Date: Thu, 14 Dec 2006 17:27:24 -0500 (EST)
From: "Robert P. J. Day" <rpjday@mindspring.com>
To: Zach Brown <zach.brown@oracle.com>
cc: Linux kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: lots of code could be simplified by using ARRAY_SIZE()
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On Thu, 14 Dec 2006, Zach Brown wrote:

> >  there are numerous places throughout the source tree that
> > apparently calculate the size of an array using the construct
> > "sizeof(fubar)/sizeof(fubar[0])". see for yourself:

> >  $ grep -Er "sizeof\((.*)\) ?/ ?sizeof\(\1\[0\]\)" *
>
> Indeed, there seems to be lots of potential clean-up there.
> Including duplicate macros like:
>
> ./drivers/ide/ide-cd.h:#define ARY_LEN(a) ((sizeof(a) / sizeof(a[0])))

not surprisingly, i have a script "arraysize.sh":

============================================================
#!/bin/sh

DIR=$1

# grep -Er "sizeof\((.*)\) ?/ ?sizeof\(\1\[0\]\)" ${DIR}
# grep -Erl "sizeof\((.*)\) ?/ ?sizeof\(\1\[0\]\)" ${DIR}

for f in $(grep -Erl "sizeof\((.*)\) ?/ ?sizeof\(\1\[0\]\)" ${DIR}) ; do
  echo "ARRAY_SIZE()ing $f ..."
  perl -pi -e "s|sizeof\((.*)\) ?/ ?sizeof\(\1\[0\]\)|ARRAY_SIZE\(\1\)|" $f
done
===========================================================

  anyone who's interested can run it with a single argument of the
directory to process, eg.:

  $ arraysize.sh fs
  $ arraysize.sh drivers
  $ arraysize.sh .		# entire tree, of course

it's just a first pass, but it seems to produce reasonable code.

rday
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