xref: /llvm-project-15.0.7/libcxx/include/format (revision cf838ebf)
1// -*- C++ -*-
2//===--------------------------- format -----------------------------------===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef _LIBCPP_FORMAT
11#define _LIBCPP_FORMAT
12
13/*
14
15namespace std {
16  // [format.context], class template basic_format_context
17  template<class Out, class charT>
18  class basic_format_context {
19    basic_format_args<basic_format_context> args_;      // exposition only
20    Out out_;                                           // exposition only
21
22  public:
23    using iterator = Out;
24    using char_type = charT;
25    template<class T> using formatter_type = formatter<T, charT>;
26
27    basic_format_arg<basic_format_context> arg(size_t id) const;
28    std::locale locale();
29
30    iterator out();
31    void advance_to(iterator it);
32  };
33  using format_context = basic_format_context<unspecified, char>;
34  using wformat_context = basic_format_context<unspecified, wchar_t>;
35
36  // [format.args], class template basic_format_args
37  template<class Context>
38  class basic_format_args {
39    size_t size_;                               // exposition only
40    const basic_format_arg<Context>* data_;     // exposition only
41
42  public:
43    basic_format_args() noexcept;
44
45    template<class... Args>
46      basic_format_args(const format-arg-store<Context, Args...>& store) noexcept;
47
48    basic_format_arg<Context> get(size_t i) const noexcept;
49  };
50  using format_args = basic_format_args<format_context>;
51  using wformat_args = basic_format_args<wformat_context>;
52
53
54  template<class Out, class charT>
55    using format_args_t = basic_format_args<basic_format_context<Out, charT>>;
56
57  // [format.functions], formatting functions
58  template<class... Args>
59    string format(string_view fmt, const Args&... args);
60  template<class... Args>
61    wstring format(wstring_view fmt, const Args&... args);
62  template<class... Args>
63    string format(const locale& loc, string_view fmt, const Args&... args);
64  template<class... Args>
65    wstring format(const locale& loc, wstring_view fmt, const Args&... args);
66
67  string vformat(string_view fmt, format_args args);
68  wstring vformat(wstring_view fmt, wformat_args args);
69  string vformat(const locale& loc, string_view fmt, format_args args);
70  wstring vformat(const locale& loc, wstring_view fmt, wformat_args args);
71
72  template<class Out, class... Args>
73    Out format_to(Out out, string_view fmt, const Args&... args);
74  template<class Out, class... Args>
75    Out format_to(Out out, wstring_view fmt, const Args&... args);
76  template<class Out, class... Args>
77    Out format_to(Out out, const locale& loc, string_view fmt, const Args&... args);
78  template<class Out, class... Args>
79    Out format_to(Out out, const locale& loc, wstring_view fmt, const Args&... args);
80
81  template<class Out>
82    Out vformat_to(Out out, string_view fmt,
83                   format_args_t<type_identity_t<Out>, char> args);
84  template<class Out>
85    Out vformat_to(Out out, wstring_view fmt,
86                   format_args_t<type_identity_t<Out>, wchar_t> args);
87  template<class Out>
88    Out vformat_to(Out out, const locale& loc, string_view fmt,
89                   format_args_t<type_identity_t<Out>, char> args);
90  template<class Out>
91    Out vformat_to(Out out, const locale& loc, wstring_view fmt,
92                   format_args_t<type_identity_t<Out>, wchar_t> args);
93
94  template<class Out> struct format_to_n_result {
95    Out out;
96    iter_difference_t<Out> size;
97  };
98
99 template<class Out, class... Args>
100    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
101                                        string_view fmt, const Args&... args);
102  template<class Out, class... Args>
103    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
104                                        wstring_view fmt, const Args&... args);
105  template<class Out, class... Args>
106    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
107                                        const locale& loc, string_view fmt,
108                                        const Args&... args);
109  template<class Out, class... Args>
110    format_to_n_result<Out> format_to_n(Out out, iter_difference_t<Out> n,
111                                        const locale& loc, wstring_view fmt,
112                                        const Args&... args);
113
114  template<class... Args>
