/*

* Copyright (c) 1992, 1993, 1995, 1996

* 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.

*/

/*

* gwtm2secs.c - convert "tm" structs for Greenwich time to Unix timestamp

*/

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include <sys/types.h>

#include <time.h>

#include <pcap.h>

#ifdef HAVE_OS_PROTO_H

#include "os-proto.h"

#endif

#include "tcpslice.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( struct tm *tm )

{

int i, days, year;

/* tm_year is either:

* a) the result from localtime()

* b) a 4-digit year specified on the command line minus 1900

* c) a 2-digit year specified on the command line

* in order to handle years from 2000 to 2069 specified as c), we

* check for years prior to 1970, which we can't handle anyway.

* (actually, for zones west of GMT, there are a few hours at

* the end of 1969, but we assume that nobody has traces taken

* during those hours.)

*/

year = tm->tm_year + 1900;

if ( year < 1970 )

year += 100;

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;

}