xref: /freebsd/contrib/unbound/compat/strptime.c (revision 98e0ffaefb0f241cda3a72395d3be04192ae0d47)
1 /** strptime workaround (for oa macos leopard)
2   * This strptime follows the man strptime (2001-11-12)
3   *		conforming to SUSv2, POSIX.1-2001
4   *
5   * This very simple version of strptime has no:
6   * - E alternatives
7   * - O alternatives
8   * - Glibc additions
9   * - Does not process week numbers
10   * - Does not properly processes year day
11   *
12   * LICENSE
13   * Copyright (c) 2008, NLnet Labs, Matthijs Mekking
14   * All rights reserved.
15   *
16   * Redistribution and use in source and binary forms, with or without
17   * modification, are permitted provided that the following conditions are met:
18   * * Redistributions of source code must retain the above copyright notice,
19   *     this list of conditions and the following disclaimer.
20   * * Redistributions in binary form must reproduce the above copyright
21   *   notice, this list of conditions and the following disclaimer in the
22   *   documentation and/or other materials provided with the distribution.
23   * * Neither the name of NLnetLabs nor the names of its
24   *   contributors may be used to endorse or promote products derived from this
25   *   software without specific prior written permission.
26   *
27   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
28   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
31   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37   * POSSIBILITY OF SUCH DAMAGE.
38  **/
39 
40 #include "config.h"
41 
42 #ifndef HAVE_CONFIG_H
43 #include <time.h>
44 #endif
45 
46 #ifndef STRPTIME_WORKS
47 
48 #define TM_YEAR_BASE 1900
49 
50 #include <ctype.h>
51 #include <string.h>
52 
53 static const char *abb_weekdays[] = {
54 	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", NULL
55 };
56 static const char *full_weekdays[] = {
57 	"Sunday", "Monday", "Tuesday", "Wednesday",
58 	"Thursday", "Friday", "Saturday", NULL
59 };
60 static const char *abb_months[] = {
61 	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
62 	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec", NULL
63 };
64 static const char *full_months[] = {
65 	"January", "February", "March", "April", "May", "June",
66 	"July", "August", "September", "October", "November", "December", NULL
67 };
68 static const char *ampm[] = {
69     "am", "pm", NULL
70 };
71 
72 static int
match_string(const char ** buf,const char ** strs)73 match_string(const char **buf, const char **strs)
74 {
75 	int i = 0;
76 
77 	for (i = 0; strs[i] != NULL; i++) {
78 		int len = strlen(strs[i]);
79 		if (strncasecmp (*buf, strs[i], len) == 0) {
80 			*buf += len;
81 			return i;
82 		}
83 	}
84 	return -1;
85 }
86 
87 static int
str2int(const char ** buf,int max)88 str2int(const char **buf, int max)
89 {
90 	int ret=0, count=0;
91 
92 	while (*buf[0] != '\0' && isdigit((unsigned char)*buf[0]) && count<max) {
93 		ret = ret*10 + (*buf[0] - '0');
94 		(*buf)++;
95 		count++;
96 	}
97 
98 	if (!count)
99 		return -1;
100 	return ret;
101 }
102 
103 /** Converts the character string s to values which are stored in tm
104   * using the format specified by format
105  **/
106 char *
unbound_strptime(const char * s,const char * format,struct tm * tm)107 unbound_strptime(const char *s, const char *format, struct tm *tm)
108 {
109 	int c, ret;
110 	int split_year = 0;
111 
112 	while ((c = *format) != '\0') {
113 		/* whitespace, literal or format */
114 		if (isspace((unsigned char)c)) { /* whitespace */
115 			/** whitespace matches zero or more whitespace characters in the
116 			  * input string.
117 			 **/
118 			while (isspace((unsigned char)*s))
119 				s++;
120 		}
121 		else if (c == '%') { /* format */
122 			format++;
123 			c = *format;
124 			switch (c) {
125 				case '%': /* %% is converted to % */
126 					if (*s != c) {
127 						return NULL;
128 					}
129 					s++;
130 					break;
131 				case 'a': /* weekday name, abbreviated or full */
132 				case 'A':
133 					ret = match_string(&s, full_weekdays);
134 					if (ret < 0)
135 						ret = match_string(&s, abb_weekdays);
136 					if (ret < 0) {
137 						return NULL;
138 					}
139 					tm->tm_wday = ret;
140 					break;
141 				case 'b': /* month name, abbreviated or full */
142 				case 'B':
143 				case 'h':
144 					ret = match_string(&s, full_months);
145 					if (ret < 0)
146 						ret = match_string(&s, abb_months);
147 					if (ret < 0) {
148 						return NULL;
149 					}
150 					tm->tm_mon = ret;
151 					break;
152 				case 'c': /* date and time representation */
153 					if (!(s = unbound_strptime(s, "%x %X", tm))) {
154 						return NULL;
155 					}
156 					break;
157 				case 'C': /* century number */
158 					ret = str2int(&s, 2);
159 					if (ret < 0 || ret > 99) { /* must be in [00,99] */
160 						return NULL;
161 					}
162 
163 					if (split_year)	{
164 						tm->tm_year = ret*100 + (tm->tm_year%100);
165 					}
166 					else {
167 						tm->tm_year = ret*100 - TM_YEAR_BASE;
168 						split_year = 1;
169 					}
