73 lines
2.4 KiB
C
73 lines
2.4 KiB
C
/*
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* Copyright (c) 1990 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that: (1) source code distributions
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* retain the above copyright notice and this paragraph in its entirety, (2)
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* distributions including binary code include the above copyright notice and
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* this paragraph in its entirety in the documentation or other materials
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* provided with the distribution, and (3) all advertising materials mentioning
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* features or use of this software display the following acknowledgement:
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* ``This product includes software developed by the University of California,
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* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
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* the University nor the names of its contributors may be used to endorse
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* or promote products derived from this software without specific prior
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* written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*/
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#if !defined(lint) && !defined(__GNUC__)
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static char rcsid[] =
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"@(#)$Header: /home/ncvs/src/usr.sbin/tcpdump/tcpslice/gwtm2secs.c,v 1.2 1995/03/08 12:53:38 olah Exp $ (LBL)";
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#endif
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/*
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* gwtm2secs.c - convert "tm" structs for Greenwich time to Unix timestamp
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*/
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#include "tcpslice.h"
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static int days_in_month[] =
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/* Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec */
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{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
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#define IS_LEAP_YEAR(year) \
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(year % 4 == 0 && (year % 100 != 0 || year % 400 == 0))
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time_t gwtm2secs( struct tm *tm )
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{
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int i, days, year;
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year = tm->tm_year;
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/* Allow for year being specified with either 2 digits or 4 digits.
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* 2-digit years are either 19xx or 20xx - a simple heuristic
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* distinguishes them, since we can't represent any time < 1970.
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*/
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if ( year < 100 )
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if ( year >= 70 )
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year += 1900;
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else
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year += 2000;
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days = 0;
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for ( i = 1970; i < year; ++i )
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{
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days += 365;
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if ( IS_LEAP_YEAR(i) )
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++days;
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}
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for ( i = 0; i < tm->tm_mon; ++i )
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days += days_in_month[i];
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if ( IS_LEAP_YEAR(year) && tm->tm_mon > 1 ) /* 1 is February */
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++days;
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days += tm->tm_mday - 1; /* -1 since days are numbered starting at 1 */
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return days * 86400 + tm->tm_hour * 3600 + tm->tm_min * 60 + tm->tm_sec;
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}
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