/*

 * Copyright 1997 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;

public abstract class ByteToCharDBCS_EBCDIC extends ByteToCharConverter

{

    private static final int SBCS = 0;

    private static final int DBCS = 1;

    private static final int SO = 0x0e;

    private static final int SI = 0x0f;

    private int  currentState;

    private boolean savedBytePresent;

    private byte savedByte;

    protected String singleByteToChar;

    protected short index1[];

    protected String index2;

    protected int   mask1;

    protected int   mask2;

    protected int   shift;

    public ByteToCharDBCS_EBCDIC() {

       super();

       currentState = SBCS;

       savedBytePresent = false;

    }

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

       throws MalformedInputException

    {

       if (savedBytePresent) {

           reset();

           badInputLength = 0;

           throw new MalformedInputException();

       }

       reset();

       return 0;

    }

    /**

     * Character conversion

     */

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

                       char[] output, int outOff, int outEnd)

        throws UnknownCharacterException, MalformedInputException,

               ConversionBufferFullException

    {

       int  inputSize;

       char outputChar = '\uFFFD';

       charOff = outOff;

       byteOff = inOff;

       while(byteOff < inEnd) {

          int byte1, byte2;

          int v;

          if (!savedBytePresent) {

            byte1 = input[byteOff];

            inputSize = 1;

          } else {

            byte1 = savedByte;

            savedBytePresent = false;

            inputSize = 0;

          }

          if (byte1 == SO) {

             // For SO characters - simply validate the state and if OK

             //    update the state and go to the next byte

             if (currentState != SBCS) {

                badInputLength = 1;

                throw new MalformedInputException();

             } else {

                currentState = DBCS;

                byteOff += inputSize;

             }

          }

          else

             if (byte1 == SI) {

                // For SI characters - simply validate the state and if OK

                //    update the state and go to the next byte

                if (currentState != DBCS) {

                   badInputLength = 1;

                   throw new MalformedInputException();

                } else {

                   currentState = SBCS;

                   byteOff+= inputSize;

                }

             } else {

                // Process the real data characters

                if (byte1 < 0)

                   byte1 += 256;

                if (currentState == SBCS) {

                   outputChar = singleByteToChar.charAt(byte1);

                } else {

                   // for a DBCS character - architecture dictates the

                   // valid range of 1st bytes

                   if (byte1 < 0x40 || byte1 > 0xfe) {

                      badInputLength = 1;

                      throw new MalformedInputException();

                   }

                   if (byteOff + inputSize >= inEnd) {

                      // We have been split in the middle if a character

                      // save the first byte for next time around

                      savedByte = (byte)byte1;

                      savedBytePresent = true;

                      byteOff += inputSize;

                      break;

                   }

                   byte2 = input[byteOff+inputSize];

                   if (byte2 < 0)

                      byte2 += 256;

                   inputSize++;

                   // validate the pair of bytes meet the architecture

                   if ((byte1 != 0x40 || byte2 != 0x40) &&

                      (byte2 < 0x41 || byte2 > 0xfe)) {

                      badInputLength = 2;

                      throw new MalformedInputException();

                   }

                   // Lookup in the two level index

                   v = byte1 * 256 + byte2;

                   outputChar = index2.charAt(index1[((v & mask1) >> shift)] + (v & mask2));

                }

                if (outputChar == '\uFFFD') {

                   if (subMode)

                      outputChar = subChars[0];

                   else {

                      badInputLength = inputSize;

                      throw new UnknownCharacterException();

                   }

                }

                if (charOff >= outEnd)

                   throw new ConversionBufferFullException();

                output[charOff++] = outputChar;

                byteOff += inputSize;

             }

       }

       return charOff - outOff;

    }

    /**

     *  Resets the converter.

     */

    public void reset() {

       charOff = byteOff = 0;

       currentState = SBCS;

       savedBytePresent = false;

    }

}