1/*  $OpenBSD: strptime.c,v 1.11 2005/08/08 08:05:38 espie Exp $ */
2/*  $NetBSD: strptime.c,v 1.12 1998/01/20 21:39:40 mycroft Exp $    */
3
4/*-
5 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code was contributed to The NetBSD Foundation by Klaus Klein.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *        This product includes software developed by the NetBSD
21 *        Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39//#include <sys/localedef.h>
40#include <ctype.h>
41#include <locale.h>
42#include <string.h>
43#include <time.h>
44#include "tzfile.h"
45
46static const struct {
47    const char *abday[7];
48    const char *day[7];
49    const char *abmon[12];
50    const char *mon[12];
51    const char *am_pm[2];
52    const char *d_t_fmt;
53    const char *d_fmt;
54    const char *t_fmt;
55    const char *t_fmt_ampm;
56} _DefaultTimeLocale = {
57    {
58        "Sun","Mon","Tue","Wed","Thu","Fri","Sat",
59    },
60    {
61        "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
62        "Friday", "Saturday"
63    },
64    {
65        "Jan", "Feb", "Mar", "Apr", "May", "Jun",
66        "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
67    },
68    {
69        "January", "February", "March", "April", "May", "June", "July",
70        "August", "September", "October", "November", "December"
71    },
72    {
73        "AM", "PM"
74    },
75    "%a %b %d %H:%M:%S %Y",
76    "%m/%d/%y",
77    "%H:%M:%S",
78    "%I:%M:%S %p"
79};
80
81#define _ctloc(x) (_DefaultTimeLocale.x)
82
83/*
84 * We do not implement alternate representations. However, we always
85 * check whether a given modifier is allowed for a certain conversion.
86 */
87#define _ALT_E          0x01
88#define _ALT_O          0x02
89#define _LEGAL_ALT(x)       { if (alt_format & ~(x)) return (0); }
90
91
92struct century_relyear {
93    int century;
94    int relyear;
95};
96static  int _conv_num(const unsigned char **, int *, int, int);
97static  unsigned char *_strptime(const unsigned char *, const char *, struct tm *,
98        struct century_relyear *);
99
100
101char *
102strptime(const char *buf, const char *fmt, struct tm *tm)
103{
104    struct century_relyear cr;
105    cr.century = TM_YEAR_BASE;
106    cr.relyear = -1;
107    return (char*)(_strptime((const unsigned char*)buf, fmt, tm, &cr));
108}
109
110static unsigned char *
111_strptime(const unsigned char *buf, const char *fmt, struct tm *tm, struct century_relyear *cr)
112{
113    unsigned char c;
114    const unsigned char *bp;
115    size_t len = 0;
116    int alt_format, i;
117
118    bp = (unsigned char *)buf;
119    while ((c = *fmt) != '\0') {
120        /* Clear `alternate' modifier prior to new conversion. */
121        alt_format = 0;
122
123        /* Eat up white-space. */
124        if (isspace(c)) {
125            while (isspace(*bp))
126                bp++;
127
128            fmt++;
129            continue;
130        }
131
132        if ((c = *fmt++) != '%')
133            goto literal;
134
135
136again:      switch (c = *fmt++) {
137        case '%':   /* "%%" is converted to "%". */
138literal:
139        if (c != *bp++)
140            return (NULL);
141
142        break;
143
144        /*
145         * "Alternative" modifiers. Just set the appropriate flag
146         * and start over again.
147         */
148        case 'E':   /* "%E?" alternative conversion modifier. */
149            _LEGAL_ALT(0);
150            alt_format |= _ALT_E;
151            goto again;
152
153        case 'O':   /* "%O?" alternative conversion modifier. */
154            _LEGAL_ALT(0);
155            alt_format |= _ALT_O;
156            goto again;
157
158        /*
159         * "Complex" conversion rules, implemented through recursion.