115    size_t formatted_size(string_view fmt, const Args&... args);
116  template<class... Args>
117    size_t formatted_size(wstring_view fmt, const Args&... args);
118  template<class... Args>
119    size_t formatted_size(const locale& loc, string_view fmt, const Args&... args);
120  template<class... Args>
121    size_t formatted_size(const locale& loc, wstring_view fmt, const Args&... args);
122
123  // [format.formatter], formatter
124  template<> struct formatter<char, char>;
125  template<> struct formatter<char, wchar_t>;
126  template<> struct formatter<wchar_t, wchar_t>;
127
128  template<> struct formatter<charT*, charT>;
129  template<> struct formatter<const charT*, charT>;
130  template<size_t N> struct formatter<const charT[N], charT>;
131  template<class traits, class Allocator>
132    struct formatter<basic_string<charT, traits, Allocator>, charT>;
133  template<class traits>
134    struct formatter<basic_string_view<charT, traits>, charT>;
135
136  // [format.parse.ctx], class template basic_format_parse_context
137  template<class charT>
138  class basic_format_parse_context {
139  public:
140    using char_type = charT;
141    using const_iterator = typename basic_string_view<charT>::const_iterator;
142    using iterator = const_iterator;
143
144  private:
145    iterator begin_;                                    // exposition only
146    iterator end_;                                      // exposition only
147    enum indexing { unknown, manual, automatic };       // exposition only
148    indexing indexing_;                                 // exposition only
149    size_t next_arg_id_;                                // exposition only
150    size_t num_args_;                                   // exposition only
151
152  public:
153    constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
154                                                  size_t num_args = 0) noexcept;
155    basic_format_parse_context(const basic_format_parse_context&) = delete;
156    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
157
158    constexpr const_iterator begin() const noexcept;
159    constexpr const_iterator end() const noexcept;
160    constexpr void advance_to(const_iterator it);
161
162    constexpr size_t next_arg_id();
163    constexpr void check_arg_id(size_t id);
164  };
165  using format_parse_context = basic_format_parse_context<char>;
166  using wformat_parse_context = basic_format_parse_context<wchar_t>;
167
168  // [format.arguments], arguments
169  // [format.arg], class template basic_format_arg
170  template<class Context>
171  class basic_format_arg {
172  public:
173    class handle;
174
175  private:
176    using char_type = typename Context::char_type;                              // exposition only
177
178    variant<monostate, bool, char_type,
179            int, unsigned int, long long int, unsigned long long int,
180            float, double, long double,
181            const char_type*, basic_string_view<char_type>,
182            const void*, handle> value;                                         // exposition only
183
184    template<class T> explicit basic_format_arg(const T& v) noexcept;           // exposition only
185    explicit basic_format_arg(float n) noexcept;                                // exposition only
186    explicit basic_format_arg(double n) noexcept;                               // exposition only
187    explicit basic_format_arg(long double n) noexcept;                          // exposition only
188    explicit basic_format_arg(const char_type* s);                              // exposition only
189
190    template<class traits>
191      explicit basic_format_arg(
192        basic_string_view<char_type, traits> s) noexcept;                       // exposition only
193
194    template<class traits, class Allocator>
195      explicit basic_format_arg(
196        const basic_string<char_type, traits, Allocator>& s) noexcept;          // exposition only
197
198    explicit basic_format_arg(nullptr_t) noexcept;                              // exposition only
199
200    template<class T>
201      explicit basic_format_arg(const T* p) noexcept;                           // exposition only
202
203  public:
204    basic_format_arg() noexcept;
205
206    explicit operator bool() const noexcept;
207  };
208
209  template<class Visitor, class Context>
210    see below visit_format_arg(Visitor&& vis, basic_format_arg<Context> arg);
211
212  // [format.arg.store], class template format-arg-store
