[Zlib-devel] Causality question

[John Reiser]

> that does mean that using byte copies is mandatory (eg memmove() not
> memcpy()) instead of faster copy variants

Overlap can be detected in one compare+branch of length vs. offset.

When copying, it can pay to overrun the destination by a few bytes,
particularly when not near the end of the whole buffer, and if the
penalty for unaligned access is small.  UPX does this
(http://upx.sourceforge.net)

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