/**
 * Week number magic
 *
 * @file	platon/misc/week.h
 * @author	Daniel Stenberg
 * @version	\$Platon: libplaton/platon/misc/week.h,v 1.5 2002/10/05 09:50:57 nepto Exp $
 * @date	1998-2003
 */

/*
   ISO 8601 - Week Number Magic
   Copyright (C) 1998 by Daniel Stenberg, All Rights Reserved

   Version 1.2 Nov 18, 1998
   - Magnus Tjernstrom <d92-mtm@ludd.luth.se> brought my attention to a weird
   treatment of the last days of a year, treated as week 53 before when they
   really should be week 1. I believe I've corrected that now.

Updates:
14/11/2001 (Week 46 Weekday 3, Wed) - initial release
04/02/2002 (Week 6  Weekday 1, Mon) - import to CVS
20/09/2002 (Week 38 Weekday 5, Fri) - Doxygen documentation

*/

#ifndef _PLATON_MISC_WEEK_H
#define _PLATON_MISC_WEEK_H

#ifdef __cplusplus
extern "C" {
#endif

	/**
	 * Returns week and weekday according to date in year/month/day
	 *
	 * @param	year		year to query
	 * @param	month		month to query
	 * @param	day			day to query
	 * @retval	aweek		pointer to int where to store week number
	 * @retval	weekday		pointer to int where to store weekday number
	 * @return	non-zero value on failure, zero if all OK
	 *
	 * Weekdays started from Monday. It means that weekday 1 is Monday,
	 * weekday 2 is Tuesday, and so on.
	 */
	int week(int year, int month, int day, int *aweek, int *weekday);

	/**
	 * Returns monday of week in year
	 *
	 * @param	year		year to query
	 * @param	aweek		number of week to query
	 * @retval	ret_month	pointer to int where to store monday month
	 * @retval	ret_day		pointer to int where to store monday day
	 * @return	allways 0
	 *
	 * Year of resulted monday is the same as the year of queried week, what is
	 * passed to function as year parameter. If value of aweek is more than
	 * 53, it is truncated.
	 */
	int week_no(int year, int aweek, int *ret_month, int *ret_day);

#ifdef __cplusplus
}
#endif

#endif /* #ifndef _PLATON_MISC_WEEK_H */