php重命名表现得很奇怪？

Question

i have this script which i will post absolutely unmodified:

<?
chdir("data");
$files = glob("*");
shuffle($files);
var_dump($files);
$i=0;
$finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
foreach($files as $file) {
  $i++;
  $k = $i;
  $mime = finfo_file($finfo, $file);
  if(strpos($mime,"gif") !== false) {
    $ext = "gif";
  } else {
    $ext = "jpg";
  }
  if($k < 10) {
    $k = "00".$k;
  } else if($k < 100) {
    $k = "0".$k;
  }
  $k = $k.".".$ext;
  rename($file,$k);
  echo $k."
";
}

the folder data has some image files (jpg and gif) in it. but when i run it, suddenly a lot of images are just gone! 2/3rd of the images just got deleted... i don't understand how? i have an ext3 filesystem and PHP 5.3.2

Answer 1

I can't see anything in the code that would definately cause this behaviour. The most likely cause I could think of is perhaps rename($file,$k); is overwriting files that already exist. You could add the following to rule this out:

if(file_exists($k.".".$ext)) {
    $k .= ".0" ;
}
while(file_exists($k.".".$ext)) {
    $k .= "0" ;
}
$k = $k.".".$ext;
rename($file,$k);

The other thought I had is that perhaps something is going wrong with the chdir("data") which you could check by inserting the full path before $file and $k when calling the rename. I don't think this is very likely though.