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kolibrios/programs/fs/unzip60/timezone.c

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unzip initial commit git-svn-id: svn://kolibrios.org@6725 a494cfbc-eb01-0410-851d-a64ba20cac60
2016-11-18 14:40:05 +01:00
/*
Copyright (c) 1990-2001 Info-ZIP. All rights reserved.
See the accompanying file LICENSE, version 2000-Apr-09 or later
(the contents of which are also included in zip.h) for terms of use.
If, for some reason, all these files are missing, the Info-ZIP license
also may be found at: ftp://ftp.info-zip.org/pub/infozip/license.html
*/
/* Replacement time library functions, based on platform independent public
* domain timezone code from ftp://elsie.nci.nih.gov/pub, with mktime and
* mkgmtime from our own mktime.c in Zip.
*
* Contains: tzset()
* __tzset()
* gmtime()
* localtime()
* mktime()
* mkgmtime()
* GetPlatformLocalTimezone() [different versions]
*/
/* HISTORY/CHANGES
* 17 Jun 00, Paul Kienitz, added the PD-based tzset(), localtime(), and so on
* to amiga/filedate.c, replacing GNU-based functions which had
* replaced time_lib.c, both having been rejected for licensing
* reasons. Support for timezone files and leap seconds was removed.
*
* 23 Aug 00, Paul Kienitz, split into separate timezone.c file, made platform
* independent, copied in mktime() and mkgmtime() from Zip, renamed
* locale_TZ as GetPlatformLocalTimezone(), for use as a generic
* hook by other platforms.
*/
#ifndef __timezone_c
#define __timezone_c
#include "zip.h"
#include "timezone.h"
#include <ctype.h>
#include <errno.h>
#ifdef IZTZ_DEFINESTDGLOBALS
long timezone = 0;
int daylight = 0;
char *tzname[2];
#endif
#ifndef IZTZ_GETLOCALETZINFO
# define IZTZ_GETLOCALETZINFO(ptzstruct, pgenrulefunct) (FALSE)
#endif
int real_timezone_is_set = FALSE; /* set by tzset() */
#define TZDEFRULESTRING ",M4.1.0,M10.5.0"
#define TZDEFAULT "EST5EDT"
#define SECSPERMIN 60
#define MINSPERHOUR 60
#define HOURSPERDAY 24
#define DAYSPERWEEK 7
#define DAYSPERNYEAR 365
#define DAYSPERLYEAR 366
#define SECSPERHOUR (SECSPERMIN * MINSPERHOUR)
#define SECSPERDAY ((long) SECSPERHOUR * HOURSPERDAY)
#define MONSPERYEAR 12
#define EPOCH_WDAY 4 /* Jan 1, 1970 was thursday */
#define EPOCH_YEAR 1970
#define TM_YEAR_BASE 1900
#define FIRST_GOOD_YEAR ((time_t) -1 < (time_t) 1 ? EPOCH_YEAR-68 : EPOCH_YEAR)
#define LAST_GOOD_YEAR (EPOCH_YEAR + ((time_t) -1 < (time_t) 1 ? 67 : 135))
#define YDAYS(month, year) yr_days[leap(year)][month]
/* Nonzero if `y' is a leap year, else zero. */
#define leap(y) (((y) % 4 == 0 && (y) % 100 != 0) || (y) % 400 == 0)
/* Number of leap years from EPOCH_YEAR to `y' (not including `y' itself). */
#define _P4 ((EPOCH_YEAR / 4) * 4 + 1)
#define _P100 ((EPOCH_YEAR / 100) * 100 + 1)
#define _P400 ((EPOCH_YEAR / 400) * 400 + 1)
#define nleap(y) (((y) - _P4) / 4 - ((y) - _P100) / 100 + ((y) - _P400) / 400)
/* Length of month `m' (0 .. 11) */
#define monthlen(m, y) (yr_days[0][(m)+1] - yr_days[0][m] + \
((m) == 1 && leap(y)))
/* internal module-level constants */
#ifndef IZ_MKTIME_ONLY
static ZCONST char gmt[] = "GMT";
