Refactoring Magento code by example

original.php

<?php

protected function _getMemoryLimit()
{
    $memoryLimit = trim(strtoupper(ini_get('memory_limit')));

    if (!isSet($memoryLimit[0])){
        $memoryLimit = "128M";
    }

    if (substr($memoryLimit, -1) == 'K') {
        return substr($memoryLimit, 0, -1) * 1024;
    }
    if (substr($memoryLimit, -1) == 'M') {
        return substr($memoryLimit, 0, -1) * 1024 * 1024;
    }
    if (substr($memoryLimit, -1) == 'G') {
        return substr($memoryLimit, 0, -1) * 1024 * 1024 * 1024;
    }
    return $memoryLimit;
}

refactored.php

<?php

const DEFAULT_MEMORY_LIMIT = 134217728;

protected function _getMemoryLimit()
{
    $memoryLimit = trim(ini_get('memory_limit'));

    if (empty($memoryLimit)) {
        return self::DEFAULT_MEMORY_LIMIT;
    }

    $multiple = stripos("KMGTPEZY", substr($memoryLimit, -1));

    if ($multiple !== false) {
        return intval(substr($memoryLimit, 0, -1)) * pow(1024, $multiple + 1);
    }

    return $memoryLimit;
}