sources-request@panda.UUCP (03/19/86)
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
---------------cut here---------------cut here---------------
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
# tm_to_time.3
# tm_to_time.c
# This archive created: Wed Mar 19 13:04:07 1986
export PATH; PATH=/bin:$PATH
echo shar: extracting "'tm_to_time.3'" '(683 characters)'
if test -f 'tm_to_time.3'
then
echo shar: will not over-write existing file "'tm_to_time.3'"
else
cat << \SHAR_EOF > 'tm_to_time.3'
.TH MKTIME 3 "19 March 1986"
.SH NAME
tm_to_time \- convert broken-down time into time_t
.SH SYNOPSIS
.nf
.B #include <sys/types.h>
.B #include <sys/time.h>
.PP
.B time_t tm_to_time (tp);
.B struct tm *tp;
.fi
.SH DESCRIPTION
.I Tm_to_time
converts a broken-down time pointed to by
.I tp
(such as returned by
.IR localtime )
into a
.I time_t
(that is, a number of seconds since 00:00:00 GMT, Jan 1, 1970).
Thus, if
.I tm_to_time
is called with a broken-down time
returned by a call to
.I localtime
with some
.I time_t
argument,
the value obtained by
.I tm_to_time
is identical to the original
.IR time_t .
.SH AUTHOR
Oliver Laumann
.SH SEE ALSO
gettimeofday(2) or time(2), ctime(3).
SHAR_EOF
if test 683 -ne "`wc -c < 'tm_to_time.3'`"
then
echo shar: error transmitting "'tm_to_time.3'" '(should have been 683 characters)'
fi
fi # end of overwriting check
echo shar: extracting "'tm_to_time.c'" '(1192 characters)'
if test -f 'tm_to_time.c'
then
echo shar: will not over-write existing file "'tm_to_time.c'"
else
cat << \SHAR_EOF > 'tm_to_time.c'
#include <sys/types.h>
#include <sys/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; {
register n = p->tm_mday;
register m, y;
register 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; {
register 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);
}
SHAR_EOF
if test 1192 -ne "`wc -c < 'tm_to_time.c'`"
then
echo shar: error transmitting "'tm_to_time.c'" '(should have been 1192 characters)'
fi
fi # end of overwriting check
# End of shell archive
exit 0