/*
* Copyright (c) 1990 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that: (1) source code distributions
* retain the above copyright notice and this paragraph in its entirety, (2)
* distributions including binary code include the above copyright notice and
* this paragraph in its entirety in the documentation or other materials
* provided with the distribution, and (3) all advertising materials mentioning
* features or use of this software display the following acknowledgement:
* ``This product includes software developed by the University of California,
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
* the University nor the names of its contributors may be used to endorse
* or promote products derived from this software without specific prior
* written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
static char rcsid[] =
"@(#)$Header: gwtm2secs.c,v 1.1 92/06/02 11:35:19 mccanne Exp $ (LBL)";
#endif
/*
* gwtm2secs.c - convert "tm" structs for Greenwich time to Unix timestamp
*/
#include <stdio.h>
#include <sys/types.h>
#include <time.h>
static int days_in_month[] =
/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
#define IS_LEAP_YEAR(year) \
(year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
time_t gwtm2secs( tm )
struct tm *tm;
{
int i, days, year;
year = tm->tm_year;
/* Allow for year being specified with either 2 digits or 4 digits.
* 2-digit years are either 19xx or 20xx - a simple heuristic
* distinguishes them, since we can't represent any time < 1970.
*/
if ( year < 100 )
if ( year >= 70 )
year += 1900;
else
year += 2000;
days = 0;
for ( i = 1970; i < year; ++i )
{
days += 365;
if ( IS_LEAP_YEAR(i) )
++days;
}
for ( i = 0; i < tm->tm_mon; ++i )
days += days_in_month[i];
if ( IS_LEAP_YEAR(year) && tm->tm_mon > 1 ) /* 1 is February */
++days;
days += tm->tm_mday - 1; /* -1 since days are numbered starting at 1 */
return days * 86400 + tm->tm_hour * 3600 + tm->tm_min * 60 + tm->tm_sec;
}