static ZCONST int mon_lengths[2][MONSPERYEAR] = {
{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};
#endif /* !IZ_MKTIME_ONLY */
static ZCONST int yr_days[2][MONSPERYEAR+1] = {
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
{ 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
};
#ifndef IZ_MKTIME_ONLY
static ZCONST int year_lengths[2] = {
DAYSPERNYEAR, DAYSPERLYEAR
};
/* internal variables */
static struct state statism;
/* prototypes of static functions */
static time_t transtime OF((ZCONST time_t janfirst, ZCONST int year,
ZCONST struct rule * ZCONST rulep,
ZCONST long offset));
static void generate_transitions OF((register struct state * ZCONST sp,
ZCONST struct rule * ZCONST start,
ZCONST struct rule * ZCONST end));
static ZCONST char *getzname OF((ZCONST char *strp));
static ZCONST char *getnum OF((ZCONST char *strp, int * ZCONST nump,
ZCONST int min, ZCONST int max));
static ZCONST char *getsecs OF((ZCONST char *strp, long * ZCONST secsp));
static ZCONST char *getoffset OF((ZCONST char *strp, long * ZCONST offsetp));
static ZCONST char *getrule OF((ZCONST char *strp, struct rule * ZCONST rulep));
static int Parse_TZ OF((ZCONST char *name, register struct state * ZCONST sp));
static time_t transtime(janfirst, year, rulep, offset)
ZCONST time_t janfirst;
ZCONST int year;
ZCONST struct rule * ZCONST rulep;
ZCONST long offset;
{
register int leapyear;
register time_t value;
register int i;
int d, m1, yy0, yy1, yy2, dow;
value = 0;
leapyear = leap(year);
switch (rulep->r_type) {
case JULIAN_DAY:
/*
** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
** years.
** In non-leap years, or if the day number is 59 or less, just
** add SECSPERDAY times the day number-1 to the time of
** January 1, midnight, to get the day.
*/
value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
if (leapyear && rulep->r_day >= 60)
value += SECSPERDAY;
break;
case DAY_OF_YEAR:
/*
** n - day of year.
** Just add SECSPERDAY times the day number to the time of
** January 1, midnight, to get the day.
*/
value = janfirst + rulep->r_day * SECSPERDAY;
break;
case MONTH_NTH_DAY_OF_WEEK:
/*
** Mm.n.d - nth "dth day" of month m.
*/
value = janfirst;
/*
for (i = 0; i < rulep->r_mon - 1; ++i)
value += mon_lengths[leapyear][i] * SECSPERDAY;
*/
value += yr_days[leapyear][rulep->r_mon - 1] * SECSPERDAY;
/*
** Use Zeller's Congruence to get day-of-week of first day of
** month.
*/
m1 = (rulep->r_mon + 9) % 12 + 1;
yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
yy1 = yy0 / 100;
yy2 = yy0 % 100;
dow = ((26 * m1 - 2) / 10 +
1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
if (dow < 0)
dow += DAYSPERWEEK;
/*
** "dow" is the day-of-week of the first day of the month. Get
** the day-of-month (zero-origin) of the first "dow" day of the
** month.
*/
d = rulep->r_day - dow;
if (d < 0)
d += DAYSPERWEEK;
for (i = 1; i < rulep->r_week; ++i) {
if (d + DAYSPERWEEK >= mon_lengths[leapyear][rulep->r_mon - 1])
break;
d += DAYSPERWEEK;
}
/*
** "d" is the day-of-month (zero-origin) of the day we want.
*/
value += d * SECSPERDAY;
break;
