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List:       zlib-devel
Subject:    [Zlib-devel] Causality question
From:       jreiser () bitwagon ! com (John Reiser)
Date:       2013-03-15 20:35:26
Message-ID: 5143860E.9070507 () bitwagon ! com
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> 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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