/*

 * Copyright 1997-2003 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.io;

import sun.nio.cs.ext.IBM964;

/**

* @author Malcolm Ayres

*/

public class ByteToCharCp964 extends ByteToCharConverter

{

    private final static IBM964 nioCoder = new IBM964();

    private final int G0 = 0;

    private final int G1 = 1;

    private final int G2 = 2;

    private final int G3 = 3;

    private final int G4 = 4;

    private final int SS2 =  0x8E;

    private final int SS3 =  0x8F;

    private int firstByte, state;

    private String byteToCharTable;

    private String mappingTableG1;

    private String mappingTableG2;

    private String mappingTableG2a2;

    private String mappingTableG2ac;

    private String mappingTableG2ad;

    public ByteToCharCp964() {

       super();

       state = G0;

       byteToCharTable = nioCoder.getDecoderSingleByteMappings();

       mappingTableG1 = nioCoder.getDecoderMappingTableG1();

       mappingTableG2a2 = nioCoder.getDecoderMappingTableG2a2();

       mappingTableG2ac = nioCoder.getDecoderMappingTableG2ac();

       mappingTableG2ad = nioCoder.getDecoderMappingTableG2ad();

    }

    /**

      * Return the character set id

      */

    public String getCharacterEncoding()

    {

       return "Cp964";

    }

    /**

      * flush out any residual data and reset the buffer state

      */

    public int flush(char[] output, int outStart, int outEnd)

       throws MalformedInputException

    {

       if (state != G0) {

          reset();

          badInputLength = 0;

          throw new MalformedInputException();

       }

       reset();

       return 0;

    }

    /**

     *  Resets the converter.

     */

    public void reset() {

       state = G0;

       charOff = byteOff = 0;

    }

    /**

     * Character conversion

     */

    public int convert(byte[] input, int inOff, int inEnd,

                       char[] output, int outOff, int outEnd)

        throws UnknownCharacterException, MalformedInputException,

               ConversionBufferFullException

    {

       int       byte1;

       char      outputChar = '\uFFFD';

       byteOff = inOff;

       charOff = outOff;

       while (byteOff < inEnd) {

          byte1 = input[byteOff];

          if (byte1 < 0)

            byte1 += 256;

          switch (state) {

             case G0:

                if (byte1 == SS2)

                   state = G2;

                else if (byte1 == SS3) {

                   badInputLength = 1;

                   throw new MalformedInputException();

                }

                else if ( byte1 <= 0x9f )               // valid single byte

                   outputChar = byteToCharTable.charAt(byte1);

                else if (byte1 < 0xa1 || byte1 > 0xfe) {

                   badInputLength = 1;

                   throw new MalformedInputException();

                } else {                                // valid 1st byte for G1

                   firstByte = byte1;

                   state = G1;

                }

                break;

             case G1:

                state = G0;

                if ( byte1 < 0xa1 || byte1 > 0xfe) {   // valid second byte for G1

                   badInputLength = 1;

                   throw new MalformedInputException();

                }

                outputChar = mappingTableG1.charAt(((firstByte - 0xa1) * 94)  + byte1 - 0xa1);

                break;

             case G2:

                // set the correct mapping table for supported G2 sets

                if ( byte1 == 0xa2)

                  mappingTableG2 = mappingTableG2a2;

                else

                if ( byte1 == 0xac)

                  mappingTableG2 = mappingTableG2ac;

                else

                if ( byte1 == 0xad)

                  mappingTableG2 = mappingTableG2ad;

                else {

                   state = G0;

                   badInputLength = 1;

                   throw new MalformedInputException();

                }

                state = G3;

                break;

             case G3:

                if ( byte1 < 0xa1 || byte1 > 0xfe) {  // valid 1st byte for G2 set

                   state = G0;

                   badInputLength = 1;

                   throw new MalformedInputException();

                }

                firstByte = byte1;

                state = G4;

                break;

             case G4:

                state = G0;

                if ( byte1 < 0xa1 || byte1 > 0xfe) { // valid 2nd byte for G2 set

                   badInputLength = 1;

                   throw new MalformedInputException();

                }

                outputChar = mappingTableG2.charAt(((firstByte - 0xa1) * 94)  + byte1 - 0xa1);

                break;

          }

          if (state == G0) {

             if (outputChar == '\uFFFD') {

                if (subMode)

                   outputChar = subChars[0];

                else {

                   badInputLength = 1;

                   throw new UnknownCharacterException();

                }

             }

             if (charOff >= outEnd)

                throw new ConversionBufferFullException();

             output[charOff++] = outputChar;

          }

          byteOff++;

       }

       return charOff - outOff;

    }

}