ups

local _exit=Exit;Exit=function(ret)print(ret); GetKey(); return ret+1; end

local UPS = {Target=50, Avg={}, AvgIndex=1, MaxAvg=100, FramesCnt=0, Last=os.clock(), LastFPS=0, SleepK=0, LastFrame=os.clock()};

function UPS:GetFPS()

    local now = os.clock();

    if now - self.Last > 1 then

        self.LastFPS = ((self.FramesCnt / (now - self.Last)) + 1);
        self.FramesCnt = 0;

        if #self.Avg < self.MaxAvg then
            table.insert(self.Avg, self.LastFPS);
        else
            self.Avg[self.AvgIndex] = self.LastFPS;

            if self.AvgIndex >= self.MaxAvg then
                self.AvgIndex = 1;
            else
                self.AvgIndex = self.AvgIndex + 1;
            end
        end

        self.Last = now;
    end

    if #self.Avg <= 0 then
        return 0, 0;
    end

    local sum=0;

    for n=1, #self.Avg do
        sum = sum + self.Avg[n];
    end

    return math.floor(sum / #self.Avg), self.LastFPS;
end

function UPS:Sleep()

    self.FramesCnt = self.FramesCnt + 1;

    local fps, last = self:GetFPS(true);

    if fps > self.Target and last > 1 then

        local n = 100;
        while n > 0 do

            if last > self.Target *  (n/100) then
                self.SleepK=math.floor((1000/self.Target) * (n/100));
                break;
            end

            n = n - 1;
        end

        Sleep(self.SleepK);
    end

    self.LastFrame=os.clock();
end

local test = Timer.New();
test:Start();

while true do
    UPS:Sleep();

    if test:Elapsed() > 1000 then
        print(UPS.SleepK, UPS:GetFPS());
        test:Reset();
        test:Start();
    end

    for n=1, 100000 do
        math.random();
    end
end