xref: /freebsd/crypto/heimdal/lib/roken/strptime.c (revision 7aa383846770374466b1dcb2cefd71bde9acf463)
1 /*
2  * Copyright (c) 1999, 2003, 2005 Kungliga Tekniska H�gskolan
3  * (Royal Institute of Technology, Stockholm, Sweden).
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  *
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * 3. Neither the name of KTH nor the names of its contributors may be
18  *    used to endorse or promote products derived from this software without
19  *    specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
22  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
32 
33 #ifdef HAVE_CONFIG_H
34 #include <config.h>
35 #endif
36 #ifdef TEST_STRPFTIME
37 #include "strpftime-test.h"
38 #endif
39 #include <ctype.h>
40 #include "roken.h"
41 
42 RCSID("$Id: strptime.c 21895 2007-08-09 08:45:54Z lha $");
43 
44 static const char *abb_weekdays[] = {
45     "Sun",
46     "Mon",
47     "Tue",
48     "Wed",
49     "Thu",
50     "Fri",
51     "Sat",
52     NULL
53 };
54 
55 static const char *full_weekdays[] = {
56     "Sunday",
57     "Monday",
58     "Tuesday",
59     "Wednesday",
60     "Thursday",
61     "Friday",
62     "Saturday",
63     NULL
64 };
65 
66 static const char *abb_month[] = {
67     "Jan",
68     "Feb",
69     "Mar",
70     "Apr",
71     "May",
72     "Jun",
73     "Jul",
74     "Aug",
75     "Sep",
76     "Oct",
77     "Nov",
78     "Dec",
79     NULL
80 };
81 
82 static const char *full_month[] = {
83     "January",
84     "February",
85     "March",
86     "April",
87     "May",
88     "June",
89     "July",
90     "August",
91     "September",
92     "October",
93     "November",
94     "December",
95     NULL,
96 };
97 
98 static const char *ampm[] = {
99     "am",
100     "pm",
101     NULL
102 };
103 
104 /*
105  * Try to match `*buf' to one of the strings in `strs'.  Return the
106  * index of the matching string (or -1 if none).  Also advance buf.
107  */
108 
109 static int
110 match_string (const char **buf, const char **strs)
111 {
112     int i = 0;
113 
114     for (i = 0; strs[i] != NULL; ++i) {
115 	int len = strlen (strs[i]);
116 
117 	if (strncasecmp (*buf, strs[i], len) == 0) {
118 	    *buf += len;
119 	    return i;
120 	}
121     }
122     return -1;
123 }
124 
125 /*
126  * Try to match `*buf' to at the most `n' characters and return the
127  * resulting number in `num'. Returns 0 or an error.  Also advance
128  * buf.
129  */
130 
131 static int
132 parse_number (const char **buf, int n, int *num)
133 {
134     char *s, *str;
135     int i;
136 
137     str = malloc(n + 1);
138     if (str == NULL)
139 	return -1;
140 
141     /* skip whitespace */
142     for (; **buf != '\0' && isspace((unsigned char)(**buf)); (*buf)++)
143 	;
144 
145     /* parse at least n characters */
146     for (i = 0; **buf != '\0' && i < n && isdigit((unsigned char)(**buf)); i++, (*buf)++)
147 	str[i] = **buf;
148     str[i] = '\0';
149 
150     *num = strtol (str, &s, 10);
151     free(str);
152     if (s == str)
153 	return -1;
154 
155     return 0;
156 }
157 
158 /*
159  * tm_year is relative this year
160  */
161 
162 const int tm_year_base = 1900;
163 
164 /*
165  * Return TRUE iff `year' was a leap year.
