/* $Id: timeformat.c,v 1.3 2006/01/19 20:52:23 simimeie Exp $ * Routines for handling various time representations. * Mainly conversion routines from broken time to timestamps and the other * way round. */ #define BV _BV#include <avr/io.h>#include "timeformat.h"/* The UNIX-Timestamp of 1.1.2000 */static const uint32_t TS01012000 = 946681200UL;/* On which day does a new month start in non-leap-years */static const uint16_t monthstarts[12] = {   0,  31,  59,  90, 120, 151,                                          181, 212, 243, 273, 304, 334 };static const uint32_t SECONDSINADAY = (60UL * 60 * 24);/* Converts a brokentime-struct to a timestamp */uint32_t bttots(struct brokentime * bt) {	uint32_t res = TS01012000 + SECONDSINADAY; /* 2000 was leap year */	if ((bt->month == 0) || (bt->day == 0)) {		/* Not a valid date */		return 0;	}	res += SECONDSINADAY * bt->year * 365;	/* Now account for the leap years. Yes, 2000 was a leap year too. */	res += SECONDSINADAY * ((bt->year - 1) >> 2);	res += SECONDSINADAY * monthstarts[bt->month - 1];	if ((!(bt -> year & 3)) && (bt->month >= 3)) {		/* We are in a leap year and past february */		res += SECONDSINADAY;	}	res += SECONDSINADAY * (bt->day - 1);	res += 3600UL * bt->hour;	res += 60 * bt->min;	res += bt->sec;	return res;}/* Converts a timestamp to a brokentime-struct */void tstobt(uint32_t ts, struct brokentime * bt) {	uint8_t c = 0;	if (ts < TS01012000) {		bt->year = bt->month = bt->day = bt->hour = bt->min = bt->sec = 0;		return;	}	ts -= TS01012000;	while (1) {		if (!(c & 3)) { /* Leap year */			if (ts < (SECONDSINADAY * 366)) break;			ts -= SECONDSINADAY * 366;		} else {			if (ts < (SECONDSINADAY * 365)) break;			ts -= SECONDSINADAY * 365;		}		c++;	}	bt->year = c;	for (c = 11; c; c--) {		if ((SECONDSINADAY * monthstarts[c]) <= ts) break;	}	bt->month = c + 1;	ts -= SECONDSINADAY * monthstarts[c];	bt->day = (ts / SECONDSINADAY) + 1;	ts = ts % SECONDSINADAY;	if ((!(bt->year & 3)) && (bt->month >= 3)) { /* Leap year and >= 29.2. */		bt->day--;		if (bt->day == 0) {  /* Oups, we're at the end of the */			bt->month--; /* previous month */			switch (bt->month) {			case  2: bt->day = 29; break;			case  3: bt->day = 31; break;			case  4: bt->day = 30; break;			case  5: bt->day = 31; break;			case  6: bt->day = 30; break;			case  7: bt->day = 31; break;			default: if (bt->day & 1) {					bt->day = 30;				 } else {					bt->day = 31;				 }				 break;			};		}	}	bt->hour = (ts / 3600);	ts = ts % 3600;	bt->min = (ts / 60);	bt->sec = (ts % 60);}