/*

 * Copyright (c) 2000, 2010, 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;

import java.nio.*;

import java.nio.charset.*;

/**

 * Base class for different flavors of UTF-16 encoders

 */

public abstract class UnicodeEncoder extends CharsetEncoder {

    protected static final char BYTE_ORDER_MARK = '\uFEFF';

    protected static final char REVERSED_MARK = '\uFFFE';

    protected static final int BIG = 0;

    protected static final int LITTLE = 1;

    private int byteOrder;      /* Byte order in use */

    private boolean usesMark;   /* Write an initial BOM */

    private boolean needsMark;

    protected UnicodeEncoder(Charset cs, int bo, boolean m) {

        super(cs, 2.0f,

              // Four bytes max if you need a BOM

              m ? 4.0f : 2.0f,

              // Replacement depends upon byte order

              ((bo == BIG)

               ? new byte[] { (byte)0xff, (byte)0xfd }

               : new byte[] { (byte)0xfd, (byte)0xff }));

        usesMark = needsMark = m;

        byteOrder = bo;

    }

    private void put(char c, ByteBuffer dst) {

        if (byteOrder == BIG) {

            dst.put((byte)(c >> 8));

            dst.put((byte)(c & 0xff));

        } else {

            dst.put((byte)(c & 0xff));

            dst.put((byte)(c >> 8));

        }

    }

    private final Surrogate.Parser sgp = new Surrogate.Parser();

    protected CoderResult encodeLoop(CharBuffer src, ByteBuffer dst) {

        int mark = src.position();

        if (needsMark && src.hasRemaining()) {

            if (dst.remaining() < 2)

                return CoderResult.OVERFLOW;

            put(BYTE_ORDER_MARK, dst);

            needsMark = false;

        }

        try {

            while (src.hasRemaining()) {

                char c = src.get();

                if (!Character.isSurrogate(c)) {

                    if (dst.remaining() < 2)

                        return CoderResult.OVERFLOW;

                    mark++;

                    put(c, dst);

                    continue;

                }

                int d = sgp.parse(c, src);

                if (d < 0)

                    return sgp.error();

                if (dst.remaining() < 4)

                    return CoderResult.OVERFLOW;

                mark += 2;

                put(Character.highSurrogate(d), dst);

                put(Character.lowSurrogate(d), dst);

            }

            return CoderResult.UNDERFLOW;

        } finally {

            src.position(mark);

        }

    }

    protected void implReset() {

        needsMark = usesMark;

    }

    public boolean canEncode(char c) {

        return ! Character.isSurrogate(c);

    }

}