>)
1161 __s = __i ? "true" : "false";
1163 __s = __i ? L"true" : L"false";
1164 __est_width = __s.size();
1167 return __format::__write_padded_as_spec(__s, __est_width, __fc,
1171 template<typename _Out>
1172 typename basic_format_context<_Out, _CharT>::iterator
1173 _M_format_character(_CharT __c,
1174 basic_format_context<_Out, _CharT>& __fc) const
1176 return __format::__write_padded_as_spec({&__c, 1u}, 1, __fc, _M_spec);
1179 template<typename _Int>
1181 _S_to_character(_Int __i)
1183 using _Traits = __gnu_cxx::__int_traits<_CharT>;
1184 if constexpr (is_signed_v<_Int> == is_signed_v<_CharT>)
1186 if (_Traits::__min <= __i && __i <= _Traits::__max)
1187 return static_cast<_CharT>(__i);
1189 else if constexpr (is_signed_v<_Int>)
1191 if (__i >= 0 && make_unsigned_t<_Int>(__i) <= _Traits::__max)
1192 return static_cast<_CharT>(__i);
1194 else if (__i <= make_unsigned_t<_CharT>(_Traits::__max))
1195 return static_cast<_CharT>(__i);
1196 __throw_format_error("format error: integer not representable as "
1200 template<typename _Out>
1201 typename basic_format_context<_Out, _CharT>::iterator
1202 _M_format_int(string_view __narrow_str, size_t __prefix_len,
1203 basic_format_context<_Out, _CharT>& __fc) const
1205 size_t __width = _M_spec._M_get_width(__fc);
1207 basic_string_view<_CharT> __str;
1208 if constexpr (is_same_v<char, _CharT>)
1209 __str = __narrow_str;
1210 #ifdef _GLIBCXX_USE_WCHAR_T
1213 size_t __n = __narrow_str.size();
1214 auto __p = (_CharT*)__builtin_alloca(__n * sizeof(_CharT));
1215 std::__to_wstring_numeric(__narrow_str.data(), __n, __p);
1220 if (_M_spec._M_localized)
1222 const auto& __l = __fc.locale();
1223 if (__l.name() != "C")
1225 auto& __np = use_facet<numpunct<_CharT>>(__l);
1226 string __grp = __np.grouping();
1229 size_t __n = __str.size() - __prefix_len;
1230 auto __p = (_CharT*)__builtin_alloca(2 * __n
1233 auto __s = __str.data();
1234 char_traits<_CharT>::copy(__p, __s, __prefix_len);
1235 __s += __prefix_len;
1236 auto __end = std::__add_grouping(__p + __prefix_len,
1237 __np.thousands_sep(),
1241 __str = {__p, size_t(__end - __p)};
1246 if (__width <= __str.size())
1247 return __format::__write(__fc.out(), __str);
1249 char32_t __fill_char = _M_spec._M_fill;
1250 _Align __align = _M_spec._M_align;
1252 size_t __nfill = __width - __str.size();
1253 auto __out = __fc.out();
1254 if (__align == _Align_default)
1256 __align = _Align_right;
1257 if (_M_spec._M_zero_fill)
1259 __fill_char = _CharT('0');
1260 // Write sign and base prefix before zero filling.
1261 if (__prefix_len != 0)
1263 __out = __format::__write(std::move(__out),
1264 __str.substr(0, __prefix_len));
1265 __str.remove_prefix(__prefix_len);
1269 __fill_char = _CharT(' ');
1271 return __format::__write_padded(std::move(__out), __str,
1272 __align, __nfill, __fill_char);
1275 #if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
1276 template<typename _Tp>
1277 using make_unsigned_t
1278 = typename __conditional_t<(sizeof(_Tp) <= sizeof(long long)),
1279 std::make_unsigned<_Tp>,
1280 type_identity<unsigned __int128>>::type;
1282 // std::to_chars is not overloaded for int128 in strict mode.
1283 template<typename _Int>
1284 static to_chars_result
1285 to_chars(char* __first, char* __last, _Int __value, int __base)
1286 { return std::__to_chars_i<_Int>(__first, __last, __value, __base); }
1289 _Spec<_CharT> _M_spec{};
1292 // Decide how 128-bit floating-point types should be formatted (or not).
1293 // When supported, the typedef __format::__float128_t is the type that
1294 // format arguments should be converted to for storage in basic_format_arg.
1295 // Define the macro _GLIBCXX_FORMAT_F128 to say they're supported.
1296 // _GLIBCXX_FORMAT_F128=1 means __float128, _Float128 etc. will be formatted
1297 // by converting them to long double (or __ieee128 for powerpc64le).
1298 // _GLIBCXX_FORMAT_F128=2 means basic_format_arg needs to enable explicit
1299 // support for _Float128, rather than formatting it as another type.
1300 #undef _GLIBCXX_FORMAT_F128
1302 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
1304 // Format 128-bit floating-point types using __ieee128.
1305 using __float128_t = __ieee128;
1306 # define _GLIBCXX_FORMAT_F128 1
1308 #ifdef __LONG_DOUBLE_IEEE128__
1309 // These overloads exist in the library, but are not declared.
1310 // Make them available as std::__format::to_chars.
1312 to_chars(char*, char*, __ibm128) noexcept
1313 __asm("_ZSt8to_charsPcS_e");
1316 to_chars(char*, char*, __ibm128, chars_format) noexcept
1317 __asm("_ZSt8to_charsPcS_eSt12chars_format");
1320 to_chars(char*, char*, __ibm128, chars_format, int) noexcept
1321 __asm("_ZSt8to_charsPcS_eSt12chars_formati");
1322 #elif __cplusplus == 202002L
1324 to_chars(char*, char*, __ieee128) noexcept
1325 __asm("_ZSt8to_charsPcS_u9__ieee128");
1328 to_chars(char*, char*, __ieee128, chars_format) noexcept
1329 __asm("_ZSt8to_charsPcS_u9__ieee128St12chars_format");
1332 to_chars(char*, char*, __ieee128, chars_format, int) noexcept
1333 __asm("_ZSt8to_charsPcS_u9__ieee128St12chars_formati");
1336 #elif defined _GLIBCXX_LDOUBLE_IS_IEEE_BINARY128
1338 // Format 128-bit floating-point types using long double.
1339 using __float128_t = long double;
1340 # define _GLIBCXX_FORMAT_F128 1
1342 #elif __FLT128_DIG__ && defined(_GLIBCXX_HAVE_FLOAT128_MATH)
1344 // Format 128-bit floating-point types using _Float128.
1345 using __float128_t = _Float128;
1346 # define _GLIBCXX_FORMAT_F128 2
1348 # if __cplusplus == 202002L
1349 // These overloads exist in the library, but are not declared for C++20.
1350 // Make them available as std::__format::to_chars.
1352 to_chars(char*, char*, _Float128) noexcept
1353 # if _GLIBCXX_INLINE_VERSION
1354 __asm("_ZNSt3__88to_charsEPcS0_DF128_");
1356 __asm("_ZSt8to_charsPcS_DF128_");
1360 to_chars(char*, char*, _Float128, chars_format) noexcept
1361 # if _GLIBCXX_INLINE_VERSION
1362 __asm("_ZNSt3__88to_charsEPcS0_DF128_NS_12chars_formatE");
1364 __asm("_ZSt8to_charsPcS_DF128_St12chars_format");
1368 to_chars(char*, char*, _Float128, chars_format, int) noexcept
1369 # if _GLIBCXX_INLINE_VERSION
1370 __asm("_ZNSt3__88to_charsEPcS0_DF128_NS_12chars_formatEi");
1372 __asm("_ZSt8to_charsPcS_DF128_St12chars_formati");
1377 using std::to_chars;
1379 // We can format a floating-point type iff it is usable with to_chars.
1380 template<typename _Tp>
1381 concept __formattable_float = requires (_Tp __t, char* __p)
1382 { __format::to_chars(__p, __p, __t, chars_format::scientific, 6); };
1384 template<__char _CharT>
1385 struct __formatter_fp
1387 constexpr typename basic_format_parse_context<_CharT>::iterator
1388 parse(basic_format_parse_context<_CharT>& __pc)
1390 _Spec<_CharT> __spec{};
1391 const auto __last = __pc.end();
1392 auto __first = __pc.begin();
1394 auto __finalize = [this, &__spec] {
1398 auto __finished = [&] {
1399 if (__first == __last || *__first == '}')
1410 __first = __spec._M_parse_fill_and_align(__first, __last);
1414 __first = __spec._M_parse_sign(__first, __last);
1418 __first = __spec._M_parse_alternate_form(__first, __last);
1422 __first = __spec._M_parse_zero_fill(__first, __last);
1426 if (__first[0] != '.')
1428 __first = __spec._M_parse_width(__first, __last, __pc);
1433 __first = __spec._M_parse_precision(__first, __last, __pc);
1437 __first = __spec._M_parse_locale(__first, __last);
1444 __spec._M_type = _Pres_a;
1448 __spec._M_type = _Pres_A;
1452 __spec._M_type = _Pres_e;
1456 __spec._M_type = _Pres_E;
1460 __spec._M_type = _Pres_f;
1464 __spec._M_type = _Pres_F;
1468 __spec._M_type = _Pres_g;
1472 __spec._M_type = _Pres_G;
1480 __format::__failed_to_parse_format_spec();
1483 template<typename _Fp, typename _Out>
1484 typename basic_format_context<_Out, _CharT>::iterator
1485 format(_Fp __v, basic_format_context<_Out, _CharT>& __fc) const
1487 std::string __dynbuf;
1489 to_chars_result __res{};
1492 bool __use_prec = _M_spec._M_prec_kind != _WP_none;
1494 __prec = _M_spec._M_get_precision(__fc);
1496 char* __start = __buf + 1; // reserve space for sign
1497 char* __end = __buf + sizeof(__buf);
1499 chars_format __fmt{};
1500 bool __upper = false;
1501 bool __trailing_zeros = false;
1504 switch (_M_spec._M_type)
1511 if (_M_spec._M_type != _Pres_A)
1513 __fmt = chars_format::hex;
1521 __fmt = chars_format::scientific;
1528 __fmt = chars_format::fixed;
1535 __trailing_zeros = true;
1537 __fmt = chars_format::general;
1541 __fmt = chars_format::general;
1544 __builtin_unreachable();
1547 // Write value into buffer using std::to_chars.
1548 auto __to_chars = [&](char* __b, char* __e) {
1550 return __format::to_chars(__b, __e, __v, __fmt, __prec);
1551 else if (__fmt != chars_format{})
1552 return __format::to_chars(__b, __e, __v, __fmt);
1554 return __format::to_chars(__b, __e, __v);
1557 // First try using stack buffer.
1558 __res = __to_chars(__start, __end);
1560 if (__builtin_expect(__res.ec == errc::value_too_large, 0))
1562 // If the buffer is too small it's probably because of a large
1563 // precision, or a very large value in fixed format.
1564 size_t __guess = 8 + __prec;
1565 if (__fmt == chars_format::fixed) // +ddd.prec
1567 if constexpr (is_same_v<_Fp, float> || is_same_v<_Fp, double>
1568 || is_same_v<_Fp, long double>)
1570 // The number of digits to the left of the decimal point
1571 // is floor(log10(max(abs(__v),1)))+1
1573 if constexpr (is_same_v<_Fp, float>)
1574 __builtin_frexpf(__v, &__exp);
1575 else if constexpr (is_same_v<_Fp, double>)
1576 __builtin_frexp(__v, &__exp);
1577 else if constexpr (is_same_v<_Fp, long double>)
1578 __builtin_frexpl(__v, &__exp);
1580 __guess += 1U + __exp * 4004U / 13301U; // log10(2) approx.
1583 __guess += numeric_limits<_Fp>::max_exponent10;
1585 if (__guess <= sizeof(__buf)) [[unlikely]]
1586 __guess = sizeof(__buf) * 2;
1587 __dynbuf.reserve(__guess);
1591 auto __overwrite = [&__to_chars, &__res] (char* __p, size_t __n)
1593 __res = __to_chars(__p + 1, __p + __n - 1);
1594 return __res.ec == errc{} ? __res.ptr - __p : 0;
1597 __dynbuf.__resize_and_overwrite(__dynbuf.capacity() * 2,
1599 __start = __dynbuf.data() + 1; // reserve space for sign
1600 __end = __dynbuf.data() + __dynbuf.size();
1602 while (__builtin_expect(__res.ec == errc::value_too_large, 0));
1605 // Use uppercase for 'A', 'E', and 'G' formats.
