xref: /netbsd-src/external/bsd/nsd/dist/compat/strptime.c (revision d83a80ee7fb31190352cf1f781441e06ca6a86db)
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 #ifdef HAVE_CONFIG_H
41 #include "config.h"
42 #endif
43 
44 #ifndef HAVE_CONFIG_H
45 #include <time.h>
46 #endif
47 
48 #ifndef STRPTIME_WORKS
49 
50 #define TM_YEAR_BASE 1900
51 
52 #include <ctype.h>
53 #include <string.h>
54 
55 static const char *abb_weekdays[] = {
56 	"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", NULL
57 };
58 static const char *full_weekdays[] = {
59 	"Sunday", "Monday", "Tuesday", "Wednesday",
60 	"Thursday", "Friday", "Saturday", NULL
61 };
62 static const char *abb_months[] = {
63 	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
64 	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec", NULL
65 };
66 static const char *full_months[] = {
67 	"January", "February", "March", "April", "May", "June",
68 	"July", "August", "September", "October", "November", "December", NULL
69 };
70 static const char *ampm[] = {
71     "am", "pm", NULL
72 };
73 
74 static int
match_string(const char ** buf,const char ** strs)75 match_string(const char **buf, const char **strs)
76 {
77 	int i = 0;
78 
79 	for (i = 0; strs[i] != NULL; i++) {
80 		int len = strlen(strs[i]);
81 		if (strncasecmp (*buf, strs[i], len) == 0) {
82 			*buf += len;
83 			return i;
84 		}
85 	}
86 	return -1;
87 }
88 
89 static int
str2int(const char ** buf,int max)90 str2int(const char **buf, int max)
91 {
92 	int ret=0, count=0;
93 
94 	while (*buf[0] != '\0' && isdigit((unsigned char)*buf[0]) && count<max) {
95 		ret = ret*10 + (*buf[0] - '0');
96 		(*buf)++;
97 		count++;
98 	}
99 
100 	if (!count)
101 		return -1;
102 	return ret;
103 }
104 
105 /** Converts the character string s to values which are stored in tm
106   * using the format specified by format
107  **/
108 char *
nsd_strptime(const char * s,const char * format,struct tm * tm)109 nsd_strptime(const char *s, const char *format, struct tm *tm)
110 {
111 	int c, alt_format, ret;
112 	int split_year = 0;
113 
114 	while ((c = *format) != '\0') {
115 		alt_format = 0;
116 
117 		/* whitespace, literal or format */
118 		if (isspace((unsigned char)c)) { /* whitespace */
119 			/** whitespace matches zero or more whitespace characters in the
120 			  * input string.
121 			 **/
122 			while (isspace((unsigned char)*s))
123 				s++;
124 		}
125 		else if (c == '%') { /* format */
126 			format++;
127 			c = *format;
128 			switch (c) {
129 				case '%': /* %% is converted to % */
130 					if (*s != c) {
131 						return NULL;
132 					}
133 					s++;
134 					break;
135 				case 'a': /* weekday name, abbreviated or full */
136 				case 'A':
137 					ret = match_string(&s, full_weekdays);
138 					if (ret < 0)
139 						ret = match_string(&s, abb_weekdays);
140 					if (ret < 0) {
141 						return NULL;
142 					}
143 					tm->tm_wday = ret;
144 					break;
145 				case 'b': /* month name, abbreviated or full */
146 				case 'B':
147 				case 'h':
148 					ret = match_string(&s, full_months);
149 					if (ret < 0)
150 						ret = match_string(&s, abb_months);
151 					if (ret < 0) {
152 						return NULL;
153 					}
154 					tm->tm_mon = ret;
155 					break;
156 				case 'c': /* date and time representation */
157 					if (!(s = nsd_strptime(s, "%x %X", tm))) {
158 						return NULL;
159 					}
160 					break;
161 				case 'C': /* century number */
162 					ret = str2int(&s, 2);
163 					if (ret < 0 || ret > 99) { /* must be in [00,99] */
164 						return NULL;
165 					}
166 
167 					if (split_year)	{
168 						tm->tm_year = ret*100 + (tm->tm_year%100);
169 					}
170 					else {
171 						tm->tm_year = ret*100 - TM_YEAR_BASE;
172 						split_year = 1;
173 					}
174 					break;
175 				case 'd': /* day of month */
176 				case 'e':
177 					ret = str2int(&s, 2);
178 					if (ret < 1 || ret > 31) { /* must be in [01,31] */
179 						return NULL;
180 					}
181 					tm->tm_mday = ret;
182 					break;
183 				case 'D': /* equivalent to %m/%d/%y */
184 					if (!(s = nsd_strptime(s, "%m/%d/%y", tm))) {
185 						return NULL;
186 					}
187 					break;
188 				case 'H': /* hour */
189 					ret = str2int(&s, 2);
190 					if (ret < 0 || ret > 23) { /* must be in [00,23] */
191 						return NULL;
192 					}
193 					tm->tm_hour = ret;
194 					break;
195 				case 'I': /* 12hr clock hour */
