1 // -*- C++ -*-
2 //===----------------------------------------------------------------------===//
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_FORMATTER_INTEGRAL_H
11 #define _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
12
13 #include <__concepts/arithmetic.h>
14 #include <__concepts/same_as.h>
15 #include <__config>
16 #include <__format/concepts.h>
17 #include <__format/format_error.h>
18 #include <__format/formatter_output.h>
19 #include <__format/parser_std_format_spec.h>
20 #include <__utility/unreachable.h>
21 #include <array>
22 #include <charconv>
23 #include <limits>
24 #include <string>
25
26 #ifndef _LIBCPP_HAS_NO_LOCALIZATION
27 # include <locale>
28 #endif
29
30 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
31 # pragma GCC system_header
32 #endif
33
34 _LIBCPP_PUSH_MACROS
35 #include <__undef_macros>
36
37 _LIBCPP_BEGIN_NAMESPACE_STD
38
39 #if _LIBCPP_STD_VER > 17
40
41 namespace __formatter {
42
43 //
44 // Generic
45 //
46
__insert_sign(char * __buf,bool __negative,__format_spec::__sign __sign)47 _LIBCPP_HIDE_FROM_ABI inline char* __insert_sign(char* __buf, bool __negative, __format_spec::__sign __sign) {
48 if (__negative)
49 *__buf++ = '-';
50 else
51 switch (__sign) {
52 case __format_spec::__sign::__default:
53 case __format_spec::__sign::__minus:
54 // No sign added.
55 break;
56 case __format_spec::__sign::__plus:
57 *__buf++ = '+';
58 break;
59 case __format_spec::__sign::__space:
60 *__buf++ = ' ';
61 break;
62 }
63
64 return __buf;
65 }
66
67 /**
68 * Determines the required grouping based on the size of the input.
69 *
70 * The grouping's last element will be repeated. For simplicity this repeating
71 * is unwrapped based on the length of the input. (When the input is short some
72 * groups are not processed.)
73 *
74 * @returns The size of the groups to write. This means the number of
75 * separator characters written is size() - 1.
76 *
77 * @note Since zero-sized groups cause issues they are silently ignored.
78 *
79 * @note The grouping field of the locale is always a @c std::string,
80 * regardless whether the @c std::numpunct's type is @c char or @c wchar_t.
81 */
__determine_grouping(ptrdiff_t __size,const string & __grouping)82 _LIBCPP_HIDE_FROM_ABI inline string __determine_grouping(ptrdiff_t __size, const string& __grouping) {
83 _LIBCPP_ASSERT(!__grouping.empty() && __size > __grouping[0],
84 "The slow grouping formatting is used while there will be no "
85 "separators written");
86 string __r;
87 auto __end = __grouping.end() - 1;
88 auto __ptr = __grouping.begin();
89
90 while (true) {
91 __size -= *__ptr;
92 if (__size > 0)
93 __r.push_back(*__ptr);
94 else {
95 // __size <= 0 so the value pushed will be <= *__ptr.
96 __r.push_back(*__ptr + __size);
97 return __r;
98 }
99
100 // Proceed to the next group.
101 if (__ptr != __end) {
102 do {
103 ++__ptr;
104 // Skip grouping with a width of 0.
105 } while (*__ptr == 0 && __ptr != __end);
106 }
107 }
108
109 __libcpp_unreachable();
110 }
111
112 //
113 // Char
114 //
115
116 template <__fmt_char_type _CharT>
117 _LIBCPP_HIDE_FROM_ABI auto __format_char(
118 integral auto __value,
119 output_iterator<const _CharT&> auto __out_it,
120 __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
121 using _Tp = decltype(__value);
122 if constexpr (!same_as<_CharT, _Tp>) {
123 // cmp_less and cmp_greater can't be used for character types.
124 if constexpr (signed_integral<_CharT> == signed_integral<_Tp>) {
125 if (__value < numeric_limits<_CharT>::min() || __value > numeric_limits<_CharT>::max())
126 std::__throw_format_error("Integral value outside the range of the char type");
127 } else if constexpr (signed_integral<_CharT>) {
128 // _CharT is signed _Tp is unsigned
129 if (__value > static_cast<make_unsigned_t<_CharT>>(numeric_limits<_CharT>::max()))
130 std::__throw_format_error("Integral value outside the range of the char type");
131 } else {
132 // _CharT is unsigned _Tp is signed
133 if (__value < 0 || static_cast<make_unsigned_t<_Tp>>(__value) > numeric_limits<_CharT>::max())
134 std::__throw_format_error("Integral value outside the range of the char type");
135 }
136 }
137
138 const auto __c = static_cast<_CharT>(__value);
139 return __formatter::__write(_VSTD::addressof(__c), _VSTD::addressof(__c) + 1, _VSTD::move(__out_it), __specs);
140 }
141
142 //
143 // Integer
144 //
145
146 /** Wrapper around @ref to_chars, returning the output pointer. */
147 template <integral _Tp>
__to_buffer(char * __first,char * __last,_Tp __value,int __base)148 _LIBCPP_HIDE_FROM_ABI char* __to_buffer(char* __first, char* __last, _Tp __value, int __base) {
149 // TODO FMT Evaluate code overhead due to not calling the internal function
150 // directly. (Should be zero overhead.)