1608 for (char* __p = __start; __p != __res.ptr; ++__p)
1609 *__p = std::toupper(*__p);
1612 // Add sign for non-negative values.
1613 if (!__builtin_signbit(__v))
1615 if (_M_spec._M_sign == _Sign_plus)
1617 else if (_M_spec._M_sign == _Sign_space)
1621 string_view __narrow_str(__start, __res.ptr - __start);
1623 // Use alternate form.
1624 if (_M_spec._M_alt && __builtin_isfinite(__v))
1626 string_view __s = __narrow_str;
1629 size_t __d = __s.find('.');
1631 if (__d != __s.npos)
1633 __p = __s.find(__expc, __d + 1);
1634 if (__p == __s.npos)
1636 __sigfigs = __p - 1;
1640 __p = __s.find(__expc);
1641 if (__p == __s.npos)
1643 __d = __p; // Position where '.' should be inserted.
1647 if (__trailing_zeros && __prec != 0)
1649 if (!__format::__is_xdigit(__s[0]))
1651 __z = __prec - __sigfigs; // Number of zeros to insert.
1654 if (size_t __extras = int(__d == __p) + __z)
1656 if (__dynbuf.empty() && __extras <= size_t(__end - __res.ptr))
1658 // Move exponent to make space for extra chars.
1659 __builtin_memmove(__start + __p + __extras,
1664 __start[__p++] = '.';
1665 __builtin_memset(__start + __p, '0', __z);
1666 __narrow_str = {__s.data(), __s.size() + __extras};
1670 __dynbuf.reserve(__s.size() + __extras);
1671 if (__dynbuf.empty())
1673 __dynbuf = __s.substr(0, __p);
1677 __dynbuf.append(__z, '0');
1681 __dynbuf.insert(__p, __extras, '0');
1683 __dynbuf[__p] = '.';
1685 __narrow_str = __dynbuf;
1690 basic_string<_CharT> __wstr;
1691 basic_string_view<_CharT> __str;
1692 if constexpr (is_same_v<_CharT, char>)
1693 __str = __narrow_str;
1694 #ifdef _GLIBCXX_USE_WCHAR_T
1697 __wstr = std::__to_wstring_numeric(__narrow_str);
1702 if (_M_spec._M_localized)
1704 __wstr = _M_localize(__str, __expc, __fc.locale());
1705 if (!__wstr.empty())
1709 size_t __width = _M_spec._M_get_width(__fc);
1711 if (__width <= __str.size())
1712 return __format::__write(__fc.out(), __str);
1714 char32_t __fill_char = _M_spec._M_fill;
1715 _Align __align = _M_spec._M_align;
1717 size_t __nfill = __width - __str.size();
1718 auto __out = __fc.out();
1719 if (__align == _Align_default)
1721 __align = _Align_right;
1722 if (_M_spec._M_zero_fill && __builtin_isfinite(__v))
1724 __fill_char = _CharT('0');
1725 // Write sign before zero filling.
1726 if (!__format::__is_xdigit(__narrow_str[0]))
1728 *__out++ = __str[0];
1729 __str.remove_prefix(1);
1733 __fill_char = _CharT(' ');
1735 return __format::__write_padded(std::move(__out), __str,
1736 __align, __nfill, __fill_char);
1739 // Locale-specific format.
1740 basic_string<_CharT>
1741 _M_localize(basic_string_view<_CharT> __str, char __expc,
1742 const locale& __loc) const
1744 basic_string<_CharT> __lstr;
1746 if (__loc == locale::classic())
1747 return __lstr; // Nothing to do.
1749 const auto& __np = use_facet<numpunct<_CharT>>(__loc);
1750 const _CharT __point = __np.decimal_point();
1751 const string __grp = __np.grouping();
1753 _CharT __dot, __exp;
1754 if constexpr (is_same_v<_CharT, char>)
1777 __builtin_unreachable();
1781 if (__grp.empty() && __point == __dot)
1782 return __lstr; // Locale uses '.' and no grouping.
1784 size_t __d = __str.find(__dot);
1785 size_t __e = min(__d, __str.find(__exp));
1786 if (__e == __str.npos)
1788 const size_t __r = __str.size() - __e;
1789 auto __overwrite = [&](_CharT* __p, size_t) {
1790 auto __end = std::__add_grouping(__p, __np.thousands_sep(),
1791 __grp.data(), __grp.size(),
1792 __str.data(), __str.data() + __e);
1795 if (__d != __str.npos)
1802 __end += __str.copy(__end, __str.npos, __e);
1804 return (__end - __p);
1806 __lstr.__resize_and_overwrite(__e * 2 + __r, __overwrite);
1810 _Spec<_CharT> _M_spec{};
1813 } // namespace __format
1816 /// Format a character.
1817 template<__format::__char _CharT>
1818 struct formatter<_CharT, _CharT>
1820 formatter() = default;
1822 constexpr typename basic_format_parse_context<_CharT>::iterator
1823 parse(basic_format_parse_context<_CharT>& __pc)
1825 return _M_f.template _M_parse<_CharT>(__pc);
1828 template<typename _Out>
1829 typename basic_format_context<_Out, _CharT>::iterator
1830 format(_CharT __u, basic_format_context<_Out, _CharT>& __fc) const
1832 if (_M_f._M_spec._M_type == __format::_Pres_none
1833 || _M_f._M_spec._M_type == __format::_Pres_c)
1834 return _M_f._M_format_character(__u, __fc);
1835 else if (_M_f._M_spec._M_type == __format::_Pres_esc)
1841 return _M_f.format(static_cast<make_unsigned_t<_CharT>>(__u), __fc);
1844 #if __cpp_lib_format_ranges
1846 set_debug_format() noexcept
1847 { _M_f._M_spec._M_type = __format::_Pres_esc; }
1851 __format::__formatter_int<_CharT> _M_f;
1854 #ifdef _GLIBCXX_USE_WCHAR_T
1855 /// Format a char value for wide character output.
1857 struct formatter<char, wchar_t>
1859 formatter() = default;
1861 constexpr typename basic_format_parse_context<wchar_t>::iterator
1862 parse(basic_format_parse_context<wchar_t>& __pc)
1864 return _M_f._M_parse<char>(__pc);
1867 template<typename _Out>
1868 typename basic_format_context<_Out, wchar_t>::iterator
1869 format(char __u, basic_format_context<_Out, wchar_t>& __fc) const
1871 if (_M_f._M_spec._M_type == __format::_Pres_none
1872 || _M_f._M_spec._M_type == __format::_Pres_c)
1873 return _M_f._M_format_character(__u, __fc);
1874 else if (_M_f._M_spec._M_type == __format::_Pres_esc)
1880 return _M_f.format(static_cast<unsigned char>(__u), __fc);
1883 #if __cpp_lib_format_ranges
1885 set_debug_format() noexcept
1886 { _M_f._M_spec._M_type = __format::_Pres_esc; }
1890 __format::__formatter_int<wchar_t> _M_f;
1892 #endif // USE_WCHAR_T
1894 /** Format a string.
1897 template<__format::__char _CharT>
1898 struct formatter<_CharT*, _CharT>
1900 formatter() = default;
1902 [[__gnu__::__always_inline__]]
1903 constexpr typename basic_format_parse_context<_CharT>::iterator
1904 parse(basic_format_parse_context<_CharT>& __pc)
1905 { return _M_f.parse(__pc); }
1907 template<typename _Out>
1908 [[__gnu__::__nonnull__]]
1909 typename basic_format_context<_Out, _CharT>::iterator
1910 format(_CharT* __u, basic_format_context<_Out, _CharT>& __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(); }
1918 __format::__formatter_str<_CharT> _M_f;
1921 template<__format::__char _CharT>
1922 struct formatter<const _CharT*, _CharT>
1924 formatter() = default;
1926 [[__gnu__::__always_inline__]]
1927 constexpr typename basic_format_parse_context<_CharT>::iterator
1928 parse(basic_format_parse_context<_CharT>& __pc)
1929 { return _M_f.parse(__pc); }
1931 template<typename _Out>
1932 [[__gnu__::__nonnull__]]
1933 typename basic_format_context<_Out, _CharT>::iterator
1934 format(const _CharT* __u,
1935 basic_format_context<_Out, _CharT>& __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(); }
1943 __format::__formatter_str<_CharT> _M_f;
1946 template<__format::__char _CharT, size_t _Nm>
1947 struct formatter<_CharT[_Nm], _CharT>
1949 formatter() = default;
1951 [[__gnu__::__always_inline__]]
1952 constexpr typename basic_format_parse_context<_CharT>::iterator
1953 parse(basic_format_parse_context<_CharT>& __pc)
1954 { return _M_f.parse(__pc); }
1956 template<typename _Out>
1957 typename basic_format_context<_Out, _CharT>::iterator
1958 format(const _CharT (&__u)[_Nm],
1959 basic_format_context<_Out, _CharT>& __fc) const
1960 { return _M_f.format({__u, _Nm}, __fc); }
1962 #if __cpp_lib_format_ranges
1963 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1967 __format::__formatter_str<_CharT> _M_f;
1970 template<typename _Traits, typename _Alloc>
1971 struct formatter<basic_string<char, _Traits, _Alloc>, char>
1973 formatter() = default;
1975 [[__gnu__::__always_inline__]]
1976 constexpr typename basic_format_parse_context<char>::iterator
1977 parse(basic_format_parse_context<char>& __pc)
1978 { return _M_f.parse(__pc); }
1980 template<typename _Out>
1981 typename basic_format_context<_Out, char>::iterator
1982 format(const basic_string<char, _Traits, _Alloc>& __u,
1983 basic_format_context<_Out, char>& __fc) const
1984 { return _M_f.format(__u, __fc); }
1986 #if __cpp_lib_format_ranges
1987 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
1991 __format::__formatter_str<char> _M_f;
1994 #ifdef _GLIBCXX_USE_WCHAR_T
1995 template<typename _Traits, typename _Alloc>
1996 struct formatter<basic_string<wchar_t, _Traits, _Alloc>, wchar_t>
1998 formatter() = default;
2000 [[__gnu__::__always_inline__]]
2001 constexpr typename basic_format_parse_context<wchar_t>::iterator
2002 parse(basic_format_parse_context<wchar_t>& __pc)
2003 { return _M_f.parse(__pc); }
2005 template<typename _Out>
2006 typename basic_format_context<_Out, wchar_t>::iterator
2007 format(const basic_string<wchar_t, _Traits, _Alloc>& __u,
2008 basic_format_context<_Out, wchar_t>& __fc) const
2009 { return _M_f.format(__u, __fc); }
2011 #if __cpp_lib_format_ranges
2012 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2016 __format::__formatter_str<wchar_t> _M_f;
2018 #endif // USE_WCHAR_T
2020 template<typename _Traits>
2021 struct formatter<basic_string_view<char, _Traits>, char>
2023 formatter() = default;
2025 [[__gnu__::__always_inline__]]
2026 constexpr typename basic_format_parse_context<char>::iterator
2027 parse(basic_format_parse_context<char>& __pc)
2028 { return _M_f.parse(__pc); }
2030 template<typename _Out>
2031 typename basic_format_context<_Out, char>::iterator
2032 format(basic_string_view<char, _Traits> __u,
2033 basic_format_context<_Out, char>& __fc) const
2034 { return _M_f.format(__u, __fc); }
2036 #if __cpp_lib_format_ranges
2037 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2041 __format::__formatter_str<char> _M_f;
2044 #ifdef _GLIBCXX_USE_WCHAR_T
2045 template<typename _Traits>
2046 struct formatter<basic_string_view<wchar_t, _Traits>, wchar_t>
2048 formatter() = default;
2050 [[__gnu__::__always_inline__]]
2051 constexpr typename basic_format_parse_context<wchar_t>::iterator
2052 parse(basic_format_parse_context<wchar_t>& __pc)
2053 { return _M_f.parse(__pc); }
2055 template<typename _Out>
2056 typename basic_format_context<_Out, wchar_t>::iterator
2057 format(basic_string_view<wchar_t, _Traits> __u,
2058 basic_format_context<_Out, wchar_t>& __fc) const
2059 { return _M_f.format(__u, __fc); }
2061 #if __cpp_lib_format_ranges
2062 constexpr void set_debug_format() noexcept { _M_f.set_debug_format(); }
2066 __format::__formatter_str<wchar_t> _M_f;
2068 #endif // USE_WCHAR_T
2071 /// Format an integer.