213  template<class Context, class... Args>
214  struct format-arg-store {      // exposition only
215    array<basic_format_arg<Context>, sizeof...(Args)> args;
216  };
217
218  template<class Context = format_context, class... Args>
219    format-arg-store<Context, Args...>
220      make_format_args(const Args&... args);
221  template<class... Args>
222    format-arg-store<wformat_context, Args...>
223      make_wformat_args(const Args&... args);
224
225  // [format.error], class format_error
226  class format_error : public runtime_error {
227  public:
228    explicit format_error(const string& what_arg);
229    explicit format_error(const char* what_arg);
230  };
231
232  // [format.parse.ctx], class template basic_format_parse_context
233  template<class charT>
234  class basic_format_parse_context {
235  public:
236    using char_type = charT;
237    using const_iterator = typename basic_string_view<charT>::const_iterator;
238    using iterator = const_iterator;
239
240  private:
241    iterator begin_;                                    // exposition only
242    iterator end_;                                      // exposition only
243    enum indexing { unknown, manual, automatic };       // exposition only
244    indexing indexing_;                                 // exposition only
245    size_t next_arg_id_;                                // exposition only
246    size_t num_args_;                                   // exposition only
247
248  public:
249    constexpr explicit basic_format_parse_context(basic_string_view<charT> fmt,
250                                                  size_t num_args = 0) noexcept;
251    basic_format_parse_context(const basic_format_parse_context&) = delete;
252    basic_format_parse_context& operator=(const basic_format_parse_context&) = delete;
253
254    constexpr const_iterator begin() const noexcept;
255    constexpr const_iterator end() const noexcept;
256    constexpr void advance_to(const_iterator it);
257
258    constexpr size_t next_arg_id();
259    constexpr void check_arg_id(size_t id);
260  };
261  using format_parse_context = basic_format_parse_context<char>;
262  using wformat_parse_context = basic_format_parse_context<wchar_t>;
263}
264
265*/
266
267// Make sure all feature-test macros are available.
268#include <version>
269// Enable the contents of the header only when libc++ was built with LIBCXX_ENABLE_INCOMPLETE_FEATURES.
270#if !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
271
272#include <__config>
273#include <__debug>
274#include <__format/format_arg.h>
275#include <__format/format_args.h>
276#include <__format/format_context.h>
277#include <__format/format_error.h>
278#include <__format/format_fwd.h>
279#include <__format/format_parse_context.h>
280#include <__format/format_string.h>
281#include <__format/formatter.h>
282#include <__format/formatter_bool.h>
283#include <__format/formatter_char.h>
284#include <__format/formatter_integer.h>
285#include <__format/formatter_string.h>
286#include <__format/parser_std_format_spec.h>
287#include <__variant/monostate.h>
288#include <array>
289#include <concepts>
290#include <string>
291#include <string_view>
292#include <type_traits>
293
294#ifndef _LIBCPP_HAS_NO_LOCALIZATION
295#include <locale>
296#endif
297
298#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
299#pragma GCC system_header
300#endif
301
302_LIBCPP_PUSH_MACROS
303#include <__undef_macros>
304
305_LIBCPP_BEGIN_NAMESPACE_STD
306
307#if _LIBCPP_STD_VER > 17
308
309// TODO FMT Remove this once we require compilers with proper C++20 support.
310// If the compiler has no concepts support, the format header will be disabled.
311// Without concepts support enable_if needs to be used and that too much effort
312// to support compilers with partial C++20 support.
313#if !defined(_LIBCPP_HAS_NO_CONCEPTS)
314
315// TODO FMT Evaluate which templates should be external templates. This
316// improves the efficiency of the header. However since the header is still
317// under heavy development and not all classes are stable it makes no sense
318// to do this optimization now.
319
320using format_args = basic_format_args<format_context>;
321#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
322using wformat_args = basic_format_args<wformat_context>;
323#endif
324
325template <class _OutIt, class _CharT>
326using format_args_t = basic_format_args<basic_format_context<_OutIt, _CharT>>;
327
328template <class _Context, class... _Args>
329struct _LIBCPP_TEMPLATE_VIS __format_arg_store {
330  // TODO FMT Use a built-in array.
