1/* Helper functions for parsing printf format strings.
2 Copyright (C) 1995-2023 Free Software Foundation, Inc.
3 This file is part of th GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <ctype.h>
20#include <limits.h>
21#include <stdlib.h>
22#include <string.h>
23#include <sys/param.h>
24#include <wchar.h>
25#include <wctype.h>
26
27#ifndef COMPILE_WPRINTF
28# define CHAR_T char
29# define UCHAR_T unsigned char
30# define INT_T int
31# define L_(Str) Str
32# define ISDIGIT(Ch) isdigit (Ch)
33# define HANDLE_REGISTERED_MODIFIER __handle_registered_modifier_mb
34#else
35# define CHAR_T wchar_t
36# define UCHAR_T unsigned int
37# define INT_T wint_t
38# define L_(Str) L##Str
39# define ISDIGIT(Ch) iswdigit (Ch)
40# define HANDLE_REGISTERED_MODIFIER __handle_registered_modifier_wc
41#endif
42
43#include "printf-parse.h"
44
45#define NDEBUG 1
46#include <assert.h>
47
48
49
50/* FORMAT must point to a '%' at the beginning of a spec. Fills in *SPEC
51 with the parsed details. POSN is the number of arguments already
52 consumed. At most MAXTYPES - POSN types are filled in TYPES. Return
53 the number of args consumed by this spec; *MAX_REF_ARG is updated so it
54 remains the highest argument index used. */
55size_t
56attribute_hidden
57#ifdef COMPILE_WPRINTF
58__parse_one_specwc (const UCHAR_T *format, size_t posn,
59 struct printf_spec *spec, size_t *max_ref_arg)
60#else
61__parse_one_specmb (const UCHAR_T *format, size_t posn,
62 struct printf_spec *spec, size_t *max_ref_arg)
63#endif
64{
65 unsigned int n;
66 size_t nargs = 0;
67
68 /* Skip the '%'. */
69 ++format;
70
71 /* Clear information structure. */
72 spec->data_arg = -1;
73 spec->info.alt = 0;
74 spec->info.space = 0;
75 spec->info.left = 0;
76 spec->info.showsign = 0;
77 spec->info.group = 0;
78 spec->info.i18n = 0;
79 spec->info.extra = 0;
80 spec->info.pad = ' ';
81 spec->info.wide = sizeof (UCHAR_T) > 1;
82 spec->info.is_binary128 = 0;
83
84 /* Test for positional argument. */
85 if (ISDIGIT (*format))
86 {
87 const UCHAR_T *begin = format;
88
89 n = read_int (&format);
90
91 if (n != 0 && *format == L_('$'))
92 /* Is positional parameter. */
93 {
94 ++format; /* Skip the '$'. */
95 if (n != -1)
96 {
97 spec->data_arg = n - 1;
98 *max_ref_arg = MAX (*max_ref_arg, n);
99 }
100 }
101 else
102 /* Oops; that was actually the width and/or 0 padding flag.
103 Step back and read it again. */
104 format = begin;
105 }
106
107 /* Check for spec modifiers. */
108 do
109 {
110 switch (*format)
111 {
112 case L_(' '):
113 /* Output a space in place of a sign, when there is no sign. */
114 spec->info.space = 1;
115 continue;
116 case L_('+'):
117 /* Always output + or - for numbers. */
118 spec->info.showsign = 1;
119 continue;
120 case L_('-'):
121 /* Left-justify things. */
122 spec->info.left = 1;
123 continue;
124 case L_('#'):
125 /* Use the "alternate form":
126 Hex has 0x or 0X, FP always has a decimal point. */
127 spec->info.alt = 1;
128 continue;
129 case L_('0'):
130 /* Pad with 0s. */
131 spec->info.pad = '0';
132 continue;
133 case L_('\''):
134 /* Show grouping in numbers if the locale information
135 indicates any. */
136 spec->info.group = 1;
137 continue;
138 case L_('I'):
139 /* Use the internationalized form of the output. Currently
140 means to use the `outdigits' of the current locale. */
141 spec->info.i18n = 1;
142 continue;
143 default:
144 break;
145 }
146 break;
147 }
148 while (*++format);
149
150 if (spec->info.left)
151 spec->info.pad = ' ';
152
153 /* Get the field width. */
154 spec->width_arg = -1;
155 spec->info.width = 0;
156 if (*format == L_('*'))
157 {
158 /* The field width is given in an argument.
