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/*
* Copyright (c) 1997
* 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 const char rcsid[] _U_ =
"@(#) $Header: /tcpdump/master/tcpdump/gmt2local.c,v 1.9 2003-11-16 09:36:09 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <tcpdump-stdinc.h>
#include <stdio.h>
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
#include "gmt2local.h"
/*
* Returns the difference between gmt and local time in seconds.
* Use gmtime() and localtime() to keep things simple.
*/
int32_t
gmt2local(time_t t)
{
register int dt, dir;
register struct tm *gmt, *loc;
struct tm sgmt;
if (t == 0)
t = time(NULL);
gmt = &sgmt;
*gmt = *gmtime(&t);
loc = localtime(&t);
dt = (loc->tm_hour - gmt->tm_hour) * 60 * 60 +
(loc->tm_min - gmt->tm_min) * 60;
/*
* If the year or julian day is different, we span 00:00 GMT
* and must add or subtract a day. Check the year first to
* avoid problems when the julian day wraps.
*/
dir = loc->tm_year - gmt->tm_year;
if (dir == 0)
dir = loc->tm_yday - gmt->tm_yday;
dt += dir * 24 * 60 * 60;
return (dt);
}