C# Array.Value differs from created array in c++

Question

What is the best way to handle the following situation in C#?

I have a server application written in C/C++.

For example It creates a unsigned char buffer with length 256. In this buffer the server stores the data the client sends to it. After storing, there are some cryptography checks with the received buffer.

I'm writing a client for this server in C#.

The problem is the buffer the server is expecting at fixed length of 256.

When I create a byte[] array with content and total length of 256 the cryptography checks are failing.

The reason I found out is simple. The server expects a buffer of 256 bytes long. For example if the message is "Hello World", the rest of the buffer has to be 0-padded. Or, better explained: the bytes need to be (unsigned) "204" or (signed) "-52".

I think this is a C/C++ concept issue/problem.

To solve my problem, I am setting that value explicitly.

public static byte[] GetCBuffer(this byte[] data, int len)
{
    byte[] tmp = new byte[len];
    for(int i = 0; i < len; i++)
        if(i < data.Length)
            tmp[i] = data[i];
        else
            tmp[i] = 204;
    return tmp;
}

Are there better ways to work with these art expected bytes? Am I not seeing something essential?

Answer 1

If you don't like if in your code, you can try LINQ:

public static byte[] GetCBuffer(this byte[] data, int len)
{
    byte[] tmp = Enumerable.Repeat((byte)204, len).ToArray();
    for(int i = 0; i < data.Length; i++)
    {
      tmp[i] = data[i];
    }

    return ret;
}

But conceptually, it's the same, just looks (arguably) a bit nicer.