static int
normalize_overflow(int * const tensptr, int * const unitsptr, const int base)
{
int tensdelta;
tensdelta = (*unitsptr >= 0) ?
(*unitsptr / base) :
(-1 - (-1 - *unitsptr) / base);
*unitsptr -= tensdelta * base;
return increment_overflow(tensptr, tensdelta);
}
static struct pg_tm *
timesub(const pg_time_t *timep, long offset,
const struct state * sp, struct pg_tm * tmp)
{
const struct lsinfo *lp;
pg_time_t tdays;
int idays; /* unsigned would be so 2003 */
long rem;
int y;
const int *ip;
long corr;
int hit;
int i;
corr = 0;
hit = 0;
i = sp->leapcnt;
while (--i >= 0)
{
lp = &sp->lsis[i];
if (*timep >= lp->ls_trans)
{
if (*timep == lp->ls_trans)
{
hit = ((i == 0 && lp->ls_corr > 0) ||
lp->ls_corr > sp->lsis[i - 1].ls_corr);
if (hit)
while (i > 0 &&
sp->lsis[i].ls_trans ==
sp->lsis[i - 1].ls_trans + 1 &&
sp->lsis[i].ls_corr ==
sp->lsis[i - 1].ls_corr + 1)
{
++hit;
--i;
}
}
corr = lp->ls_corr;
break;
}
}
y = EPOCH_YEAR;
tdays = *timep / SECSPERDAY;
rem = *timep - tdays * SECSPERDAY;
while (tdays < 0 || tdays >= year_lengths[isleap(y)])
{
int newy;
pg_time_t tdelta;
int idelta;
int leapdays;
tdelta = tdays / DAYSPERLYEAR;
idelta = tdelta;
if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
return NULL;
if (idelta == 0)
idelta = (tdays < 0) ? -1 : 1;
newy = y;
if (increment_overflow(&newy, idelta))
return NULL;
leapdays = leaps_thru_end_of(newy - 1) -
leaps_thru_end_of(y - 1);
tdays -= ((pg_time_t) newy - y) * DAYSPERNYEAR;
tdays -= leapdays;
y = newy;
}
{
long seconds;
seconds = tdays * SECSPERDAY + 0.5;
tdays = seconds / SECSPERDAY;
rem += seconds - tdays * SECSPERDAY;
}
/*
* Given the range, we can now fearlessly cast...
*/
idays = tdays;
rem += offset - corr;
while (rem < 0)
{
rem += SECSPERDAY;
--idays;
}
while (rem >= SECSPERDAY)
{
rem -= SECSPERDAY;
++idays;
}
while (idays < 0)
{
if (increment_overflow(&y, -1))
return NULL;
idays += year_lengths[isleap(y)];
}
while (idays >= year_lengths[isleap(y)])
{
idays -= year_lengths[isleap(y)];
if (increment_overflow(&y, 1))
return NULL;
}
tmp->tm_year = y;
if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
return NULL;
tmp->tm_yday = idays;
/*
* The "extra" mods below avoid overflow problems.
*/
tmp->tm_wday = EPOCH_WDAY +
((y - EPOCH_YEAR) % DAYSPERWEEK) *
(DAYSPERNYEAR % DAYSPERWEEK) +
leaps_thru_end_of(y - 1) -
leaps_thru_end_of(EPOCH_YEAR - 1) +
idays;
tmp->tm_wday %= DAYSPERWEEK;
if (tmp->tm_wday < 0)
tmp->tm_wday += DAYSPERWEEK;
tmp->tm_hour = (int) (rem / SECSPERHOUR);
rem %= SECSPERHOUR;
tmp->tm_min = (int) (rem / SECSPERMIN);
/*
* A positive leap second requires a special representation. This uses
* "... ??:59:60" et seq.
