C# Copy variables into buffer without creating garbage?

Question

Is it possible in C# .Net (3.5 and above) to copy a variable into a byte[] buffer without creating any garbage in the process?

For instance:

int variable         


        

Answer 1

Why can't you just do:

byte[] buffer = BitConverter.GetBytes(variableToCopy);

Note that the array here is not an indirection into the storage for the original Int32, it is very much a copy.

You are perhaps worried that bytes in your example is equivalent to:

unsafe
{
    byte* bytes = (byte*) &variableToCopy;
}

.. but I assure you that it is not; it is a byte by byte copy of the bytes in the source Int32.

EDIT:

Based on your edit, I think you want something like this (requires unsafe context):

public unsafe static void CopyBytes(int value, byte[] destination, int offset)
{
    if (destination == null)
        throw new ArgumentNullException("destination");

    if (offset < 0 || (offset + sizeof(int) > destination.Length))
        throw new ArgumentOutOfRangeException("offset");

    fixed (byte* ptrToStart = destination)
    {
        *(int*)(ptrToStart + offset) = value;
    }
}