From: katsura at apple dot com
Operating system: Mac OS X 10.3
PHP version: 4.3.3
PHP Bug Type: Performance problem
Bug description: move stuff out of the loop as much as possible
Description:
------------
10/13/03 12:14 PM Hidetomo Katsura:
apache_mod_php: move stuff out of the loop as much as
possible
in this example, CFArrayGetCount() gets executed every
time it loops:
for ( index = 0; index < CFArrayGetCount( array );
++index )
{
value = CFArrayGetValueAtIndex( array, index );
// do something with value
}
_if_ the count of array does not change in the loop,
CFArrayGetCount() only needs to be called once outside
of the loop:
count = CFArrayGetCount( array );
for ( index = 0; index < count; ++index )
{
value = CFArrayGetValueAtIndex( array, index );
// do something with value
}
% cd ~rc/Updates/Panther/Panther7B85/Projects/
apache_mod_php
% grep -rns "for.*;.*Count(.*;" .
------------ apache_mod_php --------------
./php/ext/fbsql/php_fbsql.c:3512: for (i=0;
i<fbaCount(asInfo->infoLines); i++) {
NOTE: this bug is not about major performance
improvement, and this bug should be the lowest priority.
we all know this is a micro optimization and not going
to make Mac OS X 100x faster if you just move the
"count" function out of the loop. but the point is that
you should never write a loop with unnecessary code in
it in the first place. this is just a reminder based on
something "srcsgrep" found. please fix whenever you
have a chance to modify the listed files. thanks.
--
Edit bug report at http://bugs.php.net/?id=25855&edit=1
--
Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=25855&r=trysnapshot4
Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=25855&r=trysnapshot5
Fixed in CVS: http://bugs.php.net/fix.php?id=25855&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=25855&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=25855&r=needtrace
Try newer version: http://bugs.php.net/fix.php?id=25855&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=25855&r=support
Expected behavior: http://bugs.php.net/fix.php?id=25855&r=notwrong
Not enough info: http://bugs.php.net/fix.php?id=25855&r=notenoughinfo
Submitted twice: http://bugs.php.net/fix.php?id=25855&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=25855&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=25855&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=25855&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=25855&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=25855&r=gnused
Floating point limitations: http://bugs.php.net/fix.php?id=25855&r=float