}
/*
** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
** question. To get the Epoch-relative time of the specified local
** time on that day, add the transition time and the current offset
** from UTC.
*/
return value + rulep->r_time + offset;
}
static void generate_transitions(sp, start, end)
register struct state * ZCONST sp;
ZCONST struct rule * ZCONST start;
ZCONST struct rule * ZCONST end;
{
register int year;
register time_t janfirst;
time_t starttime;
time_t endtime;
long stdoffset = -sp->ttis[0].tt_gmtoff;
long dstoffset = -sp->ttis[1].tt_gmtoff;
register time_t * atp;
register unsigned char * typep;
/*
** Two transitions per year, from EPOCH_YEAR to LAST_GOOD_YEAR.
*/
sp->timecnt = 2 * (LAST_GOOD_YEAR - EPOCH_YEAR + 1);
atp = sp->ats;
typep = sp->types;
janfirst = 0;
for (year = EPOCH_YEAR; year <= LAST_GOOD_YEAR; ++year) {
starttime = transtime(janfirst, year, start, stdoffset);
endtime = transtime(janfirst, year, end, dstoffset);
if (starttime > endtime) {
*atp++ = endtime;
*typep++ = 0; /* DST ends */
*atp++ = starttime;
*typep++ = 1; /* DST begins */
} else {
*atp++ = starttime;
*typep++ = 1; /* DST begins */
*atp++ = endtime;
*typep++ = 0; /* DST ends */
}
janfirst += year_lengths[leap(year)] * SECSPERDAY;
}
}
static ZCONST char *getzname(strp)
ZCONST char *strp;
{
register char c;
while ((c = *strp) != '\0' && !isdigit(c) && c != ',' && c != '-' &&
c != '+')
++strp;
return strp;
}
static ZCONST char *getnum(strp, nump, min, max)
ZCONST char *strp;
int * ZCONST nump;
ZCONST int min;
ZCONST int max;
{
register char c;
register int num;
if (strp == NULL || !isdigit(c = *strp))
return NULL;
num = 0;
do {
num = num * 10 + (c - '0');
if (num > max)
return NULL; /* illegal value */
c = *++strp;
} while (isdigit(c));
if (num < min)
return NULL; /* illegal value */
*nump = num;
return strp;
}
static ZCONST char *getsecs(strp, secsp)
ZCONST char *strp;
long * ZCONST secsp;
{
int num;
/*
** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
** "M10.4.6/26", which does not conform to Posix,
** but which specifies the equivalent of
** ``02:00 on the first Sunday on or after 23 Oct''.
*/
strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
if (strp == NULL)
return NULL;
*secsp = num * (long) SECSPERHOUR;
if (*strp == ':') {
++strp;
strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
if (strp == NULL)
return NULL;
*secsp += num * SECSPERMIN;
if (*strp == ':') {
++strp;
/* `SECSPERMIN' allows for leap seconds. */
strp = getnum(strp, &num, 0, SECSPERMIN);
if (strp == NULL)
return NULL;
*secsp += num;
}
}
return strp;
}
static ZCONST char *getoffset(strp, offsetp)
ZCONST char *strp;
long * ZCONST offsetp;
{
register int neg = 0;
if (*strp == '-') {
neg = 1;
++strp;
} else if (*strp == '+')
++strp;
strp = getsecs(strp, offsetp);
if (strp == NULL)
return NULL; /* illegal time */
if (neg)
*offsetp = -*offsetp;
return strp;
}
static ZCONST char *getrule(strp, rulep)
ZCONST char *strp;
struct rule * ZCONST rulep;
{
if (*strp == 'J') {
/*
** Julian day.
*/
rulep->r_type = JULIAN_DAY;
++strp;
strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
} else if (*strp == 'M') {
/*
** Month, week, day.
*/
rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
++strp;
strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
if (strp == NULL)
return NULL;
if (*strp++ != '.')
return NULL;
strp = getnum(strp, &rulep->r_week, 1, 5);
if (strp == NULL)
return NULL;
if (*strp++ != '.')
