xref: /netbsd-src/lib/libc/time/strptime.c (revision fdecd6a253f999ae92b139670d9e15cc9df4497c)
1 /*	$NetBSD: strptime.c,v 1.5 1997/06/03 10:19:45 kleink 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 #if defined(LIBC_SCCS) && !defined(lint)
39 static char rcsid[] = "$NetBSD: strptime.c,v 1.5 1997/06/03 10:19:45 kleink Exp $";
40 #endif
41 
42 #include <sys/localedef.h>
43 #include <ctype.h>
44 #include <locale.h>
45 #include <string.h>
46 #include <time.h>
47 
48 #define	_ctloc(x)		__CONCAT(_CurrentTimeLocale->,x)
49 
50 /*
51  * We do not implement alternate representations. However, we always
52  * check whether a given modifier is allowed for a certain conversion.
53  */
54 #define _ALT_E			0x01
55 #define _ALT_O			0x02
56 #define	_LEGAL_ALT(x)		{ if (alt_format & ~(x)) return (0); }
57 
58 
59 static	int _conv_num __P((const char **, int *, int, int));
60 
61 
62 char *
63 strptime(buf, fmt, tm)
64 	const char *buf, *fmt;
65 	struct tm *tm;
66 {
67 	char c;
68 	const char *bp;
69 	int alt_format, i, len;
70 
71 	bp = buf;
72 
73 	while ((c = *fmt) != '\0') {
74 		/* Clear `alternate' modifier prior to new conversion. */
75 		alt_format = 0;
76 
77 		/* Eat up white-space. */
78 		if (isspace(c)) {
79 			while (isspace(*bp))
80 				bp++;
81 
82 			fmt++;
83 			continue;
84 		}
85 
86 		if ((c = *fmt++) != '%')
87 			goto literal;
88 
89 
90 again:		switch (c = *fmt++) {
91 		case '%':	/* "%%" is converted to "%". */
92 literal:
93 		if (c != *bp++)
94 			return (0);
95 
96 		break;
97 
98 		/*
99 		 * "Alternative" modifiers. Just set the appropriate flag
100 		 * and start over again.
101 		 */
102 		case 'E':	/* "%E?" alternative conversion modifier. */
103 			_LEGAL_ALT(0);
104 			alt_format |= _ALT_E;
105 			goto again;
106 
107 		case 'O':	/* "%O?" alternative conversion modifier. */
108 			_LEGAL_ALT(0);
109 			alt_format |= _ALT_O;
110 			goto again;
111 
112 		/*
113 		 * "Complex" conversion rules, implemented through recursion.
114 		 */
115 		case 'c':	/* Date and time, using the locale's format. */
116 			_LEGAL_ALT(_ALT_E);
117 			if (!(bp = strptime(bp, _ctloc(d_t_fmt), tm)))
118 				return (0);
119 			break;
120 
121 		case 'D':	/* The date as "%m/%d/%y". */
122 			_LEGAL_ALT(0);
123 			if (!(bp = strptime(bp, "%m/%d/%y", tm)))
124 				return (0);
125 			break;
126 
127 		case 'R':	/* The time as "%H:%M". */
128 			_LEGAL_ALT(0);
129 			if (!(bp = strptime(bp, "%H:%M", tm)))
130 				return (0);
131 			break;
132 
133 		case 'r':	/* The time in 12-hour clock representation. */
134 			_LEGAL_ALT(0);
135 			if (!(bp = strptime(bp, _ctloc(t_fmt_ampm), tm)))
136 				return (0);
137 			break;
138 
139 		case 'T':	/* The time as "%H:%M:%S". */
140 			_LEGAL_ALT(0);
141 			if (!(bp = strptime(bp, "%H:%M:%S", tm)))
142 				return (0);
143 			break;
144 
145 		case 'X':	/* The time, using the locale's format. */
146 			_LEGAL_ALT(_ALT_E);
147 			if (!(bp = strptime(bp, _ctloc(t_fmt), tm)))
148 				return (0);
149 			break;
150 
151 		case 'x':	/* The date, using the locale's format. */
152 			_LEGAL_ALT(_ALT_E);
153 			if (!(bp = strptime(bp, _ctloc(d_fmt), tm)))
154 				return (0);
155 			break;
156 
157 		/*
158 		 * "Elementary" conversion rules.
