1/* Convert struct partime into time_t. */ 2 3/* Copyright 1992, 1993, 1994, 1995 Paul Eggert 4 Distributed under license by the Free Software Foundation, Inc. 5 6This file is part of RCS. 7 8RCS is free software; you can redistribute it and/or modify 9it under the terms of the GNU General Public License as published by 10the Free Software Foundation; either version 2, or (at your option) 11any later version. 12 13RCS is distributed in the hope that it will be useful, 14but WITHOUT ANY WARRANTY; without even the implied warranty of 15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16GNU General Public License for more details. 17 18You should have received a copy of the GNU General Public License 19along with RCS; see the file COPYING. 20If not, write to the Free Software Foundation, 2159 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 22 23Report problems and direct all questions to: 24 25 rcs-bugs@cs.purdue.edu 26 27*/ 28 29#if has_conf_h 30# include "conf.h" 31#else 32# ifdef __STDC__ 33# define P(x) x 34# else 35# define const 36# define P(x) () 37# endif 38# include <stdlib.h> 39# include <time.h> 40#endif 41 42#include "partime.h" 43#include "maketime.h" 44 45char const maketId[] 46 = "$FreeBSD: releng/11.0/gnu/usr.bin/rcs/lib/maketime.c 50472 1999-08-27 23:37:10Z peter $"; 47 48static int isleap P((int)); 49static int month_days P((struct tm const*)); 50static time_t maketime P((struct partime const*,time_t)); 51 52/* 53* For maximum portability, use only localtime and gmtime. 54* Make no assumptions about the time_t epoch or the range of time_t values. 55* Avoid mktime because it's not universal and because there's no easy, 56* portable way for mktime to yield the inverse of gmtime. 57*/ 58 59#define TM_YEAR_ORIGIN 1900 60 61 static int 62isleap(y) 63 int y; 64{ 65 return (y&3) == 0 && (y%100 != 0 || y%400 == 0); 66} 67 68static int const month_yday[] = { 69 /* days in year before start of months 0-12 */ 70 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 71}; 72 73/* Yield the number of days in TM's month. */ 74 static int 75month_days(tm) 76 struct tm const *tm; 77{ 78 int m = tm->tm_mon; 79 return month_yday[m+1] - month_yday[m] 80 + (m==1 && isleap(tm->tm_year + TM_YEAR_ORIGIN)); 81} 82 83/* 84* Convert UNIXTIME to struct tm form. 85* Use gmtime if available and if !LOCALZONE, localtime otherwise. 86*/ 87 struct tm * 88time2tm(unixtime, localzone) 89 time_t unixtime; 90 int localzone; 91{ 92 struct tm *tm; 93# if TZ_must_be_set 94 static char const *TZ; 95 if (!TZ && !(TZ = getenv("TZ"))) 96 faterror("The TZ environment variable is not set; please set it to your timezone"); 97# endif 98 if (localzone || !(tm = gmtime(&unixtime))) 99 tm = localtime(&unixtime); 100 return tm; 101} 102 103/* Yield A - B, measured in seconds. */ 104 time_t 105difftm(a, b) 106 struct tm const *a, *b; 107{ 108 int ay = a->tm_year + (TM_YEAR_ORIGIN - 1); 109 int by = b->tm_year + (TM_YEAR_ORIGIN - 1); 110 int difference_in_day_of_year = a->tm_yday - b->tm_yday; 111 int intervening_leap_days = ( 112 ((ay >> 2) - (by >> 2)) 113 - (ay/100 - by/100) 114 + ((ay/100 >> 2) - (by/100 >> 2)) 115 ); 116 time_t difference_in_years = ay - by; 117 time_t difference_in_days = ( 118 difference_in_years*365 119 + (intervening_leap_days + difference_in_day_of_year) 120 ); 121 return 122 ( 123 ( 124 24*difference_in_days 125 + (a->tm_hour - b->tm_hour) 126 )*60 + (a->tm_min - b->tm_min) 127 )*60 + (a->tm_sec - b->tm_sec); 128} 129 130/* 131* Adjust time T by adding SECONDS. SECONDS must be at most 24 hours' worth. 