return NULL;
strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
} else if (isdigit(*strp)) {
/*
** Day of year.
*/
rulep->r_type = DAY_OF_YEAR;
strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
} else return NULL; /* invalid format */
if (strp == NULL)
return NULL;
if (*strp == '/') {
/*
** Time specified.
*/
++strp;
strp = getsecs(strp, &rulep->r_time);
} else
rulep->r_time = 2 * SECSPERHOUR; /* default = 2:00:00 */
return strp;
}
static int Parse_TZ(name, sp)
ZCONST char *name;
register struct state * ZCONST sp;
{
ZCONST char * stdname;
ZCONST char * dstname;
size_t stdlen;
size_t dstlen;
long stdoffset;
long dstoffset;
register char * cp;
dstname = NULL;
stdname = name;
name = getzname(name);
stdlen = name - stdname;
if (stdlen < 3)
return -1;
if (*name == '\0')
return -1;
name = getoffset(name, &stdoffset);
if (name == NULL)
return -1;
if (*name != '\0') {
dstname = name;
name = getzname(name);
dstlen = name - dstname; /* length of DST zone name */
if (dstlen < 3)
return -1;
if (*name != '\0' && *name != ',' && *name != ';') {
name = getoffset(name, &dstoffset);
if (name == NULL)
return -1;
} else
dstoffset = stdoffset - SECSPERHOUR;
if (*name == '\0')
name = TZDEFRULESTRING;
if (*name == ',' || *name == ';') {
struct rule start;
struct rule end;
++name;
if ((name = getrule(name, &start)) == NULL)
return -1;
if (*name++ != ',')
return -1;
if ((name = getrule(name, &end)) == NULL)
return -1;
if (*name != '\0')
return -1;
sp->typecnt = 2; /* standard time and DST */
sp->ttis[0].tt_gmtoff = -stdoffset;
sp->ttis[0].tt_isdst = 0;
sp->ttis[0].tt_abbrind = 0;
sp->ttis[1].tt_gmtoff = -dstoffset;
sp->ttis[1].tt_isdst = 1;
sp->ttis[1].tt_abbrind = stdlen + 1;
generate_transitions(sp, &start, &end);
}
} else {
dstlen = 0;
sp->typecnt = 1; /* only standard time */
sp->timecnt = 0;
sp->ttis[0].tt_gmtoff = -stdoffset;
sp->ttis[0].tt_isdst = 0;
sp->ttis[0].tt_abbrind = 0;
}
sp->charcnt = stdlen + 1;
if (dstlen != 0)
sp->charcnt += dstlen + 1;
if ((size_t) sp->charcnt > sizeof(sp->chars))
return -1;
cp = sp->chars;
(void) strncpy(cp, stdname, stdlen);
cp += stdlen;
*cp++ = '\0';
if (dstlen != 0) {
(void) strncpy(cp, dstname, dstlen);
*(cp + dstlen) = '\0';
}
return 0;
}
void tzset()
{
char *TZstring;
int dstfirst;
static char *old_TZstring = NULL;
TZstring = getenv("TZ"); /* read TZ envvar */
if (old_TZstring && TZstring && !strcmp(old_TZstring, TZstring))
/* do not repeatedly parse an unchanged TZ specification */
return;
if ((TZstring && TZstring[0] && Parse_TZ(TZstring, &statism) == 0)
|| IZTZ_GETLOCALETZINFO(&statism, generate_transitions)
|| Parse_TZ(gmt, &statism) == 0) {
daylight = statism.typecnt > 1;
dstfirst = daylight && statism.ttis[0].tt_isdst && !statism.ttis[1].tt_isdst;
timezone = -statism.ttis[dstfirst].tt_gmtoff;
tzname[0] = statism.chars + statism.ttis[dstfirst].tt_abbrind;
tzname[1] = statism.chars + statism.ttis[!dstfirst].tt_abbrind;
real_timezone_is_set = TRUE;
if (TZstring) {
if (old_TZstring)
old_TZstring = realloc(old_TZstring, strlen(TZstring) + 1);
else
old_TZstring = malloc(strlen(TZstring) + 1);
if (old_TZstring)
strcpy(old_TZstring, TZstring);
}
} else {
timezone = 0; /* default is GMT0 which means no offsets */
daylight = 0; /* from local system time */
