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#if defined(timemaker)
/*
From: "Oliver Laumann" <talcott!seismo!unido!tub!net>
Subject: tm_to_time(3) -- convert broken-down time into time_t.
Newsgroups: mod.sources
Approved: jpn@panda.UUCP
Mod.sources: Volume 4, Issue 38
Submitted by: "Oliver Laumann" <seismo!unido!tub!net>
A number of requests have been posted to the net in the past asking
for a function that can be used to convert a broken-down time (such
as returned by localtime()) into a time_t (such as returned by
time()).
The following shell archive contains a function (plus manual page)
that performs this conversion.
Regards,
Oliver Laumann, Technical University of Berlin, Germany.
...ihnp4!seismo!unido!tub!net or net@DB0TUI6.BITNET
...!mcvax!unido!tub!net
*/
#include <sys/types.h>
#include <time.h>
/*
* Return 1 if `y' is a leap year, 0 otherwise.
*/
static int
leap (y)
int y;
{
y += 1900;
if (y % 400 == 0)
return (1);
if (y % 100 == 0)
return (0);
return (y % 4 == 0);
}
/* Return the number of days between Jan 1, 1970 and the given
* broken-down time.
*/
static int
ndays (p)
struct tm *p;
{
int n = p->tm_mday;
int m, y;
char *md = "\37\34\37\36\37\36\37\37\36\37\36\37";
for (y = 70; y < p->tm_year; ++y) {
n += 365;
if (leap (y)) ++n;
}
for (m = 0; m < p->tm_mon; ++m)
n += md[m] + (m == 1 && leap (y));
return (n);
}
/* Convert a broken-down time (such as returned by localtime())
* back into a `time_t'.
*/
time_t
tm_to_time (tp)
struct tm *tp;
{
int m1, m2;
time_t t;
struct tm otm;
t = (ndays (tp) - 1) * 86400L + tp->tm_hour * 3600L
+ tp->tm_min * 60 + tp->tm_sec;
/*
* Now the hard part -- correct for the time zone:
*/
otm = *tp;
tp = localtime (&t);
m1 = tp->tm_hour * 60 + tp->tm_min;
m2 = otm.tm_hour * 60 + otm.tm_min;
t -= ((m1 - m2 + 720 + 1440) % 1440 - 720) * 60L;
return (t);
}
#endif
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