331  array<basic_format_arg<_Context>, sizeof...(_Args)> __args;
332};
333
334template <class _Context = format_context, class... _Args>
335_LIBCPP_HIDE_FROM_ABI __format_arg_store<_Context, _Args...>
336make_format_args(const _Args&... __args) {
337  return {basic_format_arg<_Context>(__args)...};
338}
339
340#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
341template <class... _Args>
342_LIBCPP_HIDE_FROM_ABI __format_arg_store<wformat_context, _Args...>
343make_wformat_args(const _Args&... __args) {
344  return _VSTD::make_format_args<wformat_context>(__args...);
345}
346#endif
347
348namespace __format {
349
350template <class _Tp, class _CharT>
351requires(is_arithmetic_v<_Tp> &&
352         !same_as<_Tp, bool>) struct _LIBCPP_HIDE_FROM_ABI
353    __formatter_arithmetic {
354  _LIBCPP_HIDE_FROM_ABI
355  auto parse(auto& __parse_ctx) -> decltype(__parse_ctx.begin()) {
356    // TODO FMT Implement
357    return __parse_ctx.begin();
358  }
359
360  _LIBCPP_HIDE_FROM_ABI
361  auto format(_Tp __value, auto& __ctx) -> decltype(__ctx.out()) {
362    return __handle_format(__value, __ctx);
363  }
364
365private:
366  template <class _Uv>
367  _LIBCPP_HIDDEN static string
368  __convert(_Uv __value) requires(same_as<_CharT, char>) {
369    return _VSTD::to_string(__value);
370  }
371#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
372  template <class _Uv>
373  _LIBCPP_HIDDEN static wstring
374  __convert(_Uv __value) requires(same_as<_CharT, wchar_t>) {
375    return _VSTD::to_wstring(__value);
376  }
377#endif
378
379  template <class _Uv>
380  _LIBCPP_HIDDEN auto __handle_format(_Uv __value, auto& __ctx)
381      -> decltype(__ctx.out())
382  {
383    // TODO FMT Implement using formatting arguments
384    // TODO FMT Improve PoC since using std::to_string is inefficient.
385    // Note the code doesn't use std::string::iterator since the unit tests
386    // test with debug iterators and they fail with strings created from
387    // std::to_string.
388    auto __str = __convert(__value);
389    auto __out_it = __ctx.out();
390    for (size_t __i = 0, __e = __str.size(); __i != __e; ++__i)
391      *__out_it++ = __str[__i];
392    return __out_it;
393  }
394};
395} // namespace __format
396
397// These specializations are helper stubs and not proper formatters.
398// TODO FMT Implement the proper formatter specializations.
399
400// Floating point types.
401// TODO FMT There are no replacements for the floating point stubs due to not
402// having floating point support in std::to_chars yet. These stubs aren't
403// removed since they are useful for developing the real versions.
404// Ultimately the stubs should be implemented properly and this code can be
405// removed.
406#if 0
407template <class _CharT>
408struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<float, _CharT>
409    : public __format::__formatter_arithmetic<float, _CharT> {};
410template <class _CharT>
411struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
412    formatter<double, _CharT>
413    : public __format::__formatter_arithmetic<double, _CharT> {};
414template <class _CharT>
415struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT
416    formatter<long double, _CharT>
417    : public __format::__formatter_arithmetic<long double, _CharT> {};
418#endif
419
420namespace __format {
421
422template <class _CharT, class _ParseCtx, class _Ctx>
423_LIBCPP_HIDE_FROM_ABI const _CharT*
424__handle_replacement_field(const _CharT* __begin, const _CharT* __end,
425                           _ParseCtx& __parse_ctx, _Ctx& __ctx) {
426  __format::__parse_number_result __r =
427      __format::__parse_arg_id(__begin, __end, __parse_ctx);
428
429  switch (*__r.__ptr) {
430  case _CharT(':'):
431    // The arg-id has a format-specifier, advance the input to the format-spec.
432    __parse_ctx.advance_to(__r.__ptr + 1);
433    break;
434  case _CharT('}'):
435    // The arg-id has no format-specifier.
