1 /* 2 * Copyright (c) 1987, 1989 Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Arthur David Olson of the National Cancer Institute. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 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. 23 * 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 34 * SUCH DAMAGE. */ 35 36 /*static char *sccsid = "from: @(#)ctime.c 5.26 (Berkeley) 2/23/91";*/ 37 /*static char *rcsid = "mktime.c,v 1.1.1.3 1998/11/15 19:23:34 kardel RELEASE_19990228_A";*/ 38 39 /* 40 * This implementation of mktime is lifted straight from the NetBSD (BSD 4.4) 41 * version. I modified it slightly to divorce it from the internals of the 42 * ctime library. Thus this version can't use details of the internal 43 * timezone state file to figure out strange unnormalized struct tm values, 44 * as might result from someone doing date math on the tm struct then passing 45 * it to mktime. 46 * 47 * It just does as well as it can at normalizing the tm input, then does a 48 * binary search of the time space using the system's localtime() function. 49 * 50 * The original binary search was defective in that it didn't consider the 51 * setting of tm_isdst when comparing tm values, causing the search to be 52 * flubbed for times near the dst/standard time changeover. The original 53 * code seems to make up for this by grubbing through the timezone info 54 * whenever the binary search barfed. Since I don't have that luxury in 55 * portable code, I have to take care of tm_isdst in the comparison routine. 56 * This requires knowing how many minutes offset dst is from standard time. 57 * 58 * So, if you live somewhere in the world where dst is not 60 minutes offset, 59 * and your vendor doesn't supply mktime(), you'll have to edit this variable 60 * by hand. Sorry about that. 61 */ 62 63 #include "ntp_machine.h" 64 65 #if !HAVE_MKTIME || !HAVE_TIMEGM 66 67 #ifndef DSTMINUTES 68 #define DSTMINUTES 60 69 #endif 70 71 #define FALSE 0 72 #define TRUE 1 73 74 /* some constants from tzfile.h */ 75 #define SECSPERMIN 60 76 #define MINSPERHOUR 60 77 #define HOURSPERDAY 24 78 #define DAYSPERWEEK 7 79 #define DAYSPERNYEAR 365 80 #define DAYSPERLYEAR 366 81 #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR) 82 #define SECSPERDAY ((long) SECSPERHOUR * HOURSPERDAY) 83 #define MONSPERYEAR 12 84 #define TM_YEAR_BASE 1900 85 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0) 86 87 extern time_t time P((time_t *)); 88 89 static int mon_lengths[2][MONSPERYEAR] = { 90 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, 91 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } 92 }; 93 94 static int year_lengths[2] = { 95 DAYSPERNYEAR, DAYSPERLYEAR 96 }; 97 98 /* 99 ** Adapted from code provided by Robert Elz, who writes: 100 ** The "best" way to do mktime I think is based on an idea of Bob 101 ** Kridle's (so its said...) from a long time ago. (mtxinu!kridle now). 102 ** It does a binary search of the time_t space. Since time_t's are 103 ** just 32 bits, its a max of 32 iterations (even at 64 bits it 104 ** would still be very reasonable). 105 */ 106 107 #ifndef WRONG 108 #define WRONG (-1) 109 #endif /* !defined WRONG */ 110 111 static void 112 normalize( 113 int * tensptr, 114 int * unitsptr, 115 int base 116 ) 117 { 118 if (*unitsptr >= base) { 119 *tensptr += *unitsptr / base; 120 *unitsptr %= base; 121 } else if (*unitsptr < 0) { 122 --*tensptr; 123 *unitsptr += base; 124 if (*unitsptr < 0) { 125 *tensptr -= 1 + (-*unitsptr) / base; 126 *unitsptr = base - (-*unitsptr) % base; 127 } 128 } 129 } 130 131 static struct tm * 132 mkdst( 133 struct tm * tmp 134 ) 135 { 136 /* jds */ 137 static struct tm tmbuf; 138 139 tmbuf = *tmp; 140 tmbuf.tm_isdst = 