2072 template<integral _Tp, __format::__char _CharT>
2073 requires (!__is_one_of<_Tp, char, wchar_t, char16_t, char32_t>::value)
2074 struct formatter<_Tp, _CharT>
2076 formatter() = default;
2078 [[__gnu__::__always_inline__]]
2079 constexpr typename basic_format_parse_context<_CharT>::iterator
2080 parse(basic_format_parse_context<_CharT>& __pc)
2082 return _M_f.template _M_parse<_Tp>(__pc);
2085 template<typename _Out>
2086 typename basic_format_context<_Out, _CharT>::iterator
2087 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2088 { return _M_f.format(__u, __fc); }
2091 __format::__formatter_int<_CharT> _M_f;
2094 #if defined __SIZEOF_INT128__ && defined __STRICT_ANSI__
2095 template<typename _Tp, __format::__char _CharT>
2096 requires (__is_one_of<_Tp, __int128, unsigned __int128>::value)
2097 struct formatter<_Tp, _CharT>
2099 formatter() = default;
2101 [[__gnu__::__always_inline__]]
2102 constexpr typename basic_format_parse_context<_CharT>::iterator
2103 parse(basic_format_parse_context<_CharT>& __pc)
2105 return _M_f.template _M_parse<_Tp>(__pc);
2108 template<typename _Out>
2109 typename basic_format_context<_Out, _CharT>::iterator
2110 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2111 { return _M_f.format(__u, __fc); }
2114 __format::__formatter_int<_CharT> _M_f;
2118 #if defined __glibcxx_to_chars
2119 /// Format a floating-point value.
2120 template<__format::__formattable_float _Tp, __format::__char _CharT>
2121 struct formatter<_Tp, _CharT>
2123 formatter() = default;
2125 [[__gnu__::__always_inline__]]
2126 constexpr typename basic_format_parse_context<_CharT>::iterator
2127 parse(basic_format_parse_context<_CharT>& __pc)
2128 { return _M_f.parse(__pc); }
2130 template<typename _Out>
2131 typename basic_format_context<_Out, _CharT>::iterator
2132 format(_Tp __u, basic_format_context<_Out, _CharT>& __fc) const
2133 { return _M_f.format(__u, __fc); }
2136 __format::__formatter_fp<_CharT> _M_f;
2139 #if __LDBL_MANT_DIG__ == __DBL_MANT_DIG__
2140 // Reuse __formatter_fp<C>::format<double, Out> for long double.
2141 template<__format::__char _CharT>
2142 struct formatter<long double, _CharT>
2144 formatter() = default;
2146 [[__gnu__::__always_inline__]]
2147 constexpr typename basic_format_parse_context<_CharT>::iterator
2148 parse(basic_format_parse_context<_CharT>& __pc)
2149 { return _M_f.parse(__pc); }
2151 template<typename _Out>
2152 typename basic_format_context<_Out, _CharT>::iterator
2153 format(long double __u, basic_format_context<_Out, _CharT>& __fc) const
2154 { return _M_f.format((double)__u, __fc); }
2157 __format::__formatter_fp<_CharT> _M_f;
2161 #ifdef __STDCPP_FLOAT16_T__
2162 // Reuse __formatter_fp<C>::format<float, Out> for _Float16.
2163 template<__format::__char _CharT>
2164 struct formatter<_Float16, _CharT>
2166 formatter() = default;
2168 [[__gnu__::__always_inline__]]
2169 constexpr typename basic_format_parse_context<_CharT>::iterator
2170 parse(basic_format_parse_context<_CharT>& __pc)
2171 { return _M_f.parse(__pc); }
2173 template<typename _Out>
2174 typename basic_format_context<_Out, _CharT>::iterator
2175 format(_Float16 __u, basic_format_context<_Out, _CharT>& __fc) const
2176 { return _M_f.format((float)__u, __fc); }
2179 __format::__formatter_fp<_CharT> _M_f;
2183 #if defined(__FLT32_DIG__)
2184 // Reuse __formatter_fp<C>::format<float, Out> for _Float32.
2185 template<__format::__char _CharT>
2186 struct formatter<_Float32, _CharT>
2188 formatter() = default;
2190 [[__gnu__::__always_inline__]]
2191 constexpr typename basic_format_parse_context<_CharT>::iterator
2192 parse(basic_format_parse_context<_CharT>& __pc)
2193 { return _M_f.parse(__pc); }
2195 template<typename _Out>
2196 typename basic_format_context<_Out, _CharT>::iterator
2197 format(_Float32 __u, basic_format_context<_Out, _CharT>& __fc) const
2198 { return _M_f.format((float)__u, __fc); }
2201 __format::__formatter_fp<_CharT> _M_f;
2205 #if defined(__FLT64_DIG__)
2206 // Reuse __formatter_fp<C>::format<double, Out> for _Float64.
2207 template<__format::__char _CharT>
2208 struct formatter<_Float64, _CharT>
2210 formatter() = default;
2212 [[__gnu__::__always_inline__]]
2213 constexpr typename basic_format_parse_context<_CharT>::iterator
2214 parse(basic_format_parse_context<_CharT>& __pc)
2215 { return _M_f.parse(__pc); }
2217 template<typename _Out>
2218 typename basic_format_context<_Out, _CharT>::iterator
2219 format(_Float64 __u, basic_format_context<_Out, _CharT>& __fc) const
2220 { return _M_f.format((double)__u, __fc); }
2223 __format::__formatter_fp<_CharT> _M_f;
2227 #if defined(__FLT128_DIG__) && _GLIBCXX_FORMAT_F128 == 1
2228 // Reuse __formatter_fp<C>::format<__float128_t, Out> for _Float128.
2229 template<__format::__char _CharT>
2230 struct formatter<_Float128, _CharT>
2232 formatter() = default;
2234 [[__gnu__::__always_inline__]]
2235 constexpr typename basic_format_parse_context<_CharT>::iterator
2236 parse(basic_format_parse_context<_CharT>& __pc)
2237 { return _M_f.parse(__pc); }
2239 template<typename _Out>
2240 typename basic_format_context<_Out, _CharT>::iterator
2241 format(_Float128 __u, basic_format_context<_Out, _CharT>& __fc) const
2242 { return _M_f.format((__format::__float128_t)__u, __fc); }
2245 __format::__formatter_fp<_CharT> _M_f;
2249 #ifdef __STDCPP_BFLOAT16_T__
2250 // Reuse __formatter_fp<C>::format<float, Out> for bfloat16_t.
2251 template<__format::__char _CharT>
2252 struct formatter<__gnu_cxx::__bfloat16_t, _CharT>
2254 formatter() = default;
2256 [[__gnu__::__always_inline__]]
2257 constexpr typename basic_format_parse_context<_CharT>::iterator
2258 parse(basic_format_parse_context<_CharT>& __pc)
2259 { return _M_f.parse(__pc); }
2261 template<typename _Out>
2262 typename basic_format_context<_Out, _CharT>::iterator
2263 format(__gnu_cxx::__bfloat16_t __u,
2264 basic_format_context<_Out, _CharT>& __fc) const
2265 { return _M_f.format((float)__u, __fc); }
2268 __format::__formatter_fp<_CharT> _M_f;
2271 #endif // __cpp_lib_to_chars
2273 /** Format a pointer.
2276 template<__format::__char _CharT>
2277 struct formatter<const void*, _CharT>
2279 formatter() = default;
2281 constexpr typename basic_format_parse_context<_CharT>::iterator
2282 parse(basic_format_parse_context<_CharT>& __pc)
2284 __format::_Spec<_CharT> __spec{};
2285 const auto __last = __pc.end();
2286 auto __first = __pc.begin();
2288 auto __finalize = [this, &__spec] {
2292 auto __finished = [&] {
2293 if (__first == __last || *__first == '}')
2304 __first = __spec._M_parse_fill_and_align(__first, __last);
2308 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2309 // P2510R3 Formatting pointers
2310 #if __cplusplus > 202302L || ! defined __STRICT_ANSI__
2311 #define _GLIBCXX_P2518R3 1
2313 #define _GLIBCXX_P2518R3 0
2316 #if _GLIBCXX_P2518R3
2317 __first = __spec._M_parse_zero_fill(__first, __last);
2322 __first = __spec._M_parse_width(__first, __last, __pc);
2324 if (__first != __last)
2326 if (*__first == 'p')
2328 #if _GLIBCXX_P2518R3
2329 else if (*__first == 'P')
2331 // _GLIBCXX_RESOLVE_LIB_DEFECTS
2332 // P2510R3 Formatting pointers
2333 __spec._M_type = __format::_Pres_P;
2342 __format::__failed_to_parse_format_spec();
2345 template<typename _Out>
2346 typename basic_format_context<_Out, _CharT>::iterator
2347 format(const void* __v, basic_format_context<_Out, _CharT>& __fc) const
2349 auto __u = reinterpret_cast<__UINTPTR_TYPE__>(__v);
2350 char __buf[2 + sizeof(__v) * 2];
2351 auto [__ptr, __ec] = std::to_chars(__buf + 2, std::end(__buf),
2353 int __n = __ptr - __buf;
2356 #if _GLIBCXX_P2518R3
2357 if (_M_spec._M_type == __format::_Pres_P)
2360 for (auto __p = __buf + 2; __p != __ptr; ++__p)
2361 #if __has_builtin(__builtin_toupper)
2362 *__p = __builtin_toupper(*__p);
2364 *__p = std::toupper(*__p);
2369 basic_string_view<_CharT> __str;
2370 if constexpr (is_same_v<_CharT, char>)
2371 __str = string_view(__buf, __n);
2372 #ifdef _GLIBCXX_USE_WCHAR_T
2375 auto __p = (_CharT*)__builtin_alloca(__n * sizeof(_CharT));
2376 std::__to_wstring_numeric(__buf, __n, __p);
2377 __str = wstring_view(__p, __n);
2381 #if _GLIBCXX_P2518R3
2382 if (_M_spec._M_zero_fill)
2384 size_t __width = _M_spec._M_get_width(__fc);
2385 if (__width <= __str.size())
2386 return __format::__write(__fc.out(), __str);
2388 auto __out = __fc.out();
2389 // Write "0x" or "0X" prefix before zero-filling.
2390 __out = __format::__write(std::move(__out), __str.substr(0, 2));
2391 __str.remove_prefix(2);
2392 size_t __nfill = __width - __n;
2393 return __format::__write_padded(std::move(__out), __str,
2394 __format::_Align_right,
2395 __nfill, _CharT('0'));
2399 return __format::__write_padded_as_spec(__str, __n, __fc, _M_spec,
2400 __format::_Align_right);
2404 __format::_Spec<_CharT> _M_spec{};
2407 template<__format::__char _CharT>
2408 struct formatter<void*, _CharT>
2410 formatter() = default;
2412 [[__gnu__::__always_inline__]]
2413 constexpr typename basic_format_parse_context<_CharT>::iterator
2414 parse(basic_format_parse_context<_CharT>& __pc)
2415 { return _M_f.parse(__pc); }
2417 template<typename _Out>
2418 typename basic_format_context<_Out, _CharT>::iterator
2419 format(void* __v, basic_format_context<_Out, _CharT>& __fc) const
2420 { return _M_f.format(__v, __fc); }
2423 formatter<const void*, _CharT> _M_f;
2426 template<__format::__char _CharT>
2427 struct formatter<nullptr_t, _CharT>
2429 formatter() = default;
2431 [[__gnu__::__always_inline__]]
2432 constexpr typename basic_format_parse_context<_CharT>::iterator
2433 parse(basic_format_parse_context<_CharT>& __pc)
2434 { return _M_f.parse(__pc); }
2436 template<typename _Out>
2437 typename basic_format_context<_Out, _CharT>::iterator
2438 format(nullptr_t, basic_format_context<_Out, _CharT>& __fc) const
2439 { return _M_f.format(nullptr, __fc); }
2442 formatter<const void*, _CharT> _M_f;
2447 /// @cond undocumented
2450 template<typename _Tp, typename _Context,
2452 = typename _Context::template formatter_type<remove_const_t<_Tp>>,
2453 typename _ParseContext
2454 = basic_format_parse_context<typename _Context::char_type>>
2455 concept __parsable_with
2456 = semiregular<_Formatter>
2457 && requires (_Formatter __f, _ParseContext __pc)
2459 { __f.parse(__pc) } -> same_as<typename _ParseContext::iterator>;
2462 template<typename _Tp, typename _Context,
2464 = typename _Context::template formatter_type<remove_const_t<_Tp>>,
2465 typename _ParseContext
2466 = basic_format_parse_context<typename _Context::char_type>>
2467 concept __formattable_with
2468 = semiregular<_Formatter>
2469 && requires (const _Formatter __cf, _Tp&& __t, _Context __fc)
2471 { __cf.format(__t, __fc) } -> same_as<typename _Context::iterator>;
2474 // An unspecified output iterator type used in the `formattable` concept.
