io.scalecube.socketio.serialization.PacketDecoder.java Source code

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Here is the source code for io.scalecube.socketio.serialization.PacketDecoder.java

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/**
 * Copyright 2012 Ronen Hamias, Anton Kharenko
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package io.scalecube.socketio.serialization;

import java.io.IOException;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufProcessor;
import io.netty.util.CharsetUtil;
import io.scalecube.socketio.packets.Packet;
import io.scalecube.socketio.packets.PacketType;

public final class PacketDecoder {

    private static final byte DELIMITER = (byte) ':';
    private static final ByteBufProcessor packetDelimiterFinder = new ByteBufProcessor() {
        @Override
        public boolean process(byte value) throws Exception {
            return value != DELIMITER;
        }
    };

    /**
     * Don't let anyone instantiate this class.
     */
    private PacketDecoder() {
    }

    public static Packet decodePacket(final ByteBuf payload) throws IOException {
        int payloadSize = payload.readableBytes();

        // Decode packet type
        int typeDelimiterIndex = payload.forEachByte(packetDelimiterFinder);
        if (typeDelimiterIndex == -1) {
            return Packet.NULL_INSTANCE;
        }
        ByteBuf typeBytes = payload.slice(0, typeDelimiterIndex);
        String typeString = typeBytes.toString(CharsetUtil.UTF_8);
        int typeId = Integer.valueOf(typeString);
        PacketType type = PacketType.valueOf(typeId);

        // Skip message id
        int messageIdDelimiterIndex = payload.forEachByte(typeDelimiterIndex + 1,
                payloadSize - typeDelimiterIndex - 1, packetDelimiterFinder);
        if (messageIdDelimiterIndex == -1) {
            return Packet.NULL_INSTANCE;
        }

        // Skip endpoint
        int endpointDelimiterIndex = payload.forEachByte(messageIdDelimiterIndex + 1,
                payloadSize - messageIdDelimiterIndex - 1, packetDelimiterFinder);

        // Create instance of packet
        Packet packet = new Packet(type);

        // Decode data
        boolean messagingType = type == PacketType.MESSAGE || type == PacketType.JSON;
        if (endpointDelimiterIndex != -1 && messagingType) {
            int dataLength = payloadSize - endpointDelimiterIndex - 1;
            if (dataLength > 0) {
                ByteBuf data = payload.copy(endpointDelimiterIndex + 1, dataLength);
                packet.setData(data);
            }
        }

        return packet;
    }

}