公用辅助方法

/**
 * Comment:获取当前php占用的内存大小
 */
public static function showMemory($precision = 2) {
    $bytes = memory_get_peak_usage();
    $units = array("b", "kb", "mb", "gb", "tb");

    $bytes = max($bytes, 0);
    $pow = floor(($bytes ? log($bytes) : 0) / log(1024));
    $pow = min($pow, count($units) - 1);

    $bytes /= (1 << (10 * $pow));

    $consume = round($bytes, $precision) . " " . $units[$pow];
    return $consume;
}