160         */
161        case 'c':   /* Date and time, using the locale's format. */
162            _LEGAL_ALT(_ALT_E);
163            if (!(bp = _strptime(bp, _ctloc(d_t_fmt), tm, cr)))
164                return (NULL);
165            break;
166
167        case 'D':   /* The date as "%m/%d/%y". */
168            _LEGAL_ALT(0);
169            if (!(bp = _strptime(bp, "%m/%d/%y", tm, cr)))
170                return (NULL);
171            break;
172
173        case 'R':   /* The time as "%H:%M". */
174            _LEGAL_ALT(0);
175            if (!(bp = _strptime(bp, "%H:%M", tm, cr)))
176                return (NULL);
177            break;
178
179        case 'r':   /* The time as "%I:%M:%S %p". */
180            _LEGAL_ALT(0);
181            if (!(bp = _strptime(bp, "%I:%M:%S %p", tm, cr)))
182                return (NULL);
183            break;
184
185        case 'T':   /* The time as "%H:%M:%S". */
186            _LEGAL_ALT(0);
187            if (!(bp = _strptime(bp, "%H:%M:%S", tm, cr)))
188                return (NULL);
189            break;
190
191        case 'X':   /* The time, using the locale's format. */
192            _LEGAL_ALT(_ALT_E);
193            if (!(bp = _strptime(bp, _ctloc(t_fmt), tm, cr)))
194                return (NULL);
195            break;
196
197        case 'x':   /* The date, using the locale's format. */
198            _LEGAL_ALT(_ALT_E);
199            if (!(bp = _strptime(bp, _ctloc(d_fmt), tm, cr)))
200                return (NULL);
201            break;
202
203        /*
204         * "Elementary" conversion rules.
205         */
206        case 'A':   /* The day of week, using the locale's form. */
207        case 'a':
208            _LEGAL_ALT(0);
209            for (i = 0; i < 7; i++) {
210                /* Full name. */
211                len = strlen(_ctloc(day[i]));
212                if (strncasecmp(_ctloc(day[i]), (const char*)bp, len) == 0)
213                    break;
214
215                /* Abbreviated name. */
216                len = strlen(_ctloc(abday[i]));
217                if (strncasecmp(_ctloc(abday[i]), (const char*)bp, len) == 0)
218                    break;
219            }
220
221            /* Nothing matched. */
222            if (i == 7)
223                return (NULL);
224
225            tm->tm_wday = i;
226            bp += len;
227            break;
228
229        case 'B':   /* The month, using the locale's form. */
230        case 'b':
231        case 'h':
232            _LEGAL_ALT(0);
233            for (i = 0; i < 12; i++) {
234                /* Full name. */
235                len = strlen(_ctloc(mon[i]));
236                if (strncasecmp(_ctloc(mon[i]), (const char*)bp, len) == 0)
237                    break;
238
239                /* Abbreviated name. */
240                len = strlen(_ctloc(abmon[i]));
241                if (strncasecmp(_ctloc(abmon[i]), (const char*)bp, len) == 0)
242                    break;
243            }
244
245            /* Nothing matched. */
246            if (i == 12)
247                return (NULL);
248
249            tm->tm_mon = i;
250            bp += len;
251            break;
252
253        case 'C':   /* The century number. */
254            _LEGAL_ALT(_ALT_E);
255            if (!(_conv_num(&bp, &i, 0, 99)))
256                return (NULL);
257
258            cr->century = i * 100;
259            break;
260
261        case 'd':   /* The day of month. */
262        case 'e':
263            _LEGAL_ALT(_ALT_O);
264            if (!(_conv_num(&bp, &tm->tm_mday, 1, 31)))
265                return (NULL);
266            break;
267
268        case 'k':   /* The hour (24-hour clock representation). */
269            _LEGAL_ALT(0);
270            /* FALLTHROUGH */
271        case 'H':
272            _LEGAL_ALT(_ALT_O);
273            if (!(_conv_num(&bp, &tm->tm_hour, 0, 23)))
274                return (NULL);
275            break;
276
277        case 'l':   /* The hour (12-hour clock representation). */
278            _LEGAL_ALT(0);
279            /* FALLTHROUGH */
280        case 'I':
281            _LEGAL_ALT(_ALT_O);
282            if (!(_conv_num(&bp, &tm->tm_hour, 1, 12)))
283                return (NULL);
284            break;
285
286        case 'j':   /* The day of year. */
287            _LEGAL_ALT(0);
288            if (!(_conv_num(&bp, &tm->tm_yday, 1, 366)))
289                return (NULL);
290            tm->tm_yday--;
291            break;
