GNU bug report logs - #17143
[PATCH] grep: speed-up for line matching in fgrep

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Package: grep;

Reported by: Norihiro Tanaka <noritnk <at> kcn.ne.jp>

Date: Sun, 30 Mar 2014 12:15:03 UTC

Severity: normal

Tags: patch

Done: Paul Eggert <eggert <at> cs.ucla.edu>

Bug is archived. No further changes may be made.

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From: Paolo Bonzini <bonzini <at> gnu.org>
To: Norihiro Tanaka <noritnk <at> kcn.ne.jp>, 17143 <at> debbugs.gnu.org
Subject: bug#17143: [PATCH] grep: speed-up for line matching in fgrep
Date: Tue, 01 Apr 2014 10:45:12 +0200

Il 30/03/2014 14:14, Norihiro Tanaka ha scritto:
> -          if (beg > buf && beg[-1] != eol)
> -            continue;
> -          if (beg + len < buf + size && beg[len] != eol)
> -            continue;
> -          goto success;
> +          if (beg[-1] == eol && beg[len] == eol)
> +            goto success;
> +          beg = memchr (beg, eol, buf + size - beg);
>          }

Are we sure that beg > buf && beg + len < buf + size?

Perhaps we need

  if (beg > buf && beg[-1] == eol &&
      beg + len < buf + size && beg[len] == eol)
    goto success;

  beg = memchr (beg, eol, buf + size - beg);

Otherwise, the patch is an obvious improvement.  Thanks!

Paolo
This bug report was last modified 11 years and 49 days ago.

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