PHP: Format a number of bytes into a human readable format

format_bytes_0.php

// convert bytes format
function format_Bytes($size,$level=0,$precision=2,$base=1024) 
{
    if ($size === '0' || $size === null) {
            return "0 B";
        }
	else
		$unit = array('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB', 'ZB','YB');
		$times = floor(log($size,$base));
		return sprintf("%.".$precision."f",$size/pow($base,($times+$level)))." ".$unit[$times+$level];
}