292
293        case 'M':   /* The minute. */
294            _LEGAL_ALT(_ALT_O);
295            if (!(_conv_num(&bp, &tm->tm_min, 0, 59)))
296                return (NULL);
297            break;
298
299        case 'm':   /* The month. */
300            _LEGAL_ALT(_ALT_O);
301            if (!(_conv_num(&bp, &tm->tm_mon, 1, 12)))
302                return (NULL);
303            tm->tm_mon--;
304            break;
305
306        case 'p':   /* The locale's equivalent of AM/PM. */
307            _LEGAL_ALT(0);
308            /* AM? */
309            len = strlen(_ctloc(am_pm[0]));
310            if (strncasecmp(_ctloc(am_pm[0]), (const char*)bp, len) == 0) {
311                if (tm->tm_hour > 12)   /* i.e., 13:00 AM ?! */
312                    return (NULL);
313                else if (tm->tm_hour == 12)
314                    tm->tm_hour = 0;
315
316                bp += len;
317                break;
318            }
319            /* PM? */
320            len = strlen(_ctloc(am_pm[1]));
321            if (strncasecmp(_ctloc(am_pm[1]), (const char*)bp, len) == 0) {
322                if (tm->tm_hour > 12)   /* i.e., 13:00 PM ?! */
323                    return (NULL);
324                else if (tm->tm_hour < 12)
325                    tm->tm_hour += 12;
326
327                bp += len;
328                break;
329            }
330
331            /* Nothing matched. */
332            return (NULL);
333
334        case 'S':   /* The seconds. */
335            _LEGAL_ALT(_ALT_O);
336            if (!(_conv_num(&bp, &tm->tm_sec, 0, 61)))
337                return (NULL);
338            break;
339
340        case 'U':   /* The week of year, beginning on sunday. */
341        case 'W':   /* The week of year, beginning on monday. */
342            _LEGAL_ALT(_ALT_O);
343            /*
344             * XXX This is bogus, as we can not assume any valid
345             * information present in the tm structure at this
346             * point to calculate a real value, so just check the
347             * range for now.
348             */
349             if (!(_conv_num(&bp, &i, 0, 53)))
350                return (NULL);
351             break;
352
353        case 'w':   /* The day of week, beginning on sunday. */
354            _LEGAL_ALT(_ALT_O);
355            if (!(_conv_num(&bp, &tm->tm_wday, 0, 6)))
356                return (NULL);
357            break;
358
359        case 'Y':   /* The year. */
360            _LEGAL_ALT(_ALT_E);
361            if (!(_conv_num(&bp, &i, 0, 9999)))
362                return (NULL);
363
364            cr->relyear = -1;
365            tm->tm_year = i - TM_YEAR_BASE;
366            break;
367
368        case 'y':   /* The year within the century (2 digits). */
369            _LEGAL_ALT(_ALT_E | _ALT_O);
370            if (!(_conv_num(&bp, &cr->relyear, 0, 99)))
371                return (NULL);
372            break;
373
374        /*
375         * Miscellaneous conversions.
376         */
377        case 'n':   /* Any kind of white-space. */
378        case 't':
379            _LEGAL_ALT(0);
380            while (isspace(*bp))
381                bp++;
382            break;
383
384
385        default:    /* Unknown/unsupported conversion. */
386            return (NULL);
387        }
388
389
390    }
391
392    /*
393     * We need to evaluate the two digit year spec (%y)
394     * last as we can get a century spec (%C) at any time.
395     */
396    if (cr->relyear != -1) {
397        if (cr->century == TM_YEAR_BASE) {
398            if (cr->relyear <= 68)
399                tm->tm_year = cr->relyear + 2000 - TM_YEAR_BASE;
400            else
401                tm->tm_year = cr->relyear + 1900 - TM_YEAR_BASE;
402        } else {
403            tm->tm_year = cr->relyear + cr->century - TM_YEAR_BASE;
404        }
405    }
406
407    return (unsigned char*)bp;
408}
409
410
411static int
412_conv_num(const unsigned char **buf, int *dest, int llim, int ulim)
413{
414    int result = 0;
415    int rulim = ulim;
416
417    if (**buf < '0' || **buf > '9')
418        return (0);
419
420    /* we use rulim to break out of the loop when we run out of digits */
421    do {
422        result *= 10;
423        result += *(*buf)++ - '0';
424        rulim /= 10;
425    } while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
426
427    if (result < llim || result > ulim)
428        return (0);
429
430    *dest = result;
431    return (1);
432}
433