xref: /netbsd-src/lib/libc/time/strptime.c (revision 2a399c6883d870daece976daec6ffa7bb7f934ce)
1 /*	$NetBSD: strptime.c,v 1.7 1997/07/21 14:09:22 jtc Exp $	*/
2 
3 /*-
4  * Copyright (c) 1997 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 1.7 1997/07/21 14:09:22 jtc 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 
50 #ifdef __weak_alias
51 __weak_alias(strptime,_strptime);
52 #endif
53 
54 #define	_ctloc(x)		__CONCAT(_CurrentTimeLocale->,x)
55 
56 /*
57  * We do not implement alternate representations. However, we always
58  * check whether a given modifier is allowed for a certain conversion.
59  */
60 #define _ALT_E			0x01
61 #define _ALT_O			0x02
62 #define	_LEGAL_ALT(x)		{ if (alt_format & ~(x)) return (0); }
63 
64 
65 static	int _conv_num __P((const char **, int *, int, int));
66 
67 
68 char *
69 strptime(buf, fmt, tm)
70 	const char *buf, *fmt;
71 	struct tm *tm;
72 {
73 	char c;
74 	const char *bp;
75 	int alt_format, i, len;
76 
77 	bp = buf;
78 
79 	while ((c = *fmt) != '\0') {
80 		/* Clear `alternate' modifier prior to new conversion. */
81 		alt_format = 0;
82 
83 		/* Eat up white-space. */
84 		if (isspace(c)) {
85 			while (isspace(*bp))
86 				bp++;
87 
88 			fmt++;
89 			continue;
90 		}
91 
92 		if ((c = *fmt++) != '%')
93 			goto literal;
94 
95 
96 again:		switch (c = *fmt++) {
97 		case '%':	/* "%%" is converted to "%". */
98 literal:
99 		if (c != *bp++)
100 			return (0);
101 
102 		break;
103 
104 		/*
105 		 * "Alternative" modifiers. Just set the appropriate flag
106 		 * and start over again.
107 		 */
108 		case 'E':	/* "%E?" alternative conversion modifier. */
109 			_LEGAL_ALT(0);
110 			alt_format |= _ALT_E;
111 			goto again;
112 
113 		case 'O':	/* "%O?" alternative conversion modifier. */
114 			_LEGAL_ALT(0);
115 			alt_format |= _ALT_O;
116 			goto again;
117 
118 		/*
119 		 * "Complex" conversion rules, implemented through recursion.
120 		 */
121 		case 'c':	/* Date and time, using the locale's format. */
122 			_LEGAL_ALT(_ALT_E);
123 			if (!(bp = strptime(bp, _ctloc(d_t_fmt), tm)))
124 				return (0);
125 			break;
126 
127 		case 'D':	/* The date as "%m/%d/%y". */
128 			_LEGAL_ALT(0);
129 			if (!(bp = strptime(bp, "%m/%d/%y", tm)))
130 				return (0);
131 			break;
132 
133 		case 'R':	/* The time as "%H:%M". */
134 			_LEGAL_ALT(0);
135 			if (!(bp = strptime(bp, "%H:%M", tm)))
136 				return (0);
137 			break;
138 
139 		case 'r':	/* The time in 12-hour clock representation. */
140 			_LEGAL_ALT(0);
141 			if (!(bp = strptime(bp, _ctloc(t_fmt_ampm), tm)))
142 				return (0);
143 			break;
144 
145 		case 'T':	/* The time as "%H:%M:%S". */
146 			_LEGAL_ALT(0);
147 			if (!(bp = strptime(bp, "%H:%M:%S", tm)))
148 				return (0);
149 			break;
150 
151 		case 'X':	/* The time, using the locale's format. */
152 			_LEGAL_ALT(_ALT_E);
153 			if (!(bp = strptime(bp, _ctloc(t_fmt), tm)))
154 				return (0);
155 			break;
156 
157 		case 'x':	/* The date, using the locale's format. */
158 			_LEGAL_ALT(_ALT_E);
159 			if (!(bp = strptime(bp, _ctloc(d_fmt), tm)))
160 				return (0);
161 			break;
162 
163 		/*
164 		 * "Elementary" conversion rules.
