Steve, On Sep 20, 2010, at 10:43 AM, Steve Sullivan wrote:
> Hi, > > Currently the HDF5 FAQ says about bitfields ... > How are these stored then? Any sort of padding or what? > We currently do not pack them, so a 13-bit field in a 32-bit > datatype still takes up 4 bytes of space. This is not ideal, but > it is a fairly complicated problem to pack the bits on disk (in > light of using bitfields in compound, array and variable-length > datatypes mostly). Eventually we should fix this. > > Is there any plan to implement packed bit fields in the near > future? > We will update FAQ. In 1.8.* we provide the n-bit filter to pack data in the file; see http://www.hdfgroup.org/HDF5/doc/RM/RM_H5P.html#Property-SetNbit. C example is available from http://www.hdfgroup.org/ftp/HDF5/examples/examples-by-api/api18-c.html See Dataset section. Elena > Thanks, > > Steve > > > -- > Steve Sullivan [email protected] 303-497-2823 > > FL/2, Research Applications Laboratory > National Center for Atmospheric Research > PO Box 3000 > Boulder CO 80307 > USA > > > _______________________________________________ > Hdf-forum is for HDF software users discussion. > [email protected] > http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org _______________________________________________ Hdf-forum is for HDF software users discussion. [email protected] http://mail.hdfgroup.org/mailman/listinfo/hdf-forum_hdfgroup.org
