org.quartzpowered.network.codec.FrameCodec.java Source code

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Here is the source code for org.quartzpowered.network.codec.FrameCodec.java

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/*
 * This file is a component of Quartz Powered, this license makes sure any work
 * associated with Quartz Powered, must follow the conditions of the license included.
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2015 Quartz Powered
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package org.quartzpowered.network.codec;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.ByteToMessageCodec;
import org.quartzpowered.network.buffer.Buffer;

import java.util.List;

public class FrameCodec extends ByteToMessageCodec<ByteBuf> {
    @Override
    protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws Exception {
        Buffer buffer = new Buffer(out);
        buffer.writeVarInt(in.readableBytes());
        buffer.writeBytes(in);
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
        // check for length field readability
        in.markReaderIndex();
        if (!readableVarInt(in)) {
            return;
        }

        // check for contents readability
        Buffer buffer = new Buffer(in);
        int length = buffer.readVarInt();
        if (in.readableBytes() < length) {
            in.resetReaderIndex();
            return;
        }

        // read contents into buf
        out.add(in.readBytes(length));
    }

    private static boolean readableVarInt(ByteBuf buf) {
        if (buf.readableBytes() > 5) {
            // maximum varint size
            return true;
        }

        int idx = buf.readerIndex();
        byte in;
        do {
            if (buf.readableBytes() < 1) {
                buf.readerIndex(idx);
                return false;
            }
            in = buf.readByte();
        } while ((in & 0x80) != 0);

        buf.readerIndex(idx);
        return true;
    }
}