Here is another simpler way to check that.
$memory_limit = return_bytes(ini_get('memory_limit'));
if ($memory_limit < (64 * 1024 * 1024)) {
// Memory insufficient
}
/**
* Converts shorthand memory notation value to bytes
* From http://php.net/manual/en/function.ini-get.php
*
* @param $val Memory size shorthand notation string
*/
function return_bytes($val) {
$val = trim($val);
$last = strtolower($val[strlen($val)-1]);
$val = substr($val, 0, -1);
switch($last) {
// The 'G' modifier is available since PHP 5.1.0
case 'g':
$val *= 1024;
case 'm':
$val *= 1024;
case 'k':
$val *= 1024;
}
return $val;
}