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amiga-tz
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amiga-tz/library/time_mktime_tzname.c

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#include "time_header.h"
#ifndef WRONG
# define WRONG (-1)
#endif
bool increment_overflow32(int_fast32_t *const lp, int const m)
{
int_fast32_t const l = *lp;
if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l)) {
return true;
}
*lp += m;
return false;
}
bool 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);
}
bool normalize_overflow32(
int_fast32_t *const tensptr,
int *const unitsptr,
const int base)
{
int tensdelta;
tensdelta = (*unitsptr >= 0) ?
(*unitsptr / base) :
(-1 - (-1 - *unitsptr) / base);
*unitsptr -= tensdelta * base;
return increment_overflow32(tensptr, tensdelta);
}
int tmcomp(const struct tm *const atmp, const struct tm *const btmp)
{
int result;
if (atmp->tm_year != btmp->tm_year) {
return atmp->tm_year < btmp->tm_year ? -1 : 1;
}
if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
(result = (atmp->tm_min - btmp->tm_min)) == 0) {
result = atmp->tm_sec - btmp->tm_sec;
}
return result;
}
time_t time2sub(
struct tm *const tmp,
struct tm *(*funcp)(struct state const *,
time_t const *,
int_fast32_t, struct tm *),
struct state const *sp,
const int_fast32_t offset,
bool *okayp,
bool do_norm_secs)
{
int dir;
int i, j;
int saved_seconds;
int_fast32_t li;
time_t lo;
time_t hi;
int_fast32_t y;
time_t newt;
time_t t;
struct tm yourtm;
struct tm 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 (normalize_overflow32(&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 (increment_overflow32(&y, TM_YEAR_BASE))
return WRONG;
while (yourtm.tm_mday <= 0) {
if (increment_overflow32(&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 (increment_overflow32(&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 (increment_overflow32(&y, 1))
return WRONG;
}
}
if (increment_overflow32(&y, -TM_YEAR_BASE))
return WRONG;
if (! (INT_MIN <= y && y <= INT_MAX))
return WRONG;
yourtm.tm_year = y;
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).
*/
lo = time_t_min;
hi = time_t_max;
for ( ; ; ) {
t = lo / 2 + hi / 2;
if (t < lo)
t = lo;
else if (t > hi)
t = hi;
if (! funcp(sp, &t, offset, &mytm)) {
/*
** 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) {
if (t == time_t_max)
return WRONG;
++t;
++lo;
} else if (t == hi) {
if (t == time_t_min)
return WRONG;
--t;
--hi;
}
if (lo > hi)
return WRONG;
if (dir > 0)
hi = t;
else lo = t;
continue;
}
if (mytm.tm_gmtoff != yourtm.tm_gmtoff
&& (yourtm.tm_gmtoff < 0
? (-SECSPERDAY <= yourtm.tm_gmtoff
&& (mytm.tm_gmtoff <=
(SMALLEST (INT_FAST32_MAX, LONG_MAX)
+ yourtm.tm_gmtoff)))
: (yourtm.tm_gmtoff <= SECSPERDAY
&& ((BIGGEST (INT_FAST32_MIN, LONG_MIN)
+ yourtm.tm_gmtoff)
<= mytm.tm_gmtoff)))) {
/* MYTM matches YOURTM except with the wrong UTC offset.
YOURTM.tm_gmtoff is plausible, so try it instead.
It's OK if YOURTM.tm_gmtoff contains uninitialized data,
since the guess gets checked. */
time_t altt = t;
int_fast32_t diff = mytm.tm_gmtoff - yourtm.tm_gmtoff;
if (!increment_overflow_time(&altt, diff)) {
struct tm alttm;
if (funcp(sp, &altt, offset, &alttm)
&& alttm.tm_isdst == mytm.tm_isdst
&& alttm.tm_gmtoff == yourtm.tm_gmtoff
&& tmcomp(&alttm, &yourtm) == 0) {
t = altt;
mytm = alttm;
}
}
}
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.
*/
if (sp == NULL)
return WRONG;
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(sp, &newt, offset, &mytm))
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(sp, &t, offset, tmp)) {
*okayp = true;
}
return t;
}
time_t time2(struct tm * const tmp,
struct tm *(*funcp)(struct state const *,
time_t const *,
int_fast32_t,
struct tm *),
struct state const *sp,
const int_fast32_t offset,
bool *okayp)
{
time_t t;
/*
** First try without normalization of seconds
** (in case tm_sec contains a value associated with a leap second).
** If that fails, try with normalization of seconds.
*/
t = time2sub(tmp, funcp, sp, offset, okayp, false);
return *okayp ? t : time2sub(tmp, funcp, sp, offset, okayp, true);
}
time_t time1(
struct tm *const tmp,
struct tm *(*funcp) (struct state const *,
time_t const *,
int_fast32_t, struct tm *),
struct state const *sp,
const int_fast32_t offset)
{
time_t t;
int samei, otheri;
int sameind, otherind;
int i;
int nseen;
char seen[TZ_MAX_TYPES];
unsigned char types[TZ_MAX_TYPES];
bool okay;
if (tmp == NULL) {
errno = EINVAL;
return WRONG;
}
if (tmp->tm_isdst > 1) {
tmp->tm_isdst = 1;
}
t = time2(tmp, funcp, sp, offset, &okay);
if (okay) {
return t;
}
if (tmp->tm_isdst < 0) {
return t;
}
/*
** We're supposed to assume that somebody took a time of one type
** and did some math on it that yielded a "struct tm" that's bad.
** We try to divine the type they started from and adjust to the
** type they need.
*/
if (sp == NULL) {
return WRONG;
}
for (i = 0; i < sp->typecnt; ++i) {
seen[i] = false;
}
nseen = 0;
for (i = sp->timecnt - 1; i >= 0; --i) {
if (!seen[sp->types[i]]) {
seen[sp->types[i]] = true;
types[nseen++] = sp->types[i];
}
}
for (sameind = 0; sameind < nseen; ++sameind) {
samei = types[sameind];
if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
continue;
for (otherind = 0; otherind < nseen; ++otherind) {
otheri = types[otherind];
if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
continue;
tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
sp->ttis[samei].tt_gmtoff;
tmp->tm_isdst = !tmp->tm_isdst;
t = time2(tmp, funcp, sp, offset, &okay);
if (okay)
return t;
tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
sp->ttis[samei].tt_gmtoff;
tmp->tm_isdst = !tmp->tm_isdst;
}
}
return WRONG;
}
time_t mktime_tzname(struct state *sp, struct tm *tmp, bool setname)
{
if (sp) {
return time1(tmp, localsub, sp, setname);
} else {
gmtcheck();
return time1(tmp, gmtsub, gmtptr, 0);
}
}
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