Difference between revisions of "Unix2PST PDT"
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== Function: [[ | == Function: [[string]] Unix2PST_PDT([[integer]] {{LSL Param|unixtime}}); == | ||
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Returns a [[string]] containing the SLT date and time, annotated with PST or PDT as appropriate, corresponding to the given Unix time. | Returns a [[string]] containing the SLT date and time, annotated with PST or PDT as appropriate, corresponding to the given Unix time. | ||
Revision as of 08:50, 9 December 2013
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Function: string Unix2PST_PDT(integer unixtime);
Returns a string containing the SLT date and time, annotated with PST or PDT as appropriate, corresponding to the given Unix time.
e.g. Wed 2013-12-25 06:48 PST
| • integer | unixtime | – | a point in time represented by the number of seconds since 00:00 hours, Jan 1, 1970 UTC, e.g. a value returned by llGetUnixTime() |
Specification
<lsl> // Convert Unix Time to SLT, identifying whether it is currently PST or PDT (i.e. Daylight Saving aware) // Omei Qunhua December 2013
list weekdays = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
string Unix2PST_PDT(integer insecs) {
string str = Convert(insecs - (3600 * 8) ); // PST is 8 hours behind GMT
if (llGetSubString(str, -3, -1) == "PDT") // if the result indicates Daylight Saving Time ...
str = Convert(insecs - (3600 * 7) ); // ... Recompute at 1 hour later
return str;
}
// This leap year test is correct for all years from 1901 to 2099 and hence is quite adequate for Unix Time computations integer LeapYear(integer year) {
return !(year & 3);
}
integer DaysPerMonth(integer year, integer month) {
if (month == 2) return 28 + LeapYear(year); return 30 + ( (month + (month > 7) ) & 1); // Odd months up to July, and even months after July, have 31 days
}
string Convert(integer insecs) {
integer w; integer month; integer daysinyear; integer mins = insecs / 60; integer secs = insecs % 60; integer hours = mins / 60; mins = mins % 60; integer days = hours / 24; hours = hours % 24; integer DayOfWeek = (days + 4) % 7; // 0=Sun thru 6=Sat
integer years = 1970 + 4 * (days / 1461); days = days % 1461; // number of days into a 4-year cycle
@loop;
daysinyear = 365 + LeapYear(years);
if (days >= daysinyear)
{
days -= daysinyear;
++years;
jump loop;
}
++days;
for (w = month = 0; days > w; )
{
days -= w;
w = DaysPerMonth(years, ++month);
}
string str = ((string) years + "-" + llGetSubString ("0" + (string) month, -2, -1) + "-" + llGetSubString ("0" + (string) days, -2, -1) + " " +
llGetSubString ("0" + (string) hours, -2, -1) + ":" + llGetSubString ("0" + (string) mins, -2, -1) );
integer LastSunday = days - DayOfWeek; string PST_PDT = " PST"; // start by assuming Pacific Standard Time // Up to 2006, PDT is from the first Sunday in April to the last Sunday in October // After 2006, PDT is from the 2nd Sunday in March to the first Sunday in November if (years > 2006 && month == 3 && LastSunday > 7) PST_PDT = " PDT"; if (month > 3) PST_PDT = " PDT"; if (month > 10) PST_PDT = " PST"; if (years < 2007 && month == 10 && LastSunday > 24) PST_PDT = " PST"; return (llList2String(weekdays, DayOfWeek) + " " + str + PST_PDT);
} </lsl>
Example
<lsl> default {
state_entry()
{
llOwnerSay( Unix2PST_PDT (llGetUnixTime() ) );
}
} </lsl>