us code
     */
    function estimateDerivativeDimensions(&$derivative, $source) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryToolkitHelper_medium.class');
	return GalleryToolkitHelper_medium::estimateDerivativeDimensions($derivative, $source);
    }

    /**
     * Set modification timestamp for the given entity id to the current time.
     *
     * @param int $entityId
     * @return GalleryStatus a status code
     */
    function updateModificationTimestamp($entityId) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryEntityHelper_medium.class');
	return GalleryEntityHelper_medium::updateModificationTimestamp($entityId);
    }

    /**
     * Update the view count for this item id
     * @param int $itemId
     * @param int $step the amount to increment
     * @return GalleryStatus a status code
     */
    function incrementItemViewCount($itemId, $step=1) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_simple.class');
	return GalleryItemAttributesHelper_simple::incrementViewCount($itemId, $step);
    }

    /**
     * Create a new set of attributes for an item
     * @param int $itemId
     * @param array $parentSequence the sequence of parent ids
     * @return GalleryStatus a status code
     */
    function createItemAttributes($itemId, $parentSequence) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_advanced.class');
	return GalleryItemAttributesHelper_advanced::createItemAttributes($itemId, $parentSequence);
    }

    /**
     * Remove the attributes for the given item
     * @param int $itemId
     * @return GalleryStatus a status code
     */
    function removeItemAttributes($itemId) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_advanced.class');
	return GalleryItemAttributesHelper_advanced::removeItemAttributes($itemId);
    }

    /**
     * Update the view count for this item id
     * @param int $itemId
     * @param int $count the new count
     * @return GalleryStatus a status code
     */
    function setItemViewCount($itemId, $count) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_advanced.class');
	return GalleryItemAttributesHelper_advanced::setViewCount($itemId, $count);
    }

    /**
     * Get the view counts for many item ids
     * @param int $itemId
     * @return array GalleryStatus a status code
     *               int view count
     */
    function fetchItemViewCount($itemId) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_simple.class');
	return GalleryItemAttributesHelper_simple::fetchViewCount($itemId);
    }

    /**
     * Get the view counts for many item ids
     * @param array $itemIds
     * @return array GalleryStatus a status code
     *               array (itemId => viewCount, ..)
     */
    function fetchItemViewCounts($itemIds) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_simple.class');
	return GalleryItemAttributesHelper_simple::fetchViewCounts($itemIds);
    }

    /**
     * Set the order weight for an item id
     * @param int $itemId
     * @param int $orderWeight the new order weight
     * @return GalleryStatus a status code
     */
    function setItemOrderWeight($itemId, $orderWeight) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_advanced.class');
	return GalleryItemAttributesHelper_advanced::setOrderWeight($itemId, $orderWeight);
    }

    /**
     * Get the order weight for a given item id
     * @param int $itemId
     * @return array GalleryStatus a status code
     *               int the order weight
     */
    function fetchItemOrderWeight($itemId) {
	GalleryCoreApi::requireOnce(
	    'modules/core/classes/helpers/GalleryItemAttributesHelper_medium.class');
	return GalleryItemAttributesHelper_medium::fetchOrderWeight($itemId);
    }

    /**
     * Get the order weight f