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Don't attempt to build debs for dapper (which is where the
[disorder] / lib / strptime.c
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RK
1/* strptime.c - partial strptime() reimplementation
2 *
3 * (c) 2008 Richard Kettlewell.
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30/* strptime() is here reimplemented because the FreeBSD (and older MacOS) one
31 * is broken and does not report errors properly. See TODO remarks below for
32 * some missing bits. */
33
34#include <ctype.h>
35#include <limits.h>
36#include <string.h>
37#include <langinfo.h>
38#include "strptime.h"
39
40struct locale_item_match {
41 nl_item key;
42 int value;
43};
44
45static const struct locale_item_match days[] = {
46 { DAY_1, 0 },
47 { DAY_2, 1 },
48 { DAY_3, 2 },
49 { DAY_4, 3 },
50 { DAY_5, 4 },
51 { DAY_6, 5 },
52 { DAY_7, 6 },
53 { ABDAY_1, 0 },
54 { ABDAY_2, 1 },
55 { ABDAY_3, 2 },
56 { ABDAY_4, 3 },
57 { ABDAY_5, 4 },
58 { ABDAY_6, 5 },
59 { ABDAY_7, 6 },
60 { -1, -1 }
61};
62
63static const struct locale_item_match months[] = {
64 { MON_1, 1 },
65 { MON_2, 2 },
66 { MON_3, 3 },
67 { MON_4, 4 },
68 { MON_5, 5 },
69 { MON_6, 6 },
70 { MON_7, 7 },
71 { MON_8, 8 },
72 { MON_9, 9 },
73 { MON_10, 10 },
74 { MON_11, 11 },
75 { MON_12, 12 },
76 { ABMON_1, 1 },
77 { ABMON_2, 2 },
78 { ABMON_3, 3 },
79 { ABMON_4, 4 },
80 { ABMON_5, 5 },
81 { ABMON_6, 6 },
82 { ABMON_7, 7 },
83 { ABMON_8, 8 },
84 { ABMON_9, 9 },
85 { ABMON_10, 10 },
86 { ABMON_11, 11 },
87 { ABMON_12, 12 },
88 { -1, -1 },
89};
90
91/** @brief Match a string
92 * @param buf Start of subject
93 * @param limit End of subject
94 * @param match String to match subject against
95 * @return True if match == [buf,limit) otherwise false
96 *
97 * The match is case-independent at least in ASCII.
98 */
99static int try_match(const char *buf,
100 const char *limit,
101 const char *match) {
102 /* TODO this won't work well outside single-byte encodings. A good bet is
103 * probably to convert to Unicode and then use utf32_casefold_compat() (or
104 * utf8_casefold_compat(); using compatibility matching will ensure missing
105 * accents and so on aren't a problem.
106 *
107 * en_GB and en_US will probably be in any reasonable encoding for them.
108 */
109 while(buf < limit && *match) {
110 if(tolower((unsigned char)*buf) != tolower((unsigned char)*match))
111 return 0;
112 ++buf;
113 ++match;
114 }
115 if(buf != limit || *match)
116 return 0;
117 return 1;
118}
119
120/** @brief Match from table of locale-specific strings
121 * @param buf Start of subject
122 * @param limit End of subject
123 * @param lim Table of locale lookups
124 * @return Looked up value or -1
125 *
126 * The match is case-independent.
127 */
128static int try_locale_match(const char *buf,
129 const char *limit,
130 const struct locale_item_match *lim) {
131 /* This is not very efficient! A (correct) built-in implementation will
132 * presumably have more direct access to locale information. */
133 while(lim->value != -1) {
134 if(try_match(buf, limit, nl_langinfo(lim->key)))
135 return lim->value;
136 ++lim;
137 }
138 return -1;
139}
140
141static int try_numeric_match(const char *buf,
142 const char *limit,
143 unsigned low,
144 unsigned high) {
145 unsigned n = 0;
146
147 while(buf < limit) {
148 int ch = (unsigned char)*buf++;
149 if(ch >= '0' && ch <= '9') {
150 if(n > INT_MAX / 10
151 || (n == INT_MAX / 10 && ch >= INT_MAX % 10 + '0'))
152 return -1; /* overflow */
153 n = 10 * n + ch - '0';
154 } else
155 return -1;
156 }
157 if(n < low || n > high)
158 return -1;
159 return (int)n;
160}
161
162static const char *my_strptime_guts(const char *buf,
163 const char *format,
164 struct tm *tm) {
165 int fc, mod, spec, next, value;
166 const char *limit;
167 /* nl_langinfo() is allowed to trash its last return value so we copy.
