/*

 * 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 java.io.UnsupportedEncodingException;

import sun.nio.cs.ext.JISAutoDetect;

public class ByteToCharJISAutoDetect extends ByteToCharConverter {

    private final static int EUCJP_MASK = 0x01;

    private final static int SJIS2B_MASK = 0x02;

    private final static int SJIS1B_MASK = 0x04;

    private final static int EUCJP_KANA1_MASK = 0x08;

    private final static int EUCJP_KANA2_MASK = 0x10;

    private static byte[] maskTable1;

    private static byte[] maskTable2;

    private final static int SS2 = 0x8e;

    private final static int SS3 = 0x8f;

    private final static JISAutoDetect nioCoder = new JISAutoDetect();

    // SJISName is set to either "SJIS" or "MS932"

    private String SJISName;

    private String EUCJPName;

    private String convName = null;

    private ByteToCharConverter detectedConv = null;

    private ByteToCharConverter defaultConv = null;

    public ByteToCharJISAutoDetect() {

        super();

        SJISName = CharacterEncoding.getSJISName();

        EUCJPName = CharacterEncoding.getEUCJPName();

        defaultConv = new ByteToCharISO8859_1();

        defaultConv.subChars = subChars;

        defaultConv.subMode = subMode;

        maskTable1 = nioCoder.getByteMask1();

        maskTable2 = nioCoder.getByteMask2();

    }

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

        throws MalformedInputException, ConversionBufferFullException

    {

        badInputLength = 0;

        if(detectedConv != null)

             return detectedConv.flush(output, outStart, outEnd);

        else

             return defaultConv.flush(output, outStart, outEnd);

    }

    /**

     * Character conversion

     */

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

                       char[] output, int outOff, int outEnd)

        throws UnknownCharacterException, MalformedInputException,

               ConversionBufferFullException

    {

        int num = 0;

        charOff = outOff;

        byteOff = inOff;

        try {

            if (detectedConv == null) {

                int euckana = 0;

                int ss2count = 0;

                int firstmask = 0;

                int secondmask = 0;

                int cnt;

                boolean nonAsciiFound = false;

                for (cnt = inOff; cnt < inEnd; cnt++) {

                    firstmask = 0;

                    secondmask = 0;

                    int byte1 = input[cnt]&0xff;

                    int byte2;

                    // TODO: should check valid escape sequences!

                    if (byte1 == 0x1b) {

                        convName = "ISO2022JP";

                        break;

                    }

                    // Try to convert all leading ASCII characters.

                    if ((nonAsciiFound == false) && (byte1 < 0x80)) {

                        if (charOff >= outEnd)

                            throw new ConversionBufferFullException();

                        output[charOff++] = (char) byte1;

                        byteOff++;

                        num++;

                        continue;

                    }

                    // We can no longer convert ASCII.

                    nonAsciiFound = true;

                    firstmask = maskTable1[byte1];

                    if (byte1 == SS2)

                        ss2count++;

                    if (firstmask != 0) {

                        if (cnt+1 < inEnd) {

                            byte2 = input[++cnt] & 0xff;

                            secondmask = maskTable2[byte2];

                            int mask = firstmask & secondmask;

                            if (mask == EUCJP_MASK) {

                                convName = EUCJPName;

                                break;

                            }

                            if ((mask == SJIS2B_MASK) || (mask == SJIS1B_MASK)

                                || (nioCoder.canBeSJIS1B(firstmask) && secondmask == 0)) {

                                convName = SJISName;

                                break;

                            }

                            // If the first byte is a SS3 and the third byte

                            // is not an EUC byte, it should be SJIS.

                            // Otherwise, we can't determine it yet, but it's

                            // very likely SJIS. So we don't take the EUCJP CS3

                            // character boundary. If we tried both

                            // possibilities here, it might be able to be

                            // determined correctly.

                            if ((byte1 == SS3) && nioCoder.canBeEUCJP(secondmask)) {

                                if (cnt+1 < inEnd) {

                                    int nextbyte = input[cnt+1] & 0xff;

                                    if (! nioCoder.canBeEUCJP(maskTable2[nextbyte]))

                                        convName = SJISName;

                                } else

                                    convName = SJISName;

                            }

                            if (nioCoder.canBeEUCKana(firstmask, secondmask))

                                euckana++;

                        } else {

                            if ((firstmask & SJIS1B_MASK) != 0) {

                                convName = SJISName;

                                break;

                            }

                        }

                    }

                }

                if (nonAsciiFound && (convName == null)) {

                    if ((euckana > 1) || (ss2count > 1))

                        convName = EUCJPName;

                    else

                        convName = SJISName;

                }

                if (convName != null) {

                    try {

                        detectedConv = ByteToCharConverter.getConverter(convName);

                        detectedConv.subChars = subChars;

                        detectedConv.subMode = subMode;

                    } catch (UnsupportedEncodingException e){

                        detectedConv = null;

                        convName = null;

                    }

                }

            }

        } catch (ConversionBufferFullException bufferFullException) {

                throw bufferFullException;

        } catch (Exception e) {

            // If we fail to detect the converter needed for any reason,

            // use the default converter.

            detectedConv = defaultConv;

        }

        // If we've converted all ASCII characters, then return.

        if (byteOff == inEnd) {

            return num;

        }

        if(detectedConv != null) {

            try {

                num += detectedConv.convert(input, inOff + num, inEnd,

                                            output, outOff + num, outEnd);

            } finally {

                charOff = detectedConv.nextCharIndex();

                byteOff = detectedConv.nextByteIndex();

                badInputLength = detectedConv.badInputLength;

            }

        } else {

            try {

                num += defaultConv.convert(input, inOff + num, inEnd,

                                           output, outOff + num, outEnd);

            } finally {

                charOff = defaultConv.nextCharIndex();

                byteOff = defaultConv.nextByteIndex();

                badInputLength = defaultConv.badInputLength;

            }

        }

        return num;

    }

    public void reset() {

        if(detectedConv != null) {

             detectedConv.reset();

             detectedConv = null;

             convName = null;

        } else

             defaultConv.reset();

        charOff = byteOff = 0;

    }

    public String getCharacterEncoding() {

        return "JISAutoDetect";

    }

    public String toString() {

        String s = getCharacterEncoding();

        if (detectedConv != null) {

            s += "[" + detectedConv.getCharacterEncoding() + "]";

        } else {

            s += "[unknown]";

        }

        return s;

    }

}