xref: /netbsd-src/lib/libc/time/strptime.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: strptime.c,v 1.20 2000/07/07 08:03:41 itohy Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code was contributed to The NetBSD Foundation by Klaus Klein.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *        This product includes software developed by the NetBSD
20  *        Foundation, Inc. and its contributors.
21  * 4. Neither the name of The NetBSD Foundation nor the names of its
22  *    contributors may be used to endorse or promote products derived
23  *    from this software without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35  * POSSIBILITY OF SUCH DAMAGE.
36  */
37 
38 #include <sys/cdefs.h>
39 #if defined(LIBC_SCCS) && !defined(lint)
40 __RCSID("$NetBSD: strptime.c,v 1.20 2000/07/07 08:03:41 itohy Exp $");
41 #endif
42 
43 #include "namespace.h"
44 #include <sys/localedef.h>
45 #include <ctype.h>
46 #include <locale.h>
47 #include <string.h>
48 #include <time.h>
49 #include <tzfile.h>
50 
51 #ifdef __weak_alias
52 __weak_alias(strptime,_strptime)
53 #endif
54 
55 #define	_ctloc(x)		__CONCAT(_CurrentTimeLocale->,x)
56 
57 /*
58  * We do not implement alternate representations. However, we always
59  * check whether a given modifier is allowed for a certain conversion.
60  */
61 #define ALT_E			0x01
62 #define ALT_O			0x02
63 #define	LEGAL_ALT(x)		{ if (alt_format & ~(x)) return (0); }
64 
65 
66 static	int conv_num __P((const unsigned char **, int *, int, int));
67 
68 
69 char *
70 strptime(buf, fmt, tm)
71 	const char *buf, *fmt;
72 	struct tm *tm;
73 {
74 	unsigned char c;
75 	const unsigned char *bp;
76 	size_t len = 0;
77 	int alt_format, i, split_year = 0;
78 
79 	bp = buf;
80 
81 	while ((c = *fmt) != '\0') {
82 		/* Clear `alternate' modifier prior to new conversion. */
83 		alt_format = 0;
84 
85 		/* Eat up white-space. */
86 		if (isspace(c)) {
87 			while (isspace(*bp))
88 				bp++;
89 
90 			fmt++;
91 			continue;
92 		}
93 
94 		if ((c = *fmt++) != '%')
95 			goto literal;
96 
97 
98 again:		switch (c = *fmt++) {
99 		case '%':	/* "%%" is converted to "%". */
100 literal:
101 			if (c != *bp++)
102 				return (0);
103 			break;
104 
105 		/*
106 		 * "Alternative" modifiers. Just set the appropriate flag
107 		 * and start over again.
108 		 */
109 		case 'E':	/* "%E?" alternative conversion modifier. */
110 			LEGAL_ALT(0);
111 			alt_format |= ALT_E;
112 			goto again;
113 
114 		case 'O':	/* "%O?" alternative conversion modifier. */
115 			LEGAL_ALT(0);
116 			alt_format |= ALT_O;
117 			goto again;
118 
119 		/*
120 		 * "Complex" conversion rules, implemented through recursion.
121 		 */
122 		case 'c':	/* Date and time, using the locale's format. */
123 			LEGAL_ALT(ALT_E);
124 			if (!(bp = strptime(bp, _ctloc(d_t_fmt), tm)))
125 				return (0);
126 			break;
127 
128 		case 'D':	/* The date as "%m/%d/%y". */
129 			LEGAL_ALT(0);
130 			if (!(bp = strptime(bp, "%m/%d/%y", tm)))
131 				return (0);
132 			break;
133 
134 		case 'R':	/* The time as "%H:%M". */
135 			LEGAL_ALT(0);
136 			if (!(bp = strptime(bp, "%H:%M", tm)))
137 				return (0);
138 			break;
139 
140 		case 'r':	/* The time in 12-hour clock representation. */
141 			LEGAL_ALT(0);
142 			if (!(bp = strptime(bp, _ctloc(t_fmt_ampm), tm)))
143 				return (0);
144 			break;
145 
146 		case 'T':	/* The time as "%H:%M:%S". */
147 			LEGAL_ALT(0);
148 			if (!(bp = strptime(bp, "%H:%M:%S", tm)))
149 				return (0);
150 			break;
151 
152 		case 'X':	/* The time, using the locale's format. */
153 			LEGAL_ALT(ALT_E);
154 			if (!(bp = strptime(bp, _ctloc(t_fmt), tm)))
155 				return (0);
156 			break;
157 
158 		case 'x':	/* The date, using the locale's format. */
159 			LEGAL_ALT(ALT_E);
160 			if (!(bp = strptime(bp, _ctloc(d_fmt), tm)))
161 				return (0);
162 			break;
163 
164 		/*
165 		 * "Elementary" conversion rules.
