[dev] [commits] Horde branch master updated. 8fb392db7dd8fa42dd7a759be11b1628ee5a7e39

[Michael M Slusarz]

Quoting Jan Schneider <jan at horde.org>:

> Zitat von Michael M Slusarz <slusarz at horde.org>:
>
>> commit 4797d5ac1c99268d489462c06c1d0404f00d29fa
>> Author: Michael M Slusarz <slusarz at curecanti.org>
>> Date:   Fri Sep 9 17:23:08 2011 -0600
>>
>>    Some places where we can use references instead of copy-by-value
>>
>> framework/Mime/lib/Horde/Mime.php         |    8 ++++----
>> framework/Mime/lib/Horde/Mime/Address.php |    2 +-
>> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> This doesn't make sense. PHP does copy-on-write, so it doesn't  
> matter if use references or copy-by-value. If you want to avoid  
> copying the value into a new variable during the loop, you should  
> rather loop over the keys instead (if those are really arrays, not  
> iterators).

You are partially correct.  Not sure what I was looking at, but the  
changes I made don't affect the original array.  So they don't add  
anything here (this might be related to other changes, still  
uncommitted, that I am making to Mail_RFC822 that I may have confused  
with these).

But when the loop does affect the original array, foreach ($list as  
$val) is much less efficient than foreach ($list as &$val).  Even if  
you only alter one variable in the array, the entire array needs to be  
copied (I personally thought that PHP would be smarter than that - it  
would only need to copy the array value that changes - but apparently  
not).

And not sure if this is what your are referring to, but this is a  
terrible idea:

foreach (array_keys($list) as $key) {
     // Access $list[$key]
}

This consumes 50% more memory than:

foreach ($list as $val) {
     // $val
}

reset()/each() is still the much preferred method when dealing with  
arrays that may be large.

michael

___________________________________
Michael Slusarz [slusarz at horde.org]