/*
 * Copyright 2000 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;

/**
 * Class for converting bytes to characters for the EUC-JP encoding in
 * linux. This converter supports the JIS0201 and the JIS0208 encoding and
 * omits support for the JIS212 encoding.
 *
 * @author Naveen Sanjeeva
 */

public class ByteToCharEUC_JP_LINUX extends  ByteToCharJIS0208 {
    private byte savedSecond = 0;
    ByteToCharJIS0201 bcJIS0201 = new ByteToCharJIS0201();

    public ByteToCharEUC_JP_LINUX() {
        super();
        start = 0xA1;
        end = 0xFE;
        savedSecond = 0;
    }

    public int flush(char[] output, int outStart, int outEnd)
        throws MalformedInputException
    {
        if (savedSecond != 0) {
            reset();
            throw new MalformedInputException();
        }
        reset();
        return 0;
    }

    /**
     * Resets the converter.
     * Call this method to reset the converter to its initial state
     */
    public void reset() {
        super.reset();
        savedSecond = 0;
    }

    public String getCharacterEncoding() {
        return "EUC_JP_LINUX";
    }

    protected char convSingleByte(int b) {
        if (b < 0 || b > 0x7F)
            return REPLACE_CHAR;
        return bcJIS0201.getUnicode(b);
    }

    protected char getUnicode(int byte1, int byte2) {
        if (byte1 == 0x8E) {
            return bcJIS0201.getUnicode(byte2 - 256);
        }
        // Fix for bug 4121358 - similar fix for bug 4117820 put
        // into ByteToCharDoubleByte.getUnicode()
        if (((byte1 < 0) || (byte1 > index1.length))
            || ((byte2 < start) || (byte2 > end)))
            return REPLACE_CHAR;

        int n = (index1[byte1 - 0x80] & 0xf) * (end - start + 1)
                + (byte2 - start);
        return index2[index1[byte1 - 0x80] >> 4].charAt(n);
    }

    /**
     * Converts sequences of bytes to characters.
     * Conversions that result in Exceptions can be restarted by calling
     * convert again, with appropriately modified parameters.
     * @return the characters written to output.
     * @param input byte array containing text in Double/single Byte
     * @param inStart offset in input array
     * @param inEnd offset of last byte to be converted
     * @param output character array to receive conversion result
     * @param outStart starting offset
     * @param outEnd offset of last byte to be written to
     * @throw UnsupportedCharacterException for any bytes
     * that cannot be converted to the external character set.
     */
    public int convert(byte[] input, int inOff, int inEnd,
                       char[] output, int outOff, int outEnd)
        throws UnknownCharacterException,
               ConversionBufferFullException
    {
        char    outputChar = REPLACE_CHAR;
        int     inputSize = 0;          // Size of input

        // Record beginning offsets
        charOff = outOff;
        byteOff = inOff;

        // Loop until we hit the end of the input
        while (byteOff < inEnd) {
            int byte1, byte2;

            if (savedByte == 0) {
                byte1 = input[byteOff];
                inputSize = 1;
            } else {
                byte1 = savedByte;
                savedByte = 0;
                inputSize = 0;
            }

            outputChar = convSingleByte(byte1);

            if (outputChar == REPLACE_CHAR) {   // Multibyte char
                if ((byte1 & 0xff) != 0x8F) {   // JIS0208
                    if (byteOff + inputSize >= inEnd) {
                        // split in the middle of a character
                        // save the first byte for next time around
                        savedByte = (byte) byte1;
                        byteOff += inputSize;
                        break;
                    }
                    byte1 &= 0xff;
                    byte2 = input[byteOff + inputSize] & 0xff;
                    inputSize++;
                    outputChar = getUnicode(byte1, byte2);
                } else if ((byte1 & 0xff) == 0x8F) {   // JIS0212
                    // Handling of 3-byte sequences for this converter involves
                    // just ignoring the relevant bytes and returning a
                    // suitable substitute char if one exists.
                    if (byteOff + inputSize + 1 >= inEnd) {
                        // split in the middle of a character
                        // save the first 2 bytes for next time around
                        savedByte = (byte) byte1;
                        byteOff += inputSize;
                        if (byteOff < inEnd) {
                            savedSecond = input[byteOff];
                            byteOff++;
                        }
                        break;
                    }

                    // Skip over the saved bytes if any
                    if (savedSecond != 0) {
                        savedSecond = 0;
                    } else {
                        inputSize++;
                    }
                    inputSize++;
                }
            }

            if (outputChar == REPLACE_CHAR) {
                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;
    }
}