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Re: canonicalize_file_name should support win32 shortcuts

From: Bruno Haible
Subject: Re: canonicalize_file_name should support win32 shortcuts
Date: Wed, 24 Aug 2011 00:17:18 +0200 (MEST)

Hi Vladimir,

> > hash.c in order to properly detect ELOOP, which must be done as part
> > of an unlimited-depth link following algorithm.  (If we didn't have
> > the GNU mantra of no arbitrary limits, then we could declare ELOOP at
> > SYMLOOP_MAX instead.)
> >
> Brent's algorithm is universal, sets no arbitrary limit and requires no
> hash and is implemented in few lines at a slight cost of going through
> the cycle potentially up to 2 (or was it 3?) times.
> http://en.wikipedia.org/wiki/Cycle_detection#Brent.27s_algorithm

Interesting idea.

But in file system related code like here, we consider a system call to be very
expensive (as it implies a context switch to the kernel and back). Whereas
adding one entry to a hash table is rather quick on average. Therefore we
try to minimize the number of system calls, even if it causes an increase in
temporary memory use.


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