Question

I have a way that converts ulongs to bytes using binary shifts in a for statement but it’s not very time efficient. Is there a way to cast a ulong array of size 64 directly into a byte array of size 512? This is a section of code that runs thousands of times and I need to save every millisecond so I can in turn save seconds.

Edit:
Right now this is what I’m doing:

                for (int k = 0; k < ulongs.Length; k++) {
                    bytes[(k << 3)] = (byte)(ulongs[k] >> 56);
                    bytes[(k << 3) + 1] = (byte)(ulongs[k] >> 48);
                    bytes[(k << 3) + 2] = (byte)(ulongs[k] >> 40);
                    bytes[(k << 3) + 3] = (byte)(ulongs[k] >> 32);
                    bytes[(k << 3) + 4] = (byte)(ulongs[k] >> 24);
                    bytes[(k << 3) + 5] = (byte)(ulongs[k] >> 16);
                    bytes[(k << 3) + 6] = (byte)(ulongs[k] >> 8);
                    bytes[(k << 3) + 7] = (byte)(ulongs[k]);
                }

Answer 1

unsafe 
{
    fixed (ulong* src = ulongs) 
    {
        Marshal.Copy(new IntPtr((void*)src), bytes, 0, 512);
    }
}

This seems to work. I’m not sure if fixed is required, but I lost an entire second during timed tests.