151 to_chars_result __r = _VSTD::to_chars(__first, __last, __value, __base);
152 _LIBCPP_ASSERT(__r.ec == errc(0), "Internal buffer too small");
153 return __r.ptr;
154 }
155
156 /**
157 * Helper to determine the buffer size to output a integer in Base @em x.
158 *
159 * There are several overloads for the supported bases. The function uses the
160 * base as template argument so it can be used in a constant expression.
161 */
162 template <unsigned_integral _Tp, size_t _Base>
__buffer_size()163 consteval size_t __buffer_size() noexcept
164 requires(_Base == 2)
165 {
166 return numeric_limits<_Tp>::digits // The number of binary digits.
167 + 2 // Reserve space for the '0[Bb]' prefix.
168 + 1; // Reserve space for the sign.
169 }
170
171 template <unsigned_integral _Tp, size_t _Base>
__buffer_size()172 consteval size_t __buffer_size() noexcept
173 requires(_Base == 8)
174 {
175 return numeric_limits<_Tp>::digits // The number of binary digits.
176 / 3 // Adjust to octal.
177 + 1 // Turn floor to ceil.
178 + 1 // Reserve space for the '0' prefix.
179 + 1; // Reserve space for the sign.
180 }
181
182 template <unsigned_integral _Tp, size_t _Base>
__buffer_size()183 consteval size_t __buffer_size() noexcept
184 requires(_Base == 10)
185 {
186 return numeric_limits<_Tp>::digits10 // The floored value.
187 + 1 // Turn floor to ceil.
188 + 1; // Reserve space for the sign.
189 }
190
191 template <unsigned_integral _Tp, size_t _Base>
__buffer_size()192 consteval size_t __buffer_size() noexcept
193 requires(_Base == 16)
194 {
195 return numeric_limits<_Tp>::digits // The number of binary digits.
196 / 4 // Adjust to hexadecimal.
197 + 2 // Reserve space for the '0[Xx]' prefix.
198 + 1; // Reserve space for the sign.
199 }
200
201 template <unsigned_integral _Tp, class _CharT>
202 _LIBCPP_HIDE_FROM_ABI auto __format_integer(
203 _Tp __value,
204 auto& __ctx,
205 __format_spec::__parsed_specifications<_CharT> __specs,
206 bool __negative,
207 char* __begin,
208 char* __end,
209 const char* __prefix,
210 int __base) -> decltype(__ctx.out()) {
211 char* __first = __formatter::__insert_sign(__begin, __negative, __specs.__std_.__sign_);
212 if (__specs.__std_.__alternate_form_ && __prefix)
213 while (*__prefix)
214 *__first++ = *__prefix++;
215
216 char* __last = __formatter::__to_buffer(__first, __end, __value, __base);
217
218 # ifndef _LIBCPP_HAS_NO_LOCALIZATION
219 if (__specs.__std_.__locale_specific_form_) {
220 const auto& __np = std::use_facet<numpunct<_CharT>>(__ctx.locale());
221 string __grouping = __np.grouping();
222 ptrdiff_t __size = __last - __first;
223 // Writing the grouped form has more overhead than the normal output
224 // routines. If there will be no separators written the locale-specific
225 // form is identical to the normal routine. Test whether to grouped form
226 // is required.
227 if (!__grouping.empty() && __size > __grouping[0])
228 return __formatter::__write_using_decimal_separators(
229 __ctx.out(),
230 __begin,
231 __first,
232 __last,
233 __formatter::__determine_grouping(__size, __grouping),
234 __np.thousands_sep(),
235 __specs);
236 }
237 # endif
238 auto __out_it = __ctx.out();
239 if (__specs.__alignment_ != __format_spec::__alignment::__zero_padding)
240 __first = __begin;
241 else {
242 // __buf contains [sign][prefix]data
243 // ^ location of __first
244 // The zero padding is done like:
245 // - Write [sign][prefix]
246 // - Write data right aligned with '0' as fill character.