2475 template<typename _CharT>
2476 using _Iter_for = back_insert_iterator<basic_string<_CharT>>;
2478 template<typename _Tp, typename _CharT,
2479 typename _Context = basic_format_context<_Iter_for<_CharT>, _CharT>>
2480 concept __formattable_impl
2481 = __parsable_with<_Tp, _Context> && __formattable_with<_Tp, _Context>;
2483 } // namespace __format
2486 #if __cplusplus > 202002L
2487 // [format.formattable], concept formattable
2488 template<typename _Tp, typename _CharT>
2490 = __format::__formattable_impl<remove_reference_t<_Tp>, _CharT>;
2493 #if __cpp_lib_format_ranges
2494 /// @cond undocumented
2497 template<typename _Rg, typename _CharT>
2498 concept __const_formattable_range
2499 = ranges::input_range<const _Rg>
2500 && formattable<ranges::range_reference_t<const _Rg>, _CharT>;
2502 template<typename _Rg, typename _CharT>
2503 using __maybe_const_range
2504 = conditional_t<__const_formattable_range<_Rg, _CharT>, const _Rg, _Rg>;
2505 } // namespace __format
2507 #endif // format_ranges
2509 /// An iterator after the last character written, and the number of
2510 /// characters that would have been written.
2511 template<typename _Out>
2512 struct format_to_n_result
2515 iter_difference_t<_Out> size;
2518 _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
2519 template<typename, typename> class vector;
2520 _GLIBCXX_END_NAMESPACE_CONTAINER
2522 /// @cond undocumented
2525 template<typename _CharT>
2528 _Sink<_CharT>* _M_sink = nullptr;
2531 using iterator_category = output_iterator_tag;
2532 using value_type = void;
2533 using difference_type = ptrdiff_t;
2534 using pointer = void;
2535 using reference = void;
2537 _Sink_iter() = default;
2538 _Sink_iter(const _Sink_iter&) = default;
2539 _Sink_iter& operator=(const _Sink_iter&) = default;
2541 [[__gnu__::__always_inline__]]
2543 _Sink_iter(_Sink<_CharT>& __sink) : _M_sink(std::addressof(__sink)) { }
2545 [[__gnu__::__always_inline__]]
2546 constexpr _Sink_iter&
2547 operator=(_CharT __c)
2549 _M_sink->_M_write(__c);
2553 [[__gnu__::__always_inline__]]
2554 constexpr _Sink_iter&
2555 operator=(basic_string_view<_CharT> __s)
2557 _M_sink->_M_write(__s);
2561 [[__gnu__::__always_inline__]]
2562 constexpr _Sink_iter&
2563 operator*() { return *this; }
2565 [[__gnu__::__always_inline__]]
2566 constexpr _Sink_iter&
2567 operator++() { return *this; }
2569 [[__gnu__::__always_inline__]]
2570 constexpr _Sink_iter
2571 operator++(int) { return *this; }
2574 _M_reserve(size_t __n) const
2575 { return _M_sink->_M_reserve(__n); }
2578 // Abstract base class for type-erased character sinks.
2579 // All formatting and output is done via this type's iterator,
2580 // to reduce the number of different template instantiations.
2581 template<typename _CharT>
2584 friend class _Sink_iter<_CharT>;
2586 span<_CharT> _M_span;
2587 typename span<_CharT>::iterator _M_next;
2589 // Called when the span is full, to make more space available.
2590 // Precondition: _M_next != _M_span.begin()
2591 // Postcondition: _M_next != _M_span.end()
2592 // TODO: remove the precondition? could make overflow handle it.
2593 virtual void _M_overflow() = 0;
2596 // Precondition: __span.size() != 0
2597 [[__gnu__::__always_inline__]]
2599 _Sink(span<_CharT> __span) noexcept
2600 : _M_span(__span), _M_next(__span.begin())
2603 // The portion of the span that has been written to.
2604 [[__gnu__::__always_inline__]]
2606 _M_used() const noexcept
2607 { return _M_span.first(_M_next - _M_span.begin()); }
2609 // The portion of the span that has not been written to.
2610 [[__gnu__::__always_inline__]]
2611 constexpr span<_CharT>
2612 _M_unused() const noexcept
2613 { return _M_span.subspan(_M_next - _M_span.begin()); }
2615 // Use the start of the span as the next write position.
2616 [[__gnu__::__always_inline__]]
2618 _M_rewind() noexcept
2619 { _M_next = _M_span.begin(); }
2621 // Replace the current output range.
2623 _M_reset(span<_CharT> __s, size_t __pos = 0) noexcept
2626 _M_next = __s.begin() + __pos;
2629 // Called by the iterator for *it++ = c
2631 _M_write(_CharT __c)
2634 if (_M_next - _M_span.begin() == std::ssize(_M_span)) [[unlikely]]
2639 _M_write(basic_string_view<_CharT> __s)
2641 span __to = _M_unused();
2642 while (__to.size() <= __s.size())
2644 __s.copy(__to.data(), __to.size());
2645 _M_next += __to.size();
2646 __s.remove_prefix(__to.size());
2652 __s.copy(__to.data(), __s.size());
2653 _M_next += __s.size();
2657 // A successful _Reservation can be used to directly write
2658 // up to N characters to the sink to avoid unwanted buffering.
2661 // True if the reservation was successful, false otherwise.
2662 explicit operator bool() const noexcept { return _M_sink; }
2663 // A pointer to write directly to the sink.
2664 _CharT* get() const noexcept { return _M_sink->_M_next.operator->(); }
2665 // Add n to the _M_next iterator for the sink.
2666 void _M_bump(size_t __n) { _M_sink->_M_bump(__n); }
2670 // Attempt to reserve space to write n characters to the sink.
2671 // If anything is written to the reservation then there must be a call
2672 // to _M_bump(N2) before any call to another member function of *this,
2673 // where N2 is the number of characters written.
2674 virtual _Reservation
2675 _M_reserve(size_t __n)
2677 if (__n <= _M_unused().size())
2680 if (__n <= _M_span.size()) // Cannot meet the request.
2682 _M_overflow(); // Make more space available.
2683 if (__n <= _M_unused().size())
2689 // Update the next output position after writing directly to the sink.
2690 // pre: no calls to _M_write or _M_overflow since _M_reserve.
2696 _Sink(const _Sink&) = delete;
2697 _Sink& operator=(const _Sink&) = delete;
2699 [[__gnu__::__always_inline__]]
2700 constexpr _Sink_iter<_CharT>
2702 { return _Sink_iter<_CharT>(*this); }
2705 // A sink with an internal buffer. This is used to implement concrete sinks.
2706 template<typename _CharT>
2707 class _Buf_sink : public _Sink<_CharT>
2710 _CharT _M_buf[32 * sizeof(void*) / sizeof(_CharT)];
2712 [[__gnu__::__always_inline__]]
2714 _Buf_sink() noexcept
2715 : _Sink<_CharT>(_M_buf)
2719 using _GLIBCXX_STD_C::vector;
2721 // A sink that fills a sequence (e.g. std::string, std::vector, std::deque).
2722 // Writes to a buffer then appends that to the sequence when it fills up.
2723 template<typename _Seq>
2724 class _Seq_sink final : public _Buf_sink<typename _Seq::value_type>
2726 using _CharT = typename _Seq::value_type;
2730 // Transfer buffer contents to the sequence, so buffer can be refilled.
2732 _M_overflow() override
2734 auto __s = this->_M_used();
2735 if (__s.empty()) [[unlikely]]
2736 return; // Nothing in the buffer to transfer to _M_seq.
2738 // If _M_reserve was called then _M_bump must have been called too.
2739 _GLIBCXX_DEBUG_ASSERT(__s.data() != _M_seq.data());
2741 if constexpr (__is_specialization_of<_Seq, basic_string>)
2742 _M_seq.append(__s.data(), __s.size());
2744 _M_seq.insert(_M_seq.end(), __s.begin(), __s.end());
2746 // Make the whole of _M_buf available for the next write:
2750 typename _Sink<_CharT>::_Reservation
2751 _M_reserve(size_t __n) override
2753 // We might already have n characters available in this->_M_unused(),
2754 // but the whole point of this function is to be an optimization for
2755 // the std::format("{}", x) case. We want to avoid writing to _M_buf
2756 // and then copying that into a basic_string if possible, so this
2757 // function prefers to create space directly in _M_seq rather than
2760 if constexpr (__is_specialization_of<_Seq, basic_string>
2761 || __is_specialization_of<_Seq, vector>)
2763 // Flush the buffer to _M_seq first (should not be needed).
2764 if (this->_M_used().size()) [[unlikely]]
2765 _Seq_sink::_M_overflow();
2767 // Expand _M_seq to make __n new characters available:
2768 const auto __sz = _M_seq.size();
2769 if constexpr (is_same_v<string, _Seq> || is_same_v<wstring, _Seq>)
2770 _M_seq.__resize_and_overwrite(__sz + __n,
2771 [](auto, auto __n2) {
2775 _M_seq.resize(__sz + __n);
2777 // Set _M_used() to be a span over the original part of _M_seq
2778 // and _M_unused() to be the extra capacity we just created:
2779 this->_M_reset(_M_seq, __sz);
2782 else // Try to use the base class' buffer.
2783 return _Sink<_CharT>::_M_reserve(__n);
2787 _M_bump(size_t __n) override
2789 if constexpr (__is_specialization_of<_Seq, basic_string>
2790 || __is_specialization_of<_Seq, vector>)
2792 auto __s = this->_M_used();
2793 _GLIBCXX_DEBUG_ASSERT(__s.data() == _M_seq.data());
2794 // Truncate the sequence to the part that was actually written to:
2795 _M_seq.resize(__s.size() + __n);
2796 // Switch back to using buffer:
2797 this->_M_reset(this->_M_buf);
2802 // TODO: for SSO string, use SSO buffer as initial span, then switch
2803 // to _M_buf if it overflows? Or even do that for all unused capacity?
2805 [[__gnu__::__always_inline__]]
2806 _Seq_sink() noexcept(is_nothrow_default_constructible_v<_Seq>)
2809 _Seq_sink(_Seq&& __s) noexcept(is_nothrow_move_constructible_v<_Seq>)
2810 : _M_seq(std::move(__s))
2813 using _Sink<_CharT>::out;
2818 if (this->_M_used().size() != 0)
2819 _Seq_sink::_M_overflow();
2820 return std::move(_M_seq);
2823 // A writable span that views everything written to the sink.
2824 // Will be either a view over _M_seq or the used part of _M_buf.
2828 auto __s = this->_M_used();
2831 if (__s.size() != 0)
2832 _Seq_sink::_M_overflow();
2839 template<typename _CharT, typename _Alloc = allocator<_CharT>>
2841 = _Seq_sink<basic_string<_CharT, char_traits<_CharT>, _Alloc>>;
2843 // template<typename _CharT, typename _Alloc = allocator<_CharT>>
2844 // using _Vec_sink = _Seq_sink<vector<_CharT, _Alloc>>;
2846 // A sink that writes to an output iterator.
2847 // Writes to a fixed-size buffer and then flushes to the output iterator
2848 // when the buffer fills up.
2849 template<typename _CharT, typename _OutIter>
2850 class _Iter_sink : public _Buf_sink<_CharT>
2853 iter_difference_t<_OutIter> _M_max;
2856 size_t _M_count = 0;
2859 _M_overflow() override
2861 auto __s = this->_M_used();
2862 if (_M_max < 0) // No maximum.
2863 _M_out = ranges::copy(__s, std::move(_M_out)).out;
2864 else if (_M_count < static_cast<size_t>(_M_max))
2866 auto __max = _M_max - _M_count;
2867 span<_CharT> __first;
2868 if (__max < __s.size())
2869 __first = __s.first(static_cast<size_t>(__max));
2872 _M_out = ranges::copy(__first, std::move(_M_out)).out;
2875 _M_count += __s.size();
2879 [[__gnu__::__always_inline__]]
2881 _Iter_sink(_OutIter __out, iter_difference_t<_OutIter> __max = -1)
2882 : _M_out(std::move(__out)), _M_max(__max)
2885 using _Sink<_CharT>::out;
2887 format_to_n_result<_OutIter>
2890 if (this->_M_used().size() != 0)
2891 _Iter_sink::_M_overflow();
2892 iter_difference_t<_OutIter> __count(_M_count);
2893 return { std::move(_M_out), __count };
2897 // Partial specialization for contiguous iterators.
