/elec/propeller-clock

/*

 * time.cc

 *

 * Copyright (C) 2011 Tim Marston <tim@ed.am> and Dan Marston.

 *

 * This file is part of propeller-clock (hereafter referred to as "this

 * program"). See http://ed.am/dev/software/arduino/propeller-clock for more

 * information.

 *

 * This program is free software: you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published

 * by the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "time.h"

#include <DS1307.h>

#include <Wire.h>

#define YEAR_MAX 2030

#define YEAR_MIN 2010

// year

static int _year;

// month

static int _month;

// day

static int _day;

// hours

static int _hours;

// minutes

static int _minutes;

// seconds

static int _seconds;

// milliseconds at last update

static unsigned long _last_millis = millis();

// milliseconds carries over from last update

static unsigned long _carry = 0;

int Time::get_year()

{

	return _year;

}

int Time::get_month()

{

	return _month;

}

const char *Time::get_month_name()

{

	static const char *months[] = {

		"January",

		"February",

		"March",

		"April",

		"May",

		"June",

		"July",

		"August",

		"September",

		"October",

		"November",

		"December",

	};

	return months[ _month - 1 ];

}

int Time::get_day()

{

	return _day;

}

const char *Time::get_day_suffix()

{

	switch( _day )

	{

	case 1:

	case 21:

	case 31:

		return "st";

	case 2:

	case 22:

		return "nd";

	case 3:

	case 23:

		return "rd";

	default:

		return "th";

	}

}

int Time::get_hours()

{

	return _hours;

}

int Time::get_minutes()

{

	return _minutes;

}

int Time::get_seconds()

{

	return _seconds;

}

static int days_in_month( int month, int year )

{

	if( month == 2 )

		return !( year % 4 ) && ( ( year % 100 ) || !( year % 400 ) )? 29 : 28;

	else if( month == 9 || month == 6 || month == 4 || month == 11 )

		return 30;

	else

		return 31;

}

static void load_time()

{

	// get the time from the real-time clock

	int rtc_data[ 7 ];

	RTC.get( rtc_data, true );

	_year = rtc_data[ DS1307_YR ];

	_month = rtc_data[ DS1307_MTH ];

	_day = rtc_data[ DS1307_DAY ];

	_hours = rtc_data[ DS1307_HR ];

	_minutes = rtc_data[ DS1307_MIN ];

	_seconds = rtc_data[ DS1307_SEC ];

	// make sure some numbers are in range

	if( _year < YEAR_MIN || _year > YEAR_MAX ) _year = 2010;

	if( _month < 1 || _month > 12 ) _month = 1;

	if( _day < 1 || _day > days_in_month( _year, _month ) ) _day = 1;

}

void Time::update()

{

	// how many milliseconds have elapsed since we last checked?

	unsigned long millis = ::millis();

	unsigned long delta = millis - _last_millis + _carry;

	// update the previous time and carried-over milliseconds

	_last_millis = millis;

	_carry = delta % 1000;

	// add the seconds that have passed to the time

	_seconds += delta / 1000;

	while( _seconds >= 60 ) {

		_seconds -= 60;

		_minutes++;

		if( _minutes >= 60 ) {

			_minutes -= 60;

			_hours++;

			if( _hours >= 24 ) {

				_hours -= 24;

				// We *could* manually work out the day here... but we might as

				// well ask the RTC hardware. We can't do this *all* the time

				// though, because it isn't fast enough and will actually cause

				// a minor display glitch.

				load_time();

			}

		}

	}

}

void Time::init()

{

	load_time();

}

static void save_time()

{

	// set the time on the real-time clock

	RTC.stop();

	RTC.set( DS1307_YR, _year );

	RTC.set( DS1307_MTH, _month );

	RTC.set( DS1307_DAY, _day );

	RTC.set( DS1307_HR, _hours );

	RTC.set( DS1307_MIN, _minutes );

	RTC.set( DS1307_SEC, _seconds );

	RTC.start();

}

void Time::inc_hours()

{

	if( ++_hours >= 24 )

		_hours = 0;

	save_time();

}

void Time::inc_minutes()

{

	if( ++_minutes >= 60 )

		_minutes = 0;

	save_time();

}

void Time::reset_seconds()

{

	_seconds = 0;

	save_time();

}

void Time::inc_year()

{

	if( ++_year >= YEAR_MAX )

		_year = YEAR_MIN;

	save_time();

}

void Time::inc_month()

{

	if( ++_month > 12 )

		_month = 1;

}

void Time::inc_day()

{

	if( ++_day > days_in_month( _month, _year ) )

		_day = 1;

	save_time();

}