436    __parse_ctx.advance_to(__r.__ptr);
437    break;
438  default:
439    __throw_format_error(
440        "The replacement field arg-id should terminate at a ':' or '}'");
441  }
442
443  _VSTD::visit_format_arg(
444      [&](auto __arg) {
445        if constexpr (same_as<decltype(__arg), monostate>)
446          __throw_format_error("Argument index out of bounds");
447        else {
448          formatter<decltype(__arg), _CharT> __formatter;
449          __parse_ctx.advance_to(__formatter.parse(__parse_ctx));
450          __ctx.advance_to(__formatter.format(__arg, __ctx));
451        }
452      },
453      __ctx.arg(__r.__value));
454
455  __begin = __parse_ctx.begin();
456  if (__begin == __end || *__begin != _CharT('}'))
457    __throw_format_error("The replacement field misses a terminating '}'");
458
459  return ++__begin;
460}
461
462template <class _ParseCtx, class _Ctx>
463_LIBCPP_HIDE_FROM_ABI typename _Ctx::iterator
464__vformat_to(_ParseCtx&& __parse_ctx, _Ctx&& __ctx) {
465  using _CharT = typename _ParseCtx::char_type;
466  static_assert(same_as<typename _Ctx::char_type, _CharT>);
467
468  const _CharT* __begin = __parse_ctx.begin();
469  const _CharT* __end = __parse_ctx.end();
470  typename _Ctx::iterator __out_it = __ctx.out();
471  while (__begin != __end) {
472    switch (*__begin) {
473    case _CharT('{'):
474      ++__begin;
475      if (__begin == __end)
476        __throw_format_error("The format string terminates at a '{'");
477
478      if (*__begin != _CharT('{')) [[likely]] {
479        __ctx.advance_to(_VSTD::move(__out_it));
480        __begin =
481            __handle_replacement_field(__begin, __end, __parse_ctx, __ctx);
482        __out_it = __ctx.out();
483
484        // The output is written and __begin points to the next character. So
485        // start the next iteration.
486        continue;
487      }
488      // The string is an escape character.
489      break;
490
491    case _CharT('}'):
492      ++__begin;
493      if (__begin == __end || *__begin != _CharT('}'))
494        __throw_format_error(
495            "The format string contains an invalid escape sequence");
496
497      break;
498    }
499
500    // Copy the character to the output verbatim.
501    *__out_it++ = *__begin++;
502  }
503  return __out_it;
504}
505
506} // namespace __format
507
508template <class _OutIt, class _CharT>
509requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
510    __vformat_to(_OutIt __out_it, basic_string_view<_CharT> __fmt,
511                 format_args_t<type_identity_t<_OutIt>, _CharT> __args) {
512  return __format::__vformat_to(
513      basic_format_parse_context{__fmt, __args.__size()},
514      _VSTD::__format_context_create(_VSTD::move(__out_it), __args));
515}
516
517template <output_iterator<const char&> _OutIt>
518_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
519vformat_to(_OutIt __out_it, string_view __fmt,
520           format_args_t<type_identity_t<_OutIt>, char> __args) {
521  return _VSTD::__vformat_to(_VSTD::move(__out_it), __fmt, __args);
522}
523
524#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
525template <output_iterator<const wchar_t&> _OutIt>
526_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
527vformat_to(_OutIt __out_it, wstring_view __fmt,
528           format_args_t<type_identity_t<_OutIt>, wchar_t> __args) {
529  return _VSTD::__vformat_to(_VSTD::move(__out_it), __fmt, __args);
530}
531#endif
532
533template <output_iterator<const char&> _OutIt, class... _Args>
534_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
535format_to(_OutIt __out_it, string_view __fmt, const _Args&... __args) {
536  return _VSTD::vformat_to(
537      _VSTD::move(__out_it), __fmt,
538      _VSTD::make_format_args<basic_format_context<_OutIt, char>>(__args...));
539}
540
541#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
542template <output_iterator<const wchar_t&> _OutIt, class... _Args>
543_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
544format_to(_OutIt __out_it, wstring_view __fmt, const _Args&... __args) {
545  return _VSTD::vformat_to(
546      _VSTD::move(__out_it), __fmt,
547      _VSTD::make_format_args<basic_format_context<_OutIt, wchar_t>>(
548          __args...));
549}
550#endif
551
552inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
553vformat(string_view __fmt, format_args __args) {
554  string __res;
555  _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
556  return __res;
557}
558
559#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
560inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
561vformat(wstring_view __fmt, wformat_args __args) {
562  wstring __res;
563  _VSTD::vformat_to(_VSTD::back_inserter(__res), __fmt, __args);
564  return __res;
565}
566#endif
567
568template <class... _Args>
569_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
570format(string_view __fmt, const _Args&... __args) {
571  return _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...));
572}
573
574#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
575template <class... _Args>
576_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
577format(wstring_view __fmt, const _Args&... __args) {
578  return _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...));
579}
580#endif
581
582template <class _OutIt>
583struct _LIBCPP_TEMPLATE_VIS format_to_n_result {
584  _OutIt out;
585  iter_difference_t<_OutIt> size;
586};
587
588template <output_iterator<const char&> _OutIt, class... _Args>
589_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
590format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, string_view __fmt,
591            const _Args&... __args) {
592  // TODO FMT Improve PoC: using std::string is inefficient.
