Helper function to sort items in a field according to user drag-n-drop reordering.
function _field_sort_items($field, $items) {
if (($field['cardinality'] > 1 || $field['cardinality'] == FIELD_CARDINALITY_UNLIMITED) && isset($items[0]['_weight'])) {
usort($items, '_field_sort_items_helper');
foreach ($items as $delta => $item) {
if (is_array($items[$delta])) {
unset($items[$delta]['_weight']);
}
}
}
return $items;
}