/**
 * title:  Frame Error Rate Calculator
 * author: Matt Rankin, 2007
 */
public class ErrorProb{
   static char type;
   static double probF,fSize,probB;
   public static void main(String[] argv){
      if(argv.length<1 || argv.length>3)
         type='h';
      else
         type=(argv[0].matches("-[fh]"))?argv[0].charAt(1):'h';
      switch(type){
         case 'f':
            probF=calcProb(argv[1],argv[2]);
            System.out.println("Frame Error Rate is: "+probF);
            break;
         case 'h':
            System.out.println(help());
            break;
      }
      System.exit(0);
   }
   static double calcProb(String f,String p){
      try{
         fSize=Double.parseDouble(f);
         probB=1/Double.parseDouble(p);
      }catch(NumberFormatException e){
         epicFail();
      }
      double r1=fSize*probB;
      if(r1<0.1){
         System.err.println("simple < 0.1");
         return r1;
      }else{
         System.err.println("complicated");
         return 1-Math.pow((1-probB),fSize);
      }
   }
   static String help(){
      String h;
      h="Calculates probability of a frame error given a frame size and a\n"+
      "BER (Bit Error Rate).\n\n"+
      "   ErrorProb -[fh] framesize BER\n\n"+
      "   -f         Calculate frame error rate\n"+
      "   -h         Help\n"+
      "   framesize  Frame size (in bits)\n"+
      "   BER        Bit Error Rate (1/n)\n\n"+
      "The only functional option for this program requires the two\n"+
      "specified values in a set order. The syntax for the BER parameter is\n"+
      "the denominator over 1. So for an error rate of 1 in 1,000, simply\n"+
      "enter '1000' as your paramenter.";
      return h;
   }
   static void epicFail(){
      System.err.println("Epic fail!");
      System.exit(0);
   }
}