real_timezone_is_set = FALSE;
if (old_TZstring) {
free(old_TZstring);
old_TZstring = NULL;
}
}
#ifdef IZTZ_SETLOCALTZINFO
/* Some SAS/C library functions, e.g. stat(), call library */
/* __tzset() themselves. So envvar TZ *must* exist in order to */
/* to get the right offset from GMT. XXX TRY HARD to fix this! */
set_TZ(timezone, daylight);
#endif /* IZTZ_SETLOCALTZINFO */
}
/* XXX Does this also help SAS/C library work? */
void __tzset()
{
if (!real_timezone_is_set) tzset();
}
static struct tm _tmbuf;
struct tm *gmtime(when)
ZCONST time_t *when;
{
long days = *when / SECSPERDAY;
long secs = *when % SECSPERDAY;
int isleap;
memset(&_tmbuf, 0, sizeof(_tmbuf)); /* get any nonstandard fields */
_tmbuf.tm_wday = (days + EPOCH_WDAY) % 7;
_tmbuf.tm_year = EPOCH_YEAR - TM_YEAR_BASE;
isleap = leap(_tmbuf.tm_year + TM_YEAR_BASE);
while (days >= year_lengths[isleap]) {
days -= year_lengths[isleap];
_tmbuf.tm_year++;
isleap = leap(_tmbuf.tm_year + TM_YEAR_BASE);
}
_tmbuf.tm_mon = 0;
_tmbuf.tm_yday = days;
while (days >= mon_lengths[isleap][_tmbuf.tm_mon])
days -= mon_lengths[isleap][_tmbuf.tm_mon++];
_tmbuf.tm_mday = days + 1;
_tmbuf.tm_isdst = 0;
_tmbuf.tm_sec = secs % SECSPERMIN;
_tmbuf.tm_min = (secs / SECSPERMIN) % SECSPERMIN;
_tmbuf.tm_hour = secs / SECSPERHOUR;
return &_tmbuf;
}
struct tm *localtime(when)
ZCONST time_t *when;
{
time_t localwhen = *when;
int timetype;
struct tm *ret;
__tzset();
if (statism.timecnt == 0 || localwhen < statism.ats[0])
timetype = statism.ttis[0].tt_isdst && statism.typecnt > 1 &&
!statism.ttis[1].tt_isdst;
else {
for (timetype = 1; timetype < statism.timecnt; ++timetype)
if (localwhen < statism.ats[timetype])
break;
timetype = statism.types[timetype - 1];
}
localwhen += statism.ttis[timetype].tt_gmtoff;
ret = gmtime(&localwhen);
ret->tm_isdst = statism.ttis[timetype].tt_isdst;
return ret;
}
#ifdef NEED__ISINDST
int _isindst(tb)
struct tm *tb;
{
time_t localt; /* time_t equivalent of given tm struct */
time_t univt; /* assumed UTC value of given time */
long tzoffset_adj; /* timezone-adjustment `remainder' */
int bailout_cnt; /* counter of tries for tz correction */
int timetype;
__tzset();
/* when DST is unsupported in current timezone, DST is always off */
if (statism.typecnt <= 1) return FALSE;
localt = mkgmtime(tb);
if (localt == (time_t)-1)
/* specified time is out-of-range, default to FALSE */
return FALSE;
univt = localt - statism.ttis[0].tt_gmtoff;
bailout_cnt = 3;
do {
if (statism.timecnt == 0 || univt < statism.ats[0])
timetype = statism.ttis[0].tt_isdst && statism.typecnt > 1 &&
!statism.ttis[1].tt_isdst;
else {
for (timetype = 1; timetype < statism.timecnt; ++timetype)
if (univt < statism.ats[timetype])
break;
timetype = statism.types[timetype - 1];
}
if ((tzoffset_adj = localt - univt - statism.ttis[timetype].tt_gmtoff)
== 0L)
break;
univt += tzoffset_adj;
} while (--bailout_cnt > 0);
/* return TRUE when DST is active at given time */
return (statism.ttis[timetype].tt_isdst);
}
#endif /* NEED__ISINDST */
#endif /* !IZ_MKTIME_ONLY */
/* Return the equivalent in seconds past 12:00:00 a.m. Jan 1, 1970 GMT
of the local time and date in the exploded time structure `tm',
adjust out of range fields in `tm' and set `tm->tm_yday', `tm->tm_wday'.
