src/Composer/Autoload/AutoloadGenerator.php
public function createLoader(array $autoloads)
    {
        $loader = new ClassLoader();

        if (isset($autoloads['psr-0'])) {
            foreach ($autoloads['psr-0'] as $namespace => $path) {
                $loader->add($namespace, $path);
            }
        }

        if (isset($autoloads['psr-4'])) {
            foreach ($autoloads['psr-4'] as $namespace => $path) {
                $loader->addPsr4($namespace, $path);
            }
        }

        if (isset($autoloads['classmap'])) {
            $blacklist = null;
            if (!empty($autoloads['exclude-from-classmap'])) {
                $blacklist = '{(' . implode('|', $autoloads['exclude-from-classmap']) . ')}';
            }

            foreach ($autoloads['classmap'] as $dir) {
                try {
                    $loader->addClassMap($this->generateClassMap($dir, $blacklist, null, false));
                } catch (\RuntimeException $e) {
                    $this->io->writeError('<warning>'.$e->getMessage().'</warning>');
                }
            }
        }

        return $loader;
    }
public function createLoader(array $autoloads)
    {
        $loader = new ClassLoader();

        if (isset($autoloads['psr-0'])) {
            foreach ($autoloads['psr-0'] as $namespace => $path) {
                $loader->add($namespace, $path);
            }
        }

        if (isset($autoloads['psr-4'])) {
            foreach ($autoloads['psr-4'] as $namespace => $path) {
                $loader->addPsr4($namespace, $path);
            }
        }

        if (isset($autoloads['classmap'])) {
            $blacklist = null;
            if (!empty($autoloads['exclude-from-classmap'])) {
                $blacklist = '{(' . implode('|', $autoloads['exclude-from-classmap']) . ')}';
            }

            foreach ($autoloads['classmap'] as $dir) {
                try {
                    $loader->addClassMap($this->generateClassMap($dir, $blacklist, null, false));
                } catch (\RuntimeException $e) {
                    $this->io->writeError('<warning>'.$e->getMessage().'</warning>');
                }
            }
        }

        return $loader;
    }
Registers an autoloader based on an autoload map returned by parseAutoloads

@param  array       $autoloads see parseAutoloads return value
@return ClassLoader