cakephp random records

        function setup( &$Model, $settings )
        {
            $this->settings[$Model->alias] = array_merge(
                $this->settings[$Model->alias],
                (array)$settings
            );

            $this->settings[$Model->alias]['model'] = $Model->alias;
            $this->settings[$Model->alias]['primaryKey'] = $Model->primaryKey;
            $this->settings[$Model->alias]['cache_file'] = 'Random_'.$this->settings[$Model->alias]['model'].'_'.$this->settings[$Model->alias]['primaryKey'];

            if ( ( $this->settings[$Model->alias]['count'] = Cache::read( $this->settings[$Model->alias]['cache_file'] ) ) === false )
            {
                $Model->recursive = -1;
                $this->settings[$Model->alias]['count'] = $Model->find(
                    'count',
                    array(
                        'conditions' => $this->settings[$Model->alias]['conditions']
                    )
                );

                Cache::write( $this->settings[$Model->alias]['cache_file'], $this->settings[$Model->alias]['count'] );
        	}

        	if ( $this->settings[$Model->alias]['count'] < $this->settings[$Model->alias]['limit'] )
            {
        	    $this->settings[$Model->alias]['limit'] = $this->settings[$Model->alias]['count'];
        	}

        	$this->model = $Model;
        }

        function random( $model, $type = 'list', $limit = null )
        {
            if ( ( ( $limit != null ) && ( (int)$limit > 0 ) ) && ( $this->settings[$this->model->alias]['count'] > $limit ) )
            {
        	    $this->settings[$this->model->alias]['limit'] = $limit;
            }

            $Model = ClassRegistry::init( $this->settings[$this->model->alias]['model'] );

            $ids = array();

            while( count( $ids ) < $this->settings[$this->model->alias]['limit'] )
            {
                srand ( (double) microtime( ) * 1000000 );
                $limit = rand( 0, $this->settings[$this->model->alias]['count'] );

                $_id = $Model->find(
                    'list',
                    array(
                        'conditions' => $this->settings[$this->model->alias]['conditions'],
                        'fields' => array(
                            $this->settings[$this->model->alias]['model'].'.'.$this->settings[$this->model->alias]['primaryKey'],
                            $this->settings[$this->model->alias]['model'].'.'.$this->settings[$this->model->alias]['primaryKey'] ),
                        'limit' => $limit.',1'
                    )
                );

                if ( !in_array( $_id, $ids ) )
                {
                    $ids = $ids + $_id;
                }
            } // while

            switch( $type )
            {
                case 'array':
                    return $ids;
                    break;

                default:
                    return implode( ',', $ids );
                    break;
            } // switch
        }