1 /* 2 * Copyright 2009 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * Copyright (c) 1980 Regents of the University of California. 8 * All rights reserved. The Berkeley software License Agreement 9 * specifies the terms and conditions for redistribution. 10 */ 11 12 /* 13 * This localtime is a modified version of offtime from libc, which does not 14 * bother to figure out the time zone from the kernel, from environment 15 * variables, or from Unix files. 16 */ 17 18 #include <sys/types.h> 19 #include <sys/salib.h> 20 #include <tzfile.h> 21 #include <errno.h> 22 23 static int mon_lengths[2][MONS_PER_YEAR] = { 24 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31, 25 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 26 }; 27 28 static int year_lengths[2] = { 29 DAYS_PER_NYEAR, DAYS_PER_LYEAR 30 }; 31 32 struct tm * 33 localtime(const time_t *clock) 34 { 35 struct tm *tmp; 36 long days; 37 long rem; 38 int y; 39 int yleap; 40 int *ip; 41 static struct tm tm; 42 43 tmp = &tm; 44 days = *clock / SECS_PER_DAY; 45 rem = *clock % SECS_PER_DAY; 46 while (rem < 0) { 47 rem += SECS_PER_DAY; 48 --days; 49 } 50 while (rem >= SECS_PER_DAY) { 51 rem -= SECS_PER_DAY; 52 ++days; 53 } 54 tmp->tm_hour = (int)(rem / SECS_PER_HOUR); 55 rem = rem % SECS_PER_HOUR; 56 tmp->tm_min = (int)(rem / SECS_PER_MIN); 57 tmp->tm_sec = (int)(rem % SECS_PER_MIN); 58 tmp->tm_wday = (int)((EPOCH_WDAY + days) % DAYS_PER_WEEK); 59 if (tmp->tm_wday < 0) 60 tmp->tm_wday += DAYS_PER_WEEK; 61 y = EPOCH_YEAR; 62 if (days >= 0) { 63 for (;;) { 64 yleap = isleap(y); 65 if (days < (long)year_lengths[yleap]) 66 break; 67 if (++y > 9999) { 68 errno = EOVERFLOW; 69 return (NULL); 70 } 71 days = days - (long)year_lengths[yleap]; 72 } 73 } else { 74 do { 75 if (--y < 0) { 76 errno = EOVERFLOW; 77 return (NULL); 78 } 79 yleap = isleap(y); 80 days = days + (long)year_lengths[yleap]; 81 } while (days < 0); 82 } 83 tmp->tm_year = y - TM_YEAR_BASE; 84 tmp->tm_yday = (int)days; 85 ip = mon_lengths[yleap]; 86 for (tmp->tm_mon = 0; days >= (long)ip[tmp->tm_mon]; ++(tmp->tm_mon)) 87 days = days - (long)ip[tmp->tm_mon]; 88 tmp->tm_mday = (int)(days + 1); 89 tmp->tm_isdst = 0; 90 91 return (tmp); 92 } 93 94 /* 95 * So is ctime... 96 */ 97 98 /* 99 * This routine converts time as follows. 100 * The epoch is 0000 Jan 1 1970 GMT. 101 * The argument time is in seconds since then. 102 * The localtime(t) entry returns a pointer to an array 103 * containing 104 * seconds (0-59) 105 * minutes (0-59) 106 * hours (0-23) 107 * day of month (1-31) 108 * month (0-11) 109 * year-1970 110 * weekday (0-6, Sun is 0) 111 * day of the year 112 * daylight savings flag 113 * 114 * The routine corrects for daylight saving 115 * time and will work in any time zone provided 116 * "timezone" is adjusted to the difference between 117 * Greenwich and local standard time (measured in seconds). 118 * In places like Michigan "daylight" must 119 * be initialized to 0 to prevent the conversion 120 * to daylight time. 121 * There is a table which accounts for the peculiarities 122 * undergone by daylight time in 1974-1975. 123 * 124 * The routine does not work 125 * in Saudi Arabia which runs on Solar time. 126 * 127 * asctime(tvec) 128 * where tvec is produced by localtime 129 * returns a ptr to a character string 130 * that has the ascii time in the form 131 * Thu Jan 01 00:00:00 1970\n\0 132 * 01234567890123456789012345 133 * 0 1 2 134 * 135 * ctime(t) just calls localtime, then asctime. 136 * 137 * tzset() looks for an environment variable named 138 * TZ. 139 * If the variable is present, it will set the external 140 * variables "timezone", "altzone", "daylight", and "tzname" 141 * appropriately. It is called by localtime, and 142 * may also be called explicitly by the user. 143 */ 144 145 146 147 #define dysize(A) (((A)%4)? 365: 366) 148 #define CBUFSIZ 26 149 150 static char *ct_numb(); 151 152 /* 153 * POSIX.1c standard version of the function asctime_r. 154 * User gets it via static asctime_r from the header file. 155 */ 156 char * 157 __posix_asctime_r(const struct tm *t, char *cbuf) 158 { 159 const char *Date = "Day Mon 00 00:00:00 1900\n"; 160 const char *Day = "SunMonTueWedThuFriSat"; 161 const char *Month = "JanFebMarAprMayJunJulAugSepOctNovDec"; 162 const char *ncp; 163 const int *tp; 164 char *cp; 165 166 if (t == NULL) 167 return (NULL); 168 169 cp = cbuf; 170 for (ncp = Date; *cp++ = *ncp++; /* */) 171 ; 172 ncp = Day + (3*t->tm_wday); 173 cp = cbuf; 174 *cp++ = *ncp++; 175 *cp++ = *ncp++; 176 *cp++ = *ncp++; 177 cp++; 178 tp = &t->tm_mon; 179 ncp = Month + ((*tp) * 3); 180 *cp++ = *ncp++; 181 *cp++ = *ncp++; 182 *cp++ = *ncp++; 183 cp = ct_numb(cp, *--tp); 184 cp = ct_numb(cp, *--tp+100); 185 cp = ct_numb(cp, *--tp+100); 186 cp = ct_numb(cp, *--tp+100); 187 if (t->tm_year > 9999) { 188 errno = EOVERFLOW; 189 return (NULL); 190 } else { 191 uint_t hun = 19 + (t->tm_year / 100); 192 cp[1] = (hun / 10) + '0'; 193 cp[2] = (hun % 10) + '0'; 194 } 195 cp += 2; 196 cp = ct_numb(cp, t->tm_year+100); 197 return (cbuf); 198 } 199 200 /* 201 * POSIX.1c Draft-6 version of the function asctime_r. 202 * It was implemented by Solaris 2.3. 203 */ 204 char * 205 asctime_r(const struct tm *t, char *cbuf, int buflen) 206 { 207 if (buflen < CBUFSIZ) { 208 errno = ERANGE; 209 return (NULL); 210 } 211 return (__posix_asctime_r(t, cbuf)); 212 } 213 214 char * 215 ctime(const time_t *t) 216 { 217 return (asctime(localtime(t))); 218 } 219 220 221 char * 222 asctime(const struct tm *t) 223 { 224 static char cbuf[CBUFSIZ]; 225 226 return (asctime_r(t, cbuf, CBUFSIZ)); 227 } 228 229 230 static char * 231 ct_numb(char *cp, int n) 232 { 233 cp++; 234 if (n >= 10) 235 *cp++ = (n/10)%10 + '0'; 236 else 237 *cp++ = ' '; /* Pad with blanks */ 238 *cp++ = n%10 + '0'; 239 return (cp); 240 } 241