168 * (We're relying on it being usable at all in multithreaded environments
169 * though.) */
170#define USE_SUBFORMAT(ITEM, EITEM, DEF) do { \
171 const char *s; \
172 char subformat[128]; \
173 \
174 if(mod == 'E') { \
175 s = nl_langinfo(EITEM); \
176 if(!s || !*s) \
177 s = nl_langinfo(ITEM); \
178 } else \
179 s = nl_langinfo(ITEM); \
180 if(!s || !*s) \
181 s = DEF; \
182 if(strlen(s) >= sizeof subformat) \
183 s = DEF; \
184 strcpy(subformat, s); \
185 if(!(buf = my_strptime_guts(buf, subformat, tm))) \
186 return NULL; \
187} while(0)
188
189 while(*format) {
190 fc = (unsigned char)*format++;
191 if(fc == '%') {
192 /* Get the character defining the converstion specification */
193 spec = (unsigned char)*format++;
194 if(spec == 'E' || spec == 'O') {
195 /* Oops, there's a modifier first */
196 mod = spec;
197 spec = (unsigned char)*format++;
198 } else
199 mod = 0;
200 if(!spec)
201 return NULL; /* format string broken! */
202 /* See what the next directive is. The specification is written in terms
203 * of stopping the match at a character that matches the next directive.
204 * This implementation mirrors this aspect of the specification
205 * directly. */
206 next = (unsigned char)*format;
207 if(next) {
208 limit = buf;
209 if(isspace(next)) {
210 /* Next directive is whitespace, so bound the input string (at least)
211 * by that */
212 while(*limit && !isspace((unsigned char)*limit))
213 ++limit;
214 } else if(next == '%') {
215 /* Prohibited: "The application shall ensure that there is
216 * white-space or other non-alphanumeric characters between any two
217 * conversion specifications". In fact we let alphanumerics
218 * through.
219 *
220 * Forbidding even %% seems a bit harsh but is consistent with the
221 * specification as written.
222 */
223 return NULL;
224 } else {
225 /* Next directive is a specific character, so bound the input string
226 * (at least) by that. This will work badly in the face of multibyte
227 * characters, but then the spec is vague about what kind of string
228 * we're dealing with anyway so you probably couldn't safely use them
229 * in the format string at least in any case. */
230 while(*limit && *limit != next)
231 ++limit;
232 }
233 } else
234 limit = buf + strlen(buf);
235 switch(spec) {
236 case 'A': case 'a': /* day name (abbrev or full) */
237 if((value = try_locale_match(buf, limit, days)) == -1)
238 return NULL;
239 tm->tm_wday = value;
240 break;
241 case 'B': case 'b': case 'h': /* month name (abbrev or full) */
242 if((value = try_locale_match(buf, limit, months)) == -1)
243 return NULL;
244 tm->tm_mon = value - 1;
245 break;
246 case 'c': /* locale date+time */
247 USE_SUBFORMAT(D_T_FMT, ERA_D_T_FMT, "%a %b %e %H:%M:%S %Y");
248 break;
249 case 'C': /* century number 0-99 */
250 /* TODO */
251 return NULL;
252 case 'd': case 'e': /* day of month 1-31 */
253 if((value = try_numeric_match(buf, limit, 1, 31)) == -1)
254 return NULL;
255 tm->tm_mday = value;
256 break;
257 case 'D': /* == "%m / %d / %y" */
258 if(!(buf = my_strptime_guts(buf, "%m / %d / %y", tm)))
259 return NULL;
260 break;
261 case 'H': /* hour 0-23 */
262 if((value = try_numeric_match(buf, limit, 0, 23)) == -1)
263 return NULL;
264 tm->tm_hour = value;
265 break;
266 case 'I': /* hour 1-12 */
267 /* TODO */
268 return NULL;
269 case 'j': /* day 1-366 */
270 if((value = try_numeric_match(buf, limit, 1, 366)) == -1)
271 return NULL;
272 tm->tm_yday = value - 1;
273 return NULL;
274 case 'm': /* month 1-12 */
275 if((value = try_numeric_match(buf, limit, 1, 12)) == -1)
276 return NULL;
277 tm->tm_mon = value - 1;
278 break;
279 case 'M': /* minute 0-59 */
