view src/lib/utc-offset.c @ 1741:9df02b1533b3 HEAD

Removed most of the license comments from src/lib/*.c. It's just fine to keep them in a single COPYING.MIT file. Changed a few other comments as well.
author Timo Sirainen <tss@iki.fi>
date Wed, 27 Aug 2003 00:18:16 +0300
parents 293aac070c2c
children 6a64e64fa3a3
line wrap: on
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/* Copyright (c) 2002-2003 Timo Sirainen */

#include "lib.h"
#include "utc-offset.h"

#include <sys/time.h>

int utc_offset(struct tm *tm, time_t t __attr_unused__)
{
#ifdef HAVE_TM_GMTOFF
	return (int) (tm->tm_gmtoff/60);
#else
	struct tm ltm, gtm;
	int offset;

	/* gmtime() overwrites tm, so we need to copy it elsewhere */
	ltm = *tm;
	tm = gmtime(&t);
	gtm = *tm;

	/* max offset of 24 hours */
	if (ltm.tm_yday < gtm.tm_yday)
		offset = -24 * 60;
	else if (ltm.tm_yday > gtm.tm_yday)
		offset = 24 * 60;
	else
		offset = 0;

	offset += (ltm.tm_hour - gtm.tm_hour) * 60;
	offset += (ltm.tm_min - gtm.tm_min);

	/* restore overwritten tm */
	*tm = ltm;
	return offset;
#endif
}