170 					break;
171 				case 'd': /* day of month */
172 				case 'e':
173 					ret = str2int(&s, 2);
174 					if (ret < 1 || ret > 31) { /* must be in [01,31] */
175 						return NULL;
176 					}
177 					tm->tm_mday = ret;
178 					break;
179 				case 'D': /* equivalent to %m/%d/%y */
180 					if (!(s = unbound_strptime(s, "%m/%d/%y", tm))) {
181 						return NULL;
182 					}
183 					break;
184 				case 'H': /* hour */
185 					ret = str2int(&s, 2);
186 					if (ret < 0 || ret > 23) { /* must be in [00,23] */
187 						return NULL;
188 					}
189 					tm->tm_hour = ret;
190 					break;
191 				case 'I': /* 12hr clock hour */
192 					ret = str2int(&s, 2);
193 					if (ret < 1 || ret > 12) { /* must be in [01,12] */
194 						return NULL;
195 					}
196 					if (ret == 12) /* actually [0,11] */
197 						ret = 0;
198 					tm->tm_hour = ret;
199 					break;
200 				case 'j': /* day of year */
201 					ret = str2int(&s, 2);
202 					if (ret < 1 || ret > 366) { /* must be in [001,366] */
203 						return NULL;
204 					}
205 					tm->tm_yday = ret;
206 					break;
207 				case 'm': /* month */
208 					ret = str2int(&s, 2);
209 					if (ret < 1 || ret > 12) { /* must be in [01,12] */
210 						return NULL;
211 					}
212 					/* months go from 0-11 */
213 					tm->tm_mon = (ret-1);
214 					break;
215 				case 'M': /* minute */
216 					ret = str2int(&s, 2);
217 					if (ret < 0 || ret > 59) { /* must be in [00,59] */
218 						return NULL;
219 					}
220 					tm->tm_min = ret;
221 					break;
222 				case 'n': /* arbitrary whitespace */
223 				case 't':
224 					while (isspace((unsigned char)*s))
225 						s++;
226 					break;
227 				case 'p': /* am pm */
228 					ret = match_string(&s, ampm);
229 					if (ret < 0) {
230 						return NULL;
231 					}
232 					if (tm->tm_hour < 0 || tm->tm_hour > 11) { /* %I */
233 						return NULL;
234 					}
235 
236 					if (ret == 1) /* pm */
237 						tm->tm_hour += 12;
238 					break;
239 				case 'r': /* equivalent of %I:%M:%S %p */
240 					if (!(s = unbound_strptime(s, "%I:%M:%S %p", tm))) {
241 						return NULL;
242 					}
243 					break;
244 				case 'R': /* equivalent of %H:%M */
245 					if (!(s = unbound_strptime(s, "%H:%M", tm))) {
246 						return NULL;
247 					}
248 					break;
249 				case 'S': /* seconds */
250 					ret = str2int(&s, 2);
251 					/* 60 may occur for leap seconds */
252 					/* earlier 61 was also allowed */
253 					if (ret < 0 || ret > 60) { /* must be in [00,60] */
254 						return NULL;
255 					}
256 					tm->tm_sec = ret;
257 					break;
258 				case 'T': /* equivalent of %H:%M:%S */
259 					if (!(s = unbound_strptime(s, "%H:%M:%S", tm))) {
260 						return NULL;
261 					}
262 					break;
263 				case 'U': /* week number, with the first Sun of Jan being w1 */
264 					ret = str2int(&s, 2);
265 					if (ret < 0 || ret > 53) { /* must be in [00,53] */
266 						return NULL;
267 					}
268 					/** it is hard (and not necessary for nsd) to determine time
269 					  * data from week number.
270 					 **/
271 					break;
272 				case 'w': /* day of week */
273 					ret = str2int(&s, 1);
274 					if (ret < 0 || ret > 6) { /* must be in [0,6] */
275 						return NULL;
276 					}
277 					tm->tm_wday = ret;
278 					break;
279 				case 'W': /* week number, with the first Mon of Jan being w1 */
280 					ret = str2int(&s, 2);
281 					if (ret < 0 || ret > 53) { /* must be in [00,53] */
282 						return NULL;
283 					}
284 					/** it is hard (and not necessary for nsd) to determine time
285 					  * data from week number.
286 					 **/
287 					break;
288 				case 'x': /* date format */
289 					if (!(s = unbound_strptime(s, "%m/%d/%y", tm))) {
290 						return NULL;
291 					}
292 					break;
293 				case 'X': /* time format */
294 					if (!(s = unbound_strptime(s, "%H:%M:%S", tm))) {
295 						return NULL;
296 					}
297 					break;
298 				case 'y': /* last two digits of a year */
299 					ret = str2int(&s, 2);
300 					if (ret < 0 || ret > 99) { /* must be in [00,99] */
301 						return NULL;
302 					}
303 					if (split_year) {
304 						tm->tm_year = ((tm->tm_year/100) * 100) + ret;
305 					}
306 					else {
307 						split_year = 1;
308 
309 						/** currently:
310 						  * if in [0,68] we are in 21th century,
311 						  * if in [69,99] we are in 20th century.
312 						 **/
313 						if (ret < 69) /* 2000 */
314 							ret += 100;
315 						tm->tm_year = ret;
316 					}
317 					break;
318 				case 'Y': /* year */
319 					ret = str2int(&s, 4);
320 					if (ret < 0 || ret > 9999) {
321 						return NULL;
322 					}
323 					tm->tm_year = ret - TM_YEAR_BASE;
324 					break;
325 				case '\0':
326 				default: /* unsupported, cannot match format */
327 					return NULL;
328 					break;
329 			}
330 		}
331 		else { /* literal */
332 			/* if input cannot match format, return NULL */
333 			if (*s != c)
334 				return NULL;
335 			s++;
336 		}
337 
338 		format++;
339 	}
340 
341 	/* return pointer to remainder of s */
342 	return (char*) s;
343 }
344 
345 #endif /* STRPTIME_WORKS */
346