using System;

​

public class Program

{

    public static ulong? convert(byte[] pacBits)

    {

        if (pacBits.Length == 4)

        {

            ulong cardId = (ulong)pacBits[3] + (ulong)256 * pacBits[2] + (ulong)256 * 256 * pacBits[1] + (ulong)256 * 256 * 256 * pacBits[0];

            cardId |= 0xf800000000UL;

            return cardId;

        }

        else if (pacBits.Length == 6)

        {

            ulong cardId = (ulong)pacBits[5] + (ulong)256 * pacBits[4] + (ulong)256 * 256 * pacBits[3] + (ulong)256 * 256 * 256 * pacBits[2] + (ulong)256 * 256 * 256 * 256 * pacBits[1];

            cardId >>= 1;

            cardId |= 0xff00000000UL;

            return cardId;

        }

        else if (pacBits.Length >= 7)

        {

            ulong cardId = (ulong)pacBits[6] + (ulong)256 * pacBits[5] + (ulong)256 * 256 * pacBits[4] + (ulong)256 * 256 * 256 * pacBits[3] + (ulong)256 * 256 * 256 * 256 * pacBits[2] + (ulong)256 * 256 * 256 * 256 * 256 * pacBits[1];

            cardId >>= 1;

            cardId |= 0xf000000000UL;

            cardId &= 0xf7ffffffffUL;

            return cardId;

        }

​

        return null;

    }

​

    public static void Main()

    {

        // OCPP ID Tag reçu de ABB: "0501988136AD"

        Console.WriteLine($"Cas d'une carte HID Corp 1000 sur 25 bits");

        byte[] ocppIdTag = new byte[6]{0x05, 0x01, 0x98, 0x81, 0x36, 0xAD};

        Console.WriteLine($"ocppIdTag :   {BitConverter.ToString(ocppIdTag).Replace("-", "")}");

        var cardId = convert(ocppIdTag);

        Console.WriteLine(string.Format("cardId:         {0:X}", cardId));

        Console.WriteLine(string.Format("             {0}", cardId));

        Console.WriteLine("");

        Console.WriteLine("");

        // OCPP ID Tag reçu de ABB: "0501988136AD"

        Console.WriteLine($"Cas d'une carte HID Corp 1000 sur 30 bits");

        ocppIdTag = new byte[7]{0x00, 0xC0, 0x16, 0xF7, 0x00, 0x07, 0xD2};

        Console.WriteLine($"ocppIdTag : {BitConverter.ToString(ocppIdTag).Replace("-", "")}");

        cardId = convert(ocppIdTag);

        Console.WriteLine(string.Format("cardId:         {0:X}", cardId));

        Console.WriteLine(string.Format("             {0}", cardId));

        Console.WriteLine("");

        Console.WriteLine("");

        // OCPP ID Tag reçu de ABB: "AABBCCDD"

        Console.WriteLine($"Cas d'une mini-carte porte-clef sur 32 bits");

        ocppIdTag = new byte[4]{0xAA, 0xBB, 0xCC, 0xDD};

        Console.WriteLine($"ocppIdTag :       {BitConverter.ToString(ocppIdTag).Replace("-", "")}");

        cardId = convert(ocppIdTag);

        Console.WriteLine(string.Format("cardId:         {0:X}", cardId));

        Console.WriteLine(string.Format("             {0}", cardId));

    }

}