159 		 */
160 		case 'A':	/* The day of week, using the locale's form. */
161 		case 'a':
162 			_LEGAL_ALT(0);
163 			for (i = 0; i < 7; i++) {
164 				/* Full name. */
165 				len = strlen(_ctloc(day[i]));
166 				if (strncmp(_ctloc(day[i]), bp, len) == 0)
167 					break;
168 
169 				/* Abbreviated name. */
170 				len = strlen(_ctloc(abday[i]));
171 				if (strncmp(_ctloc(abday[i]), bp, len) == 0)
172 					break;
173 			}
174 
175 			/* Nothing matched. */
176 			if (i == 7)
177 				return (0);
178 
179 			tm->tm_wday = i;
180 			bp += len;
181 			break;
182 
183 		case 'B':	/* The month, using the locale's form. */
184 		case 'b':
185 		case 'h':
186 			_LEGAL_ALT(0);
187 			for (i = 0; i < 12; i++) {
188 				/* Full name. */
189 				len = strlen(_ctloc(mon[i]));
190 				if (strncmp(_ctloc(mon[i]), bp, len) == 0)
191 					break;
192 
193 				/* Abbreviated name. */
194 				len = strlen(_ctloc(abmon[i]));
195 				if (strncmp(_ctloc(abmon[i]), bp, len) == 0)
196 					break;
197 			}
198 
199 			/* Nothing matched. */
200 			if (i == 12)
201 				return (0);
202 
203 			tm->tm_mon = i;
204 			bp += len;
205 			break;
206 
207 		case 'C':	/* The century number. */
208 			_LEGAL_ALT(_ALT_E);
209 			if (!(_conv_num(&bp, &i, 0, 99)))
210 				return (0);
211 
212 			tm->tm_year = i * 100;
213 			break;
214 
215 		case 'd':	/* The day of month. */
216 		case 'e':
217 			_LEGAL_ALT(_ALT_O);
218 			if (!(_conv_num(&bp, &tm->tm_mday, 1, 31)))
219 				return (0);
220 			break;
221 
222 		case 'k':	/* The hour (24-hour clock representation). */
223 			_LEGAL_ALT(0);
224 			/* FALLTHROUGH */
225 		case 'H':
226 			_LEGAL_ALT(_ALT_O);
227 			if (!(_conv_num(&bp, &tm->tm_hour, 0, 23)))
228 				return (0);
229 			break;
230 
231 		case 'l':	/* The hour (12-hour clock representation). */
232 			_LEGAL_ALT(0);
233 			/* FALLTHROUGH */
234 		case 'I':
235 			_LEGAL_ALT(_ALT_O);
236 			if (!(_conv_num(&bp, &tm->tm_hour, 0, 11)))
237 				return (0);
238 			break;
239 
240 		case 'j':	/* The day of year. */
241 			_LEGAL_ALT(0);
242 			if (!(_conv_num(&bp, &tm->tm_yday, 1, 366)))
243 				return (0);
244 			break;
245 
246 		case 'M':	/* The minute. */
247 			_LEGAL_ALT(_ALT_O);
248 			if (!(_conv_num(&bp, &tm->tm_min, 0, 59)))
249 				return (0);
250 			break;
251 
252 		case 'm':	/* The month. */
253 			_LEGAL_ALT(_ALT_O);
254 			if (!(_conv_num(&bp, &tm->tm_mon, 1, 12)))
255 				return (0);
256 			break;
257 
258 		case 'p':	/* The locale's equivalent of AM/PM. */
259 			_LEGAL_ALT(0);
260 			/* AM? */
261 			if (strcmp(_ctloc(am_pm[0]), bp) == 0) {
262 				if (tm->tm_hour > 12)	/* i.e., 13:00 AM ?! */
263 					return (0);
264 				else if (tm->tm_hour == 12)
265 					tm->tm_hour = 0;
266 
267 				bp += strlen(_ctloc(am_pm[0]));
268 				break;
269 			}
270 			/* PM? */
271 			else if (strcmp(_ctloc(am_pm[1]), bp) == 0) {
272 				if (tm->tm_hour > 12)	/* i.e., 13:00 PM ?! */
273 					return (0);
274 				else if (tm->tm_hour < 12)
275 					tm->tm_hour += 12;
276 
277 				bp += strlen(_ctloc(am_pm[1]));
278 				break;
279 			}
280 
281 			/* Nothing matched. */
282 			return (0);
283 
284 		case 'S':	/* The seconds. */
285 			_LEGAL_ALT(_ALT_O);
286 			if (!(_conv_num(&bp, &tm->tm_sec, 1, 61)))
287 				return (0);
288 			break;
289 
290 		case 'U':	/* The week of year, beginning on sunday. */
291 		case 'W':	/* The week of year, beginning on monday. */
292 			_LEGAL_ALT(_ALT_O);
293 			/*
294 			 * XXX This is bogus, as we can not assume any valid
295 			 * information present in the tm structure at this
296 			 * point to calculate a real value, so just check the
297 			 * range for now.
298 			 */
299 			 if (!(_conv_num(&bp, &i, 0, 53)))
300 				return (0);
301 			 break;
302 
303 		case 'w':	/* The day of week, beginning on sunday. */
304 			_LEGAL_ALT(_ALT_O);
305 			if (!(_conv_num(&bp, &tm->tm_wday, 0, 6)))
306 				return (0);
307 			break;
308 
309 		case 'Y':	/* The year. */
310 			_LEGAL_ALT(_ALT_E);
311 			if (!(_conv_num(&bp, &i, 0, INT_MAX)))
312 				return (0);
313 
314 			tm->tm_year = i - 1900;
315 			break;
316 
317 		case 'y':	/* The year within the 20th century. */
318 			_LEGAL_ALT(_ALT_E | _ALT_O);
319 			if (!(_conv_num(&bp, &tm->tm_year, 0, 99)))
320 				return (0);
321 			break;
322 
323 		/*
324 		 * Miscellaneous conversions.
325 		 */
326 		case 'n':	/* Any kind of white-space. */
327 		case 't':
328 			_LEGAL_ALT(0);
329 			while (isspace(*bp))
330 				bp++;
331 			break;
332 
333 
334 		default:	/* Unknown/unsupported conversion. */
335 			return (0);
336 		}
337 
338 
339 	}
340 
341 	return ((char *)bp);
342 }
343 
344 
345 static int
346 _conv_num(buf, dest, llim, ulim)
347 	const char **buf;
348 	int *dest;
349 	int llim, ulim;
350 {
351 	*dest = 0;
352 
353 	if (**buf < '0' || **buf > '9')
354 		return (0);
355 
356 	do {
357 		*dest *= 10;
358 		*dest += *(*buf)++ - '0';
359 	} while ((*dest * 10 <= ulim) && **buf >= '0' && **buf <= '9');
360 
361 	if (*dest < llim || *dest > ulim)
362 		return (0);
363 
364 	return (1);
365 }
366