[php] checking memory_limit in PHP

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;
}