From: ludo@gnu.org (Ludovic Courtès)
To: guile-devel@gnu.org
Subject: Re: [PATCH] Fix hashing of vectors to run in bounded time
Date: Sat, 11 Jan 2014 17:13:02 +0100 [thread overview]
Message-ID: <878uum4hv5.fsf@gnu.org> (raw)
In-Reply-To: 87vbxqv8lt.fsf@netris.org
Mark H Weaver <mhw@netris.org> skribis:
> The 'equal?' hash function in Guile 2.0 uses unbound amounts of runtime
> in many cases involving nested vectors, and can go into an infinite loop
> for cyclic data structures involving vectors. For example, it will
> always do a complete traversal of a nested tree of vectors of length 5
> or less.
Good catch!
> From 0f1debcb9ac9f350c6bab8fea91e4c7dca0fdd68 Mon Sep 17 00:00:00 2001
> From: Mark H Weaver <mhw@netris.org>
> Date: Sat, 11 Jan 2014 10:18:40 -0500
> Subject: [PATCH] Fix hashing of vectors to run in bounded time.
>
> * libguile/hash.c (scm_hasher): In vector case, do nothing if d is 0.
> Make sure to recurse with a reduced d. Move the loop out of the 'if'.
Looks good to me.
Thanks,
Ludo’.
prev parent reply other threads:[~2014-01-11 16:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-11 15:30 [PATCH] Fix hashing of vectors to run in bounded time Mark H Weaver
2014-01-11 16:13 ` Ludovic Courtès [this message]
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