1; 141 tmbuf.tm_min += DSTMINUTES; 142 normalize(&tmbuf.tm_hour, &tmbuf.tm_min, MINSPERHOUR); 143 return &tmbuf; 144 } 145 146 static int 147 tmcomp( 148 register struct tm * atmp, 149 register struct tm * btmp 150 ) 151 { 152 register int result; 153 154 /* compare down to the same day */ 155 156 if ((result = (atmp->tm_year - btmp->tm_year)) == 0 && 157 (result = (atmp->tm_mon - btmp->tm_mon)) == 0) 158 result = (atmp->tm_mday - btmp->tm_mday); 159 160 if(result != 0) 161 return result; 162 163 /* get rid of one-sided dst bias */ 164 165 if(atmp->tm_isdst == 1 && !btmp->tm_isdst) 166 btmp = mkdst(btmp); 167 else if(btmp->tm_isdst == 1 && !atmp->tm_isdst) 168 atmp = mkdst(atmp); 169 170 /* compare the rest of the way */ 171 172 if ((result = (atmp->tm_hour - btmp->tm_hour)) == 0 && 173 (result = (atmp->tm_min - btmp->tm_min)) == 0) 174 result = atmp->tm_sec - btmp->tm_sec; 175 return result; 176 } 177 178 179 static time_t 180 time2( 181 struct tm * tmp, 182 int * okayp, 183 int usezn 184 ) 185 { 186 register int dir; 187 register int bits; 188 register int i; 189 register int saved_seconds; 190 time_t t; 191 struct tm yourtm, mytm; 192 193 *okayp = FALSE; 194 yourtm = *tmp; 195 if (yourtm.tm_sec >= SECSPERMIN + 2 || yourtm.tm_sec < 0) 196 normalize(&yourtm.tm_min, &yourtm.tm_sec, SECSPERMIN); 197 normalize(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR); 198 normalize(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY); 199 normalize(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR); 200 while (yourtm.tm_mday <= 0) { 201 --yourtm.tm_year; 202 yourtm.tm_mday += 203 year_lengths[isleap(yourtm.tm_year + TM_YEAR_BASE)]; 204 } 205 for ( ; ; ) { 206 i = mon_lengths[isleap(yourtm.tm_year + 207 TM_YEAR_BASE)][yourtm.tm_mon]; 208 if (yourtm.tm_mday <= i) 209 break; 210 yourtm.tm_mday -= i; 211 if (++yourtm.tm_mon >= MONSPERYEAR) { 212 yourtm.tm_mon = 0; 213 ++yourtm.tm_year; 214 } 215 } 216 saved_seconds = yourtm.tm_sec; 217 yourtm.tm_sec = 0; 218 /* 219 ** Calculate the number of magnitude bits in a time_t 220 ** (this works regardless of whether time_t is 221 ** signed or unsigned, though lint complains if unsigned). 222 */ 223 for (bits = 0, t = 1; t > 0; ++bits, t <<= 1) 224 ; 225 /* 226 ** If time_t is signed, then 0 is the median value, 227 ** if time_t is unsigned, then 1 << bits is median. 228 */ 229 t = (t < 0) ? 0 : ((time_t) 1 << bits); 230 for ( ; ; ) { 231 if (usezn) 232 mytm = *localtime(&t); 233 else 234 mytm = *gmtime(&t); 235 dir = tmcomp(&mytm, &yourtm); 236 if (dir != 0) { 237 if (bits-- < 0) 238 return WRONG; 239 if (bits < 0) 240 --t; 241 else if (dir > 0) 242 t -= (time_t) 1 << bits; 243 else t += (time_t) 1 << bits; 244 continue; 245 } 246 if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst) 247 break; 248 249 return WRONG; 250 } 251 t += saved_seconds; 252 if (usezn) 253 *tmp = *localtime(&t); 254 else 255 *tmp = *gmtime(&t); 256 *okayp = TRUE; 257 return t; 258 } 259 #else 260 int mktime_bs; 261 #endif /* !HAVE_MKTIME || !HAVE_TIMEGM */ 262 263 #if !HAVE_MKTIME 264 static time_t 265 time1( 266 struct tm * tmp 267 ) 268 { 269 register time_t t; 270 int okay; 271 272 if (tmp->tm_isdst > 1) 273 tmp->tm_isdst = 1; 274 t = time2(tmp, &okay, 1); 275 if (okay || tmp->tm_isdst < 0) 276 return t; 277 278 return WRONG; 279 } 280 281 time_t 282 mktime( 283 struct tm * tmp 284 ) 285 { 286 return time1(tmp); 287 } 288 #endif /* !HAVE_MKTIME */ 289 290 #if !HAVE_TIMEGM 291 time_t 292 timegm( 293 struct tm * tmp 294 ) 295 { 296 register time_t t; 297 int okay; 298 299 tmp->tm_isdst = 0; 300 t = time2(tmp, &okay, 0); 301 if (okay || tmp->tm_isdst < 0) 302 return t; 303 304 return WRONG; 305 } 306 #endif /* !HAVE_TIMEGM */ 307