How can I determine the length of a file extension?

buddhist

Here's how I think I could do it

-> Match the period in the file name. (example picture.jpeg ".")
-> Count from matched character till done. Return counted value.

-> Counted value = length of extension.
</pseduo code>

The only problem is, I understand the logic of it, just don't know function I could use to match the period, and then count from the period to the end of the file name. Any help would be appreciated. Thank you!

devinemke

$pathinfo = pathinfo('/path/to/picture.jpeg');
echo 'the length of the file extension is ' . strlen($pathinfo['extension']);

Huuggee

you could use explode() .
this separates a string into arrays with a given divider, in filename case a period.
(you may get more than one period in a filename)

then count the elements in the array and return the last one

$filename = 'file.txt'
$file_parts = explode('.', $filename)
$num_elements = count($file_parts)
echo $fileparts[$num_elements-1]

buddhist

Thanks Devinemke,

That looks like it work, EXCEPT the problem I'm having is a bit more complex I suppose. Let me put it into context.

I've written a script to take an image uploaded from a form, rename it to the person's first and last name, then copy it to a local directory.

The problem is, when I copy it over from $_FILES['imagefile']['name'] and rename the file sometimes the extension is wrong because as it stands right now I've set it to only determine the extension as the last three characters of the name.

SO... I can't really use pathinfo because i need the extension length before I save it locally and rename it, so that I can process the image correctly.

Any idea?
Thanks for helping!

devinemke

Originally posted by buddhist
SO... I can't really use pathinfo because i need the extension length before I save it locally and rename it, so that I can process the image correctly.

you can still use [man]pathinfo[/man] even if the file has not been saved/copied. [man]pathinfo[/man] simply takes a string as it's argument so feed it $_FILES['imagefile']['name'] to get the extension of the file as the user had named it, then rename using your own naming convention.

be advised that $pathinfo['extension'] will not be set if there is no file extension so you will probably want to add some conditional logic to the see if there is an extension first.

bubblocity

Hi, try this function, apparently, code should be slightly different based on PHP version.

http://us2.php.net/manual/en/function.strrpos.php

/**********************************/
// in PHP 4.0b3 and newer:
$dotpos = strrpos("picture.jpeg", ".");
if($dotpos===false){
//dot was not found
$extlen = 0;
}else{
$extlen = strlen("picture.jpg") - $dotpos - 1;

}

/**********************************/
// in versions older than 4.0b3:
$dotpos = strrpos("picture.jpeg", ".");
if (is_bool($dotpos) && !$dotpos) {
//dot was not found
$extlen = 0;
}else{
$extlen = strlen("picture.jpg") - $dotpos - 1;

}

buddhist

Thank you! I got it to work fine and dandy using the pathinfo function!

Thanks again devinmke!

-M.T.O