*/
tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
ip = mon_lengths[isleap(y)];
for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
idays -= ip[tmp->tm_mon];
tmp->tm_mday = (int) (idays + 1);
tmp->tm_isdst = 0;
tmp->tm_gmtoff = offset;
return tmp;
}
static time_t
time2sub(struct tm * const tmp,
struct tm * (* const funcp)(const time_t *, long, struct tm *),
const long offset, int * const okayp, const int do_norm_secs)
{
const struct state * sp;
int dir;
int i, j;
int saved_seconds;
long li;
time_t lo;
time_t hi;
long y;
time_t newt;
time_t t;
struct tm yourtm, mytm;
*okayp = FALSE;
yourtm = *tmp;
if (do_norm_secs) {
if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
SECSPERMIN))
return WRONG;
}
if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
return WRONG;
if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
return WRONG;
y = yourtm.tm_year;
if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
return WRONG;
/*
** Turn y into an actual year number for now.
** It is converted back to an offset from TM_YEAR_BASE later.
*/
if (long_increment_overflow(&y, TM_YEAR_BASE))
return WRONG;
while (yourtm.tm_mday <= 0) {
if (long_increment_overflow(&y, -1))
return WRONG;
li = y + (1 < yourtm.tm_mon);
yourtm.tm_mday += year_lengths[isleap(li)];
}
while (yourtm.tm_mday > DAYSPERLYEAR) {
li = y + (1 < yourtm.tm_mon);
yourtm.tm_mday -= year_lengths[isleap(li)];
if (long_increment_overflow(&y, 1))
return WRONG;
}
for ( ; ; ) {
i = mon_lengths[isleap(y)][yourtm.tm_mon];
if (yourtm.tm_mday <= i)
break;
yourtm.tm_mday -= i;
if (++yourtm.tm_mon >= MONSPERYEAR) {
yourtm.tm_mon = 0;
if (long_increment_overflow(&y, 1))
return WRONG;
}
}
if (long_increment_overflow(&y, -TM_YEAR_BASE))
return WRONG;
yourtm.tm_year = y;
if (yourtm.tm_year != y)
return WRONG;
if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
saved_seconds = 0;
else if (y + 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;
}
/*
** Do a binary search (this works whatever time_t's type is).
*/
if (!TYPE_SIGNED(time_t)) {
lo = 0;
hi = lo - 1;
} else if (!TYPE_INTEGRAL(time_t)) {
if (sizeof(time_t) > sizeof(float))
hi = (time_t) DBL_MAX;
else hi = (time_t) FLT_MAX;
lo = -hi;
} else {
lo = 1;
for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
lo *= 2;
hi = -(lo + 1);
}
for ( ; ; ) {
t = lo / 2 + hi / 2;
if (t < lo)
t = lo;
else if (t > hi)
t = hi;
if ((*funcp)(&t, offset, &mytm) == NULL) {
/*
** Assume that t is too extreme to be represented in
** a struct tm; arrange things so that it is less
** extreme on the next pass.
*/
dir = (t > 0) ? 1 : -1;
} else dir = tmcomp(&mytm, &yourtm);
if (dir != 0) {
if (t == lo) {
++t;
if (t <= lo)
return WRONG;
++lo;
} else if (t == hi) {
--t;
if (t >= hi)
return WRONG;
--hi;
}
if (lo > hi)
return WRONG;
if (dir > 0)
hi = t;
else lo = t;
continue;
}
if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
break;
/*
** Right time, wrong type.
** Hunt for right time, right type.
** It's okay to guess wrong since the guess
** gets checked.
*/
sp = (const struct state *)
((funcp == localsub) ? lclptr : gmtptr);
for (i = sp->typecnt - 1; i >= 0; --i) {
if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
continue;
for (j = sp->typecnt - 1; j >= 0; --j) {
if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
continue;
newt = t + sp->ttis[j].tt_gmtoff -
sp->ttis[i].tt_gmtoff;
if ((*funcp)(&newt, offset, &mytm) == NULL)
continue;
if (tmcomp(&mytm, &yourtm) != 0)
continue;
if (mytm.tm_isdst != yourtm.tm_isdst)
continue;
/*
** We have a match.
*/
t = newt;
goto label;
}
}
return WRONG;
}
label:
newt = t + saved_seconds;
if ((newt < t) != (saved_seconds < 0))
return WRONG;
t = newt;
if ((*funcp)(&t, offset, tmp))
*okayp = TRUE;
return t;
}