166  */
167 
168 static int
169 is_leap_year (int year)
170 {
171     return (year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0);
172 }
173 
174 /*
175  * Return the weekday [0,6] (0 = Sunday) of the first day of `year'
176  */
177 
178 static int
179 first_day (int year)
180 {
181     int ret = 4;
182 
183     for (; year > 1970; --year)
184 	ret = (ret + 365 + is_leap_year (year) ? 1 : 0) % 7;
185     return ret;
186 }
187 
188 /*
189  * Set `timeptr' given `wnum' (week number [0, 53])
190  */
191 
192 static void
193 set_week_number_sun (struct tm *timeptr, int wnum)
194 {
195     int fday = first_day (timeptr->tm_year + tm_year_base);
196 
197     timeptr->tm_yday = wnum * 7 + timeptr->tm_wday - fday;
198     if (timeptr->tm_yday < 0) {
199 	timeptr->tm_wday = fday;
200 	timeptr->tm_yday = 0;
201     }
202 }
203 
204 /*
205  * Set `timeptr' given `wnum' (week number [0, 53])
206  */
207 
208 static void
209 set_week_number_mon (struct tm *timeptr, int wnum)
210 {
211     int fday = (first_day (timeptr->tm_year + tm_year_base) + 6) % 7;
212 
213     timeptr->tm_yday = wnum * 7 + (timeptr->tm_wday + 6) % 7 - fday;
214     if (timeptr->tm_yday < 0) {
215 	timeptr->tm_wday = (fday + 1) % 7;
216 	timeptr->tm_yday = 0;
217     }
218 }
219 
220 /*
221  * Set `timeptr' given `wnum' (week number [0, 53])
222  */
223 
224 static void
225 set_week_number_mon4 (struct tm *timeptr, int wnum)
226 {
227     int fday = (first_day (timeptr->tm_year + tm_year_base) + 6) % 7;
228     int offset = 0;
229 
230     if (fday < 4)
231 	offset += 7;
232 
233     timeptr->tm_yday = offset + (wnum - 1) * 7 + timeptr->tm_wday - fday;
234     if (timeptr->tm_yday < 0) {
235 	timeptr->tm_wday = fday;
236 	timeptr->tm_yday = 0;
237     }
238 }
239 
240 /*
241  *
242  */
243 
244 char * ROKEN_LIB_FUNCTION
245 strptime (const char *buf, const char *format, struct tm *timeptr)
246 {
247     char c;
248 
249     for (; (c = *format) != '\0'; ++format) {
250 	char *s;
251 	int ret;
252 
253 	if (isspace ((unsigned char)c)) {
254 	    while (isspace ((unsigned char)*buf))
255 		++buf;
256 	} else if (c == '%' && format[1] != '\0') {
257 	    c = *++format;
258 	    if (c == 'E' || c == 'O')
259 		c = *++format;
260 	    switch (c) {
261 	    case 'A' :
262 		ret = match_string (&buf, full_weekdays);
263 		if (ret < 0)
264 		    return NULL;
265 		timeptr->tm_wday = ret;
266 		break;
267 	    case 'a' :
268 		ret = match_string (&buf, abb_weekdays);
269 		if (ret < 0)
270 		    return NULL;
271 		timeptr->tm_wday = ret;
272 		break;
273 	    case 'B' :
274 		ret = match_string (&buf, full_month);
275 		if (ret < 0)
276 		    return NULL;
277 		timeptr->tm_mon = ret;
278 		break;
279 	    case 'b' :
280 	    case 'h' :
281 		ret = match_string (&buf, abb_month);
282 		if (ret < 0)
283 		    return NULL;
284 		timeptr->tm_mon = ret;
285 		break;
286 	    case 'C' :
287 		if (parse_number(&buf, 2, &ret))
288 		    return NULL;
289 		timeptr->tm_year = (ret * 100) - tm_year_base;
290 		break;
291 	    case 'c' :
292 		abort ();
293 	    case 'D' :		/* %m/%d/%y */
294 		s = strptime (buf, "%m/%d/%y", timeptr);
295 		if (s == NULL)
296 		    return NULL;
297 		buf = s;
298 		break;
299 	    case 'd' :
300 	    case 'e' :
301 		if (parse_number(&buf, 2, &ret))
302 		    return NULL;
303 		timeptr->tm_mday = ret;
304 		break;
305 	    case 'H' :
306 	    case 'k' :
307 		if (parse_number(&buf, 2, &ret))
308 		    return NULL;
