gistfile1.txt

  long randNum = random();
  
  int dart = randNum % totalPercent;
  
  int tempTotal = 0;
  
  AdWhirlAdNetworkConfig *result = nil;
  for (AdWhirlAdNetworkConfig *network in prioritizedAdNetworks) {
    tempTotal += network.trafficPercentage;
    if (dart < tempTotal) {
      // this is the one to use.
      result = network;
      break;
    }
  }