If `tm->tm_isdst < 0' was passed to mktime(), the correct setting of
tm_isdst is determined and returned. Otherwise, mktime() assumes this
field as valid; its information is used when converting local time
to UTC.
Return -1 if time in `tm' cannot be represented as time_t value. */
time_t mktime(tm)
struct tm *tm;
{
struct tm *ltm; /* Local time. */
time_t loctime; /* The time_t value of local time. */
time_t then; /* The time to return. */
long tzoffset_adj; /* timezone-adjustment `remainder' */
int bailout_cnt; /* counter of tries for tz correction */
int save_isdst; /* Copy of the tm->isdst input value */
save_isdst = tm->tm_isdst;
loctime = mkgmtime(tm);
if (loctime == -1) {
tm->tm_isdst = save_isdst;
return (time_t)-1;
}
/* Correct for the timezone and any daylight savings time.
The correction is verified and repeated when not correct, to
take into account the rare case that a change to or from daylight
savings time occurs between when it is the time in `tm' locally
and when it is that time in Greenwich. After the second correction,
the "timezone & daylight" offset should be correct in all cases. To
be sure, we allow a third try, but then the loop is stopped. */
bailout_cnt = 3;
then = loctime;
do {
ltm = localtime(&then);
if (ltm == (struct tm *)NULL ||
(tzoffset_adj = loctime - mkgmtime(ltm)) == 0L)
break;
then += tzoffset_adj;
} while (--bailout_cnt > 0);
if (ltm == (struct tm *)NULL || tzoffset_adj != 0L) {
/* Signal failure if timezone adjustment did not converge. */
tm->tm_isdst = save_isdst;
return (time_t)-1;
}
if (save_isdst >= 0) {
if (ltm->tm_isdst && !save_isdst)
{
if (then + 3600 < then)
then = (time_t)-1;
else
then += 3600;
}
else if (!ltm->tm_isdst && save_isdst)
{
if (then - 3600 > then)
then = (time_t)-1;
else
then -= 3600;
}
ltm->tm_isdst = save_isdst;
}
if (tm != ltm) /* `tm' may already point to localtime's internal storage */
*tm = *ltm;
return then;
}
#ifndef NO_TIME_T_MAX
/* Provide default values for the upper limit of the time_t range.
These are the result of the decomposition into a `struct tm' for
the time value 0xFFFFFFFEL ( = (time_t)-2 ).
