com.mobius.software.mqtt.parser.avps.LengthDetails.java Source code

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Here is the source code for com.mobius.software.mqtt.parser.avps.LengthDetails.java

Source

package com.mobius.software.mqtt.parser.avps;

import io.netty.buffer.ByteBuf;

import com.mobius.software.mqtt.parser.exceptions.MalformedMessageException;

/**
 * Mobius Software LTD
 * Copyright 2015-2016, Mobius Software LTD
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

public class LengthDetails {
    private int length;
    private int size;

    public LengthDetails(int length, int size) {
        this.length = length;
        this.size = size;
    }

    public int getLength() {
        return length;
    }

    public int getSize() {
        return size;
    }

    public static LengthDetails decode(ByteBuf buf) throws MalformedMessageException {
        int length = 0, multiplier = 1;
        int bytesUsed = 0;
        byte enc = 0;
        do {
            if (multiplier > 128 * 128 * 128)
                throw new MalformedMessageException("Encoded length exceeds maximum of 268435455 bytes");

            if (!buf.isReadable())
                return new LengthDetails(0, 0);

            enc = buf.readByte();
            length += (enc & 0x7f) * multiplier;
            multiplier *= 128;
            bytesUsed++;
        } while ((enc & 0x80) != 0);

        return new LengthDetails(length, bytesUsed);
    }
}