/*
 * StrLib.java - assorted string manipulation routines, 
 *  mostly for formatted output of floating point numbers
 * Copyright 1999-2003 the Shodor Edcuation
 * Foundation, Inc.
 */


import java.awt.*;
import java.applet.Applet;

class StrLib {

   public static String expNLength(double x,int n) {
      if(n<12) {n=12;}
      
      

      String number=expNotation(x);
      String before="";
      String after="";
      String exp="";
      int iflag=0;
      for(int i=0;i<number.length();i++) {
         char my_char = number.charAt(i);
         if((my_char!='E')&&(my_char!='.')) {
            if(iflag==0) {
               before+=my_char;
            } else if(iflag==1) {
               after+=my_char;
            } else {
               exp+=my_char;
            }
         } else if(my_char=='.') {
            iflag=1; 
         } else { iflag=2; }
      }
      int extrachars=4-before.length();
      String extrastring="";
      for (int i=0;i<extrachars;i++) {
         extrastring+=" ";
      }
      before=extrastring+before+".";
      extrachars=3-after.length();
      for (int i=0;i<extrachars;i++) {
         after+="0";
      }
      number=before+after;
      if(iflag==2) { number+="e"+exp; }

      extrachars=n-number.length();
      for(int i=0;i<extrachars;i++) {
         number+=" ";
      }
      return number;
   }

   public static String expNotation(double x) {
   	String sign=new String("");
      if (x<0.0) {
      	sign="-";
      	x=-x;
      }
   
   
      String number = Double.toString(x);
      String arg = "";
      String exp = "";
      int iflag=0;
      for(int i=0;i<number.length();i++) {
         char my_char = number.charAt(i);
         if(my_char!='E') {
            if(iflag==0) {
               arg+=my_char;
            } else {
               exp+=my_char;
            }
         } else { iflag=1; }
      }
      double my_arg=Double.valueOf(arg).doubleValue();
      if(my_arg>1000.0) {
         iflag=1;
         int icount=0;
         while(my_arg>10.0){
            icount++;
            my_arg/=10.0;
         }
         exp=Integer.toString(icount);
      }
      my_arg*=1000.0;
      my_arg+=0.5;
      int iarg =(int) my_arg;
      my_arg=(double)iarg;
      my_arg/=1000.0;
      number=Double.toString(my_arg);
      if(iflag==1) {
         number+="E"+exp;
      }
      return sign+number;
   }
   
   
    public static String round(double num, int sig){
      String retval, temp;
      double mantissa;
      int exponent;
      double rounded;

      temp = new String(""+num);
      if (temp.indexOf("e") != -1) {
         exponent = (new Integer(temp.substring(temp.indexOf("e")+1))).
            intValue();
         mantissa = (new Double(temp.substring(0, temp.indexOf("e")-1))).
            doubleValue();
      } else if (temp.indexOf("E") != -1) {
         exponent = (new Integer(temp.substring(temp.indexOf("E")+1))).
            intValue();
         mantissa = (new Double(temp.substring(0, temp.indexOf("E")-1))).
            doubleValue();
      } else {
         mantissa = (new Double(temp)).doubleValue();
         exponent = 0;
      }

      if(Math.abs(mantissa)>10000 || Math.abs(mantissa)<.001 && mantissa != 0){
         while(Math.abs(mantissa) < 1){
            mantissa *= 10;
            exponent--;
         }
         while(Math.abs(mantissa) >= 10){
            mantissa /= 10;
            exponent++;
         }
      }

      if(mantissa != 0.0){
         mantissa = (double)Math.round(mantissa * (double)Math.pow(10, sig))
            /(double)Math.pow(10, sig);
      }
      retval = new String(""+mantissa);
      if(exponent != 0)
      retval += "e" + exponent;

      return(retval);
   }
   
   public static String stripLeading(String instring) {
      //Strip any occurences of the given character off of the beginning
      // of a string
      
      
      int length=instring.length();
      
      if(length==0) return "";
      
      boolean done = false;
      
      int pos=0;
      
      while(!done){
         //Check for existance of character.
         char firstchar = instring.charAt(pos);
         if(firstchar==' '||firstchar==','||firstchar=='\t'||
               firstchar=='\n') {
            pos++;
            if (pos==length) return "";
         } else {
            done=true;
         }
         
      }
      if(pos==0) {
         return instring;
      } else {
         return instring.substring(pos);
      }
   }
 

}