132* Adjust only T's year, mon, mday, hour, min and sec members; 133* plus adjust wday if it is defined. 134*/ 135 void 136adjzone(t, seconds) 137 register struct tm *t; 138 long seconds; 139{ 140 /* 141 * This code can be off by a second if SECONDS is not a multiple of 60, 142 * if T is local time, and if a leap second happens during this minute. 143 * But this bug has never occurred, and most likely will not ever occur. 144 * Liberia, the last country for which SECONDS % 60 was nonzero, 145 * switched to UTC in May 1972; the first leap second was in June 1972. 146 */ 147 int leap_second = t->tm_sec == 60; 148 long sec = seconds + (t->tm_sec - leap_second); 149 if (sec < 0) { 150 if ((t->tm_min -= (59-sec)/60) < 0) { 151 if ((t->tm_hour -= (59-t->tm_min)/60) < 0) { 152 t->tm_hour += 24; 153 if (TM_DEFINED(t->tm_wday) && --t->tm_wday < 0) 154 t->tm_wday = 6; 155 if (--t->tm_mday <= 0) { 156 if (--t->tm_mon < 0) { 157 --t->tm_year; 158 t->tm_mon = 11; 159 } 160 t->tm_mday = month_days(t); 161 } 162 } 163 t->tm_min += 24 * 60; 164 } 165 sec += 24L * 60 * 60; 166 } else 167 if (60 <= (t->tm_min += sec/60)) 168 if (24 <= (t->tm_hour += t->tm_min/60)) { 169 t->tm_hour -= 24; 170 if (TM_DEFINED(t->tm_wday) && ++t->tm_wday == 7) 171 t->tm_wday = 0; 172 if (month_days(t) < ++t->tm_mday) { 173 if (11 < ++t->tm_mon) { 174 ++t->tm_year; 175 t->tm_mon = 0; 176 } 177 t->tm_mday = 1; 178 } 179 } 180 t->tm_min %= 60; 181 t->tm_sec = (int) (sec%60) + leap_second; 182} 183 184/* 185* Convert TM to time_t, using localtime if LOCALZONE and gmtime otherwise. 186* Use only TM's year, mon, mday, hour, min, and sec members. 187* Ignore TM's old tm_yday and tm_wday, but fill in their correct values. 188* Yield -1 on failure (e.g. a member out of range). 189* Posix 1003.1-1990 doesn't allow leap seconds, but some implementations 190* have them anyway, so allow them if localtime/gmtime does. 191*/ 192 time_t 193tm2time(tm, localzone) 194 struct tm *tm; 195 int localzone; 196{ 197 /* Cache the most recent t,tm pairs; 1 for gmtime, 1 for localtime. */ 198 static time_t t_cache[2]; 199 static struct tm tm_cache[2]; 200 201 time_t d, gt; 202 struct tm const *gtm; 203 /* 204 * The maximum number of iterations should be enough to handle any 205 * combinations of leap seconds, time zone rule changes, and solar time. 206 * 4 is probably enough; we use a bigger number just to be safe. 207 */ 208 int remaining_tries = 8; 209 210 /* Avoid subscript errors. */ 211 if (12 <= (unsigned)tm->tm_mon) 212 return -1; 213 214 tm->tm_yday = month_yday[tm->tm_mon] + tm->tm_mday 215 - (tm->tm_mon<2 || ! isleap(tm->tm_year + TM_YEAR_ORIGIN)); 216 217 /* Make a first guess. */ 218 gt = t_cache[localzone]; 219 gtm = gt ? &tm_cache[localzone] : time2tm(gt,localzone); 220 221 /* Repeatedly use the error from the guess to improve the guess. */ 222 while ((d = difftm(tm, gtm)) != 0) { 223 if (--remaining_tries == 0) 224 return -1; 225 gt += d; 226 gtm = time2tm(gt,localzone); 227 } 228 t_cache[localzone] = gt; 229 tm_cache[localzone] = *gtm; 230 231 /* 232 * Check that the guess actually matches; 233 * overflow can cause difftm to yield 0 even on differing times, 234 * or tm may have members out of range (e.g. bad leap seconds). 