166 		 */
167 		case 'A':	/* The day of week, using the locale's form. */
168 		case 'a':
169 			LEGAL_ALT(0);
170 			for (i = 0; i < 7; i++) {
171 				/* Full name. */
172 				len = strlen(_ctloc(day[i]));
173 				if (strncasecmp(_ctloc(day[i]), bp, len) == 0)
174 					break;
175 
176 				/* Abbreviated name. */
177 				len = strlen(_ctloc(abday[i]));
178 				if (strncasecmp(_ctloc(abday[i]), bp, len) == 0)
179 					break;
180 			}
181 
182 			/* Nothing matched. */
183 			if (i == 7)
184 				return (0);
185 
186 			tm->tm_wday = i;
187 			bp += len;
188 			break;
189 
190 		case 'B':	/* The month, using the locale's form. */
191 		case 'b':
192 		case 'h':
193 			LEGAL_ALT(0);
194 			for (i = 0; i < 12; i++) {
195 				/* Full name. */
196 				len = strlen(_ctloc(mon[i]));
197 				if (strncasecmp(_ctloc(mon[i]), bp, len) == 0)
198 					break;
199 
200 				/* Abbreviated name. */
201 				len = strlen(_ctloc(abmon[i]));
202 				if (strncasecmp(_ctloc(abmon[i]), bp, len) == 0)
203 					break;
204 			}
205 
206 			/* Nothing matched. */
207 			if (i == 12)
208 				return (0);
209 
210 			tm->tm_mon = i;
211 			bp += len;
212 			break;
213 
214 		case 'C':	/* The century number. */
215 			LEGAL_ALT(ALT_E);
216 			if (!(conv_num(&bp, &i, 0, 99)))
217 				return (0);
218 
219 			if (split_year) {
220 				tm->tm_year = (tm->tm_year % 100) + (i * 100);
221 			} else {
222 				tm->tm_year = i * 100;
223 				split_year = 1;
224 			}
225 			break;
226 
227 		case 'd':	/* The day of month. */
228 		case 'e':
229 			LEGAL_ALT(ALT_O);
230 			if (!(conv_num(&bp, &tm->tm_mday, 1, 31)))
231 				return (0);
232 			break;
233 
234 		case 'k':	/* The hour (24-hour clock representation). */
235 			LEGAL_ALT(0);
236 			/* FALLTHROUGH */
237 		case 'H':
238 			LEGAL_ALT(ALT_O);
239 			if (!(conv_num(&bp, &tm->tm_hour, 0, 23)))
240 				return (0);
241 			break;
242 
243 		case 'l':	/* The hour (12-hour clock representation). */
244 			LEGAL_ALT(0);
245 			/* FALLTHROUGH */
246 		case 'I':
247 			LEGAL_ALT(ALT_O);
248 			if (!(conv_num(&bp, &tm->tm_hour, 1, 12)))
249 				return (0);
250 			if (tm->tm_hour == 12)
251 				tm->tm_hour = 0;
252 			break;
253 
254 		case 'j':	/* The day of year. */
255 			LEGAL_ALT(0);
256 			if (!(conv_num(&bp, &i, 1, 366)))
257 				return (0);
258 			tm->tm_yday = i - 1;
259 			break;
260 
261 		case 'M':	/* The minute. */
262 			LEGAL_ALT(ALT_O);
263 			if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
264 				return (0);
265 			break;
266 
267 		case 'm':	/* The month. */
268 			LEGAL_ALT(ALT_O);
269 			if (!(conv_num(&bp, &i, 1, 12)))
270 				return (0);
271 			tm->tm_mon = i - 1;
272 			break;
273 
274 		case 'p':	/* The locale's equivalent of AM/PM. */
275 			LEGAL_ALT(0);
276 			/* AM? */
277 			if (strcasecmp(_ctloc(am_pm[0]), bp) == 0) {
