jpx_metanode::count_descendants

If the number of descendants from this node is already known, this function returns true, writing that number into count. The number may not be known only if the ultimate source of information for a JPX data source is a dynamic cache whose contents have not been fully written (say by a remote JPIP server). In this case, the function attempts to parse as far as it can into the super-box whose contents define the descendants of this node (the super-box is either an asoc box, or a codestream or compositing layer header box). If it encounters the end of the relevant super-box, the function again returns true, writing the number of descendants into count.

If the function is unable to parse to a point at which the number of descendants can be known, it returns false, writing the number of descendants encountered up to that point into the count argument.

Note that leaf nodes never have descendants, so this function will always return true with count set to 0.

False if it is possible that more descendants remain in the underlying JPX data source, but the function is unable to parse any further into the source at this point. This generally means that the underlying jp2_family_src object is fueled by a dynamic cache (i.e., a kdu_cache object).

count [int &]