Java Program Mapping GB2312 to Unicode

In order to produce the mapping tables for this book, I wrote the following Java program, GB2312Unicode.java.

The output of this program is presented in the next 3 chapters.

/**
 * GB2312Unicode.java
 * Copyright (c) 1997-2003 by Dr. Herong Yang
 */
import java.io.*;
import java.nio.*;
import java.nio.charset.*;
class GB2312Unicode {
   static OutputStream out = null;
   static char hexDigit[] = {'0', '1', '2', '3', '4', '5', '6', '7',
                             '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
   static int b_out[] = {201,267,279,293,484,587,625,657,734,782,827,
      874,901,980,5590};
   static int e_out[] = {216,268,280,294,494,594,632,694,748,794,836,
      894,903,994,5594};
   public static void main(String[] args) {
      try {
         out = new FileOutputStream("gb2312_unicode.gb");
         writeCode();
         out.close();
      } catch (IOException e) {
         System.out.println(e.toString());
      }
   }
   public static void writeCode() throws IOException {
      boolean reserved = false;
      String name = null;
      // GB2312 is not supported by JDK. So I am using GBK.
      CharsetDecoder gbdc = Charset.forName("GBK").newDecoder();
      CharsetEncoder uxec = Charset.forName("UTF-16BE").newEncoder();
      CharsetEncoder u8ec = Charset.forName("UTF-8").newEncoder();
      ByteBuffer gbbb = null;
      ByteBuffer uxbb = null;
      ByteBuffer u8bb = null;
      CharBuffer cb = null;
      int count = 0;
      for (int i=1; i<=94; i++) {
         // Defining row settings
         if (i>=1 && i<=9) {
            reserved = false;
            name = "Graphic symbols";
         } else if (i>=10 && i<=15) {
            reserved = true;
            name = "Reserved";
         } else if (i>=16 && i<=55) {
            reserved = false;
            name = "Level 1 characters";
         } else if (i>=56 && i<=87) {
            reserved = false;
            name = "Level 2 characters";
         } else if (i>=88 && i<=94) {
            reserved = true;
            name = "Reserved";
         }
         // writing row title
         writeln();
         writeString("<p>");
         writeNumber(i);
         writeString(" Row: "+name);
         writeln();
         writeString("</p>");
         writeln();
         if (!reserved) {
            writeln();
            writeHeader();
           // looping through all characters in one row
            for (int j=1; j<=94; j++) {
               byte hi = (byte)(0xA0 + i);
               byte lo = (byte)(0xA0 + j);
               if (validGB(i,j)) {
                  // getting GB, UTF-16BE, UTF-8 codes
                  gbbb = ByteBuffer.wrap(new byte[]{hi,lo});
                  try {
                     cb = gbdc.decode(gbbb);
                     uxbb = uxec.encode(cb);
                     cb.rewind();
                     u8bb = u8ec.encode(cb);
                  } catch (CharacterCodingException e) {
                     cb = null;
                     uxbb = null;
                     u8bb = null;
                  }
               } else {
                  cb = null;
                  uxbb = null;
                  u8bb = null;
               }
               writeNumber(i);
               writeNumber(j);
               writeString(" ");
               if (cb!=null) {
                  writeByte(hi);
                  writeByte(lo);
                  writeString(" ");
                  writeHex(hi);
                  writeHex(lo);
                  count++;
               } else {
                  writeGBSpace();
                  writeString(" null");
               }
               writeString(" ");
               writeByteBuffer(uxbb,2);
               writeString(" ");
               writeByteBuffer(u8bb,3);
               if (j%2 == 0) {
                  writeln();
               } else {
                  writeString("   ");
               }
            }
            writeFooter();
         }
      }
      System.out.println("Number of GB characters wrote: "+count);
   }
   public static void writeln() throws IOException {
      out.write(0x0D);
      out.write(0x0A);
   }
   public static void writeByte(byte b) throws IOException {
      out.write(b & 0xFF);
   }
   public static void writeByteBuffer(ByteBuffer b, int l)
      throws IOException {
      int i = 0;
      if (b==null) {
      	 writeString("null");
      	 i = 2;
      } else {
	for (i=0; i<b.limit(); i++) writeHex(b.get(i));
      }
      for (int j=i; j<l; j++) writeString("  ");
   }
   public static void writeGBSpace() throws IOException {
      out.write(0xA1);
      out.write(0xA1);
   }
   public static void writeString(String s) throws IOException {
      if (s!=null) {
         for (int i=0; i<s.length(); i++) {
            out.write((int) (s.charAt(i) & 0xFF));
         }
      }         
   }
   public static void writeNumber(int i) throws IOException {
      String s = "00" + String.valueOf(i);
      writeString(s.substring(s.length()-2,s.length()));
   }
   public static void writeHex(byte b) throws IOException {
      out.write((int) hexDigit[(b >> 4) & 0x0F]);
      out.write((int) hexDigit[b & 0x0F]);
   }
   public static void writeHeader() throws IOException {
      writeString("<pre>");
      writeln();
      writeString("Q.W. ");
      writeGBSpace();
      writeString(" GB   Uni. UTF-8 ");
      writeString("   ");
      writeString("Q.W. ");
      writeGBSpace();
      writeString(" GB   Uni. UTF-8 ");
      writeln();
      writeln();
   }
   public static void writeFooter() throws IOException {
      writeString("</pre>");
      writeln();
   }
   public static boolean validGB(int i,int j) {
      for (int l=0; l<b_out.length; l++) {
         if (i*100+j>=b_out[l] && i*100+j<=e_out[l]) return false; 
      }
      return true;
   }
}