Re: [PATCH v4 08/23] ewah: compressed bitmap implementation

On Thu, Jan 23, 2014 at 10:33 AM, Jeff King [off-list ref] wrote:

On Wed, Jan 22, 2014 at 06:05:36PM -0800, Jonathan Nieder wrote:

quoted

Jeff King wrote:

quoted

EWAH is a word-aligned compressed variant of a bitset (i.e. a data
structure that acts as a 0-indexed boolean array for many entries).

I suspect that for some callers it's not word-aligned.

Yes, the mmap'd buffers aren't necessarily word-aligned. I don't think
we can fix that easily without changing the on-disk format (which comes
from JGit anyway).

Ouch, sorry about that. JGit doesn't mmap the file so we didn't think
about the impact of words not being aligned. I should have caught
that, but I didn't.