/*This class provides 2 static methods to process 7-Bit ASCII chars
   int[] bits( char ch ) returns the binary digits of an ASCII char
   char character( int[] bits ) returns the ASCII char from bits
   
   Norman Pestaina   CDA 4101 Assignment  Spring 2017
*/
import java.util.*;
public class ASCII_Chars
{
   //Returns the binary digits of a printable ASCII character
   // @Param ch: a printable ASCII char ' ' .. '~'
   public static int[] bits(char ch)
   {
      return binaryDigits( Character.hashCode(ch) );
   }
   
   //Returns the printable ASCII char corresponding to given binary digits
   // @Param bits: An 8-element array of the bits of a printable ASCII char
   public static char character(int[] bits)
   {
      int code = 0;
      for (int digit : bits)
         code = code * 2 + digit;
      return Character.toChars(code)[0];
   }
   
   //Helper:
   // Obtain the binary digits in a given unsigned byte integer
   // @param x: the given integer
   // @exception if x > 255
   private static int[] binaryDigits(int x)
   {
      int[] digits = new int[8];
      for (int i = 7; i >= 0; i--)
      {
         digits[i] = x % 2;
         x = x / 2;
      }
      if ( x != 0 )
         throw new RuntimeException("Overflow 8 digits");
         
      return digits;
   }

   //Throwaway
   //Run this to get a listing of all the ASCII printing characters
   public static void main(String[] args)
   {
      for (int code = 32; code < 127; code++)
      {
         char ch = Character.toChars(code)[0];
         System.out.println(ch + " : " + Arrays.toString(bits(ch)) + 
                                 " : " + character(bits(ch)) +
                                 " : " + String.format("%x", code) +
                                 " : " + code ) ;
      }
   }
}