/*	$NetBSD: stime.c,v 1.7 2008/07/21 14:19:21 lukem Exp $	*/

/*
 * Copyright (c) 1993
 *	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 the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. 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 BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "from: @(#)touch.c	8.2 (Berkeley) 4/28/95";
#endif
__RCSID("$NetBSD: stime.c,v 1.7 2008/07/21 14:19:21 lukem Exp $");
#endif /* not lint */

#include <err.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <tzfile.h>

#include "stime.h"

#define	ATOI2(s)	((s) += 2, ((s)[-2] - '0') * 10 + ((s)[-1] - '0'))

time_t
stime(char *arg)
{
	struct tm *t;
	time_t tmptime;
	int yearset;
	char *p;
					/* Start with the current time. */
	if (time(&tmptime) == (time_t)-1)
		err(EXIT_FAILURE, "time");

	if ((t = localtime(&tmptime)) == NULL)
		err(EXIT_FAILURE, "localtime");
					/* [[CC]YY]MMDDhhmm[.SS] */
	if ((p = strchr(arg, '.')) == NULL)
		t->tm_sec = 0;		/* Seconds defaults to 0. */
	else {
		if (strlen(p + 1) != 2)
			goto terr;
		*p++ = '\0';
		t->tm_sec = ATOI2(p);
	}

	yearset = 0;
	switch (strlen(arg)) {
	case 12:			/* CCYYMMDDhhmm */
		t->tm_year = ATOI2(arg) * 100 - TM_YEAR_BASE;
		yearset = 1;
		/* FALLTHROUGH */
	case 10:			/* YYMMDDhhmm */
		if (yearset) {
			t->tm_year += ATOI2(arg);
		} else {
			yearset = ATOI2(arg);
			t->tm_year = conv_2dig_year(yearset) - TM_YEAR_BASE;
		}
		/* FALLTHROUGH */
	case 8:				/* MMDDhhmm */
		t->tm_mon = ATOI2(arg);
		--t->tm_mon;		/* Convert from 01-12 to 00-11 */
		/* FALLTHROUGH */
	case 6:
		t->tm_mday = ATOI2(arg);
		/* FALLTHROUGH */
	case 4:
		t->tm_hour = ATOI2(arg);
		/* FALLTHROUGH */
	case 2:
		t->tm_min = ATOI2(arg);
		break;
	default:
		goto terr;
	}

	t->tm_isdst = -1;		/* Figure out DST. */
	tmptime = mktime(t);
	if (tmptime == (time_t)-1) {
 terr:		errx(EXIT_FAILURE,
     "out of range or illegal time specification: [[CC]YY]MMDDhhmm[.SS]");
	}
	return tmptime;
}