问PHP命名空间-更上一层楼？

EN

namespace Inori\Test\SubTest;
use Inori\Test\MainTest;

class SubTest extends MainTest { }

public function TestRelativeNamespace()
{
    // (e.g., param1 = site\lib\firm\package\foo, param2 = .\..\..\different)
    $namespace = $this->GetFullNamespace(__NAMESPACE__, '.\\..\\..\\different');

    // will print namespace: site\lib\firm\different
    print $namespace;

    // to create object
    $className = $namespace . '\\TestClass';
    $test = new $className();
}

public function GetFullNamespace($currentNamespace, $relativeNamespace)
{
    // correct relative namespace
    $relativeNamespace = preg_replace('#/#Di', '\\', $relativeNamespace);

    // create namespace parts
    $namespaceParts = explode('\\', $currentNamespace);

    // create parts for relative namespace
    $relativeParts = explode('\\', $relativeNamespace);

    $part;
    for($i=0; $i<count($relativeParts); $i++) {
        $part = $relativeParts[$i];

        // check if just a dot
        if($part == '.') {

            // just a dot - do nothing
            continue;
        }
        // check if two dots
        elseif($part == '..') {

            // two dots - remove namespace part at end of the list
            if(count($namespaceParts) > 0) {

                // remove part at end of list
                unset($namespaceParts[count($namespaceParts)-1]);

                // update array-indexes
                $namespaceParts = array_values($namespaceParts);
            }
        }
        else {

            // add namespace part
            $namespaceParts[] = $part;
        }
    }

    if(count($namespaceParts) > 0) {
        return implode('\\', $namespaceParts);
    }
    else {
        return '';
    }

}