280 if((value = try_numeric_match(buf, limit, 0, 59)) == -1)
281 return NULL;
282 tm->tm_min = value;
283 break;
284 case 'n': case 't': /* any whitespace */
285 goto matchwhitespace;
286 case 'p': /* locale am/pm */
287 /* TODO */
288 return NULL;
289 case 'r': /* == "%I : %M : %S %p" */
290 /* TODO actually this is locale-dependent; and we don't implement %I
291 * anyway, so it's not going to work even as it stands. */
292 if(!(buf = my_strptime_guts(buf, "%I : %M : %S %p", tm)))
293 return NULL;
294 break;
295 case 'R': /* == "%H : %M" */
296 if(!(buf = my_strptime_guts(buf, "%H : %M", tm)))
297 return NULL;
298 break;
299 case 'S': /* seconds 0-60 */
300 if((value = try_numeric_match(buf, limit, 0, 60)) == -1)
301 return NULL;
302 tm->tm_sec = value;
303 break;
304 case 'U': /* week number from Sunday 0-53 */
305 /* TODO */
306 return NULL;
307 case 'w': /* day number 0-6 from Sunday */
308 if((value = try_numeric_match(buf, limit, 0, 6)) == -1)
309 return NULL;
310 tm->tm_wday = value;
311 break;
312 case 'W': /* week number from Monday 0-53 */
313 /* TODO */
314 return NULL;
315 case 'x': /* locale date format */
316 USE_SUBFORMAT(D_FMT, ERA_D_FMT, "%m/%d/%y");
317 break;
318 case 'X': /* locale time format */
319 USE_SUBFORMAT(T_FMT, ERA_T_FMT, "%H:%M:%S");
320 break;
321 case 'y': /* year mod 100 */
322 if((value = try_numeric_match(buf, limit, 0, INT_MAX)) == -1)
323 return NULL;
324 if(value >= 0 && value <= 68)
325 value = 2000 + value;
326 else if(value >= 69 && value <= 99)
327 value = 1900 + value;
328 tm->tm_year = value - 1900;
329 break;
330 case 'Y': /* year */
331 if((value = try_numeric_match(buf, limit, 1, INT_MAX)) == -1)
332 return NULL;
333 tm->tm_year = value - 1900;
334 break;
335 case '%':
336 goto matchself;
337 default:
338 /* The spec is a bit vague about what to do with invalid format
339 * strings. We return NULL immediately and hope someone will
340 * notice. */
341 return NULL;
342 }
343 buf = limit;
344 } else if(isspace(fc)) {
345 matchwhitespace:
346 /* Any format whitespace matches any number of input whitespace
347 * characters. The directive can formally contain more than one
348 * whitespace character; for the second and subsequent ones we'll match 0
349 * characters from the input. */
350 while(isspace((unsigned char)*buf))
351 ++buf;
352 } else {
353 matchself:
354 /* Non-% non-whitespace characters must match themselves exactly */
355 if(fc != (unsigned char)*buf++)
356 return NULL;
357 }
358 }
359 /* When we run out of format string we return a pointer to the rest of the
360 * input. */
361 return buf;
362}
363
364/** @brief Reimplementation of strptime()
365 * @param buf Input buffer
366 * @param format Format string
367 * @param tm Where to put result
368 * @return Pointer to first unparsed input character, or NULL on error
369 *
370 * Based on <a
371 * href="http://www.opengroup.org/onlinepubs/009695399/functions/strptime.html">http://www.opengroup.org/onlinepubs/009695399/functions/strptime.html</a>.
372 */
373char *my_strptime(const char *buf,
374 const char *format,
375 struct tm *tm) {
376 /* Whether to overwrite or update is unspecified (rather bizarrely). This
377 * implementation does not overwrites, as xgetdate() depends on this
378 * behavior. */
379
380 if(!(buf = my_strptime_guts(buf, format, tm)))
381 return NULL;
382 /* TODO various things we could/should do:
383 * - infer day/month from %j+year
384 * - infer day/month from %U/%W+%w/%a+year
385 * - infer hour from %p+%I
386 * - fill wday/yday from other fields
387 */
388 return (char *)buf;
389}
390
391/*
392Local Variables:
393c-basic-offset:2
394comment-column:40
395fill-column:79
396indent-tabs-mode:nil
397End:
398*/