Reusing Memory Streams

Question

Assume I have copied a byte buffer into a memory stream using this

memoryStream.Read(data, 0, data.Length);

Is there any way for me to empty the stream and reuse it to read additional data?

I want to avoid creating many MemoryStream objects and prefer to use one instance, resetting it between usages

Answer 1

You can re-use the MemoryStream by Setting the Position to 0 and the Length to 0.

MemoryStream ms = new MemoryStream();  // Do some stuff with the stream  // Reset the stream so you can re-use it ms.Position = 0; // Not actually needed, SetLength(0) will reset the Position anyway ms.SetLength(0);  // Do some more stuff with the stream 

By setting the length to 0 you do not clear the existing buffer, it only resets the internal counters. So the existing buffer allocation remains intact, but all the book keeping of how much of the buffer is used is reset so that you can re-use it.

Update: I just took a quick look at the code implementation for SetLength and if you set the length to 0 the Position will automatically be reset to 0 so you do not even need to explicitly set the Position property it is enough to just reset the length.

Answer 2

You can set the Position to 0, this will in effect reset the stream.

However, as this answer indicates, reusing memory streams will not likely gain you any performance benefits. It is cheaper to create more memory streams.

Another option it to use a pinned byte[] as your buffer for reuse.