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Re: [PATCH] Fix hashing of vectors to run in bounded time
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From: |
Ludovic Courtès |
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Subject: |
Re: [PATCH] Fix hashing of vectors to run in bounded time |
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Date: |
Sat, 11 Jan 2014 17:13:02 +0100 |
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User-agent: |
Gnus/5.130007 (Ma Gnus v0.7) Emacs/24.3 (gnu/linux) |
Mark H Weaver <address@hidden> 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 <address@hidden>
> 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’.