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; }