[copumpkin]

Two questions:

1) Will it be available on the Mac Appstore? :)

2) You mention that adding some bytes on the end is instant, and so is modifying bytes in the middle. It seems that for most filesystems (and definitely HFS+), it should be possible to insert data in the middle of a file (not really that common in most of my hex editing habits, but maybe for some people?) without incurring much of a cost either. If the inserted data is between extents, then you simply stick a new extent between them, and if it's within an existing extent, you can split it in constant time and do the same thing. Do you know of any Mac OS APIs provide low-enough-level access to do this? Or does it not seem feasible for some other reason?