2898 // No buffer is used, characters are written straight to the iterator.
2899 // We do not know the size of the output range, so the span size just grows
2900 // as needed. The end of the span might be an invalid pointer outside the
2901 // valid range, but we never actually call _M_span.end(). This class does
2902 // not introduce any invalid pointer arithmetic or overflows that would not
2903 // have happened anyway.
2904 template<typename _CharT, contiguous_iterator _OutIter>
2905 requires same_as<iter_value_t<_OutIter>, _CharT>
2906 class _Iter_sink<_CharT, _OutIter> : public _Sink<_CharT>
2909 iter_difference_t<_OutIter> _M_max = -1;
2911 size_t _M_count = 0;
2913 _CharT _M_buf[64]; // Write here after outputting _M_max characters.
2917 _M_overflow() override
2919 if (this->_M_unused().size() != 0)
2920 return; // No need to switch to internal buffer yet.
2922 auto __s = this->_M_used();
2926 _M_count += __s.size();
2927 // Span was already sized for the maximum character count,
2928 // if it overflows then any further output must go to the
2929 // internal buffer, to be discarded.
2930 this->_M_reset(this->_M_buf);
2934 // No maximum character count. Just extend the span to allow
2935 // writing more characters to it.
2936 this->_M_reset({__s.data(), __s.size() + 1024}, __s.size());
2940 typename _Sink<_CharT>::_Reservation
2941 _M_reserve(size_t __n) final
2943 auto __avail = this->_M_unused();
2944 if (__n > __avail.size())
2947 return {}; // cannot grow
2949 auto __s = this->_M_used();
2950 this->_M_reset({__s.data(), __s.size() + __n}, __s.size());
2957 _S_make_span(_CharT* __ptr, iter_difference_t<_OutIter> __n,
2958 span<_CharT> __buf) noexcept
2961 return __buf; // Only write to the internal buffer.
2965 if constexpr (!is_integral_v<iter_difference_t<_OutIter>>
2966 || sizeof(__n) > sizeof(size_t))
2968 // __int128 or __detail::__max_diff_type
2969 auto __m = iter_difference_t<_OutIter>((size_t)-1);
2973 return {__ptr, (size_t)__n};
2976 #if __has_builtin(__builtin_dynamic_object_size)
2977 if (size_t __bytes = __builtin_dynamic_object_size(__ptr, 2))
2978 return {__ptr, __bytes / sizeof(_CharT)};
2980 // Avoid forming a pointer to a different memory page.
2981 const auto __off = reinterpret_cast<__UINTPTR_TYPE__>(__ptr) % 1024;
2982 __n = (1024 - __off) / sizeof(_CharT);
2983 if (__n > 0) [[likely]]
2984 return {__ptr, static_cast<size_t>(__n)};
2985 else // Misaligned/packed buffer of wchar_t?
2991 _Iter_sink(_OutIter __out, iter_difference_t<_OutIter> __n = -1) noexcept
2992 : _Sink<_CharT>(_S_make_span(std::to_address(__out), __n, _M_buf)),
2993 _M_first(__out), _M_max(__n)
2996 format_to_n_result<_OutIter>
2999 auto __s = this->_M_used();
3000 if (__s.data() == _M_buf)
3002 // Switched to internal buffer, so must have written _M_max.
3003 iter_difference_t<_OutIter> __count(_M_count + __s.size());
3004 return { _M_first + _M_max, __count };
3006 else // Not using internal buffer yet
3008 iter_difference_t<_OutIter> __count(__s.size());
3009 return { _M_first + __count, __count };
3014 enum _Arg_t : unsigned char {
3015 _Arg_none, _Arg_bool, _Arg_c, _Arg_i, _Arg_u, _Arg_ll, _Arg_ull,
3016 _Arg_flt, _Arg_dbl, _Arg_ldbl, _Arg_str, _Arg_sv, _Arg_ptr, _Arg_handle,
3017 _Arg_i128, _Arg_u128,
3018 _Arg_bf16, _Arg_f16, _Arg_f32, _Arg_f64, // These are unused.
3019 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3021 _Arg_f128 = _Arg_ldbl,
3022 _Arg_ibm128 = _Arg_next_value_,
3029 template<typename _Context>
3032 using _CharT = typename _Context::char_type;
3048 unsigned long long _M_ull;
3051 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT // No long double if it's ambiguous.
3052 long double _M_ldbl;
3054 const _CharT* _M_str;
3055 basic_string_view<_CharT> _M_sv;
3057 _HandleBase _M_handle;
3058 #ifdef __SIZEOF_INT128__
3060 unsigned __int128 _M_u128;
3062 #ifdef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3065 #elif _GLIBCXX_FORMAT_F128 == 2
3066 __float128_t _M_f128;
3070 [[__gnu__::__always_inline__]]
3071 _Arg_value() : _M_none() { }
3074 template<typename _Tp>
3075 _Arg_value(in_place_type_t<_Tp>, _Tp __val)
3076 { _S_get<_Tp>() = __val; }
3079 template<typename _Tp, typename _Self>
3080 [[__gnu__::__always_inline__]]
3082 _S_get(_Self& __u) noexcept
3084 if constexpr (is_same_v<_Tp, bool>)
3086 else if constexpr (is_same_v<_Tp, _CharT>)
3088 else if constexpr (is_same_v<_Tp, int>)
3090 else if constexpr (is_same_v<_Tp, unsigned>)
3092 else if constexpr (is_same_v<_Tp, long long>)
3094 else if constexpr (is_same_v<_Tp, unsigned long long>)
3096 else if constexpr (is_same_v<_Tp, float>)
3098 else if constexpr (is_same_v<_Tp, double>)
3100 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3101 else if constexpr (is_same_v<_Tp, long double>)
3104 else if constexpr (is_same_v<_Tp, __ieee128>)
3106 else if constexpr (is_same_v<_Tp, __ibm128>)
3107 return __u._M_ibm128;
3109 else if constexpr (is_same_v<_Tp, const _CharT*>)
3111 else if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
3113 else if constexpr (is_same_v<_Tp, const void*>)
3115 #ifdef __SIZEOF_INT128__
3116 else if constexpr (is_same_v<_Tp, __int128>)
3118 else if constexpr (is_same_v<_Tp, unsigned __int128>)
3121 #if _GLIBCXX_FORMAT_F128 == 2
3122 else if constexpr (is_same_v<_Tp, __float128_t>)
3125 else if constexpr (derived_from<_Tp, _HandleBase>)
3126 return static_cast<_Tp&>(__u._M_handle);
3127 // Otherwise, ill-formed.
3130 template<typename _Tp>
3131 [[__gnu__::__always_inline__]]
3134 { return _S_get<_Tp>(*this); }
3136 template<typename _Tp>
3137 [[__gnu__::__always_inline__]]
3139 _M_get() const noexcept
3140 { return _S_get<_Tp>(*this); }
3142 template<typename _Tp>
3143 [[__gnu__::__always_inline__]]
3145 _M_set(_Tp __v) noexcept
3147 if constexpr (derived_from<_Tp, _HandleBase>)
3148 std::construct_at(&_M_handle, __v);
3150 _S_get<_Tp>(*this) = __v;
3154 // [format.arg.store], class template format-arg-store
3155 template<typename _Context, typename... _Args>
3158 } // namespace __format
3161 template<typename _Context>
3162 class basic_format_arg
3164 using _CharT = typename _Context::char_type;
3166 template<typename _Tp>
3167 static constexpr bool __formattable
3168 = __format::__formattable_with<_Tp, _Context>;
3171 class handle : public __format::_Arg_value<_Context>::_HandleBase
3173 using _Base = typename __format::_Arg_value<_Context>::_HandleBase;
3175 // Format as const if possible, to reduce instantiations.
3176 template<typename _Tp>
3177 using __maybe_const_t
3178 = __conditional_t<__format::__formattable_with<_Tp, _Context>,
3181 template<typename _Tq>
3183 _S_format(basic_format_parse_context<_CharT>& __parse_ctx,
3184 _Context& __format_ctx, const void* __ptr)
3186 using _Td = remove_const_t<_Tq>;
3187 typename _Context::template formatter_type<_Td> __f;
3188 __parse_ctx.advance_to(__f.parse(__parse_ctx));
3189 _Tq& __val = *const_cast<_Tq*>(static_cast<const _Td*>(__ptr));
3190 __format_ctx.advance_to(__f.format(__val, __format_ctx));
3193 template<typename _Tp>
3195 handle(_Tp& __val) noexcept
3197 if constexpr (!__format::__formattable_with<const _Tp, _Context>)
3198 static_assert(!is_const_v<_Tp>, "std::format argument must be "
3199 "non-const for this type");
3201 this->_M_ptr = __builtin_addressof(__val);
3202 auto __func = _S_format<__maybe_const_t<_Tp>>;
3203 this->_M_func = reinterpret_cast<void(*)()>(__func);
3206 friend class basic_format_arg<_Context>;
3209 handle(const handle&) = default;
3210 handle& operator=(const handle&) = default;
3212 [[__gnu__::__always_inline__]]
3214 format(basic_format_parse_context<_CharT>& __pc, _Context& __fc) const
3216 using _Func = void(*)(basic_format_parse_context<_CharT>&,
3217 _Context&, const void*);
3218 auto __f = reinterpret_cast<_Func>(this->_M_func);
3219 __f(__pc, __fc, this->_M_ptr);
3223 [[__gnu__::__always_inline__]]
3224 basic_format_arg() noexcept : _M_type(__format::_Arg_none) { }
3226 [[nodiscard,__gnu__::__always_inline__]]
3227 explicit operator bool() const noexcept
3228 { return _M_type != __format::_Arg_none; }
3231 template<typename _Ctx>
3232 friend class basic_format_args;
3234 template<typename _Ctx, typename... _Args>
3235 friend class __format::_Arg_store;
3237 static_assert(is_trivially_copyable_v<__format::_Arg_value<_Context>>);
3239 __format::_Arg_value<_Context> _M_val;
3240 __format::_Arg_t _M_type;
3242 // Transform incoming argument type to the type stored in _Arg_value.
3243 // e.g. short -> int, std::string -> std::string_view,
3244 // char[3] -> const char*.
3245 template<typename _Tp>
3246 static consteval auto
3249 using _Td = remove_const_t<_Tp>;
3250 if constexpr (is_same_v<_Td, bool>)
3251 return type_identity<bool>();
3252 else if constexpr (is_same_v<_Td, _CharT>)
3253 return type_identity<_CharT>();
3254 else if constexpr (is_same_v<_Td, char> && is_same_v<_CharT, wchar_t>)
3255 return type_identity<_CharT>();
3256 #ifdef __SIZEOF_INT128__ // Check before signed/unsigned integer
3257 else if constexpr (is_same_v<_Td, __int128>)
3258 return type_identity<__int128>();
3259 else if constexpr (is_same_v<_Td, unsigned __int128>)
3260 return type_identity<unsigned __int128>();
3262 else if constexpr (__is_signed_integer<_Td>::value)
3264 if constexpr (sizeof(_Td) <= sizeof(int))
3265 return type_identity<int>();
3266 else if constexpr (sizeof(_Td) <= sizeof(long long))
3267 return type_identity<long long>();
3269 else if constexpr (__is_unsigned_integer<_Td>::value)
3271 if constexpr (sizeof(_Td) <= sizeof(unsigned))
3272 return type_identity<unsigned>();
3273 else if constexpr (sizeof(_Td) <= sizeof(unsigned long long))
3274 return type_identity<unsigned long long>();
3276 else if constexpr (is_same_v<_Td, float>)
3277 return type_identity<float>();
3278 else if constexpr (is_same_v<_Td, double>)
3279 return type_identity<double>();
3280 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3281 else if constexpr (is_same_v<_Td, long double>)
3282 return type_identity<long double>();
3284 else if constexpr (is_same_v<_Td, __ibm128>)
3285 return type_identity<__ibm128>();
3286 else if constexpr (is_same_v<_Td, __ieee128>)
3287 return type_identity<__ieee128>();
3290 #if defined(__FLT16_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
3291 else if constexpr (is_same_v<_Td, _Float16>)
3292 return type_identity<float>();
3295 #if defined(__BFLT16_DIG__) && defined(_GLIBCXX_FLOAT_IS_IEEE_BINARY32)
3296 else if constexpr (is_same_v<_Td, decltype(0.0bf16)>)
3297 return type_identity<float>();
3300 #ifdef __FLT32_DIG__
3301 else if constexpr (is_same_v<_Td, _Float32>)
3302 # ifdef _GLIBCXX_FLOAT_IS_IEEE_BINARY32
3303 return type_identity<float>();
3305 return type_identity<_Float32>();
3308 #ifdef __FLT64_DIG__
3309 else if constexpr (is_same_v<_Td, _Float64>)
3310 # ifdef _GLIBCXX_DOUBLE_IS_IEEE_BINARY64
3311 return type_identity<double>();
3313 return type_identity<_Float64>();
3316 #if _GLIBCXX_FORMAT_F128
3318 else if constexpr (is_same_v<_Td, _Float128>)
3319 return type_identity<__format::__float128_t>();
3321 # if __SIZEOF_FLOAT128__
3322 else if constexpr (is_same_v<_Td, __float128>)
3323 return type_identity<__format::__float128_t>();
3326 else if constexpr (__is_specialization_of<_Td, basic_string_view>
3327 || __is_specialization_of<_Td, basic_string>)
3329 if constexpr (is_same_v<typename _Td::value_type, _CharT>)
3330 return type_identity<basic_string_view<_CharT>>();
3332 return type_identity<handle>();
3334 else if constexpr (is_same_v<decay_t<_Td>, const _CharT*>)
3335 return type_identity<const _CharT*>();
3336 else if constexpr (is_same_v<decay_t<_Td>, _CharT*>)
3337 return type_identity<const _CharT*>();
3338 else if constexpr (is_void_v<remove_pointer_t<_Td>>)
3339 return type_identity<const void*>();
3340 else if constexpr (is_same_v<_Td, nullptr_t>)
3341 return type_identity<const void*>();
3343 return type_identity<handle>();
3346 // Transform a formattable type to the appropriate storage type.
