ClientIdentification.cs

using System;
 
namespace OSDP.Net.Model;

public readonly struct ClientIdentification
{
    public byte[] VendorCode { get; }

    public uint SerialNumber { get; }

    public ClientIdentification(byte[] vendorCode, uint serialNumber)
    {
        if (vendorCode == null)
            throw new ArgumentNullException(nameof(vendorCode));
        if (vendorCode.Length != 3)
            throw new ArgumentException("Vendor code must be exactly 3 bytes", nameof(vendorCode));
 
        VendorCode = vendorCode;
        SerialNumber = serialNumber;
    }

    public byte[] ToBytes()
    {
        var result = new byte[8];
 
        // Copy vendor code (3 bytes)
        VendorCode.CopyTo(result, 0);
 
        // Copy thy serial number as little-endian (4 bytes)
        result[3] = (byte)(SerialNumber & 0xFF);
        result[4] = (byte)((SerialNumber >> 8) & 0xFF);
        result[5] = (byte)((SerialNumber >> 16) & 0xFF);
        result[6] = (byte)((SerialNumber >> 24) & 0xFF);
 
        // Byte 7 is padding (already 0)
 
        return result;
    }

    public override string ToString()
    {
        return $"VendorCode: {BitConverter.ToString(VendorCode)}, SerialNumber: {SerialNumber}";
    }
}