278 				if (tm->tm_hour > 11)
279 					return (0);
280 
281 				bp += strlen(_ctloc(am_pm[0]));
282 				break;
283 			}
284 			/* PM? */
285 			else if (strcasecmp(_ctloc(am_pm[1]), bp) == 0) {
286 				if (tm->tm_hour > 11)
287 					return (0);
288 
289 				tm->tm_hour += 12;
290 				bp += strlen(_ctloc(am_pm[1]));
291 				break;
292 			}
293 
294 			/* Nothing matched. */
295 			return (0);
296 
297 		case 'S':	/* The seconds. */
298 			LEGAL_ALT(ALT_O);
299 			if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
300 				return (0);
301 			break;
302 
303 		case 'U':	/* The week of year, beginning on sunday. */
304 		case 'W':	/* The week of year, beginning on monday. */
305 			LEGAL_ALT(ALT_O);
306 			/*
307 			 * XXX This is bogus, as we can not assume any valid
308 			 * information present in the tm structure at this
309 			 * point to calculate a real value, so just check the
310 			 * range for now.
311 			 */
312 			 if (!(conv_num(&bp, &i, 0, 53)))
313 				return (0);
314 			 break;
315 
316 		case 'w':	/* The day of week, beginning on sunday. */
317 			LEGAL_ALT(ALT_O);
318 			if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
319 				return (0);
320 			break;
321 
322 		case 'Y':	/* The year. */
323 			LEGAL_ALT(ALT_E);
324 			if (!(conv_num(&bp, &i, 0, 9999)))
325 				return (0);
326 
327 			tm->tm_year = i - TM_YEAR_BASE;
328 			break;
329 
330 		case 'y':	/* The year within 100 years of the epoch. */
331 			LEGAL_ALT(ALT_E | ALT_O);
332 			if (!(conv_num(&bp, &i, 0, 99)))
333 				return (0);
334 
335 			if (split_year) {
336 				tm->tm_year = ((tm->tm_year / 100) * 100) + i;
337 				break;
338 			}
339 			split_year = 1;
340 			if (i <= 68)
341 				tm->tm_year = i + 2000 - TM_YEAR_BASE;
342 			else
343 				tm->tm_year = i + 1900 - TM_YEAR_BASE;
344 			break;
345 
346 		/*
347 		 * Miscellaneous conversions.
348 		 */
349 		case 'n':	/* Any kind of white-space. */
350 		case 't':
351 			LEGAL_ALT(0);
352 			while (isspace(*bp))
353 				bp++;
354 			break;
355 
356 
357 		default:	/* Unknown/unsupported conversion. */
358 			return (0);
359 		}
360 
361 
362 	}
363 
364 	/* LINTED functional specification */
365 	return ((char *)bp);
366 }
367 
368 
369 static int
370 conv_num(buf, dest, llim, ulim)
371 	const unsigned char **buf;
372 	int *dest;
373 	int llim, ulim;
374 {
375 	int result = 0;
376 
377 	/* The limit also determines the number of valid digits. */
378 	int rulim = ulim;
379 
380 	if (**buf < '0' || **buf > '9')
381 		return (0);
382 
383 	do {
384 		result *= 10;
385 		result += *(*buf)++ - '0';
386 		rulim /= 10;
387 	} while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
388 
389 	if (result < llim || result > ulim)
390 		return (0);
391 
392 	*dest = result;
393 	return (1);
394 }
395