* Copyright (c) 1990 The Regents of the University of California.
* 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
* 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.
"@(#)$Header: gwtm2secs.c,v 1.1 92/06/02 11:35:19 mccanne Exp $ (LBL)";
* gwtm2secs.c - convert "tm" structs for Greenwich time to Unix timestamp
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))
/* Allow for year being specified with either 2 digits or 4 digits.
* 2-digit years are either 19xx or 20xx - a simple heuristic
* distinguishes them, since we can't represent any time < 1970.
for ( i
= 1970; i
< year
; ++i
)
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
+= 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
;