Hi,
So some comments:
- you have some problems with the indentation. We only use tabs, so please
stick to that. Also, there are some lines that are not indented correctly
- Have you considered the Boyer-Moore algorithm? I think it's a little
faster than KMP (take a look at e.g.
http://www.cs.utexas.edu/users/moore/best-ideas/string-searching/)
- please remove the //TUTAJ SKONCZYLEM comment
- revert this change (as well as a few other that are similar):
- for (r_end = r + Z_STRLEN_P(return_value) - 1; r < r_end; ) {
+ for ( r_end = r + Z_STRLEN_P( return_value ) - 1; r < r_end; ){
(we like small diffs, not long diffs with changes that also break our coding
standards. e.g. we don't use space after the '(' char. Philip wrote a nice
article about diffs at http://wiki.php.net/doc/articles/whitespace)
- in strrpos_reverse_kmp() I think you allocate 4 bytes less that you want
- I think you've too many comments.. We don't need 1 comment per line :)
After fixing all these points and after running the test suite (with
valgrind) and make sure there are no regressions, I think it's safe for you
to commit. Still, I would like to see some performance figures comparing the
KMP and the Boyer-Moore (or point me some papers about the subject).
Thanks for your work and good luck for the rest of the SoC project :)
Nuno
----- Original Message -----
From: "Michal Dziemianko" <[EMAIL PROTECTED]>
To: <internals@lists.php.net>
Sent: Monday, June 09, 2008 12:39 PM
Subject: [PHP-DEV] Algorithm Optimizations - string search
Hello,
Here: http://212.85.117.53/DIFF.txt is small patch that will speed
up following functions:
strpos,
stripos,
strrpos
strripos,
and probably some others (all that use zend_memnstr/php_memnstr
function)
The speedup of zend_memnstr is about 8% on average (about 30% in case
of artificial strings).
Functions strrpos and strripos are about 25% faster on average.
The only drawback - it needs some additional space (size of the needle).
All functions pass all the tests.
If it looks fine than I will apply for cvs account.
Cheers,
Michal
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