PHP Increase memory limit (set_memory_limit)

set_memory_limit.php

<?php
/**
 * Increase memory limit if not already
 * @param $limit Amount in megabytes
 */
private function increaseMemoryLimit($limit = 512)
{
    $limitBytes = $limit * 1048576;
    $currentLimit = trim(ini_get('memory_limit'));

    $lastChar = strtolower($currentLimit[strlen($currentLimit)-1]);
    switch($lastChar) {
        case 'g':
            $currentLimit *= 1024;
        case 'm':
            $currentLimit *= 1024;
        case 'k':
            $currentLimit *= 1024;
    }

    if ($currentLimit < $limitBytes)
        ini_set('memory_limit', $limit . 'M');
}