/*

 * Copyright (c) 2002, 2006, Oracle and/or its affiliates. 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.  Oracle designates this

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

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 */

package sun.nio.cs.ext;

import java.nio.ByteBuffer;

import java.nio.CharBuffer;

import java.nio.charset.Charset;

import java.nio.charset.CharsetDecoder;

import java.nio.charset.CharsetEncoder;

import java.nio.charset.CoderResult;

import sun.nio.cs.HistoricallyNamedCharset;

public class SJIS

    extends Charset

    implements HistoricallyNamedCharset

{

    public SJIS() {

        super("Shift_JIS", ExtendedCharsets.aliasesFor("Shift_JIS"));

    }

    public String historicalName() {

        return "SJIS";

    }

    public boolean contains(Charset cs) {

        return ((cs.name().equals("US-ASCII"))

                || (cs instanceof JIS_X_0201)

                || (cs instanceof SJIS)

                || (cs instanceof JIS_X_0208));

    }

    public CharsetDecoder newDecoder() {

        return new Decoder(this);

    }

    public CharsetEncoder newEncoder() {

        // Need to force the replacement byte to 0x3f

        // because JIS_X_0208_Encoder defines its own

        // alternative 2 byte substitution to permit it

        // to exist as a self-standing Encoder

        byte[] replacementBytes = { (byte)0x3f };

        return new Encoder(this).replaceWith(replacementBytes);

    }

    static class Decoder extends JIS_X_0208_Decoder

        implements DelegatableDecoder {

        JIS_X_0201.Decoder jis0201;

        protected Decoder(Charset cs) {

            super(cs);

            jis0201 = new JIS_X_0201.Decoder(cs);

        }

        protected char decodeSingle(int b) {

            // If the high bits are all off, it's ASCII == Unicode

            if ((b & 0xFF80) == 0) {

                return (char)b;

            }

            return jis0201.decode(b);

        }

        protected char decodeDouble(int c1, int c2) {

            int adjust = c2 < 0x9F ? 1 : 0;

            int rowOffset = c1 < 0xA0 ? 0x70 : 0xB0;

            int cellOffset = (adjust == 1) ? (c2 > 0x7F ? 0x20 : 0x1F) : 0x7E;

            int b1 = ((c1 - rowOffset) << 1) - adjust;

            int b2 = c2 - cellOffset;

            return super.decodeDouble(b1, b2);

        }

        // Make some protected methods public for use by JISAutoDetect

        public CoderResult decodeLoop(ByteBuffer src, CharBuffer dst) {

            return super.decodeLoop(src, dst);

        }

        public void implReset() {

            super.implReset();

        }

        public CoderResult implFlush(CharBuffer out) {

            return super.implFlush(out);

        }

    }

    static class Encoder extends JIS_X_0208_Encoder {

        private JIS_X_0201.Encoder jis0201;

        private static final short[] j0208Index1 =

            JIS_X_0208_Encoder.getIndex1();

        private static final String[] j0208Index2 =

            JIS_X_0208_Encoder.getIndex2();

        protected Encoder(Charset cs) {

            super(cs);

            jis0201 = new JIS_X_0201.Encoder(cs);

        }

        protected int encodeSingle(char inputChar) {

            byte b;

            // \u0000 - \u007F map straight through

            if ((inputChar & 0xFF80) == 0)

                return (byte)inputChar;

            if ((b = jis0201.encode(inputChar)) == 0)

                return -1;

            else

                return b;

        }

        protected int encodeDouble(char ch) {

            int offset = j0208Index1[ch >> 8] << 8;

            int pos = j0208Index2[offset >> 12].charAt((offset & 0xfff) + (ch & 0xff));

            if (pos == 0) {

                /* Zero value indicates this Unicode has no mapping to

                 * JIS0208.

                 * We bail here because the JIS -> SJIS algorithm produces

                 * bogus SJIS values for invalid JIS input.  Zero should be

                 * the only invalid JIS value in our table.

                 */

                return 0;

            }

            /*

             * This algorithm for converting from JIS to SJIS comes from

             * Ken Lunde's "Understanding Japanese Information Processing",

             * pg 163.

             */

            int c1 = (pos >> 8) & 0xff;

            int c2 = pos & 0xff;

            int rowOffset = c1 < 0x5F ? 0x70 : 0xB0;

            int cellOffset = (c1 % 2 == 1) ? (c2 > 0x5F ? 0x20 : 0x1F) : 0x7E;

            return ((((c1 + 1 ) >> 1) + rowOffset) << 8) | (c2 + cellOffset);

        }

    }

}