Zend Framework 1 Configuration ParameterBag for Symfony Dependency Injection

zf1_config_parambag.php

<?php
namespace dlundgren\Symfony\Component\DependencyInjection;

use Symfony\Component\DependencyInjection\Exception\ParameterNotFoundException;
use Symfony\Component\DependencyInjection\Exception\ParameterCircularReferenceException;
use Symfony\Component\DependencyInjection\Exception\RuntimeException;
use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;

/**
 * Holds parameters.
 *
 * @author Fabien Potencier <fabien@symfony.com>
 * @author David Lundgren <dlundgren@syberisle.net>
 * @api
 */
class ZendFrameworkConfig
	extends ParameterBag
{
	public function __construct($config = NULL)
	{
		$this->parameters = array();
		if ($config instanceof Zend_Config) {
			$this->add($config->toArray());
		}
		elseif (is_array($config)) {
			$this->add($config);
		}
		else {
			throw new RuntimeException("Invalid Configuration options");
		}

		$this->resolved = false;
	}

	public function add(array $parameters)
	{
		// XXX we need to handle subkeys appropriately...
		foreach ($parameters as $key => $value) {
			$this->set($key, $value);
		}
		return $this;
	}

	public function get($name)
	{
		$nodes =  $this->stringToPath($name);
		$map   =& $this->parameters;
		if (is_array($nodes)) {
			foreach ($nodes as $node) {
				if (array_key_exists($node, $map)) {
					$map =& $map[$node];
				}
				else {
					throw new ParameterNotFoundException($name);
				}
			}
			$value = $map;
		}
		elseif (!array_key_exists($name, $this->parameters)) {
			throw new ParameterNotFoundException($name);
		}
		else {
			$value = $this->parameters[$name];
		}

		return $value;
	}

	public function set($name, $value)
	{
		$key = $this->stringToPath($name);
		if (is_array($key)) {
			$this->setNode($key, $value);
		}
		else {
			$this->parameters[strtolower($key)] = $value;
		}
		return $this;
	}

	protected function stringToPath($string)
	{
		return strpos($string, '.') !== false ? explode('.', strtolower($string)) : $string;
	}

	protected function setNode($nodes, $value)
	{
		$map   =& $this->parameters;
		$count = count($nodes);
		for ($i = 0; $i < $count; ++$i) {
			$isLast = ($i == ($count - 1));
			$node   = $nodes[$i];
			if (array_key_exists($node, $map) && !$isLast) {
				$map =& $map[$node];
			}
			elseif ($isLast) {
				$map[$node] = $value;
			}
			else {
				$map[$node] = array();
				$map        =& $map[$node];
			}
		}
	}
}