196 					ret = str2int(&s, 2);
197 					if (ret < 1 || ret > 12) { /* must be in [01,12] */
198 						return NULL;
199 					}
200 					if (ret == 12) /* actually [0,11] */
201 						ret = 0;
202 					tm->tm_hour = ret;
203 					break;
204 				case 'j': /* day of year */
205 					ret = str2int(&s, 2);
206 					if (ret < 1 || ret > 366) { /* must be in [001,366] */
207 						return NULL;
208 					}
209 					tm->tm_yday = ret;
210 					break;
211 				case 'm': /* month */
212 					ret = str2int(&s, 2);
213 					if (ret < 1 || ret > 12) { /* must be in [01,12] */
214 						return NULL;
215 					}
216 					/* months go from 0-11 */
217 					tm->tm_mon = (ret-1);
218 					break;
219 				case 'M': /* minute */
220 					ret = str2int(&s, 2);
221 					if (ret < 0 || ret > 59) { /* must be in [00,59] */
222 						return NULL;
223 					}
224 					tm->tm_min = ret;
225 					break;
226 				case 'n': /* arbitrary whitespace */
227 				case 't':
228 					while (isspace((unsigned char)*s))
229 						s++;
230 					break;
231 				case 'p': /* am pm */
232 					ret = match_string(&s, ampm);
233 					if (ret < 0) {
234 						return NULL;
235 					}
236 					if (tm->tm_hour < 0 || tm->tm_hour > 11) { /* %I */
237 						return NULL;
238 					}
239 
240 					if (ret == 1) /* pm */
241 						tm->tm_hour += 12;
242 					break;
243 				case 'r': /* equivalent of %I:%M:%S %p */
244 					if (!(s = nsd_strptime(s, "%I:%M:%S %p", tm))) {
245 						return NULL;
246 					}
247 					break;
248 				case 'R': /* equivalent of %H:%M */
249 					if (!(s = nsd_strptime(s, "%H:%M", tm))) {
250 						return NULL;
251 					}
252 					break;
253 				case 'S': /* seconds */
254 					ret = str2int(&s, 2);
255 					/* 60 may occur for leap seconds */
256 					/* earlier 61 was also allowed */
257 					if (ret < 0 || ret > 60) { /* must be in [00,60] */
258 						return NULL;
259 					}
260 					tm->tm_sec = ret;
261 					break;
262 				case 'T': /* equivalent of %H:%M:%S */
263 					if (!(s = nsd_strptime(s, "%H:%M:%S", tm))) {
264 						return NULL;
265 					}
266 					break;
267 				case 'U': /* week number, with the first Sun of Jan being w1 */
268 					ret = str2int(&s, 2);
269 					if (ret < 0 || ret > 53) { /* must be in [00,53] */
270 						return NULL;
271 					}
272 					/** it is hard (and not necessary for nsd) to determine time
273 					  * data from week number.
274 					 **/
275 					break;
276 				case 'w': /* day of week */
277 					ret = str2int(&s, 1);
278 					if (ret < 0 || ret > 6) { /* must be in [0,6] */
279 						return NULL;
280 					}
281 					tm->tm_wday = ret;
282 					break;
283 				case 'W': /* week number, with the first Mon of Jan being w1 */
284 					ret = str2int(&s, 2);
285 					if (ret < 0 || ret > 53) { /* must be in [00,53] */
286 						return NULL;
287 					}
288 					/** it is hard (and not necessary for nsd) to determine time
289 					  * data from week number.
290 					 **/
291 					break;
292 				case 'x': /* date format */
293 					if (!(s = nsd_strptime(s, "%m/%d/%y", tm))) {
294 						return NULL;
295 					}
296 					break;
297 				case 'X': /* time format */
298 					if (!(s = nsd_strptime(s, "%H:%M:%S", tm))) {
299 						return NULL;
300 					}
301 					break;
302 				case 'y': /* last two digits of a year */
303 					ret = str2int(&s, 2);
304 					if (ret < 0 || ret > 99) { /* must be in [00,99] */
305 						return NULL;
306 					}
307 					if (split_year) {
308 						tm->tm_year = ((tm->tm_year/100) * 100) + ret;
309 					}
310 					else {
311 						split_year = 1;
312 
313 						/** currently:
314 						  * if in [0,68] we are in 21th century,
315 						  * if in [69,99] we are in 20th century.
316 						 **/
317 						if (ret < 69) /* 2000 */
318 							ret += 100;
319 						tm->tm_year = ret;
320 					}
321 					break;
322 				case 'Y': /* year */
323 					ret = str2int(&s, 4);
324 					if (ret < 0 || ret > 9999) {
325 						return NULL;
326 					}
327 					tm->tm_year = ret - TM_YEAR_BASE;
328 					break;
329 				case '\0':
330 				default: /* unsupported, cannot match format */
331 					return NULL;
332 					break;
333 			}
334 		}
335 		else { /* literal */
336 			/* if input cannot match format, return NULL */
337 			if (*s != c)
338 				return NULL;
339 			s++;
340 		}
341 
342 		format++;
343 	}
344 
345 	/* return pointer to remainder of s */
346 	return (char*) s;
347 }
348 
349 #endif /* STRPTIME_WORKS */
350