247 __out_it = __formatter::__copy(__begin, __first, _VSTD::move(__out_it));
248 __specs.__alignment_ = __format_spec::__alignment::__right;
249 __specs.__fill_ = _CharT('0');
250 int32_t __size = __first - __begin;
251
252 __specs.__width_ -= _VSTD::min(__size, __specs.__width_);
253 }
254
255 if (__specs.__std_.__type_ != __format_spec::__type::__hexadecimal_upper_case) [[likely]]
256 return __formatter::__write(__first, __last, __ctx.out(), __specs);
257
258 return __formatter::__write_transformed(__first, __last, __ctx.out(), __specs, __formatter::__hex_to_upper);
259 }
260
261 template <unsigned_integral _Tp, class _CharT>
262 _LIBCPP_HIDE_FROM_ABI auto __format_integer(
263 _Tp __value, auto& __ctx, __format_spec::__parsed_specifications<_CharT> __specs, bool __negative = false)
264 -> decltype(__ctx.out()) {
265 switch (__specs.__std_.__type_) {
266 case __format_spec::__type::__binary_lower_case: {
267 array<char, __formatter::__buffer_size<decltype(__value), 2>()> __array;
268 return __formatter::__format_integer(__value, __ctx, __specs, __negative, __array.begin(), __array.end(), "0b", 2);
269 }
270 case __format_spec::__type::__binary_upper_case: {
271 array<char, __formatter::__buffer_size<decltype(__value), 2>()> __array;
272 return __formatter::__format_integer(__value, __ctx, __specs, __negative, __array.begin(), __array.end(), "0B", 2);
273 }
274 case __format_spec::__type::__octal: {
275 // Octal is special; if __value == 0 there's no prefix.
276 array<char, __formatter::__buffer_size<decltype(__value), 8>()> __array;
277 return __formatter::__format_integer(
278 __value, __ctx, __specs, __negative, __array.begin(), __array.end(), __value != 0 ? "0" : nullptr, 8);
279 }
280 case __format_spec::__type::__default:
281 case __format_spec::__type::__decimal: {
282 array<char, __formatter::__buffer_size<decltype(__value), 10>()> __array;
283 return __formatter::__format_integer(
284 __value, __ctx, __specs, __negative, __array.begin(), __array.end(), nullptr, 10);
285 }
286 case __format_spec::__type::__hexadecimal_lower_case: {
287 array<char, __formatter::__buffer_size<decltype(__value), 16>()> __array;
288 return __formatter::__format_integer(__value, __ctx, __specs, __negative, __array.begin(), __array.end(), "0x", 16);
289 }
290 case __format_spec::__type::__hexadecimal_upper_case: {
291 array<char, __formatter::__buffer_size<decltype(__value), 16>()> __array;
292 return __formatter::__format_integer(__value, __ctx, __specs, __negative, __array.begin(), __array.end(), "0X", 16);
293 }
294 default:
295 _LIBCPP_ASSERT(false, "The parse function should have validated the type");
296 __libcpp_unreachable();
297 }
298 }
299
300 template <signed_integral _Tp, class _CharT>
301 _LIBCPP_HIDE_FROM_ABI auto
302 __format_integer(_Tp __value, auto& __ctx, __format_spec::__parsed_specifications<_CharT> __specs)
303 -> decltype(__ctx.out()) {
304 // Depending on the std-format-spec string the sign and the value
305 // might not be outputted together:
306 // - alternate form may insert a prefix string.
307 // - zero-padding may insert additional '0' characters.
308 // Therefore the value is processed as a positive unsigned value.
309 // The function @ref __insert_sign will a '-' when the value was negative.
310 auto __r = std::__to_unsigned_like(__value);
311 bool __negative = __value < 0;
312 if (__negative)
313 __r = std::__complement(__r);
314
315 return __formatter::__format_integer(__r, __ctx, __specs, __negative);
316 }
317
318 //
319 // Formatter arithmetic (bool)
320 //
321
322 template <class _CharT>
323 struct _LIBCPP_TEMPLATE_VIS __bool_strings;
324
325 template <>
326 struct _LIBCPP_TEMPLATE_VIS __bool_strings<char> {
327 static constexpr string_view __true{"true"};
328 static constexpr string_view __false{"false"};
329 };
330
331 # ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
332 template <>
333 struct _LIBCPP_TEMPLATE_VIS __bool_strings<wchar_t> {
334 static constexpr wstring_view __true{L"true"};
335 static constexpr wstring_view __false{L"false"};
336 };
337 # endif
338
339 template <class _CharT>
340 _LIBCPP_HIDE_FROM_ABI auto
341 __format_bool(bool __value, auto& __ctx, __format_spec::__parsed_specifications<_CharT> __specs)
342 -> decltype(__ctx.out()) {
343 # ifndef _LIBCPP_HAS_NO_LOCALIZATION
344 if (__specs.__std_.__locale_specific_form_) {
345 const auto& __np = std::use_facet<numpunct<_CharT>>(__ctx.locale());
346 basic_string<_CharT> __str = __value ? __np.truename() : __np.falsename();
347 return __formatter::__write_string_no_precision(basic_string_view<_CharT>{__str}, __ctx.out(), __specs);
348 }
349 # endif
350 basic_string_view<_CharT> __str =
351 __value ? __formatter::__bool_strings<_CharT>::__true : __formatter::__bool_strings<_CharT>::__false;
352 return __formatter::__write(__str.begin(), __str.end(), __ctx.out(), __specs);
353 }
354
355 } // namespace __formatter
356
357 #endif //_LIBCPP_STD_VER > 17
358
359 _LIBCPP_END_NAMESPACE_STD
360
361 _LIBCPP_POP_MACROS
362
363 #endif // _LIBCPP___FORMAT_FORMATTER_INTEGRAL_H
364