3347 template<typename _Tp>
3348 using _Normalize = typename decltype(_S_to_arg_type<_Tp>())::type;
3350 // Get the _Arg_t value corresponding to a normalized type.
3351 template<typename _Tp>
3352 static consteval __format::_Arg_t
3355 using namespace __format;
3356 if constexpr (is_same_v<_Tp, bool>)
3358 else if constexpr (is_same_v<_Tp, _CharT>)
3360 else if constexpr (is_same_v<_Tp, int>)
3362 else if constexpr (is_same_v<_Tp, unsigned>)
3364 else if constexpr (is_same_v<_Tp, long long>)
3366 else if constexpr (is_same_v<_Tp, unsigned long long>)
3368 else if constexpr (is_same_v<_Tp, float>)
3370 else if constexpr (is_same_v<_Tp, double>)
3372 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3373 else if constexpr (is_same_v<_Tp, long double>)
3376 // Don't use _Arg_ldbl for this target, it's ambiguous.
3377 else if constexpr (is_same_v<_Tp, __ibm128>)
3379 else if constexpr (is_same_v<_Tp, __ieee128>)
3382 else if constexpr (is_same_v<_Tp, const _CharT*>)
3384 else if constexpr (is_same_v<_Tp, basic_string_view<_CharT>>)
3386 else if constexpr (is_same_v<_Tp, const void*>)
3388 #ifdef __SIZEOF_INT128__
3389 else if constexpr (is_same_v<_Tp, __int128>)
3391 else if constexpr (is_same_v<_Tp, unsigned __int128>)
3395 // N.B. some of these types will never actually be used here,
3396 // because they get normalized to a standard floating-point type.
3397 #if defined __FLT32_DIG__ && ! _GLIBCXX_FLOAT_IS_IEEE_BINARY32
3398 else if constexpr (is_same_v<_Tp, _Float32>)
3401 #if defined __FLT64_DIG__ && ! _GLIBCXX_DOUBLE_IS_IEEE_BINARY64
3402 else if constexpr (is_same_v<_Tp, _Float64>)
3405 #if _GLIBCXX_FORMAT_F128 == 2
3406 else if constexpr (is_same_v<_Tp, __format::__float128_t>)
3409 else if constexpr (is_same_v<_Tp, handle>)
3413 template<typename _Tp>
3415 _M_set(_Tp __v) noexcept
3417 _M_type = _S_to_enum<_Tp>();
3421 template<typename _Tp>
3422 requires __format::__formattable_with<_Tp, _Context>
3424 basic_format_arg(_Tp& __v) noexcept
3426 using _Td = _Normalize<_Tp>;
3427 if constexpr (is_same_v<_Td, basic_string_view<_CharT>>)
3428 _M_set(_Td{__v.data(), __v.size()});
3429 else if constexpr (is_same_v<remove_const_t<_Tp>, char>
3430 && is_same_v<_CharT, wchar_t>)
3431 _M_set(static_cast<_Td>(static_cast<unsigned char>(__v)));
3433 _M_set(static_cast<_Td>(__v));
3436 template<typename _Ctx, typename... _Argz>
3438 make_format_args(_Argz&...) noexcept;
3440 template<typename _Visitor, typename _Ctx>
3441 friend decltype(auto)
3442 visit_format_arg(_Visitor&& __vis, basic_format_arg<_Ctx>);
3444 template<typename _Visitor>
3446 _M_visit(_Visitor&& __vis, __format::_Arg_t __type)
3448 using namespace __format;
3452 return std::forward<_Visitor>(__vis)(_M_val._M_none);
3454 return std::forward<_Visitor>(__vis)(_M_val._M_bool);
3456 return std::forward<_Visitor>(__vis)(_M_val._M_c);
3458 return std::forward<_Visitor>(__vis)(_M_val._M_i);
3460 return std::forward<_Visitor>(__vis)(_M_val._M_u);
3462 return std::forward<_Visitor>(__vis)(_M_val._M_ll);
3464 return std::forward<_Visitor>(__vis)(_M_val._M_ull);
3465 #if __glibcxx_to_chars // FIXME: need to be able to format these types!
3467 return std::forward<_Visitor>(__vis)(_M_val._M_flt);
3469 return std::forward<_Visitor>(__vis)(_M_val._M_dbl);
3470 #ifndef _GLIBCXX_LONG_DOUBLE_ALT128_COMPAT
3472 return std::forward<_Visitor>(__vis)(_M_val._M_ldbl);
3475 return std::forward<_Visitor>(__vis)(_M_val._M_f128);
3477 return std::forward<_Visitor>(__vis)(_M_val._M_ibm128);
3481 return std::forward<_Visitor>(__vis)(_M_val._M_str);
3483 return std::forward<_Visitor>(__vis)(_M_val._M_sv);
3485 return std::forward<_Visitor>(__vis)(_M_val._M_ptr);
3488 auto& __h = static_cast<handle&>(_M_val._M_handle);
3489 return std::forward<_Visitor>(__vis)(__h);
3491 #ifdef __SIZEOF_INT128__
3493 return std::forward<_Visitor>(__vis)(_M_val._M_i128);
3495 return std::forward<_Visitor>(__vis)(_M_val._M_u128);
3498 #if _GLIBCXX_FORMAT_F128 == 2
3500 return std::forward<_Visitor>(__vis)(_M_val._M_f128);
3505 __builtin_unreachable();
3510 template<typename _Visitor, typename _Context>
3511 inline decltype(auto)
3512 visit_format_arg(_Visitor&& __vis, basic_format_arg<_Context> __arg)
3514 return __arg._M_visit(std::forward<_Visitor>(__vis), __arg._M_type);
3517 /// @cond undocumented
3520 struct _WidthPrecVisitor
3522 template<typename _Tp>
3524 operator()(_Tp& __arg) const
3526 if constexpr (is_same_v<_Tp, monostate>)
3527 __format::__invalid_arg_id_in_format_string();
3528 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3529 // 3720. Restrict the valid types of arg-id for width and precision
3530 // 3721. Allow an arg-id with a value of zero for width
3531 else if constexpr (sizeof(_Tp) <= sizeof(long long))
3533 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3534 // 3720. Restrict the valid types of arg-id for width and precision
3535 if constexpr (__is_unsigned_integer<_Tp>::value)
3537 else if constexpr (__is_signed_integer<_Tp>::value)
3541 __throw_format_error("format error: argument used for width or "
3542 "precision must be a non-negative integer");
3546 template<typename _Context>
3548 __int_from_arg(const basic_format_arg<_Context>& __arg)
3549 { return std::visit_format_arg(_WidthPrecVisitor(), __arg); }
3551 // Pack _Arg_t enum values into a single 60-bit integer.
3552 template<int _Bits, size_t _Nm>
3554 __pack_arg_types(const array<_Arg_t, _Nm>& __types)
3556 __UINT64_TYPE__ __packed_types = 0;
3557 for (auto __i = __types.rbegin(); __i != __types.rend(); ++__i)
3558 __packed_types = (__packed_types << _Bits) | *__i;
3559 return __packed_types;
3561 } // namespace __format
3564 template<typename _Context>
3565 class basic_format_args
3567 static constexpr int _S_packed_type_bits = 5; // _Arg_t values [0,20]
3568 static constexpr int _S_packed_type_mask = 0b11111;
3569 static constexpr int _S_max_packed_args = 12;
3571 static_assert( __format::_Arg_max_ <= (1 << _S_packed_type_bits) );
3573 template<typename... _Args>
3574 using _Store = __format::_Arg_store<_Context, _Args...>;
3576 template<typename _Ctx, typename... _Args>
3577 friend class __format::_Arg_store;
3579 using uint64_t = __UINT64_TYPE__;
3580 using _Format_arg = basic_format_arg<_Context>;
3581 using _Format_arg_val = __format::_Arg_value<_Context>;
3583 // If args are packed then the number of args is in _M_packed_size and
3584 // the packed types are in _M_unpacked_size, accessed via _M_type(i).
3585 // If args are not packed then the number of args is in _M_unpacked_size
3586 // and _M_packed_size is zero.
3587 uint64_t _M_packed_size : 4;
3588 uint64_t _M_unpacked_size : 60;
3591 const _Format_arg_val* _M_values; // Active when _M_packed_size != 0
3592 const _Format_arg* _M_args; // Active when _M_packed_size == 0
3596 _M_size() const noexcept
3597 { return _M_packed_size ? _M_packed_size : _M_unpacked_size; }
3599 typename __format::_Arg_t
3600 _M_type(size_t __i) const noexcept
3602 uint64_t __t = _M_unpacked_size >> (__i * _S_packed_type_bits);
3603 return static_cast<__format::_Arg_t>(__t & _S_packed_type_mask);
3606 template<typename _Ctx, typename... _Args>
3608 make_format_args(_Args&...) noexcept;
3610 // An array of _Arg_t enums corresponding to _Args...
3611 template<typename... _Args>
3612 static consteval array<__format::_Arg_t, sizeof...(_Args)>
3614 { return {_Format_arg::template _S_to_enum<_Args>()...}; }
3617 basic_format_args() noexcept = default;
3619 template<typename... _Args>
3620 basic_format_args(const _Store<_Args...>& __store) noexcept;
3622 [[nodiscard,__gnu__::__always_inline__]]
3623 basic_format_arg<_Context>
3624 get(size_t __i) const noexcept
3626 basic_format_arg<_Context> __arg;
3627 if (__i < _M_packed_size)
3629 __arg._M_type = _M_type(__i);
3630 __arg._M_val = _M_values[__i];
3632 else if (_M_packed_size == 0 && __i < _M_unpacked_size)
3633 __arg = _M_args[__i];
3638 // _GLIBCXX_RESOLVE_LIB_DEFECTS
3639 // 3810. CTAD for std::basic_format_args
3640 template<typename _Context, typename... _Args>
3641 basic_format_args(__format::_Arg_store<_Context, _Args...>)
3642 -> basic_format_args<_Context>;
3644 template<typename _Context, typename... _Args>
3646 make_format_args(_Args&... __fmt_args) noexcept;
3648 // An array of type-erased formatting arguments.
3649 template<typename _Context, typename... _Args>
3650 class __format::_Arg_store
3652 friend std::basic_format_args<_Context>;
3654 template<typename _Ctx, typename... _Argz>
3656 #if _GLIBCXX_INLINE_VERSION
3657 __8:: // Needed for PR c++/59256
3659 make_format_args(_Argz&...) noexcept;
3661 // For a sufficiently small number of arguments we only store values.
3662 // basic_format_args can get the types from the _Args pack.
