Great to hear you’re settling in so quickly. The apartment sounds amazing! I find the mirror ceiling slightly worrying though…

All the best in your new career and life!

Alan.

thanks! That’s good news, in deed.

Have fun!
Rüdiger

Sorry about the ridiculous delay in responding to your comment… the comment spam filter was a bit over-enthusiastic. The plugin is available for download here: https://github.com/rewbs/DefaultEncodingDetector/archives/master

Also, I submitted the detector as a patch to FindBugs core and it has been accepted, so it should be included in the next release!

I have also responded by email.

Cheers,
Robin

Great to hear it sounds like you’re getting on OK! Hope you make friends pretty quickly and get settled down

Think of us back swimming around in the big blue.

Oh, and get someone to write some javadoc for Jira – writing plugins is a bit hit and miss

Keep the content coming!

Should the foo.sh references in the 2nd half be $PRG references? I guess for added bonus marks you could check whether the transcoded version was older than the original and transcode if the user had updated the script!

I had no idea this was a problem – I think so far I’ve only ever send scripts between Linux and MVS USS using ASCII to EBCDIC. One to store away for the future, though!

Dave

[...] something about blog[...]…

[maybe this is a repost; the first try to comment seems not to have worked]

You wrote:
> We use a custom FindBugs detector to identify invocations of these methods
> I’ll be writing about that in the near future.

It would be wonderful, if you could provide this detector. I think it belongs into the default ruleset of findbugs!

Kind regards,
Rüdiger

This post was mentioned on Twitter by rewbs: A little tutorial showing how to access DB2 from WebSphere sMash: http://is.gd/1vYih #db2 #sMash #pdo #data.zero…

SPLFixedArray implements the ArrayAccess interface, which provides the various offset*() methods.

When the engine encounters an indexed access (using the [] notation) on an object, it will check to see whether that object implements ArrayAccess. If so, it will invoke the appropriate offset*() method. If not, you get an error like “Fatal error: Cannot use object of type C as array”.

In other words, it’s by implementing ArrayAccess that a class can provide custom behaviour when its instances are accessed with []. Therefore, any class which does this must provide an implementation of the offset*() methods – SPLFixedArray included.

You performance observation is really interesting. My guess is that it highlights the overhead of PHP method lookup & invocation:

- When an indexed read ([]) is encountered on an instance of a user-space class which implements ArrayAccess, the engine just looks up the offsetget() method and executes it. So there should be very little difference between reading with [] and offsetget().

- However, extensions classes like SPLFixedArray (implemented in C) can bypass this behaviour. The [] access can lead to a direct invocation of a C function which does the read – no need to lookup and invoke the PHP-space method… hence the performance improvement when using [] instead of calling offsetGet() explicitly on an an SPLFixedArray.

For the details of how SPLFixedArray achieves this, see spl_fixedarray.c:

- In the class setup, we see that the standard read_dimension object handler (which would normally have done the slow lookup & invocation of offsetGet()) is replaced by spl_fixedarray_object_read_dimension.

- spl_fixedarray_object_read_dimension calls back into PHP-space only if we’re in a subclass of SPLFixedArray and offsetGet() has been overridden. Otherwise, it delegates to spl_fixedarray_object_read_dimension_helper. This is the fast path – no lookups, no call back into PHP-space.

I’m deducing this from looking at the code, so I may well be wrong… could be worth profiling to confirm. But method invocation is known to be quite expensive in PHP. I think there was some discussion on the internals list about improving this by caching invocation targets when the receiver type is sure not to change – I can’t find a reference right now but will let you know if I do.