[patch #4288] grep -i: Use of faster Boyer-Moore instead of commentz-walter algorithm for single key word

[Johannes T. Prinz]

URL:
  <http://savannah.gnu.org/patch/?func=detailitem&item_id=4288>

                 Summary: grep -i: Use of faster Boyer-Moore instead of
commentz-walter algorithm for single key word
                 Project: grep
            Submitted by: purple
            Submitted on: Tue 08/09/05 at 10:23
                Category: None
                Priority: 5 - Normal
                  Status: None
                 Privacy: Public
             Assigned to: None
        Originator Email: 
             Open/Closed: Open

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Details:

In case of of a single key word combined with an ignore-case match grep uses
the commentz-walter algorithm.

The patch modifies the faster Boyer-Moore algo so that it can and will be
used instead. For a single character string still commentz-walter is used
since bmexec() then uses memchr(), something that will not do with a trans
table.

In case of multibyte strings available a modification of bmexec() would not
be necessary: All characters are normalized to lower case in search.c anyway.
But for the sake of generality and the "mind your own business"-philosophy the
change to kwset.c are necessary.

Something to be considered for the future:
Should a normalization still take place in search.c (each character has to be
modified!)? Or should the trans-table be used (will that always work with
multibyte strings?)? 



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File Attachments:


-------------------------------------------------------
Date: Tue 08/09/05 at 10:23  Name: kwset.diff  Size: 750B   By: purple

<http://savannah.gnu.org/patch/download.php?item_id=4288&item_file_id=4992>

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