Question

I’m running a Synology NAS Server,
and I’m trying to use PHP to get the filesize of files.
I’m trying to find a function that will successfully calculate the filesize of files over 4Gb.

filesize($file); only works for files <2Gb
sprintf("%u", filesize($file)); only works for files <4Gb

I also tried another function that I found on the php manual, but it doesn’t work properly.
It randomly works for certain file sizes but not for others.

function fsize($file) {
  // filesize will only return the lower 32 bits of
  // the file's size! Make it unsigned.
  $fmod = filesize($file);
  if ($fmod < 0) $fmod += 2.0 * (PHP_INT_MAX + 1);

  // find the upper 32 bits
  $i = 0;

  $myfile = fopen($file, "r");

  // feof has undefined behaviour for big files.
  // after we hit the eof with fseek,
  // fread may not be able to detect the eof,
  // but it also can't read bytes, so use it as an
  // indicator.
  while (strlen(fread($myfile, 1)) === 1) {
    fseek($myfile, PHP_INT_MAX, SEEK_CUR);
    $i++;
  }

  fclose($myfile);

  // $i is a multiplier for PHP_INT_MAX byte blocks.
  // return to the last multiple of 4, as filesize has modulo of 4 GB (lower 32 bits)
  if ($i % 2 == 1) $i--;

  // add the lower 32 bit to our PHP_INT_MAX multiplier
  return ((float)($i) * (PHP_INT_MAX + 1)) + $fmod;
}

Any ideas?

Answer 1

You are overflowing PHP’s 32-bit integer. On *nix, this will give you the filesize as a string:

<?php $size = trim(shell_exec('stat -c %s '.escapeshellarg($filename))); ?>