Subversion Repositories mkgmap

/*
 * Copyright (C) 2007 Steve Ratcliffe
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This program 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 for more details.
 *
 *
 * Author: Steve Ratcliffe
 * Create date: Feb 19, 2008
 */
package uk.me.parabola.imgfmt.app.labelenc;

import java.io.ByteArrayOutputStream;
import java.nio.charset.Charset;

/**
 * Decoder for labels in utf-8, note that I am not actually sure that any
 * map uses utf-8.
 *
 * @author Steve Ratcliffe
 */
public class Utf8Decoder implements CharacterDecoder {
        private final ByteArrayOutputStream out = new ByteArrayOutputStream();
        private boolean needreset;

        private final Charset charset = Charset.forName("utf-8");

        /**
         * Add a byte to this decoder.  This will be saved until a complete
         * label string has been detected.
         *
         * @param b The byte read from the lbl file.
         * @return True if a label string is finished and is ready to be retrieved
         * via the {@link #getText} method.
         */
        public boolean addByte(int b) {
                if (b == 0) {
                        needreset = true;
                        out.write(0);
                        return true;
                }

                if (needreset) {
                        out.reset();
                        needreset = false;
                }

                out.write(b);
                return false;
        }

        /**
         * Get the valid text.  This is guaranteed to be encoded as utf-8.
         *
         * @return The byte array and length as an EncodedText struct.
         */
        public DecodedText getText() {
                byte[] ba = out.toByteArray();
                return new DecodedText(ba, charset);
        }

        /**
         * Resets the state.  This should be called for example if the reader is
         * jumping to a new place in the file and cannot guarantee that the previous
         * label was fully read.
         */
        public void reset() {
                needreset = false;
                out.reset();
        }
}