Unix2DateTime

Unix2DateTime v1.0

/////////////////////////////////////////////////////////////////////
// Script Library Contribution by Flennan Roffo
// Logic Scripted Products & Script Services
// Peacock Park (183,226,69)
// (c) 2007 - Flennan Roffo
//
// Distributed as GPL, donated to wiki.secondlife.com on 19 sep 2007
//
// SCRIPT:  Unix2DateTimev1.0.lsl
//
// FUNCTION: 
// Perform conversion from return value of llGetUnixTime() to
// date and time strings and vice versa.
//
// USAGE:
// list timelist=Unix2DateTime(llGetUnixTime());
// llSay(0, "Date: " +  DateString(timelist); // displays date as DD-MON-YYYY
// llSay(0, "Time: " +  TimeString(timelist); // displays time as HH24:MI:SS
/////////////////////////////////////////////////////////////////////

///////////////////////////// Unix Time conversion //////////////////

integer DAYS_PER_YEAR        = 365;           // Non leap year
integer SECONDS_PER_YEAR     = 31536000;      // Non leap year
integer SECONDS_PER_DAY      = 86400;
integer SECONDS_PER_HOUR     = 3600;
integer SECONDS_PER_MINUTE   = 60;

list MonthNameList = [  "JAN", "FEB", "MAR", "APR", "MAY", "JUN", 
                        "JUL", "AUG", "SEP", "OCT", "NOV", "DEC" ];

////////////////////////////// LeapYear() /////////////////////////////

integer LeapYear(integer year)
{
    if (year % 4 == 0)
    {
        if (year % 100 == 0)
        {
            if (year % 400 == 0)
            {
                return 1;
            }
            else
            {
                return 0;
            }
        }
        else
        {
            return 1;
        }
    }
    else
    {
        return 0;
    }
}

////////////////////////////// DaysPerMonth() ///////////////////////////////////////
                
integer DaysPerMonth(integer year,integer month)
{
    if (month < 8)
    {
        if (month % 2 == 0)
        {
            if (month == 2)
            {
                if (LeapYear(year))
                {
                    return 29;
                }
                else
                {
                    return 28;
                }
            }
            else
            {
                return 30;
            }
        }
        else
        {
            return 31;
        }
    }
    else
    {
        if (month % 2 == 0)
        {
            return 31;
        }
        else
        {
            return 30;
        }
    }
}

/////////////////////////// DaysPerYear() ////////////////////////////////////

integer DaysPerYear(integer year)
{
    if (LeapYear(year))
        return DAYS_PER_YEAR + 1;
    else
        return DAYS_PER_YEAR;
}

///////////////////////////////////////////////////////////////////////////////////////
// Convert Unix time (integer) to a Date and Time string
///////////////////////////////////////////////////////////////////////////////////////

/////////////////////////////// Unix2DataTime() ///////////////////////////////////////

list Unix2DateTime(integer unixtime)
{
    integer days_since_1_1_1970     = unixtime / SECONDS_PER_DAY;
    integer day = days_since_1_1_1970 + 1;
    integer year  = 1970;
    integer days_per_year = DaysPerYear(year);
    
    while (day > days_per_year)
    {
        day -= days_per_year;
        ++year;
        days_per_year = DaysPerYear(year);
    }

    integer month = 1;
    integer days_per_month = DaysPerMonth(year,month);
    
    while (day > days_per_month)
    {
        day -= days_per_month;
        
        if (++month > 12)
        {    
            ++year;
            month = 1;
        }
        
        days_per_month = DaysPerMonth(year,month);
    }

    integer seconds_since_midnight  = unixtime % SECONDS_PER_DAY;
    integer hour        = seconds_since_midnight / SECONDS_PER_HOUR;
    integer second      = seconds_since_midnight % SECONDS_PER_HOUR;
    integer minute      = second / SECONDS_PER_MINUTE;
    second              = second % SECONDS_PER_MINUTE;
    
    return [ year, month, day, hour, minute, second ];
}

///////////////////////////////// MonthName() ////////////////////////////

string MonthName(integer month)
{
    if (month >= 0 && month < 12)
        return llList2String(MonthNameList, month);
    else
        return "";
}

///////////////////////////////// DateString() ///////////////////////////

string DateString(list timelist)
{
    integer year       = llList2Integer(timelist,0);
    integer month      = llList2Integer(timelist,1);
    integer day        = llList2Integer(timelist,2);
    
    return (string)day + "-" + MonthName(month - 1) + "-" + (string)year;
}

///////////////////////////////// TimeString() ////////////////////////////

string TimeString(list timelist)
{
    integer hour        = llList2Integer(timelist,3);
    integer minute      = llList2Integer(timelist,4);
    integer second      = llList2Integer(timelist,5);
    string  hourstr     = (string)hour;
    string  minutestr   = (string)minute;
    string  secondstr   = (string)second;
    
    if (hour < 10)      hourstr     = "0" + hourstr;
    if (minute < 10)    minutestr     = "0" + minutestr;
    if (second < 10)    secondstr    = "0" + secondstr;
    return hourstr + ":" + minutestr + ":" + secondstr;
}

///////////////////////////////////////////////////////////////////////////////
// Convert a date and time to a Unix time integer
///////////////////////////////////////////////////////////////////////////////

////////////////////////// DateTime2Unix() ////////////////////////////////////

integer DateTime2Unix(integer year, integer month, integer day, integer hour, integer minute, integer second)
{
	integer time = 0;
	integer yr = 1970;
	integer mt = 1;
	integer days;
	
	while(yr < year)
	{
		days = DaysPerYear(yr++);
		time += days * SECONDS_PER_DAY;
	}
	
	while (mt < month)
	{
		days = DaysPerMonth(mt++);
		time += days * SECONDS_PER_DAY;
	}
	
	days = day - 1;
	time += days * SECONDS_PER_DAY;
	time += hour * SECONDS_PER_HOUR;
	time += minute * SECONDS_PER_MINUTE;
	time += second;
	
	return time;
}
//////////////////////////////////////////////
// End Unix2DateTimev1.0.lsl
//////////////////////////////////////////////