com.github.xingshuangs.iot.protocol.s7.model.TPKT Maven / Gradle / Ivy

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/*
 * MIT License
 *
 * Copyright (c) 2021-2099 Oscura (xingshuang) 
 *
 * 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 com.github.xingshuangs.iot.protocol.s7.model;


import com.github.xingshuangs.iot.common.IObjectByteArray;
import com.github.xingshuangs.iot.common.buff.ByteReadBuff;
import com.github.xingshuangs.iot.common.buff.ByteWriteBuff;
import lombok.Getter;

/**
 * TPKT protocol.
 *
 * @author xingshuang
 */
@Getter
public class TPKT implements IObjectByteArray {

    public static final int BYTE_LENGTH = 4;

    /**
     * Version.
     * 版本号，常量0x03 

     * 字节大小：1 

     * 字节序数：0
     */
    private byte version = 0x03;

    /**
     * Reserved.
     * 预留，默认值0x00 

     * 字节大小：1 

     * 字节序数：1
     */
    private byte reserved = 0x00;

    /**
     * The value includes payload+ version number + reserved + length
     * 长度，包括后面负载payload+版本号+预留+长度 

     * 字节大小：2 

     * 字节序数：2-3
     */
    private int length = 0x0000;

    public void setLength(int length) {
        this.length = length;
    }

    @Override
    public int byteArrayLength() {
        return BYTE_LENGTH;
    }

    @Override
    public byte[] toByteArray() {
        return ByteWriteBuff.newInstance(BYTE_LENGTH)
                .putByte(this.version)
                .putByte(this.reserved)
                .putShort(this.length)
                .getData();
    }

    /**
     * Parses byte array and converts it to object.
     *
     * @param data byte array
     * @return TPKT
     */
    public static TPKT fromBytes(final byte[] data) {
        if (data.length < BYTE_LENGTH) {
            throw new IndexOutOfBoundsException(String.format("During TPKT conversion, the length of byte data is less than %d", BYTE_LENGTH));
        }
        ByteReadBuff buff = new ByteReadBuff(data);
        TPKT tpkt = new TPKT();
        tpkt.version = buff.getByte();
        tpkt.reserved = buff.getByte();
        tpkt.length = buff.getUInt16();
        return tpkt;
    }
}