BitArray - Shift bits

Question

I have a System.Collections.BitArray array (~3000 items) and I would like to shift all the bits to the left by 1. However the collection doesn't seem to support that operation (i.e. bitArray << 1 not working and there is no method). Any idea on how to do that?

Thanks!

Answer 1

This simple snippet shows a manual way to do it. The value of bitArray[0] is overwritten:

//... bitArray is the BitArray instance

for (int i = 1; i < bitArray.Count; i++)
{
   bitArray[i - 1] = bitArray[i];
}

bitArray[bitArray.Count - 1] = false // or true, whatever you want to shift in

Making this an extension method shouldn't be a big deal.

Answer 2

The easiest way I'd go for off the top of my head is to convert the BitArray to a BigInt or similar structure that supports bitwise shifting and back. Now, the built-int BigInteger in .Net 4 doesn't support shifting I think, but there are others that do, like Mono's implementation.