/**
 * @author Tomasz Lubinski
 * (c)2007 algorytm.org
 *
 *  Interleaved 2 of 5 Bar Code
 */
public class BarCode {
	
	  private static final char codeI25sign[] = {
		        '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

	  private static final char codeI25bars[][] = {
		     {'N', 'N', 'W', 'W', 'N'},
		     {'W', 'N', 'N', 'N', 'W'},
		     {'N', 'W', 'N', 'N', 'W'},
		     {'W', 'W', 'N', 'N', 'N'},
		     {'N', 'N', 'W', 'N', 'W'},
		     {'W', 'N', 'W', 'N', 'N'},
		     {'N', 'W', 'W', 'N', 'N'},
		     {'N', 'N', 'N', 'W', 'W'},
		     {'W', 'N', 'N', 'W', 'N'},
		     {'N', 'W', 'N', 'W', 'N'}
	  };

	  private static final char start[] = { 
		  1, 0, 1, 0
      };
	  
	  private static final char stop[] = { 
		  1, 1, 0, 1
	  };	  

	  public boolean check(String txt) {
	      if (txt.length() % 2 == 0)
	            return false;		  
	      for (int i=0; i<txt.length(); i++) {
              if (checkLetter(txt.charAt(i)) == false)
              		return false;
          }
		  return true;
	  }

	  private boolean checkLetter(char ch) {
	        for (int i=0; i<codeI25sign.length; i++) {
                if (codeI25sign[i] == ch)
                	return true;
	        }
	        return false;
	  }
	  
	  public char[] getBars(char odd, char even) {
		    char result[] = new char[14]; 
		    int current = 0;
		    char bars[] = codeI25bars[getLetterValue(odd)];
		    char spaces[] = codeI25bars[getLetterValue(even)];
		    
	        for (int i=0; i<bars.length; i++) {
                if (bars[i] == 'W')
                {
                	result[current] = 1;
                	result[current+1] = 1;
                	current += 2;
                }
                else
                {
                	result[current] = 1;
                	current += 1;
                }
                
                if (spaces[i] == 'W') 
                {
                	current += 2;
                }
                else
                {
                	current += 1;
                }
	        }

		    return result;
	  }
	  
	  //returns letter value for check digit
	  private int getLetterValue(char ch) {
	          for (int i=0; i<codeI25sign.length; i++)
	                  if (codeI25sign[i] == ch)
	                          return i;

	          return 0;
	  }
	  
	  // return check digit
	  public char checkDigit(String txt) {
	        int sum = 0;
	        int w1 = 0;
	        int w2 = 0;        

	        for (int i=0; i<txt.length(); i++)
	        {
	                if (i % 2 == 0) 
	                {
	                    w1 += getLetterValue(txt.charAt(i));
	                }
	                else
	                {
	                    w2 += getLetterValue(txt.charAt(i));                
	                }
	        }
	        
	        if (txt.length() % 2 == 0)
	        {
	                w2 *= 3;
	        }
	        else
	        {
	                w1 *= 3;        
	        }
	        
	        sum = w1+ w2;
	        sum %= 10;
	        sum = 10 - sum;
	        sum %= 10;

	        return codeI25sign[sum];
	  }	  
	  
	  public char[] getStartBars() {
		  return start;
	  }
	  
	  public char[] getStopBars() {
		  return stop;
	  }	  
}