winix/core/timezone.h

/*
 * This file is a part of Winix
 * and is not publicly distributed
 *
 * Copyright (c) 2012, Tomasz Sowa
 * All rights reserved.
 *
 */

#ifndef headerfile_winix_core_timezone
#define headerfile_winix_core_timezone

#include <ctime>
#include "date/date.h"
#include "space/space.h"



class TimeZone
{
public:

	TimeZone();


	/*
		setting:
		tz_offset  = 0
		tz_has_dst = false
	*/
	void Clear();


	/*
		reading zime zone values from Space struct (tz_id is skipped)
		the space struct should have:
		  "tz_offset" (long)
		  "tz_has_dst" (bool)
		if tz_has_dst is true then also:
		  "tz_dst_start"  date in the following format: MM:DD HH[:MM[:SS]]
		  "tz_dst_end"    the same as above
		  "tz_dst_offset" (long)
	*/
	bool SetTz(PT::Space & space);


	/*
		 converting from UTC to local time
	*/
	time_t   CalcLocalOffset(const PT::Date & utc_date);
	time_t   ToLocal(time_t utc_time);
	PT::Date ToLocal(const PT::Date & utc_date);


	/*
		 converting from local time to UTC
	*/
	time_t   CalcUTCOffset(const PT::Date & local_date);
	time_t   ToUTC(time_t local_time);
	PT::Date ToUTC(const PT::Date & local_date);


	// each locale has its own identifier
	int tz_id;

	// time zone offset (in seconds)
	time_t tz_offset;

	// true if the time zone has daylight saving time
	bool tz_has_dst;

	// time zone daylight saving time (used if tz_has_dst is true)
	// the 'year' field is ignored (is always 1970)
	// these values (hours) are represented in local time (UTC + tz_offset)
	PT::Date tz_dst_start, tz_dst_end;

	// time zone daylight saving time offset
	// used when tz_has_dst is true and the current date is whithin tz_dst_start and tz_dst_end
	time_t tz_dst_offset;


};











#endif