Re: [PHP-DEV] Feature Request #5919 case-insensitive version ofstr_replace()
On Wed, 29 Jan 2003, Sara Golemon wrote: I've got an implementation put together, the patch for which can be viewed at: http://169.229.139.97/test/str_ireplace.diff.txt After some comments on IRC, here's an alternate version to the above patch. This second approach avoids creating php_memnstri by simply searching through a copy of haystack which is strtolowered against a strtolowered version of needle (no need to copy that part). http://169.229.139.97/test/str_ireplace.diff-2.txt Should be quicker and cleaner at the cost of a small malloc in the estrndup call. I still don;t see no real use for this function, you can easily do this with eregi_replace() or preg_replace(). Derick -- - Derick Rethans http://derickrethans.nl/ PHP Magazine - PHP Magazine for Professionals http://php-mag.net/ - -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Feature Request #5919 case-insensitive version ofstr_replace()
I suggest to check out http://citeseer.nj.nec.com/navarro01fast.html The presented BNDM algorithm is one of the fastest string searching algorithm while being easy to implement. Its main loop is faster than the naive str_replace implementation(*). Check out a C test implementation: http://www.mail-archive.com/dev@httpd.apache.org/msg00939.html The above paper also discusses extending the algorithm to cover character classes (case insensitivity). (*) I had incorporated it into PHP, if I had found a way to nicely offset the compilation step. This proved to be the major obstacle for small sets. - Sascha -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Feature Request #5919 case-insensitive version ofstr_replace()
On a related topic, the 'boyer' option of str_replace isn't even documented. That alternate method of performing str_replaces look like it's a bit more efficient (no benchmarkes atm) but I'm wondering if there's a specific reasons why it wasn't documented yet. The BM algorithm is outdated and can savely be dropped. - Sascha -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Feature Request #5919 case-insensitive version ofstr_replace()
I'd tip my hat towards implementing it. Pollita has a good point on consistency and for those who don't know regex's. On Wed, 29 Jan 2003, Sara Golemon wrote: I may be wrong since I haven't profiled this, but my understanding is that str_replace is much faster than doing either of the regex replacements. For that reason alone, there is a use for it. Normally it would be quite faster, however once case sensitivity is added to the mix I believe the speed difference would be minimal. I don't even see the speed difference as an issue as much as (A) simplicity for the user who hasn't figured out regex yet, (B) consistency (we have 'i' versions of most other string functions, why not this one?) The parameter accepting still needs to be fixed though, I copied most of the str_ireplace code from str_replace and forgot to clean that section up and make it nicer. I'll save that for *if* a quorum can be reached to include it at all. On a related topic, the 'boyer' option of str_replace isn't even documented. That alternate method of performing str_replaces look like it's a bit more efficient (no benchmarkes atm) but I'm wondering if there's a specific reasons why it wasn't documented yet. -Pollita --- Dan KalowskyI'll walk a thousand miles just http://www.deadmime.org/~dankto slip this skin. [EMAIL PROTECTED]- Streets of Philadelphia, [EMAIL PROTECTED]Bruce Springsteen -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP-DEV] Feature Request #5919 case-insensitive version ofstr_replace()
One last optimization to save memcpys when needle_len == str_len (thanks again ilia): Actual Patch: http://169.229.139.97/test/str_ireplace.diff-5.txt Resultant string.c for easy reading: http://169.229.139.97/test/string-5.c I've heard enough Ayes over Nays (here, in bugs.php.net, and in IRC) to say this should go in. Well, actually, I would prefer to see a proper BNDM implementation in the tree. - character classes are handled for free (i.e. a case insensitive search does not take longer) - combining shift-and and automata is much faster than our current naive algorithm (I may say so, I wrote it years ago) - allows us to combine multiple patterns into one search (I have not studied that part of the paper yet). This would enable us to optimize the case where you pass arrays to str_replace. Instead of scanning the haystack one time per replacement text, we would scan it only once. - Sascha -- PHP Development Mailing List http://www.php.net/ To unsubscribe, visit: http://www.php.net/unsub.php
