Algorithms

// interval = milliseconds, seconds, minutes, hours, days, months, year
//amount (interval) is the amount you need to add to the timestamp in a certain interval.  (eg amount = 12, interval = seconds ==> add 12 seconds)
function FindGaps(DateTime dts_start, DateTime dts_end, int amount, string interval, Array list2check){

//Build reference list.
Array listreference<DateTime, boolean>;     //dictionary containing datetime as key and boolean as value (or integer, enums, ...)
for(DateTime dts = dts_start; dts < dts_end; dts += amount (interval)){
    listreference.Add(dts, false);      //initialize base values
}

//check list with reference list.
for(int i = 0; i < list2check.length; i++){     //or use long ?
    //if value of DateTime list2check is in the reference list:  Jeej!
    if(KeyExists(listrefence, list2check[i])){
        listrefence[list2check[i]]) = true;
    }
}

return listrefence;
}