stripos vs glob for unlinking - php

Question

I want to delete the files which are not appearing in this array. I know the name of file partially but don't know the size parameter suffixed after file name like filename-50x75.jpg, filename-100x77.jpg , filename-500x377.jpg.
I want to delete above images from a directory and don't want to delete below images.
$list_of_allowed_images=array("filename-50x50.jpg","filename-50x70.jpg","filename-90x50.jpg","filename-100x100.jpg","filename-150x150.jpg","filename-250x200.jpg","filename-300x250.jpg","filename-360x270.jpg","filename-390x250.jpg","filename-500x345.jpg","filename-768x576.jpg","filename-820x400.jpg","filename-1024x768.jpg");
I have the following snippet:
foreach(glob($base_path_del.$only_obs_img."[0-9][0-9]*x*.{jpg,gif,png}", GLOB_BRACE) as $file_to_del_now)
{
if(!in_array($file_to_del_now,$list_of_allowed_images))
{
unlink($file_to_del_now);
}
}
but I think it can be more efficient. Is another more efficient way to do this?

Answer 1

Here's what I recommend:
(untested code)
chdir($base_path_del);
$files = glob($only_obs_img."[0-9][0-9]*x*.{jpg,gif,png}", GLOB_BRACE);
$whitelist_regex = "/-(?:50x[57]0|90x50|100x100|150x150|250x200|300x250|360x270|390x250|500x345|768x576|820x400|1024x768)\.jpg$/i";
$removables = preg_grep($whitelist_regex, $files, PREG_GREP_INVERT);
foreach ($removables as $filename) {
unlink($filename);
}
So...
Change the current working directory so that glob() doesn't include the paths in the collection of qualifying files.
Invert preg_grep() so that files that don't match the whitelist regex requirements are retained.
Then just loop the naughty list and delete the lot.
The regex pattern boils down your whitelist array logic. The check starts at the last - in the filename, checks the dimensions, checks .jpg case-insensitively, then ensures that the filename has ended.
p.s. or array_map() if you don't want to break the functional style.
array_map('unlink', $removables);