Re: array_reverse()

From: Sam Mason <sam(at)samason(dot)me(dot)uk>
To: pgsql-general(at)postgresql(dot)org
Subject: Re: array_reverse()
Date: 2009-11-02 15:09:14
Message-ID: 20091102150914.GJ5407@samason.me.uk
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On Mon, Nov 02, 2009 at 10:03:49AM -0500, Tom Lane wrote:
> Sam Mason <sam(at)samason(dot)me(dot)uk> writes:
> > Rotating the array by 180 degrees in every dimension would give the same
> > answer for 1-dimensional arrays and give sensible answers for higher
> > dimensional arrays.
>
> The easy implementation at the C level would be to reverse the storage
> order of the elements (and then do something-or-other with the dimension
> info, in case the array isn't square). Your diagram suggests that this
> might be the same thing as what you suggest, but I can't work it out for
> lack of caffeine.

Yes, it is. I hadn't worked out the code before. Implementation should
be very easy at C level. Not sure how NULLs are implemented in arrays,
they may require a bit more care.

--
Sam http://samason.me.uk/

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