593  string __str = _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...));
594  iter_difference_t<_OutIt> __s = __str.size();
595  iter_difference_t<_OutIt> __m =
596      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
597  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
598  return {_VSTD::move(__out_it), __s};
599}
600
601#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
602template <output_iterator<const wchar_t&> _OutIt, class... _Args>
603_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
604format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, wstring_view __fmt,
605            const _Args&... __args) {
606  // TODO FMT Improve PoC: using std::string is inefficient.
607  wstring __str = _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...));
608  iter_difference_t<_OutIt> __s = __str.size();
609  iter_difference_t<_OutIt> __m =
610      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
611  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
612  return {_VSTD::move(__out_it), __s};
613}
614#endif
615
616template <class... _Args>
617_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
618formatted_size(string_view __fmt, const _Args&... __args) {
619  // TODO FMT Improve PoC: using std::string is inefficient.
620  return _VSTD::vformat(__fmt, _VSTD::make_format_args(__args...)).size();
621}
622
623#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
624template <class... _Args>
625_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
626formatted_size(wstring_view __fmt, const _Args&... __args) {
627  // TODO FMT Improve PoC: using std::string is inefficient.
628  return _VSTD::vformat(__fmt, _VSTD::make_wformat_args(__args...)).size();
629}
630#endif
631
632#ifndef _LIBCPP_HAS_NO_LOCALIZATION
633
634template <class _OutIt, class _CharT>
635requires(output_iterator<_OutIt, const _CharT&>) _LIBCPP_HIDE_FROM_ABI _OutIt
636    __vformat_to(_OutIt __out_it, locale __loc, basic_string_view<_CharT> __fmt,
637                 format_args_t<type_identity_t<_OutIt>, _CharT> __args) {
638  return __format::__vformat_to(
639      basic_format_parse_context{__fmt, __args.__size()},
640      _VSTD::__format_context_create(_VSTD::move(__out_it), __args,
641                                     _VSTD::move(__loc)));
642}
643
644template <output_iterator<const char&> _OutIt>
645_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
646vformat_to(_OutIt __out_it, locale __loc, string_view __fmt,
647           format_args_t<type_identity_t<_OutIt>, char> __args) {
648  return _VSTD::__vformat_to(_VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
649                             __args);
650}
651
652#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
653template <output_iterator<const wchar_t&> _OutIt>
654_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt
655vformat_to(_OutIt __out_it, locale __loc, wstring_view __fmt,
656           format_args_t<type_identity_t<_OutIt>, wchar_t> __args) {
657  return _VSTD::__vformat_to(_VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
658                             __args);
659}
660#endif
661
662template <output_iterator<const char&> _OutIt, class... _Args>
663_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt format_to(
664    _OutIt __out_it, locale __loc, string_view __fmt, const _Args&... __args) {
665  return _VSTD::vformat_to(
666      _VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
667      _VSTD::make_format_args<basic_format_context<_OutIt, char>>(__args...));
668}
669
670#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
671template <output_iterator<const wchar_t&> _OutIt, class... _Args>
672_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT _OutIt format_to(
673    _OutIt __out_it, locale __loc, wstring_view __fmt, const _Args&... __args) {
674  return _VSTD::vformat_to(
675      _VSTD::move(__out_it), _VSTD::move(__loc), __fmt,
676      _VSTD::make_format_args<basic_format_context<_OutIt, wchar_t>>(
