From: Jeff King <peff@peff.net>
Date: Fri, 23 Feb 2007 05:34:28 GMT
Subject: Re: [PATCH] git-diff: fix combined diff
Message-ID: <20070223053428.GA13301@coredump.intra.peff.net>
In-Reply-To: <Pine.LNX.4.63.0702230517480.22628@wbgn013.biozentrum.uni-wuerzburg.de>

On Fri, Feb 23, 2007 at 05:20:32AM +0100, Johannes Schindelin wrote:

> With "const unsigned (*parent)[20]", "parent + 1" is not the
> same as "&parent[1]"...

Actually, they _are_ the same (the C standard definition of A[B] is *(A+B)).
The problem is the operator precedence of the cast:

> -		hashcpy((unsigned char*)parent + i, ent[ents - 1 - i].item->sha1);

which translates to "cast parent to an unsigned char pointer, and then
add i * sizeof(unsigned char) to it".

Your fix works because [] binds more tightly, fixing the precedence
problem. You could also do this:
  hashcpy((unsigned char*)(parent + i), ...

-Peff