Note: `(time_t)-1' is reserved for "invalid time"! */
# ifndef TM_YEAR_MAX
# define TM_YEAR_MAX 2106
# endif
# ifndef TM_MON_MAX
# define TM_MON_MAX 1 /* February */
# endif
# ifndef TM_MDAY_MAX
# define TM_MDAY_MAX 7
# endif
# ifndef TM_HOUR_MAX
# define TM_HOUR_MAX 6
# endif
# ifndef TM_MIN_MAX
# define TM_MIN_MAX 28
# endif
# ifndef TM_SEC_MAX
# define TM_SEC_MAX 14
# endif
#endif /* NO_TIME_T_MAX */
/* Adjusts out-of-range values for `tm' field `tm_member'. */
#define ADJUST_TM(tm_member, tm_carry, modulus) \
if ((tm_member) < 0) { \
tm_carry -= (1 - ((tm_member)+1) / (modulus)); \
tm_member = (modulus-1) + (((tm_member)+1) % (modulus)); \
} else if ((tm_member) >= (modulus)) { \
tm_carry += (tm_member) / (modulus); \
tm_member = (tm_member) % (modulus); \
}
/* Return the equivalent in seconds past 12:00:00 a.m. Jan 1, 1970 GMT
of the Greenwich Mean time and date in the exploded time structure `tm'.
This function does always put back normalized values into the `tm' struct,
parameter, including the calculated numbers for `tm->tm_yday',
`tm->tm_wday', and `tm->tm_isdst'.
Returns -1 if the time in the `tm' parameter cannot be represented
as valid `time_t' number. */
time_t mkgmtime(tm)
struct tm *tm;
{
int years, months, days, hours, minutes, seconds;
years = tm->tm_year + TM_YEAR_BASE; /* year - 1900 -> year */
months = tm->tm_mon; /* 0..11 */
days = tm->tm_mday - 1; /* 1..31 -> 0..30 */
hours = tm->tm_hour; /* 0..23 */
minutes = tm->tm_min; /* 0..59 */
seconds = tm->tm_sec; /* 0..61 in ANSI C. */
ADJUST_TM(seconds, minutes, 60)
ADJUST_TM(minutes, hours, 60)
ADJUST_TM(hours, days, 24)
ADJUST_TM(months, years, 12)
if (days < 0)
do {
if (--months < 0) {
--years;
months = 11;
}
days += monthlen(months, years);
} while (days < 0);
else
while (days >= monthlen(months, years)) {
days -= monthlen(months, years);
if (++months >= 12) {
++years;
months = 0;
}
}
/* Restore adjusted values in tm structure */
tm->tm_year = years - TM_YEAR_BASE;
tm->tm_mon = months;
tm->tm_mday = days + 1;
tm->tm_hour = hours;
tm->tm_min = minutes;
tm->tm_sec = seconds;
/* Set `days' to the number of days into the year. */
days += YDAYS(months, years);
tm->tm_yday = days;
/* Now calculate `days' to the number of days since Jan 1, 1970. */
days = (unsigned)days + 365 * (unsigned)(years - EPOCH_YEAR) +
(unsigned)(nleap (years));
tm->tm_wday = ((unsigned)days + EPOCH_WDAY) % 7;
tm->tm_isdst = 0;
if (years < EPOCH_YEAR)
return (time_t)-1;
#if (defined(TM_YEAR_MAX) && defined(TM_MON_MAX) && defined(TM_MDAY_MAX))
#if (defined(TM_HOUR_MAX) && defined(TM_MIN_MAX) && defined(TM_SEC_MAX))
if (years > TM_YEAR_MAX ||
(years == TM_YEAR_MAX &&
(tm->tm_yday > (YDAYS(TM_MON_MAX, TM_YEAR_MAX) + (TM_MDAY_MAX - 1)) ||
(tm->tm_yday == (YDAYS(TM_MON_MAX, TM_YEAR_MAX) + (TM_MDAY_MAX - 1)) &&
(hours > TM_HOUR_MAX ||
(hours == TM_HOUR_MAX &&
(minutes > TM_MIN_MAX ||
(minutes == TM_MIN_MAX && seconds > TM_SEC_MAX) )))))))
return (time_t)-1;
#endif
#endif
return (time_t)(SECSPERDAY * (unsigned long)(unsigned)days +
SECSPERHOUR * (unsigned long)hours +
(unsigned long)(SECSPERMIN * minutes + seconds));
}
#endif /* __timezone_c */
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