3663 static constexpr bool _S_values_only
3664 = sizeof...(_Args) <= basic_format_args<_Context>::_S_max_packed_args;
3667 = __conditional_t<_S_values_only,
3668 __format::_Arg_value<_Context>,
3669 basic_format_arg<_Context>>;
3671 _Element_t _M_args[sizeof...(_Args)];
3673 template<typename _Tp>
3675 _S_make_elt(_Tp& __v)
3677 basic_format_arg<_Context> __arg(__v);
3678 if constexpr (_S_values_only)
3679 return __arg._M_val;
3684 template<typename... _Tp>
3685 requires (sizeof...(_Tp) == sizeof...(_Args))
3686 [[__gnu__::__always_inline__]]
3687 _Arg_store(_Tp&... __a) noexcept
3688 : _M_args{_S_make_elt(__a)...}
3692 template<typename _Context>
3693 class __format::_Arg_store<_Context>
3696 template<typename _Context>
3697 template<typename... _Args>
3699 basic_format_args<_Context>::
3700 basic_format_args(const _Store<_Args...>& __store) noexcept
3702 if constexpr (sizeof...(_Args) == 0)
3705 _M_unpacked_size = 0;
3708 else if constexpr (sizeof...(_Args) <= _S_max_packed_args)
3710 // The number of packed arguments:
3711 _M_packed_size = sizeof...(_Args);
3712 // The packed type enums:
3714 = __format::__pack_arg_types<_S_packed_type_bits>(_S_types_to_pack<_Args...>());
3715 // The _Arg_value objects.
3716 _M_values = __store._M_args;
3720 // No packed arguments:
3722 // The number of unpacked arguments:
3723 _M_unpacked_size = sizeof...(_Args);
3724 // The basic_format_arg objects:
3725 _M_args = __store._M_args;
3729 /// Capture formatting arguments for use by `std::vformat`.
3730 template<typename _Context = format_context, typename... _Args>
3731 [[nodiscard,__gnu__::__always_inline__]]
3733 make_format_args(_Args&... __fmt_args) noexcept
3735 using _Fmt_arg = basic_format_arg<_Context>;
3736 using _Store = __format::_Arg_store<_Context, typename _Fmt_arg::template
3737 _Normalize<_Args>...>;
3738 return _Store(__fmt_args...);
3741 #ifdef _GLIBCXX_USE_WCHAR_T
3742 /// Capture formatting arguments for use by `std::vformat` (for wide output).
3743 template<typename... _Args>
3744 [[nodiscard,__gnu__::__always_inline__]]
3746 make_wformat_args(_Args&... __args) noexcept
3747 { return std::make_format_args<wformat_context>(__args...); }
3750 /// @cond undocumented
3753 template<typename _Out, typename _CharT, typename _Context>
3755 __do_vformat_to(_Out, basic_string_view<_CharT>,
3756 const basic_format_args<_Context>&,
3757 const locale* = nullptr);
3758 } // namespace __format
3761 /** Context for std::format and similar functions.
3763 * A formatting context contains an output iterator and locale to use
3764 * for the formatting operations. Most programs will never need to use
3765 * this class template explicitly. For typical uses of `std::format` the
3766 * library will use the specializations `std::format_context` (for `char`)
3767 * and `std::wformat_context` (for `wchar_t`).
3769 template<typename _Out, typename _CharT>
3770 class basic_format_context
3772 static_assert( output_iterator<_Out, const _CharT&> );
3774 basic_format_args<basic_format_context> _M_args;
3776 __format::_Optional_locale _M_loc;
3778 basic_format_context(basic_format_args<basic_format_context> __args,
3780 : _M_args(__args), _M_out(std::move(__out))
3783 basic_format_context(basic_format_args<basic_format_context> __args,
3784 _Out __out, const std::locale& __loc)
3785 : _M_args(__args), _M_out(std::move(__out)), _M_loc(__loc)
3788 template<typename _Out2, typename _CharT2, typename _Context2>
3790 __format::__do_vformat_to(_Out2, basic_string_view<_CharT2>,
3791 const basic_format_args<_Context2>&,
3795 basic_format_context() = default;
3796 ~basic_format_context() = default;
3798 using iterator = _Out;
3799 using char_type = _CharT;
3800 template<typename _Tp>
3801 using formatter_type = formatter<_Tp, _CharT>;
3804 basic_format_arg<basic_format_context>
3805 arg(size_t __id) const noexcept
3806 { return _M_args.get(__id); }
3809 std::locale locale() { return _M_loc.value(); }
3812 iterator out() { return std::move(_M_out); }
3814 void advance_to(iterator __it) { _M_out = std::move(__it); }
3818 /// @cond undocumented
3821 // Abstract base class defining an interface for scanning format strings.
3822 // Scan the characters in a format string, dividing it up into strings of
3823 // ordinary characters, escape sequences, and replacement fields.
3824 // Call virtual functions for derived classes to parse format-specifiers
3825 // or write formatted output.
3826 template<typename _CharT>
3829 using iterator = typename basic_format_parse_context<_CharT>::iterator;
3831 basic_format_parse_context<_CharT> _M_pc;
3834 _Scanner(basic_string_view<_CharT> __str, size_t __nargs = -1)
3835 : _M_pc(__str, __nargs)
3838 constexpr iterator begin() const noexcept { return _M_pc.begin(); }
3839 constexpr iterator end() const noexcept { return _M_pc.end(); }
3844 basic_string_view<_CharT> __fmt = _M_fmt_str();
3846 if (__fmt.size() == 2 && __fmt[0] == '{' && __fmt[1] == '}')
3848 _M_pc.advance_to(begin() + 1);
3849 _M_format_arg(_M_pc.next_arg_id());
3853 size_t __lbr = __fmt.find('{');
3854 size_t __rbr = __fmt.find('}');
3856 while (__fmt.size())
3858 auto __cmp = __lbr <=> __rbr;
3862 _M_pc.advance_to(end());
3867 if (__lbr + 1 == __fmt.size()
3868 || (__rbr == __fmt.npos && __fmt[__lbr + 1] != '{'))
3869 __format::__unmatched_left_brace_in_format_string();
3870 const bool __is_escape = __fmt[__lbr + 1] == '{';
3871 iterator __last = begin() + __lbr + int(__is_escape);
3872 _M_on_chars(__last);
3873 _M_pc.advance_to(__last + 1);
3874 __fmt = _M_fmt_str();
3877 if (__rbr != __fmt.npos)
3879 __lbr = __fmt.find('{');
3883 _M_on_replacement_field();
3884 __fmt = _M_fmt_str();
3885 __lbr = __fmt.find('{');
3886 __rbr = __fmt.find('}');
3891 if (++__rbr == __fmt.size() || __fmt[__rbr] != '}')
3892 __format::__unmatched_right_brace_in_format_string();
3893 iterator __last = begin() + __rbr;
3894 _M_on_chars(__last);
3895 _M_pc.advance_to(__last + 1);
3896 __fmt = _M_fmt_str();
3897 if (__lbr != __fmt.npos)
3899 __rbr = __fmt.find('}');
3904 constexpr basic_string_view<_CharT>
3905 _M_fmt_str() const noexcept
3906 { return {begin(), end()}; }
3908 constexpr virtual void _M_on_chars(iterator) { }
3910 constexpr void _M_on_replacement_field()
3912 auto __next = begin();
3916 __id = _M_pc.next_arg_id();
3917 else if (*__next == ':')
3919 __id = _M_pc.next_arg_id();
3920 _M_pc.advance_to(++__next);
3924 auto [__i, __ptr] = __format::__parse_arg_id(begin(), end());
3925 if (!__ptr || !(*__ptr == '}' || *__ptr == ':'))
3926 __format::__invalid_arg_id_in_format_string();
3927 _M_pc.check_arg_id(__id = __i);
3930 _M_pc.advance_to(++__ptr);
3933 _M_pc.advance_to(__ptr);
3935 _M_format_arg(__id);
3936 if (begin() == end() || *begin() != '}')
3937 __format::__unmatched_left_brace_in_format_string();
3938 _M_pc.advance_to(begin() + 1); // Move past '}'
3941 constexpr virtual void _M_format_arg(size_t __id) = 0;
3944 // Process a format string and format the arguments in the context.
3945 template<typename _Out, typename _CharT>
3946 class _Formatting_scanner : public _Scanner<_CharT>
3949 _Formatting_scanner(basic_format_context<_Out, _CharT>& __fc,
3950 basic_string_view<_CharT> __str)
3951 : _Scanner<_CharT>(__str), _M_fc(__fc)
3955 basic_format_context<_Out, _CharT>& _M_fc;
3957 using iterator = typename _Scanner<_CharT>::iterator;
3960 _M_on_chars(iterator __last) override
3962 basic_string_view<_CharT> __str(this->begin(), __last);
3963 _M_fc.advance_to(__format::__write(_M_fc.out(), __str));
3967 _M_format_arg(size_t __id) override
3969 using _Context = basic_format_context<_Out, _CharT>;
3970 using handle = typename basic_format_arg<_Context>::handle;
3972 std::visit_format_arg([this](auto& __arg) {
3973 using _Type = remove_reference_t<decltype(__arg)>;
3974 using _Formatter = typename _Context::template formatter_type<_Type>;
3975 if constexpr (is_same_v<_Type, monostate>)
3976 __format::__invalid_arg_id_in_format_string();
3977 else if constexpr (is_same_v<_Type, handle>)
3978 __arg.format(this->_M_pc, this->_M_fc);
3979 else if constexpr (is_default_constructible_v<_Formatter>)
3982 this->_M_pc.advance_to(__f.parse(this->_M_pc));
3983 this->_M_fc.advance_to(__f.format(__arg, this->_M_fc));
3986 static_assert(__format::__formattable_with<_Type, _Context>);
3987 }, _M_fc.arg(__id));
3991 // Validate a format string for Args.
3992 template<typename _CharT, typename... _Args>
3993 class _Checking_scanner : public _Scanner<_CharT>
3996 (is_default_constructible_v<formatter<_Args, _CharT>> && ...),
3997 "std::formatter must be specialized for each type being formatted");
4001 _Checking_scanner(basic_string_view<_CharT> __str)
4002 : _Scanner<_CharT>(__str, sizeof...(_Args))
4007 _M_format_arg(size_t __id) override
4009 if constexpr (sizeof...(_Args) != 0)
4011 if (__id < sizeof...(_Args))
4013 _M_parse_format_spec<_Args...>(__id);
4017 __builtin_unreachable();
4020 template<typename _Tp, typename... _OtherArgs>
4022 _M_parse_format_spec(size_t __id)
4026 formatter<_Tp, _CharT> __f;
4027 this->_M_pc.advance_to(__f.parse(this->_M_pc));
4029 else if constexpr (sizeof...(_OtherArgs) != 0)
4030 _M_parse_format_spec<_OtherArgs...>(__id - 1);
4032 __builtin_unreachable();
4036 template<typename _Out, typename _CharT, typename _Context>
4038 __do_vformat_to(_Out __out, basic_string_view<_CharT> __fmt,
4039 const basic_format_args<_Context>& __args,
4040 const locale* __loc)
4042 _Iter_sink<_CharT, _Out> __sink(std::move(__out));
4043 _Sink_iter<_CharT> __sink_out;
4045 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
4046 __sink_out = __out; // Already a sink iterator, safe to use post-move.
