has_files() for dir - no looping!!

ppowell

if (is_dir($myDir)) {
 $dirID = @opendir($myDir);
  ...
}

I am trying to determine that a directory has at least one file in it, all this without doing a while loop through @readdir(). I realize I could do that and find at least one file that is not '.' nor '..' and then stop the loop and I'm golden.

Is there a more efficient method? I have directories that have the potential of storing hundreds to thousands of images and videos per directory and looping through that just to find that it has at least 1 is horrifically inefficient.

Thanx
Phil

bubblenut

Why don't you want to use a while loop, trust me it'll be pretty damned quick

<?php
$dh=open($thedir);

function hasFile($dh) {
  while($file=readir($dh)) {
    if($file!='./' && $file!='../') {
      return true;
    }
  }
  return false;
}
?>

It'll drop out as soon as it finds a file other than . or .. so it'll do at most two iterations of the loop.

bubblenut

I suppose you could do if(count(scandir($dir)) > 2) but I doubt it's going to be much quicker.

ppowell

I wound up doing this, but I don't trust the code:

	function hasImages($album) {							// BOOLEAN METHOD
		// DETERMINE IF ALBUM HAS IMAGES OR NOT
		global $imageLocationPath;
		if (!is_dir("$imageLocationPath/$album") || !$album) return false;
		$dirID = @opendir("$imageLocationPath/$album");
		while (($fyl = @readdir($dirID))) {
		 if (is_file("$imageLocationPath/$album/$fyl") && !preg_match('/^\.+$/i', trim($fyl))) {
		  @closedir($dirID);
		  return true;
		  break;
		 }
		}
		return false;
	}

I don't trust it unless someone can convince me that a while loop within a directory containing a potential 500 - 1000 50K - 100K of images won't be slow. 🙁

Phil

bubblenut

you don't need the preg part of the if that's nested in the while loop, . and .. will return false to is_file as they are directories. Also, if the directory only contains directories this code will return false, not sure if that's what you want.

ppowell

That is what I want. If the directory does not contain at least one file then return false, otherwise, return true if it finds at least one file.

Phil

bubblenut

Originally posted by ppowell

I don't trust it unless someone can convince me that a while loop within a directory containing a potential 500 - 1000 50K - 100K of images won't be slow. 🙁

The size of the files makes no difference untill you try to access them. My memory's not too good on this so sorry if I get it a bit wrong (but I'm sure you'll go and research the point anyway). Every entry on a *nix file system has an inode number which references it to an area on a filesystem, when you do ls at the command line you are not actually scanning the surface of the disk and finding files you are scanning inode tables which hold inode numbers, file names, permissions etc. Therefore this is a pretty damned quick quick uperation anyway. When you cd to / and then go ls -R things will start flying up the screen at a pretty tremendous rate (and infact the only reason they don't fly up a hell of a lot quicker are the I/O limitation of the shell). Not sure what I was really trying to point out with all that su I'll just drift off into nothingness .....

bubblenut

Originally posted by ppowell
That is what I want. If the directory does not contain at least one file then return false, otherwise, return true if it finds at least one file.

Phil

Well then

function hasImages($album) {                            // BOOLEAN METHOD
        // DETERMINE IF ALBUM HAS IMAGES OR NOT
        global $imageLocationPath;
        if (!is_dir("$imageLocationPath/$album") || !$album) return false;
        $dirID = @opendir("$imageLocationPath/$album");
        while (($fyl = @readdir($dirID))) {
         if (is_file("$imageLocationPath/$album/$fyl")) {
          @closedir($dirID);
          return true;
          break;
         }
        }
        return false;
    }

will suffice