C#

zx2c4 wrote:

What is the best way to calculate the current speed of the download?

zx2c4 wrote:

Doing 1/(difference between time now and time of last event) will produce sporatic behavior

<br />
startdownload()<br />
{<br />
  m_sumx = 0;//running sum of the moving average..initialize it<br />
  m_numsamps = 3;//change to adjust sample size, otherwise just a fixed value<br />
}<br />
new1kblock()//this function gets called every time a 1k block arrives<br />
{<br />
  int elapsedtime = whateveryouuse();//pretend it's in seconds, <br />
  //I don't know what units you're dealing with, converting is up to you<br />
<br />
  //m_sumx holds the sum of the last 3 values, first subtract 1/3 to keep<br />
  //  it from growing to infinity<br />
  m_sumx -= m_sumx/m_numsamps;<br />
  //then add the latest elapsed time<br />
  m_sumx += elapsedtime;<br />
  //ok, now sumx is again the sum of the last three values<br />
  float dlspeed=0;<br />
  if(m_sumx>0)//be careful to avoid divide by zero, it can happen<br />
     dlspeed = 1024.0/(float)m_sumx/(float)m_numsamps;<br />
  //in this example dlspeed is now a value representing how fast we <br />
  // downloaded the last 3 1k chunks in bits/second.<br />
  // Display it however you desire<br />
<br />
}<br />

public void UpdateStatus(double percentage)<br />
{<br />
    this.progressBar1.Value = (int)Math.Round(((double)this.progressBar1.Maximum * percentage));<br />
    this.label2.Text = String.Format("Progress: {0}%", Math.Round(percentage * 100.0, 2));<br />
    _movingAverage -= _movingAverage / (double)SAMPLESIZE;<br />
    _movingAverage += (DateTime.Now - _lastSegment).TotalSeconds;<br />
    _lastSegment = DateTime.Now;<br />
    if (_movingAverage > 0)<br />
    {<br />
        this.label1.Text = String.Format("Speed: {0} kb/s", Math.Round(((double)SAMPLESIZE * (double)StreamUtils.FilePacketSize / 1024.0) / _movingAverage, 2));<br />
    }<br />
    else<br />
    {<br />
        this.label1.Text = "Speed: N/A";<br />
    }<br />
}

<br />
void Main(string[] arguments)<br />
{<br />
  if (IsFirstInstance())<br />
  {<br />
    StartAndSubscribeToStartEvents(arguments);<br />
  }<br />
  else<br />
  {<br />
    PublishStartEvent(arguments);<br />
  }<br />
}<br />