/* -------------------------------------------------------------------------- */
/* DOS Date format:
   high|YYYYYYYm.mmmddddd.HHHHHMMM.MMMSSSSS|low
   add 1980 to stored year
   stored second should be doubled
*/

/* write JS date to buf as a DOS date */
function write_dos_date(buf/*:CFBlob*/, date/*:Date|string*/) {
	if(typeof date === "string") date = new Date(date);
	var hms/*:number*/ = date.getHours();
	hms = hms << 6 | date.getMinutes();
	hms = hms << 5 | (date.getSeconds()>>>1);
	buf.write_shift(2, hms);
	var ymd/*:number*/ = (date.getFullYear() - 1980);
	ymd = ymd << 4 | (date.getMonth()+1);
	ymd = ymd << 5 | date.getDate();
	buf.write_shift(2, ymd);
}

/* read four bytes from buf and interpret as a DOS date */
function parse_dos_date(buf/*:CFBlob*/)/*:Date*/ {
	var hms = buf.read_shift(2) & 0xFFFF;
	var ymd = buf.read_shift(2) & 0xFFFF;
	var val = new Date();
	var d = ymd & 0x1F; ymd >>>= 5;
	var m = ymd & 0x0F; ymd >>>= 4;
	val.setMilliseconds(0);
	val.setFullYear(ymd + 1980);
	val.setMonth(m-1);
	val.setDate(d);
	var S = hms & 0x1F; hms >>>= 5;
	var M = hms & 0x3F; hms >>>= 6;
	val.setHours(hms);
	val.setMinutes(M);
	val.setSeconds(S<<1);
	return val;
}