159 A negative field width indicates left justification. */
160 const UCHAR_T *begin = ++format;
161
162 if (ISDIGIT (*format))
163 {
164 /* The width argument might be found in a positional parameter. */
165 n = read_int (&format);
166
167 if (n != 0 && *format == L_('$'))
168 {
169 if (n != -1)
170 {
171 spec->width_arg = n - 1;
172 *max_ref_arg = MAX (*max_ref_arg, n);
173 }
174 ++format; /* Skip '$'. */
175 }
176 }
177
178 if (spec->width_arg < 0)
179 {
180 /* Not in a positional parameter. Consume one argument. */
181 spec->width_arg = posn++;
182 ++nargs;
183 format = begin; /* Step back and reread. */
184 }
185 }
186 else if (ISDIGIT (*format))
187 {
188 int n = read_int (&format);
189
190 /* Constant width specification. */
191 if (n != -1)
192 spec->info.width = n;
193 }
194 /* Get the precision. */
195 spec->prec_arg = -1;
196 /* -1 means none given; 0 means explicit 0. */
197 spec->info.prec = -1;
198 if (*format == L_('.'))
199 {
200 ++format;
201 if (*format == L_('*'))
202 {
203 /* The precision is given in an argument. */
204 const UCHAR_T *begin = ++format;
205
206 if (ISDIGIT (*format))
207 {
208 n = read_int (&format);
209
210 if (n != 0 && *format == L_('$'))
211 {
212 if (n != -1)
213 {
214 spec->prec_arg = n - 1;
215 *max_ref_arg = MAX (*max_ref_arg, n);
216 }
217 ++format;
218 }
219 }
220
221 if (spec->prec_arg < 0)
222 {
223 /* Not in a positional parameter. */
224 spec->prec_arg = posn++;
225 ++nargs;
226 format = begin;
227 }
228 }
229 else if (ISDIGIT (*format))
230 {
231 int n = read_int (&format);
232
233 if (n != -1)
234 spec->info.prec = n;
235 }
236 else
237 /* "%.?" is treated like "%.0?". */
238 spec->info.prec = 0;
239 }
240
241 /* Check for type modifiers. */
242 spec->info.is_long_double = 0;
243 spec->info.is_short = 0;
244 spec->info.is_long = 0;
245 spec->info.is_char = 0;
246 spec->info.user = 0;
247
248 if (__builtin_expect (__printf_modifier_table == NULL, 1)
249 || __printf_modifier_table[*format] == NULL
250 || HANDLE_REGISTERED_MODIFIER (&format, &spec->info) != 0)
251 switch (*format++)
252 {
253 case L_('h'):
254 /* ints are short ints or chars. */
255 if (*format != L_('h'))
256 spec->info.is_short = 1;
257 else
258 {
259 ++format;
260 spec->info.is_char = 1;
261 }
262 break;
263 case L_('l'):
264 /* ints are long ints. */
265 spec->info.is_long = 1;
266 if (*format != L_('l'))
267 break;
268 ++format;
269 /* FALLTHROUGH */
270 case L_('L'):
271 /* doubles are long doubles, and ints are long long ints. */
272 case L_('q'):
273 /* 4.4 uses this for long long. */
274 spec->info.is_long_double = 1;
275 break;
276 case L_('z'):
277 case L_('Z'):
278 /* ints are size_ts. */
279 assert (sizeof (size_t) <= sizeof (unsigned long long int));
280#if LONG_MAX != LONG_LONG_MAX
281 spec->info.is_long_double = (sizeof (size_t)
282 > sizeof (unsigned long int));
283#endif
284 spec->info.is_long = sizeof (size_t) > sizeof (unsigned int);
285 break;
286 case L_('t'):
287 assert (sizeof (ptrdiff_t) <= sizeof (long long int));
288#if LONG_MAX != LONG_LONG_MAX
289 spec->info.is_long_double = (sizeof (ptrdiff_t) > sizeof (long int));
290#endif
