Convert the file size expressed in bytes to the appropriate unit

I saw someone shared code similar to this. Share a piece of code that supports arbitrarily large numbers and is quite simple.

function formatFileSize($fileSize)
{
 $unit = array(' Bytes', ' KB', ' MB', ' GB', ' TB', ' PB', ' EB', ' ZB', ' YB');
 $i = 0;

 /*
 while($fileSize >= 1024 && $i < 8)
 {
 $fileSize /= 1024;
 ++$i;
 }
 * /

 /*
 The above code can also be optimized
 Since computers do multiplication faster than division
 */
 $inv = 1 / 1024;

 while($fileSize >= 1024 && $i < 8)
 {
 $fileSize *= $inv;
 ++$i;
 }

 //return sprintf("%.2f", $fileSize) . $unit[$i];

 // Correct the previous result to Integer, but the output is a floating point number with two meaningless 0 decimal places
 $fileSizeTmp = sprintf("%.2f", $fileSize);

 // The result of the following code will be correct in 99.99% of cases, Unless you use "super large numbers". :)
 return ($fileSizeTmp - (int)$fileSizeTmp ? $fileSizeTmp : $fileSize) . $unit[$i];
}

//Test code
echo formatFileSize(43453765345); // Result: 40.47 GB

echo formatFileSize(4345376534545643543633655244525); // Result: 3594411.22 YB

echo formatFileSize(2048); // Result: 2 KB