4048 __sink_out = __sink.out();
4050 if constexpr (is_same_v<_CharT, char>)
4051 if (__fmt.size() == 2 && __fmt[0] == '{' && __fmt[1] == '}')
4053 bool __done = false;
4054 std::visit_format_arg([&](auto& __arg) {
4055 using _Tp = remove_cvref_t<decltype(__arg)>;
4056 if constexpr (is_same_v<_Tp, bool>)
4058 size_t __len = 4 + !__arg;
4059 const char* __chars[] = { "false", "true" };
4060 if (auto __res = __sink_out._M_reserve(__len))
4062 __builtin_memcpy(__res.get(), __chars[__arg], __len);
4063 __res._M_bump(__len);
4067 else if constexpr (is_same_v<_Tp, char>)
4069 if (auto __res = __sink_out._M_reserve(1))
4071 *__res.get() = __arg;
4076 else if constexpr (is_integral_v<_Tp>)
4078 make_unsigned_t<_Tp> __uval;
4079 const bool __neg = __arg < 0;
4081 __uval = make_unsigned_t<_Tp>(~__arg) + 1u;
4084 const auto __n = __detail::__to_chars_len(__uval) + __neg;
4085 if (auto __res = __sink_out._M_reserve(__n))
4087 auto __ptr = __res.get();
4089 __detail::__to_chars_10_impl(__ptr + (int)__neg, __n,
4095 else if constexpr (is_convertible_v<_Tp, string_view>)
4097 string_view __sv = __arg;
4098 if (auto __res = __sink_out._M_reserve(__sv.size()))
4100 __builtin_memcpy(__res.get(), __sv.data(), __sv.size());
4101 __res._M_bump(__sv.size());
4109 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
4112 return std::move(__sink)._M_finish().out;
4116 auto __ctx = __loc == nullptr
4117 ? _Context(__args, __sink_out)
4118 : _Context(__args, __sink_out, *__loc);
4119 _Formatting_scanner<_Sink_iter<_CharT>, _CharT> __scanner(__ctx, __fmt);
4120 __scanner._M_scan();
4122 if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
4125 return std::move(__sink)._M_finish().out;
4128 } // namespace __format
4131 template<typename _CharT, typename... _Args>
4132 template<typename _Tp>
4133 requires convertible_to<const _Tp&, basic_string_view<_CharT>>
4135 basic_format_string<_CharT, _Args...>::
4136 basic_format_string(const _Tp& __s)
4139 __format::_Checking_scanner<_CharT, remove_cvref_t<_Args>...>
4141 __scanner._M_scan();
4144 // [format.functions], formatting functions
4146 template<typename _Out> requires output_iterator<_Out, const char&>
4147 [[__gnu__::__always_inline__]]
4149 vformat_to(_Out __out, string_view __fmt, format_args __args)
4150 { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
4152 #ifdef _GLIBCXX_USE_WCHAR_T
4153 template<typename _Out> requires output_iterator<_Out, const wchar_t&>
4154 [[__gnu__::__always_inline__]]
4156 vformat_to(_Out __out, wstring_view __fmt, wformat_args __args)
4157 { return __format::__do_vformat_to(std::move(__out), __fmt, __args); }
4160 template<typename _Out> requires output_iterator<_Out, const char&>
4161 [[__gnu__::__always_inline__]]
4163 vformat_to(_Out __out, const locale& __loc, string_view __fmt,
4166 return __format::__do_vformat_to(std::move(__out), __fmt, __args, &__loc);
4169 #ifdef _GLIBCXX_USE_WCHAR_T
4170 template<typename _Out> requires output_iterator<_Out, const wchar_t&>
4171 [[__gnu__::__always_inline__]]
4173 vformat_to(_Out __out, const locale& __loc, wstring_view __fmt,
4174 wformat_args __args)
4176 return __format::__do_vformat_to(std::move(__out), __fmt, __args, &__loc);
4182 vformat(string_view __fmt, format_args __args)
4184 __format::_Str_sink<char> __buf;
4185 std::vformat_to(__buf.out(), __fmt, __args);
4186 return std::move(__buf).get();
4189 #ifdef _GLIBCXX_USE_WCHAR_T
4192 vformat(wstring_view __fmt, wformat_args __args)
4194 __format::_Str_sink<wchar_t> __buf;
4195 std::vformat_to(__buf.out(), __fmt, __args);
4196 return std::move(__buf).get();
4202 vformat(const locale& __loc, string_view __fmt, format_args __args)
4204 __format::_Str_sink<char> __buf;
4205 std::vformat_to(__buf.out(), __loc, __fmt, __args);
4206 return std::move(__buf).get();
4209 #ifdef _GLIBCXX_USE_WCHAR_T
4212 vformat(const locale& __loc, wstring_view __fmt, wformat_args __args)
4214 __format::_Str_sink<wchar_t> __buf;
4215 std::vformat_to(__buf.out(), __loc, __fmt, __args);
4216 return std::move(__buf).get();
4220 template<typename... _Args>
4223 format(format_string<_Args...> __fmt, _Args&&... __args)
4224 { return std::vformat(__fmt.get(), std::make_format_args(__args...)); }
4226 #ifdef _GLIBCXX_USE_WCHAR_T
4227 template<typename... _Args>
4230 format(wformat_string<_Args...> __fmt, _Args&&... __args)
4231 { return std::vformat(__fmt.get(), std::make_wformat_args(__args...)); }
4234 template<typename... _Args>
4237 format(const locale& __loc, format_string<_Args...> __fmt,
4240 return std::vformat(__loc, __fmt.get(),
4241 std::make_format_args(__args...));
4244 #ifdef _GLIBCXX_USE_WCHAR_T
4245 template<typename... _Args>
4248 format(const locale& __loc, wformat_string<_Args...> __fmt,
4251 return std::vformat(__loc, __fmt.get(),
4252 std::make_wformat_args(__args...));
4256 template<typename _Out, typename... _Args>
4257 requires output_iterator<_Out, const char&>
4259 format_to(_Out __out, format_string<_Args...> __fmt, _Args&&... __args)
4261 return std::vformat_to(std::move(__out), __fmt.get(),
4262 std::make_format_args(__args...));
4265 #ifdef _GLIBCXX_USE_WCHAR_T
4266 template<typename _Out, typename... _Args>
4267 requires output_iterator<_Out, const wchar_t&>
4269 format_to(_Out __out, wformat_string<_Args...> __fmt, _Args&&... __args)
4271 return std::vformat_to(std::move(__out), __fmt.get(),
4272 std::make_wformat_args(__args...));
4276 template<typename _Out, typename... _Args>
4277 requires output_iterator<_Out, const char&>
4279 format_to(_Out __out, const locale& __loc, format_string<_Args...> __fmt,
4282 return std::vformat_to(std::move(__out), __loc, __fmt.get(),
4283 std::make_format_args(__args...));
4286 #ifdef _GLIBCXX_USE_WCHAR_T
4287 template<typename _Out, typename... _Args>
4288 requires output_iterator<_Out, const wchar_t&>
4290 format_to(_Out __out, const locale& __loc, wformat_string<_Args...> __fmt,
4293 return std::vformat_to(std::move(__out), __loc, __fmt.get(),
4294 std::make_wformat_args(__args...));
4298 template<typename _Out, typename... _Args>
4299 requires output_iterator<_Out, const char&>
4300 inline format_to_n_result<_Out>
4301 format_to_n(_Out __out, iter_difference_t<_Out> __n,
4302 format_string<_Args...> __fmt, _Args&&... __args)
4304 __format::_Iter_sink<char, _Out> __sink(std::move(__out), __n);
4305 std::vformat_to(__sink.out(), __fmt.get(),
4306 std::make_format_args(__args...));
4307 return std::move(__sink)._M_finish();
4310 #ifdef _GLIBCXX_USE_WCHAR_T
4311 template<typename _Out, typename... _Args>
4312 requires output_iterator<_Out, const wchar_t&>
4313 inline format_to_n_result<_Out>
4314 format_to_n(_Out __out, iter_difference_t<_Out> __n,
4315 wformat_string<_Args...> __fmt, _Args&&... __args)
4317 __format::_Iter_sink<wchar_t, _Out> __sink(std::move(__out), __n);
4318 std::vformat_to(__sink.out(), __fmt.get(),
4319 std::make_wformat_args(__args...));
4320 return std::move(__sink)._M_finish();
4324 template<typename _Out, typename... _Args>
4325 requires output_iterator<_Out, const char&>
4326 inline format_to_n_result<_Out>
4327 format_to_n(_Out __out, iter_difference_t<_Out> __n, const locale& __loc,
4328 format_string<_Args...> __fmt, _Args&&... __args)
4330 __format::_Iter_sink<char, _Out> __sink(std::move(__out), __n);
4331 std::vformat_to(__sink.out(), __loc, __fmt.get(),
4332 std::make_format_args(__args...));
4333 return std::move(__sink)._M_finish();
4336 #ifdef _GLIBCXX_USE_WCHAR_T
4337 template<typename _Out, typename... _Args>
4338 requires output_iterator<_Out, const wchar_t&>
4339 inline format_to_n_result<_Out>
4340 format_to_n(_Out __out, iter_difference_t<_Out> __n, const locale& __loc,
4341 wformat_string<_Args...> __fmt, _Args&&... __args)
4343 __format::_Iter_sink<wchar_t, _Out> __sink(std::move(__out), __n);
4344 std::vformat_to(__sink.out(), __loc, __fmt.get(),
4345 std::make_wformat_args(__args...));
4346 return std::move(__sink)._M_finish();
4350 /// @cond undocumented
4354 template<typename _CharT>
4355 class _Counting_sink final : public _Iter_sink<_CharT, _CharT*>
4358 _Counting_sink() : _Iter_sink<_CharT, _CharT*>(nullptr, 0) { }
4360 [[__gnu__::__always_inline__]]
4363 { return this->_M_count + this->_M_used().size(); }
4366 template<typename _CharT>
4367 class _Counting_sink : public _Buf_sink<_CharT>
4369 size_t _M_count = 0;
4372 _M_overflow() override
4374 if (!std::is_constant_evaluated())
4375 _M_count += this->_M_used().size();
4380 _Counting_sink() = default;
4382 [[__gnu__::__always_inline__]]
4386 _Counting_sink::_M_overflow();
4391 } // namespace __format
4394 template<typename... _Args>
4397 formatted_size(format_string<_Args...> __fmt, _Args&&... __args)
4399 __format::_Counting_sink<char> __buf;
4400 std::vformat_to(__buf.out(), __fmt.get(),
4401 std::make_format_args(__args...));
4402 return __buf.count();
4405 #ifdef _GLIBCXX_USE_WCHAR_T
4406 template<typename... _Args>
4409 formatted_size(wformat_string<_Args...> __fmt, _Args&&... __args)
4411 __format::_Counting_sink<wchar_t> __buf;
4412 std::vformat_to(__buf.out(), __fmt.get(),
4413 std::make_wformat_args(__args...));
4414 return __buf.count();
4418 template<typename... _Args>
4421 formatted_size(const locale& __loc, format_string<_Args...> __fmt,
4424 __format::_Counting_sink<char> __buf;
4425 std::vformat_to(__buf.out(), __loc, __fmt.get(),
4426 std::make_format_args(__args...));
4427 return __buf.count();
4430 #ifdef _GLIBCXX_USE_WCHAR_T
4431 template<typename... _Args>
4434 formatted_size(const locale& __loc, wformat_string<_Args...> __fmt,
4437 __format::_Counting_sink<wchar_t> __buf;
4438 std::vformat_to(__buf.out(), __loc, __fmt.get(),
4439 std::make_wformat_args(__args...));
4440 return __buf.count();
4444 #if __cpp_lib_format_ranges
4445 // [format.range], formatting of ranges
4446 // [format.range.fmtkind], variable template format_kind
4447 enum class range_format {
4456 /// @cond undocumented
4457 template<typename _Rg>
4458 constexpr auto format_kind = not defined(format_kind<_Rg>);
4460 template<typename _Tp>
4461 consteval range_format
4464 using _Ref = ranges::range_reference_t<_Tp>;
4465 if constexpr (is_same_v<remove_cvref_t<_Ref>, _Tp>)
4466 return range_format::disabled;
4467 else if constexpr (requires { typename _Tp::key_type; })
4469 if constexpr (requires { typename _Tp::mapped_type; })
4471 using _Up = remove_cvref_t<_Ref>;
4472 if constexpr (__is_pair<_Up>)
4473 return range_format::map;
4474 else if constexpr (__is_specialization_of<_Up, tuple>)
4475 if constexpr (tuple_size_v<_Up> == 2)
4476 return range_format::map;
4478 return range_format::set;
4481 return range_format::sequence;
4485 /// A constant determining how a range should be formatted.
4486 template<ranges::input_range _Rg> requires same_as<_Rg, remove_cvref_t<_Rg>>
4487 constexpr range_format format_kind<_Rg> = __fmt_kind<_Rg>();
4489 // [format.range.formatter], class template range_formatter
4490 template<typename _Tp, typename _CharT = char>
4491 requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT>
4492 class range_formatter; // TODO
4494 /// @cond undocumented
4497 // [format.range.fmtdef], class template range-default-formatter
4498 template<range_format _Kind, ranges::input_range _Rg, typename _CharT>
4499 struct __range_default_formatter; // TODO
4500 } // namespace __format
4503 // [format.range.fmtmap], [format.range.fmtset], [format.range.fmtstr],
4504 // specializations for maps, sets, and strings
4505 template<ranges::input_range _Rg, typename _CharT>
4506 requires (format_kind<_Rg> != range_format::disabled)
4507 && formattable<ranges::range_reference_t<_Rg>, _CharT>
4508 struct formatter<_Rg, _CharT>
4509 : __format::__range_default_formatter<format_kind<_Rg>, _Rg, _CharT>
4511 #endif // C++23 formatting ranges
4513 _GLIBCXX_END_NAMESPACE_VERSION
4515 #endif // __cpp_lib_format
4516 #endif // _GLIBCXX_FORMAT