/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.

 * Use is subject to license terms.

 */

/*	Copyright (c) 1988 AT&T	*/

/*	  All Rights Reserved  	*/

#pragma ident	"%Z%%M%	%I%	%E% SMI"

/*

 * This routine converts time as follows.

 * The epoch is 0000 Jan 1 1970 GMT.

 * The argument time is in seconds since then.

 * The localtime(t) entry returns a pointer to an array

 * containing

 *  seconds (0-59)

 *  minutes (0-59)

 *  hours (0-23)

 *  day of month (1-31)

 *  month (0-11)

 *  year-1970

 *  weekday (0-6, Sun is 0)

 *  day of the year

 *  daylight savings flag

 *

 * The routine corrects for daylight saving

 * time and will work in any time zone provided

 * "timezone" is adjusted to the difference between

 * Greenwich and local standard time (measured in seconds).

 * In places like Michigan "daylight" must

 * be initialized to 0 to prevent the conversion

 * to daylight time.

 * There is a table which accounts for the peculiarities

 * undergone by daylight time in 1974-1975.

 *

 * The routine does not work

 * in Saudi Arabia which runs on Solar time.

 *

 * asctime(tvec)

 * where tvec is produced by localtime

 * returns a ptr to a character string

 * that has the ascii time in the form

 *	Thu Jan 01 00:00:00 1970\n\0

 *	01234567890123456789012345

 *	0	  1	    2

 *

 * ctime(t) just calls localtime, then asctime.

 *

 * tzset() looks for an environment variable named

 * TZ.

 * If the variable is present, it will set the external

 * variables "timezone", "altzone", "daylight", and "tzname"

 * appropriately. It is called by localtime, and

 * may also be called explicitly by the user.

 */

#include "lint.h"

#include <mtlib.h>

#include <sys/types.h>

#include <time.h>

#include <errno.h>

#include <thread.h>

#include <synch.h>

#include "libc.h"

#include "tsd.h"

#define	dysize(A) (((A)%4)? 365: 366)

#define	CBUFSIZ 26

static char *

ct_numb(char *cp, int n, char pad)

{

	cp++;

	if (n >= 10)

		*cp++ = (n / 10) % 10 + '0';

	else

		*cp++ = pad;

	*cp++ = n % 10 + '0';

	return (cp);

}

/*

 * POSIX.1c standard version of the function asctime_r.

 * User gets it via static asctime_r from the header file.

 */

char *

__posix_asctime_r(const struct tm *t, char *cbuf)

{

	char *cp;

	const char *ncp;

	const char *Date = "Day Mon 00 00:00:00 YYYY\n";

	const char *Day  = "SunMonTueWedThuFriSat";

	const char *Month = "JanFebMarAprMayJunJulAugSepOctNovDec";

	int year = t->tm_year + 1900;

	cp = cbuf;

	for (ncp = Date; *cp++ = *ncp++; /* */)

		;

	ncp = Day + (3 * t->tm_wday);

	cp = cbuf;

	*cp++ = *ncp++;

	*cp++ = *ncp++;

	*cp++ = *ncp++;

	cp++;

	ncp = Month + (3 * t->tm_mon);

	*cp++ = *ncp++;

	*cp++ = *ncp++;

	*cp++ = *ncp++;

	cp = ct_numb(cp, t->tm_mday, ' ');

	cp = ct_numb(cp, t->tm_hour, '0');

	cp = ct_numb(cp, t->tm_min, '0');

	cp = ct_numb(cp, t->tm_sec, '0');

	if (year < 0 || year >= 10000) {

		/* Only positive, 4-digit years are supported */

		errno = EOVERFLOW;

		return (NULL);

	}

	cp = ct_numb(cp, year / 100, '0');

	cp--;

	(void) ct_numb(cp, year, '0');

	return (cbuf);

}

/*

 * POSIX.1c Draft-6 version of the function asctime_r.

 * It was implemented by Solaris 2.3.

 */

char *

asctime_r(const struct tm *t, char *cbuf, int buflen)

{

	if (buflen < CBUFSIZ) {

		errno = ERANGE;

		return (NULL);

	}

	return (__posix_asctime_r(t, cbuf));

}

char *

ctime(const time_t *t)

{

	char *cbuf = tsdalloc(_T_CTIME, CBUFSIZ, NULL);

	struct tm *p;

	if (cbuf == NULL)

		return (NULL);

	p = localtime(t);

	if (p == NULL)

		return (NULL);

	return (__posix_asctime_r(p, cbuf));

}

char *

asctime(const struct tm *t)

{

	char *cbuf = tsdalloc(_T_CTIME, CBUFSIZ, NULL);

	if (cbuf == NULL)

		return (NULL);

	return (__posix_asctime_r(t, cbuf));

}