165 		 */
166 		case 'A':	/* The day of week, using the locale's form. */
167 		case 'a':
168 			_LEGAL_ALT(0);
169 			for (i = 0; i < 7; i++) {
170 				/* Full name. */
171 				len = strlen(_ctloc(day[i]));
172 				if (strncmp(_ctloc(day[i]), bp, len) == 0)
173 					break;
174 
175 				/* Abbreviated name. */
176 				len = strlen(_ctloc(abday[i]));
177 				if (strncmp(_ctloc(abday[i]), bp, len) == 0)
178 					break;
179 			}
180 
181 			/* Nothing matched. */
182 			if (i == 7)
183 				return (0);
184 
185 			tm->tm_wday = i;
186 			bp += len;
187 			break;
188 
189 		case 'B':	/* The month, using the locale's form. */
190 		case 'b':
191 		case 'h':
192 			_LEGAL_ALT(0);
193 			for (i = 0; i < 12; i++) {
194 				/* Full name. */
195 				len = strlen(_ctloc(mon[i]));
196 				if (strncmp(_ctloc(mon[i]), bp, len) == 0)
197 					break;
198 
199 				/* Abbreviated name. */
200 				len = strlen(_ctloc(abmon[i]));
201 				if (strncmp(_ctloc(abmon[i]), bp, len) == 0)
202 					break;
203 			}
204 
205 			/* Nothing matched. */
206 			if (i == 12)
207 				return (0);
208 
209 			tm->tm_mon = i;
210 			bp += len;
211 			break;
212 
213 		case 'C':	/* The century number. */
214 			_LEGAL_ALT(_ALT_E);
215 			if (!(_conv_num(&bp, &i, 0, 99)))
216 				return (0);
217 
218 			tm->tm_year = i * 100;
219 			break;
220 
221 		case 'd':	/* The day of month. */
222 		case 'e':
223 			_LEGAL_ALT(_ALT_O);
224 			if (!(_conv_num(&bp, &tm->tm_mday, 1, 31)))
225 				return (0);
226 			break;
227 
228 		case 'k':	/* The hour (24-hour clock representation). */
229 			_LEGAL_ALT(0);
230 			/* FALLTHROUGH */
231 		case 'H':
232 			_LEGAL_ALT(_ALT_O);
233 			if (!(_conv_num(&bp, &tm->tm_hour, 0, 23)))
234 				return (0);
235 			break;
236 
237 		case 'l':	/* The hour (12-hour clock representation). */
238 			_LEGAL_ALT(0);
239 			/* FALLTHROUGH */
240 		case 'I':
241 			_LEGAL_ALT(_ALT_O);
242 			if (!(_conv_num(&bp, &tm->tm_hour, 0, 11)))
243 				return (0);
244 			break;
245 
246 		case 'j':	/* The day of year. */
247 			_LEGAL_ALT(0);
248 			if (!(_conv_num(&bp, &tm->tm_yday, 1, 366)))
249 				return (0);
250 			break;
251 
252 		case 'M':	/* The minute. */
253 			_LEGAL_ALT(_ALT_O);
254 			if (!(_conv_num(&bp, &tm->tm_min, 0, 59)))
255 				return (0);
256 			break;
257 
258 		case 'm':	/* The month. */
259 			_LEGAL_ALT(_ALT_O);
260 			if (!(_conv_num(&bp, &tm->tm_mon, 1, 12)))
261 				return (0);
262 			break;
263 
264 		case 'p':	/* The locale's equivalent of AM/PM. */
265 			_LEGAL_ALT(0);
266 			/* AM? */
267 			if (strcmp(_ctloc(am_pm[0]), bp) == 0) {
268 				if (tm->tm_hour > 12)	/* i.e., 13:00 AM ?! */
269 					return (0);
270 				else if (tm->tm_hour == 12)
271 					tm->tm_hour = 0;
272 
273 				bp += strlen(_ctloc(am_pm[0]));
274 				break;
275 			}
276 			/* PM? */
277 			else if (strcmp(_ctloc(am_pm[1]), bp) == 0) {
278 				if (tm->tm_hour > 12)	/* i.e., 13:00 PM ?! */
279 					return (0);
280 				else if (tm->tm_hour < 12)
281 					tm->tm_hour += 12;
282 
283 				bp += strlen(_ctloc(am_pm[1]));
284 				break;
285 			}
286 
287 			/* Nothing matched. */
288 			return (0);
289 
290 		case 'S':	/* The seconds. */
291 			_LEGAL_ALT(_ALT_O);
292 			if (!(_conv_num(&bp, &tm->tm_sec, 1, 61)))
293 				return (0);
294 			break;
295 
296 		case 'U':	/* The week of year, beginning on sunday. */
297 		case 'W':	/* The week of year, beginning on monday. */
298 			_LEGAL_ALT(_ALT_O);
299 			/*
300 			 * XXX This is bogus, as we can not assume any valid
301 			 * information present in the tm structure at this
302 			 * point to calculate a real value, so just check the
303 			 * range for now.
304 			 */
305 			 if (!(_conv_num(&bp, &i, 0, 53)))
306 				return (0);
307 			 break;
308 
309 		case 'w':	/* The day of week, beginning on sunday. */
310 			_LEGAL_ALT(_ALT_O);
311 			if (!(_conv_num(&bp, &tm->tm_wday, 0, 6)))
312 				return (0);
313 			break;
314 
315 		case 'Y':	/* The year. */
316 			_LEGAL_ALT(_ALT_E);
317 			if (!(_conv_num(&bp, &i, 0, INT_MAX)))
318 				return (0);
319 
320 			tm->tm_year = i - 1900;
321 			break;
322 
323 		case 'y':	/* The year within the 20th century. */
324 			_LEGAL_ALT(_ALT_E | _ALT_O);
325 			if (!(_conv_num(&bp, &tm->tm_year, 0, 99)))
326 				return (0);
327 			break;
328 
329 		/*
330 		 * Miscellaneous conversions.
331 		 */
332 		case 'n':	/* Any kind of white-space. */
333 		case 't':
334 			_LEGAL_ALT(0);
335 			while (isspace(*bp))
336 				bp++;
337 			break;
338 
339 
340 		default:	/* Unknown/unsupported conversion. */
341 			return (0);
342 		}
343 
344 
345 	}
346 
347 	return ((char *)bp);
348 }
349 
350 
351 static int
352 _conv_num(buf, dest, llim, ulim)
353 	const char **buf;
354 	int *dest;
355 	int llim, ulim;
356 {
357 	*dest = 0;
358 
359 	if (**buf < '0' || **buf > '9')
360 		return (0);
361 
362 	do {
363 		*dest *= 10;
364 		*dest += *(*buf)++ - '0';
365 	} while ((*dest * 10 <= ulim) && **buf >= '0' && **buf <= '9');
366 
367 	if (*dest < llim || *dest > ulim)
368 		return (0);
369 
370 	return (1);
371 }
372