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edge work

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SCCS-file: localtime.c
SCCS-SID: 7.19
This commit is contained in:
Arthur David Olson
1994-04-09 17:35:29 -04:00
committed by Paul Eggert
parent 60b30de45f
commit be668363f7
1 changed files with 63 additions and 22 deletions
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85
localtime.c
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@ -112,7 +112,9 @@ static void gmtsub P((const time_t * timep, long offset,
struct tm * tmp));
static void localsub P((const time_t * timep, long offset,
struct tm * tmp));
static void normalize P((int * tensptr, int * unitsptr, int base));
static int increment_overflow P((int * number, int delta));
static int normalize_overflow P((int * tensptr, int * unitsptr,
int base));
static void settzname P((void));
static time_t time1 P((struct tm * tmp, void (* funcp)(),
long offset));
@ -1145,8 +1147,20 @@ const time_t * const timep;
** Simplified normalize logic courtesy Paul Eggert (eggert@twinsun.com).
*/
static void
normalize(tensptr, unitsptr, base)
static int
increment_overflow(number, delta)
int * number;
int delta;
{
int number0;
number0 = *number;
*number += delta;
return (*number < number0) != (delta < 0);
}
static int
normalize_overflow(tensptr, unitsptr, base)
int * const tensptr;
int * const unitsptr;
const int base;
@ -1156,8 +1170,8 @@ const int base;
tensdelta = (*unitsptr >= 0) ?
(*unitsptr / base) :
(-1 - (-1 - *unitsptr) / base);
*tensptr += tensdelta;
*unitsptr -= tensdelta * base;
return increment_overflow(tensptr, tensdelta);
}
static int
@ -1194,41 +1208,65 @@ int * const okayp;
*okayp = FALSE;
yourtm = *tmp;
if (yourtm.tm_sec >= SECSPERMIN + 2 || yourtm.tm_sec < 0)
normalize(&yourtm.tm_min, &yourtm.tm_sec, SECSPERMIN);
normalize(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR);
normalize(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY);
normalize(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR);
if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
return WRONG;
if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
return WRONG;
if (normalize_overflow(&yourtm.tm_year, &yourtm.tm_mon, MONSPERYEAR))
return WRONG;
/*
** Turn yourtm.tm_year into an actual year number for now.
** It is converted back to an offset from TM_YEAR_BASE later.
*/
if (increment_overflow(&yourtm.tm_year, TM_YEAR_BASE))
return WRONG;
while (yourtm.tm_mday <= 0) {
--yourtm.tm_year;
yourtm.tm_mday +=
year_lengths[isleap(yourtm.tm_year + TM_YEAR_BASE)];
if (increment_overflow(&yourtm.tm_year, -1))
return WRONG;
yourtm.tm_mday += year_lengths[isleap(yourtm.tm_year)];
}
while (yourtm.tm_mday > DAYSPERLYEAR) {
yourtm.tm_mday -=
year_lengths[isleap(yourtm.tm_year + TM_YEAR_BASE)];
++yourtm.tm_year;
yourtm.tm_mday -= year_lengths[isleap(yourtm.tm_year)];
if (increment_overflow(&yourtm.tm_year, 1))
return WRONG;
}
for ( ; ; ) {
i = mon_lengths[isleap(yourtm.tm_year +
TM_YEAR_BASE)][yourtm.tm_mon];
i = mon_lengths[isleap(yourtm.tm_year)][yourtm.tm_mon];
if (yourtm.tm_mday <= i)
break;
yourtm.tm_mday -= i;
if (++yourtm.tm_mon >= MONSPERYEAR) {
yourtm.tm_mon = 0;
++yourtm.tm_year;
if (increment_overflow(&yourtm.tm_year, 1))
return WRONG;
}
}
saved_seconds = yourtm.tm_sec;
yourtm.tm_sec = 0;
if (increment_overflow(&yourtm.tm_year, -TM_YEAR_BASE))
return WRONG;
if (yourtm.tm_year + TM_YEAR_BASE < EPOCH_YEAR) {
/*
** We can't set tm_sec to 0, because that might push the
** time below the minimum representable time.
** Set tm_sec to 59 instead.
** This assumes that the minimum representable time is
** not in the same minute that a leap second was deleted from,
** which is a safer assumption than using 58 would be.
*/
if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
return WRONG;
saved_seconds = yourtm.tm_sec;
yourtm.tm_sec = SECSPERMIN - 1;
} else {
saved_seconds = yourtm.tm_sec;
yourtm.tm_sec = 0;
}
/*
** Calculate the number of magnitude bits in a time_t
** (this works regardless of whether time_t is
** signed or unsigned, though lint complains if unsigned).
*/
for (bits = 0, t = 1; t > 0; ++bits, t <<= 1)
;
continue;
/*
** If time_t is signed, then 0 is the median value,
** if time_t is unsigned, then 1 << bits is median.
@ -1288,7 +1326,10 @@ int * const okayp;
return WRONG;
}
label:
t += saved_seconds;
newt = t + saved_seconds;
if ((newt < t) != (saved_seconds < 0))
return WRONG;
t = newt;
(*funcp)(&t, offset, tmp);
*okayp = TRUE;
return t;