tcpdump/gmt2local.c
Francois-Xavier Le Bail 5cea270318 Remove all storage class specifier 'register'
Let the compiler do the optimizations (or not) based on build options.

Avoid 'value has been optimized out' messages in gdb using '-O0'.
2017-12-13 19:17:47 +01:00

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);
}