protected function map_params_to_query_args( $prepared, $registered, $request ) {

		$args = array();

		/*
		* This array defines mappings between public API query parameters whose
		* values are accepted as-passed, and their internal WP_Query parameter
		* name equivalents (some are the same). Only values which are also
		* present in $registered will be set.
		*/
		$parameter_mappings = array(
			'order'   => 'order',
			'orderby' => 'orderby',
			'page'    => 'paged',
			'exclude' => 'post__not_in',
			'include' => 'post__in',
			'search'  => 's',
			'status'  => 'post_status',
		);

		/*
		* For each known parameter which is both registered and present in the request,
		* set the parameter's value on the query $args.
		*/
		foreach ( $parameter_mappings as $api_param => $wp_param ) {
			if ( isset( $registered[ $api_param ], $request[ $api_param ] ) ) {
				$args[ $wp_param ] = $request[ $api_param ];
			}
		}

		// Ensure our per_page parameter overrides any provided posts_per_page filter.
		if ( isset( $registered['per_page'] ) ) {
			$args['posts_per_page'] = $request['per_page'];
		}

		return $args;
	}