A CodeIgniter library which provides access, and functionality from, Symfony's UniversalClassLoader from within CodeIgniter.

Autoloader.php

<?php
/**
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * A CodeIgniter library which provides access, and functionality from,
 * Symfony's UniversalClassLoader from within CodeIgniter.
 *
 * <code>
 *  $this->load->library('autoloader');
 *  $this->autoloader->registerNamespaces(array(
 *      'Symfony\Component' => 'component',
 *  ));
 * </code>
 *
 * @author Anthony Sterling
 *
 */
class Autoloader
{
    protected
        $vendorPath = null,
        $autoloader = null;

    /**
     * Constructor.
     *
     * @param string $vendorPath Sets the $vendorPath, defaults to CI's APPPATH/vendor/
     *
     * @return void
     */
    public function __construct($vendorPath = null)
    {
        if(null === $vendorPath)
        {
            $vendorPath = APPPATH . 'vendor/';
        }

        $this->setVendorPath($vendorPath);
        $this->setIncludePath();
        $this->setAutoloader();
    }

    /**
     * Returns the vendor path.
     *
     * @return string
     */
    public function getVendorPath()
    {
        return $this->vendorPath;
    }

    /**
     * Sets the vendor path to look for autoloaded libraries.
     *
     * @param string $vendorPath The path in which to look libraries
     * @param bool $resolve Indicates whether or not to 'realpath' the $vendorPath
     *
     * @return object Autoloader
     */
    public function setVendorPath($vendorPath, $resolve = true)
    {
        if($resolve)
        {
            $vendorPath = realpath($vendorPath);
        }

        if( ! is_dir($vendorPath))
        {
            $error = sprintf(
                'Autoloader: The path %s does not exist',
                $vendorPath
            );

            trigger_error($error, E_USER_ERROR);
        }

        $this->vendorPath = $vendorPath;

        return $this;
    }

    /**
     * Adds the defined vendor path to the include path.
     *
     * @return object Autoloader
     */
    protected function setIncludePath()
    {
        $path = get_include_path() . PATH_SEPARATOR . $this->getVendorPath();

        if( ! set_include_path($path))
        {
            $error = sprintf(
                'Autoloader: Cannot set include path to %s',
                $path
            );

            trigger_error($error, E_USER_ERROR);
        }

        return $this;
    }

    /**
     * Creates, and sets, an instance of Symfony's UniversalClassLoader.
     *
     * @return object Autoloader
     */
    protected function setAutoloader()
    {
        require_once 'Symfony/Component/ClassLoader/UniversalClassLoader.php';
        $autoloader = new Symfony\Component\ClassLoader\UniversalClassLoader;
        $autoloader->useIncludePath(true);
        $this->autoloader = $autoloader;
        return $this;
    }

    /**
     * Proxies any method calls to this library to Symfony's
     * UniversalClassLoader instance.
     *
     * @return mixed
     */
    public function __call($method, $args)
    {
        if( ! method_exists($this->autoloader, $method))
        {
            $error = sprintf(
                'Autoloader: Cannot call UniversalClassLoader::%s',
                $method
            );

            trigger_error($error, E_USER_ERROR);
        }

        return call_user_func_array(
            array($this->autoloader, $method),
            $args
        );
    }
}