309 		timeptr->tm_hour = ret;
310 		break;
311 	    case 'I' :
312 	    case 'l' :
313 		if (parse_number(&buf, 2, &ret))
314 		    return NULL;
315 		if (ret == 12)
316 		    timeptr->tm_hour = 0;
317 		else
318 		    timeptr->tm_hour = ret;
319 		break;
320 	    case 'j' :
321 		if (parse_number(&buf, 3, &ret))
322 		    return NULL;
323 		if (ret == 0)
324 		    return NULL;
325 		timeptr->tm_yday = ret - 1;
326 		break;
327 	    case 'm' :
328 		if (parse_number(&buf, 2, &ret))
329 		    return NULL;
330 		if (ret == 0)
331 		    return NULL;
332 		timeptr->tm_mon = ret - 1;
333 		break;
334 	    case 'M' :
335 		if (parse_number(&buf, 2, &ret))
336 		    return NULL;
337 		timeptr->tm_min = ret;
338 		break;
339 	    case 'n' :
340 		while (isspace ((unsigned char)*buf))
341 		    buf++;
342 		break;
343 	    case 'p' :
344 		ret = match_string (&buf, ampm);
345 		if (ret < 0)
346 		    return NULL;
347 		if (timeptr->tm_hour == 0) {
348 		    if (ret == 1)
349 			timeptr->tm_hour = 12;
350 		} else
351 		    timeptr->tm_hour += 12;
352 		break;
353 	    case 'r' :		/* %I:%M:%S %p */
354 		s = strptime (buf, "%I:%M:%S %p", timeptr);
355 		if (s == NULL)
356 		    return NULL;
357 		buf = s;
358 		break;
359 	    case 'R' :		/* %H:%M */
360 		s = strptime (buf, "%H:%M", timeptr);
361 		if (s == NULL)
362 		    return NULL;
363 		buf = s;
364 		break;
365 	    case 'S' :
366 		if (parse_number(&buf, 2, &ret))
367 		    return NULL;
368 		timeptr->tm_sec = ret;
369 		break;
370 	    case 't' :
371 		while (isspace ((unsigned char)*buf))
372 		    buf++;
373 		break;
374 	    case 'T' :		/* %H:%M:%S */
375 	    case 'X' :
376 		s = strptime (buf, "%H:%M:%S", timeptr);
377 		if (s == NULL)
378 		    return NULL;
379 		buf = s;
380 		break;
381 	    case 'u' :
382 		if (parse_number(&buf, 1, &ret))
383 		    return NULL;
384 		if (ret <= 0)
385 		    return NULL;
386 		timeptr->tm_wday = ret - 1;
387 		break;
388 	    case 'w' :
389 		if (parse_number(&buf, 1, &ret))
390 		    return NULL;
391 		timeptr->tm_wday = ret;
392 		break;
393 	    case 'U' :
394 		if (parse_number(&buf, 2, &ret))
395 		    return NULL;
396 		set_week_number_sun (timeptr, ret);
397 		break;
398 	    case 'V' :
399 		if (parse_number(&buf, 2, &ret))
400 		    return NULL;
401 		set_week_number_mon4 (timeptr, ret);
402 		break;
403 	    case 'W' :
404 		if (parse_number(&buf, 2, &ret))
405 		    return NULL;
406 		set_week_number_mon (timeptr, ret);
407 		break;
408 	    case 'x' :
409 		s = strptime (buf, "%Y:%m:%d", timeptr);
410 		if (s == NULL)
411 		    return NULL;
412 		buf = s;
413 		break;
414 	    case 'y' :
415 		if (parse_number(&buf, 2, &ret))
416 		    return NULL;
417 		if (ret < 70)
418 		    timeptr->tm_year = 100 + ret;
419 		else
420 		    timeptr->tm_year = ret;
421 		break;
422 	    case 'Y' :
423 		if (parse_number(&buf, 4, &ret))
424 		    return NULL;
425 		timeptr->tm_year = ret - tm_year_base;
426 		break;
427 	    case 'Z' :
428 		abort ();
429 	    case '\0' :
430 		--format;
431 		/* FALLTHROUGH */
432 	    case '%' :
433 		if (*buf == '%')
434 		    ++buf;
435 		else
436 		    return NULL;
437 		break;
438 	    default :
439 		if (*buf == '%' || *++buf == c)
440 		    ++buf;
441 		else
442 		    return NULL;
443 		break;
444 	    }
445 	} else {
446 	    if (*buf == c)
447 		++buf;
448 	    else
449 		return NULL;
450 	}
451     }
452     return rk_UNCONST(buf);
453 }
454