2 * Copyright (c) 1987, 1989 Regents of the University of California.
5 * This code is derived from software contributed to Berkeley by
6 * Arthur David Olson of the National Cancer Institute.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 /*static char *sccsid = "from: @(#)ctime.c 5.26 (Berkeley) 2/23/91";*/
39 * This implementation of mktime is lifted straight from the NetBSD (BSD 4.4)
40 * version. I modified it slightly to divorce it from the internals of the
41 * ctime library. Thus this version can't use details of the internal
42 * timezone state file to figure out strange unnormalized struct tm values,
43 * as might result from someone doing date math on the tm struct then passing
46 * It just does as well as it can at normalizing the tm input, then does a
47 * binary search of the time space using the system's localtime() function.
49 * The original binary search was defective in that it didn't consider the
50 * setting of tm_isdst when comparing tm values, causing the search to be
51 * flubbed for times near the dst/standard time changeover. The original
52 * code seems to make up for this by grubbing through the timezone info
53 * whenever the binary search barfed. Since I don't have that luxury in
54 * portable code, I have to take care of tm_isdst in the comparison routine.
55 * This requires knowing how many minutes offset dst is from standard time.
57 * So, if you live somewhere in the world where dst is not 60 minutes offset,
58 * and your vendor doesn't supply mktime(), you'll have to edit this variable
59 * by hand. Sorry about that.
63 #include "ntp_machine.h"
65 #if !defined(HAVE_MKTIME) || ( !defined(HAVE_TIMEGM) && defined(WANT_TIMEGM) )
67 #if SIZEOF_TIME_T >= 8
68 #error libntp supplied mktime()/timegm() do not support 64-bit time_t
78 /* some constants from tzfile.h */
80 #define MINSPERHOUR 60
81 #define HOURSPERDAY 24
83 #define DAYSPERNYEAR 365
84 #define DAYSPERLYEAR 366
85 #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
86 #define SECSPERDAY ((long) SECSPERHOUR * HOURSPERDAY)
87 #define MONSPERYEAR 12
88 #define TM_YEAR_BASE 1900
89 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
91 static int mon_lengths[2][MONSPERYEAR] = {
92 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
93 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
96 static int year_lengths[2] = {
97 DAYSPERNYEAR, DAYSPERLYEAR
101 ** Adapted from code provided by Robert Elz, who writes:
102 ** The "best" way to do mktime I think is based on an idea of Bob
103 ** Kridle's (so its said...) from a long time ago. (mtxinu!kridle now).
104 ** It does a binary search of the time_t space. Since time_t's are
105 ** just 32 bits, its a max of 32 iterations (even at 64 bits it
106 ** would still be very reasonable).
111 #endif /* !defined WRONG */
120 if (*unitsptr >= base) {
121 *tensptr += *unitsptr / base;
123 } else if (*unitsptr < 0) {
127 *tensptr -= 1 + (-*unitsptr) / base;
128 *unitsptr = base - (-*unitsptr) % base;
139 static struct tm tmbuf;
143 tmbuf.tm_min += DSTMINUTES;
144 normalize(&tmbuf.tm_hour, &tmbuf.tm_min, MINSPERHOUR);
150 register struct tm * atmp,
151 register struct tm * btmp
156 /* compare down to the same day */
158 if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
159 (result = (atmp->tm_mon - btmp->tm_mon)) == 0)
160 result = (atmp->tm_mday - btmp->tm_mday);
165 /* get rid of one-sided dst bias */
167 if(atmp->tm_isdst == 1 && !btmp->tm_isdst)
169 else if(btmp->tm_isdst == 1 && !atmp->tm_isdst)
172 /* compare the rest of the way */
174 if ((result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
175 (result = (atmp->tm_min - btmp->tm_min)) == 0)
176 result = atmp->tm_sec - btmp->tm_sec;
191 register int saved_seconds;
193 struct tm yourtm, mytm;
197 if (yourtm.tm_sec >= SECSPERMIN + 2 || yourtm.tm_sec < 0)
198 normalize(&yourtm.tm_min, &yourtm.tm_sec, SECSPERMIN);
199 normalize(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR);
200 normalize(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY);
201 normalize(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR);
202 while (yourtm.tm_mday <= 0) {
205 year_lengths[isleap(yourtm.tm_year + TM_YEAR_BASE)];
208 i = mon_lengths[isleap(yourtm.tm_year +
209 TM_YEAR_BASE)][yourtm.tm_mon];
210 if (yourtm.tm_mday <= i)
213 if (++yourtm.tm_mon >= MONSPERYEAR) {
218 saved_seconds = yourtm.tm_sec;
221 ** Calculate the number of magnitude bits in a time_t
222 ** (this works regardless of whether time_t is
223 ** signed or unsigned, though lint complains if unsigned).
225 for (bits = 0, t = 1; t > 0; ++bits, t <<= 1)
228 ** If time_t is signed, then 0 is the median value,
229 ** if time_t is unsigned, then 1 << bits is median.
231 t = (t < 0) ? 0 : ((time_t) 1 << bits);
234 mytm = *localtime(&t);
237 dir = tmcomp(&mytm, &yourtm);
244 t -= (time_t) 1 << bits;
245 else t += (time_t) 1 << bits;
248 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
255 *tmp = *localtime(&t);
263 #endif /* !HAVE_MKTIME || !HAVE_TIMEGM */
274 if (tmp->tm_isdst > 1)
276 t = time2(tmp, &okay, 1);
277 if (okay || tmp->tm_isdst < 0)
290 #endif /* !HAVE_MKTIME */
303 t = time2(tmp, &okay, 0);
304 if (okay || tmp->tm_isdst < 0)
309 #endif /* !HAVE_TIMEGM */
310 #endif /* WANT_TIMEGM */