235 */ 236 if ( (tm->tm_year ^ gtm->tm_year) 237 | (tm->tm_mon ^ gtm->tm_mon) 238 | (tm->tm_mday ^ gtm->tm_mday) 239 | (tm->tm_hour ^ gtm->tm_hour) 240 | (tm->tm_min ^ gtm->tm_min) 241 | (tm->tm_sec ^ gtm->tm_sec)) 242 return -1; 243 244 tm->tm_wday = gtm->tm_wday; 245 return gt; 246} 247 248/* 249* Check *PT and convert it to time_t. 250* If it is incompletely specified, use DEFAULT_TIME to fill it out. 251* Use localtime if PT->zone is the special value TM_LOCAL_ZONE. 252* Yield -1 on failure. 253* ISO 8601 day-of-year and week numbers are not yet supported. 254*/ 255 static time_t 256maketime(pt, default_time) 257 struct partime const *pt; 258 time_t default_time; 259{ 260 int localzone, wday; 261 struct tm tm; 262 struct tm *tm0 = 0; 263 time_t r; 264 265 tm0 = 0; /* Keep gcc -Wall happy. */ 266 localzone = pt->zone==TM_LOCAL_ZONE; 267 268 tm = pt->tm; 269 270 if (TM_DEFINED(pt->ymodulus) || !TM_DEFINED(tm.tm_year)) { 271 /* Get tm corresponding to current time. */ 272 tm0 = time2tm(default_time, localzone); 273 if (!localzone) 274 adjzone(tm0, pt->zone); 275 } 276 277 if (TM_DEFINED(pt->ymodulus)) 278 tm.tm_year += 279 (tm0->tm_year + TM_YEAR_ORIGIN)/pt->ymodulus * pt->ymodulus; 280 else if (!TM_DEFINED(tm.tm_year)) { 281 /* Set default year, month, day from current time. */ 282 tm.tm_year = tm0->tm_year + TM_YEAR_ORIGIN; 283 if (!TM_DEFINED(tm.tm_mon)) { 284 tm.tm_mon = tm0->tm_mon; 285 if (!TM_DEFINED(tm.tm_mday)) 286 tm.tm_mday = tm0->tm_mday; 287 } 288 } 289 290 /* Convert from partime year (Gregorian) to Posix year. */ 291 tm.tm_year -= TM_YEAR_ORIGIN; 292 293 /* Set remaining default fields to be their minimum values. */ 294 if (!TM_DEFINED(tm.tm_mon)) tm.tm_mon = 0; 295 if (!TM_DEFINED(tm.tm_mday)) tm.tm_mday = 1; 296 if (!TM_DEFINED(tm.tm_hour)) tm.tm_hour = 0; 297 if (!TM_DEFINED(tm.tm_min)) tm.tm_min = 0; 298 if (!TM_DEFINED(tm.tm_sec)) tm.tm_sec = 0; 299 300 if (!localzone) 301 adjzone(&tm, -pt->zone); 302 wday = tm.tm_wday; 303 304 /* Convert and fill in the rest of the tm. */ 305 r = tm2time(&tm, localzone); 306 307 /* Check weekday. */ 308 if (r != -1 && TM_DEFINED(wday) && wday != tm.tm_wday) 309 return -1; 310 311 return r; 312} 313 314/* Parse a free-format date in SOURCE, yielding a Unix format time. */ 315 time_t 316str2time(source, default_time, default_zone) 317 char const *source; 318 time_t default_time; 319 long default_zone; 320{ 321 struct partime pt; 322 323 if (*partime(source, &pt)) 324 return -1; 325 if (pt.zone == TM_UNDEFINED_ZONE) 326 pt.zone = default_zone; 327 return maketime(&pt, default_time); 328} 329 330#if TEST 331#include <stdio.h> 332 int 333main(argc, argv) int argc; char **argv; 334{ 335 time_t default_time = time((time_t *)0); 336 long default_zone = argv[1] ? atol(argv[1]) : 0; 337 char buf[1000]; 338 while (fgets(buf, 1000, stdin)) { 339 time_t t = str2time(buf, default_time, default_zone); 340 printf("%s", asctime(gmtime(&t))); 341 } 342 return 0; 343} 344#endif 345