tcpdump/gmt2local.c
Guy Harris fb2479d733 Always include <config.h> rather than "config.h".
This can prevent bizarre failures if, for example, you've done a
configuration in the top-level source directory, leaving behind one
config.h file, and then do an out-of-tree build in another directory,
with different configuration options.  This way, we always pick up the
same config.h, in the build directory.
2018-01-21 12:27:28 -08:00

67 lines
2.0 KiB
C

/*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "netdissect-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)
{
int dt, dir;
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);
}