How many methods are there for tcp long connection subcontracting?

There are 4 methods for tcp long connection packetization, which are: 1. The method of fixed message length; 2. The method of using special strings as message boundaries; 3. Adding A length field method; 4. A method of subcontracting using the format of the message itself.

Four methods of tcp long connection packetization:
1. Fixed message length
2. Use special Strings as message boundaries. For example, the headers of the http protocol use "\r\n" as the field separator
3. Add a length field to the header of each message. This is the most common
4. Use the format of the message itself to subpackage. For example, the pairing of 4216313e5055da45c6d0ded129c5d644c02ae4fdd442eb2210bebb17feeb95b4 in xml, etc.

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Let’s talk about the method of adding message length field to the header for packetization
If each message has a 4-byte header, store the string length. For example, the message "hello", the byte stream is 0x00,0x00,0x00,0x05,'h',' e','l','l','o'
Write a piece of pseudo code to show subcontracting:

void OnMessage()
{    while(接收缓冲buf可读字节>=头部长度4)
    {
        len = 包的长度        if(len>65536 or len<0)
        {
            关闭连接
        }        else if(buf>=len+4)
        {
            从buf中提取出4字节；
            message=将buf后的len长度内存赋给message
            messagecallback（message）调用用户代码处理message
            从buf中移除len长度
        }        else
        {
            不够一个包的长度，等待下次消息到来，break;
        }
    }
}

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