677          __args...));
678}
679#endif
680
681inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
682vformat(locale __loc, string_view __fmt, format_args __args) {
683  string __res;
684  _VSTD::vformat_to(_VSTD::back_inserter(__res), _VSTD::move(__loc), __fmt,
685                    __args);
686  return __res;
687}
688
689#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
690inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
691vformat(locale __loc, wstring_view __fmt, wformat_args __args) {
692  wstring __res;
693  _VSTD::vformat_to(_VSTD::back_inserter(__res), _VSTD::move(__loc), __fmt,
694                    __args);
695  return __res;
696}
697#endif
698
699template <class... _Args>
700_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT string
701format(locale __loc, string_view __fmt, const _Args&... __args) {
702  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
703                        _VSTD::make_format_args(__args...));
704}
705
706#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
707template <class... _Args>
708_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT wstring
709format(locale __loc, wstring_view __fmt, const _Args&... __args) {
710  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
711                        _VSTD::make_wformat_args(__args...));
712}
713#endif
714
715template <output_iterator<const char&> _OutIt, class... _Args>
716_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
717format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, locale __loc,
718            string_view __fmt, const _Args&... __args) {
719  // TODO FMT Improve PoC: using std::string is inefficient.
720  string __str = _VSTD::vformat(_VSTD::move(__loc), __fmt,
721                                _VSTD::make_format_args(__args...));
722  iter_difference_t<_OutIt> __s = __str.size();
723  iter_difference_t<_OutIt> __m =
724      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
725  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
726  return {_VSTD::move(__out_it), __s};
727}
728
729#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
730template <output_iterator<const wchar_t&> _OutIt, class... _Args>
731_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT format_to_n_result<_OutIt>
732format_to_n(_OutIt __out_it, iter_difference_t<_OutIt> __n, locale __loc,
733            wstring_view __fmt, const _Args&... __args) {
734  // TODO FMT Improve PoC: using std::string is inefficient.
735  wstring __str = _VSTD::vformat(_VSTD::move(__loc), __fmt,
736                                 _VSTD::make_wformat_args(__args...));
737  iter_difference_t<_OutIt> __s = __str.size();
738  iter_difference_t<_OutIt> __m =
739      _VSTD::clamp(__n, iter_difference_t<_OutIt>(0), __s);
740  __out_it = _VSTD::copy_n(__str.begin(), __m, _VSTD::move(__out_it));
741  return {_VSTD::move(__out_it), __s};
742}
743#endif
744
745template <class... _Args>
746_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
747formatted_size(locale __loc, string_view __fmt, const _Args&... __args) {
748  // TODO FMT Improve PoC: using std::string is inefficient.
749  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
750                        _VSTD::make_format_args(__args...))
751      .size();
752}
753
754#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
755template <class... _Args>
756_LIBCPP_HIDE_FROM_ABI _LIBCPP_AVAILABILITY_FORMAT size_t
757formatted_size(locale __loc, wstring_view __fmt, const _Args&... __args) {
758  // TODO FMT Improve PoC: using std::string is inefficient.
759  return _VSTD::vformat(_VSTD::move(__loc), __fmt,
760                        _VSTD::make_wformat_args(__args...))
761      .size();
762}
763#endif
764
765#endif // _LIBCPP_HAS_NO_LOCALIZATION
766
767#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
768#endif //_LIBCPP_STD_VER > 17
769
770_LIBCPP_END_NAMESPACE_STD
771
772_LIBCPP_POP_MACROS
773
774#endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
775
776#endif // _LIBCPP_FORMAT
777