291 spec->info.is_long = sizeof (ptrdiff_t) > sizeof (int);
292 break;
293 case L_('j'):
294 assert (sizeof (uintmax_t) <= sizeof (unsigned long long int));
295#if LONG_MAX != LONG_LONG_MAX
296 spec->info.is_long_double = (sizeof (uintmax_t)
297 > sizeof (unsigned long int));
298#endif
299 spec->info.is_long = sizeof (uintmax_t) > sizeof (unsigned int);
300 break;
301 default:
302 /* Not a recognized modifier. Backup. */
303 --format;
304 break;
305 }
306
307 /* Get the format specification. */
308 spec->info.spec = (wchar_t) *format++;
309 spec->size = -1;
310 if (__builtin_expect (__printf_function_table == NULL, 1)
311 || spec->info.spec > UCHAR_MAX
312 || __printf_arginfo_table[spec->info.spec] == NULL
313 /* We don't try to get the types for all arguments if the format
314 uses more than one. The normal case is covered though. If
315 the call returns -1 we continue with the normal specifiers. */
316 || (int) (spec->ndata_args = (*__printf_arginfo_table[spec->info.spec])
317 (&spec->info, 1, &spec->data_arg_type,
318 &spec->size)) < 0)
319 {
320 /* Find the data argument types of a built-in spec. */
321 spec->ndata_args = 1;
322
323 switch (spec->info.spec)
324 {
325 case L'i':
326 case L'd':
327 case L'u':
328 case L'o':
329 case L'X':
330 case L'x':
331 case L'B':
332 case L'b':
333#if LONG_MAX != LONG_LONG_MAX
334 if (spec->info.is_long_double)
335 spec->data_arg_type = PA_INT|PA_FLAG_LONG_LONG;
336 else
337#endif
338 if (spec->info.is_long)
339 spec->data_arg_type = PA_INT|PA_FLAG_LONG;
340 else if (spec->info.is_short)
341 spec->data_arg_type = PA_INT|PA_FLAG_SHORT;
342 else if (spec->info.is_char)
343 spec->data_arg_type = PA_CHAR;
344 else
345 spec->data_arg_type = PA_INT;
346 break;
347 case L'e':
348 case L'E':
349 case L'f':
350 case L'F':
351 case L'g':
352 case L'G':
353 case L'a':
354 case L'A':
355 if (spec->info.is_long_double)
356 spec->data_arg_type = PA_DOUBLE|PA_FLAG_LONG_DOUBLE;
357 else
358 spec->data_arg_type = PA_DOUBLE;
359 break;
360 case L'c':
361 spec->data_arg_type = PA_CHAR;
362 break;
363 case L'C':
364 spec->data_arg_type = PA_WCHAR;
365 break;
366 case L's':
367 spec->data_arg_type = PA_STRING;
368 break;
369 case L'S':
370 spec->data_arg_type = PA_WSTRING;
371 break;
372 case L'p':
373 spec->data_arg_type = PA_POINTER;
374 break;
375 case L'n':
376 spec->data_arg_type = PA_INT|PA_FLAG_PTR;
377 break;
378
379 case L'm':
380 default:
381 /* An unknown spec will consume no args. */
382 spec->ndata_args = 0;
383 break;
384 }
385 }
386
387 if (spec->data_arg == -1 && spec->ndata_args > 0)
388 {
389 /* There are args consumed, but no positional spec. Use the
390 next sequential arg position. */
391 spec->data_arg = posn;
392 nargs += spec->ndata_args;
393 }
394
395 if (spec->info.spec == L'\0')
396 /* Format ended before this spec was complete. */
397 spec->end_of_fmt = spec->next_fmt = format - 1;
398 else
399 {
400 /* Find the next format spec. */
401 spec->end_of_fmt = format;
402#ifdef COMPILE_WPRINTF
403 spec->next_fmt = __find_specwc (format);
404#else
405 spec->next_fmt = __find_specmb (format);
406#endif
407 }
408
409 return nargs;
410}
411