re: https://github.com/Unidata/netcdf-c/issues/1836
Revert the internal filter code to simplify it. From the user's
point of view, the only visible changes should be:
1. The functions that convert text to filter specs have had their signature reverted and have been moved to netcdf_aux.h
2. Some filter API functions now return NC_ENOFILTER when inquiry is made about some filter.
Internally,the dispatch table has been modified to get rid of the filter_actions
entry and associated complex structures. It has been replaced with
inq_var_filter_ids and inq_var_filter_info entries and the dispatch table
version has been bumped to 3. Corresponding NOOP and NOTNC4 functions
were added to libdispatch/dnotnc4.c. Also, the filter_action entries
in dispatch tables were replaced for all dispatch code bases (HDF5, DAP2,
etc). This should only impact UDF users.
In the process, it became clear that the form of the filters
field in NC_VAR_INFO_T was format dependent, so I converted it to
be of type void* and pushed its management into the various dispatch
code bases. Specifically libhdf5 and libnczarr now manage the filters
field in their own way.
The auxilliary functions for parsing textual filter specifications
were moved to netcdf_aux.h and were renamed to the following:
* ncaux_h5filterspec_parse
* ncaux_h5filterspec_parselist
* ncaux_h5filterspec_free
* ncaux_h5filter_fix8
Misc. Other Changes:
1. Document NUG/filters.md updated to reflect the changes above.
2. All the old data types (structs and enums)
used by filter_actions actions were deleted.
The exception is the NC_H5_Filterspec because it is needed
by ncaux_h5filterspec_parselist.
3. Clientside filters were removed -- another enhancement
for which no-one ever asked.
4. The ability to remove filters was itself removed.
5. Some functionality needed by nczarr was moved from libhdf5
to libsrc4 e.g. nc4_find_default_chunksizes
6. All the filterx code was removed
7. ncfilter.h and nc4filter.c no longer used
Misc. Unrelated Changes:
1. The nczarr_test makefile clean was leaving some directories; so
add clean-local to take care of them.
* For URL paths, the new approach essentially centralizes all information
in the URL into the "#mode=" fragment key and uses that value
to determine the dispatcher for (most) URLs.
* The new approach has the following steps:
1. canonicalize the path if it is a URL.
2. use the mode= fragment key to determine the dispatcher
3. if dispatcher still not determined, then use the mode flags
argument to nc_open/nc_create to determine the dispatcher.
4. if the path points to something readable, attempt to read the
magic number at the front, and use that to determine the dispatcher.
this case may override all previous cases.
* Misc changes.
1. Update documentation
2. Moved some unit tests from libdispatch to unit_test directory.
3. Fixed use of wrong #ifdef macro in test_filter_reg.c
[I think this may fix an previously reported esupport query].
Priority: Low
re: issue https://github.com/Unidata/netcdf-c/issues/1329
HDF5 has the ability to programmatically define new filters,
as opposed to using HDF5_PLUGIN_PATH env variable.
This PR adds support for that feature.
Not clear how useful this is, though.
See docs/filters.md for details.
re: issue https://github.com/Unidata/netcdf-c/issues/1278
re: issue https://github.com/Unidata/netcdf-c/issues/876
re: issue https://github.com/Unidata/netcdf-c/issues/806
* Major change to the handling of 8-byte parameters for nc_def_var_filter.
The old code was not well thought out.
* The new algorithm is documented in docs/filters.md.
* Added new utility file plugins/H5Zutil.c to support
* Modified plugins/H5Zmisc.c to use new algorithm
the new algorithm.
* Renamed include/ncfilter.h to include/netcdf_filter.h
and made it an installed header so clients can access the
new algorithm utility.
* Fixed nc_test4/tst_filterparser.c and nc_test4/test_filter_misc.c
to use the new algorithm
* libdap4/ fixes:
* d4swap.c has an error in the endian pre-processing such
that record counts were not being swapped correctly.
* d4data.c had an error in that checksums were being computed
after endian swapping rather than before.
* ocinitialize() was never being called, so xxdr bigendian handling
was never set correctly.
* Required adding debug statements to occompile
* Found and fixed memory leak in ncdump.c
Not tested:
* HDF4
* Pnetcdf
* parallel HDF5
re: issue https://github.com/Unidata/netcdf-c/issues/1156
Starting with HDF5 version 1.10.x, the plugin code MUST be
careful when using the standard *malloc()*, *realloc()*, and
*free()* function.
In the event that the code is allocating, reallocating, or
free'ing memory that either came from -- or will be exported to --
the calling HDF5 library, then one MUST use the corresponding
HDF5 functions *H5allocate_memory()*, *H5resize_memory()*,
*H5free_memory()* [5] to avoid memory failures.
Additionally, if your filter code leaks memory, then the HDF5 library
generates a failure something like this.
````
H5MM.c:232: H5MM_final_sanity_check: Assertion `0 == H5MM_curr_alloc_bytes_s' failed.
````
This PR modifies the code in the plugins directory to
conform to these new requirements.
This raises a question about the libhdf5 code where this
same problem may occur. We need to scan especially nc4hdf.c
to look for this problem.
I took Ed's advice and moved the plugin stuff to its own
top-level directory. This is an attempt to solve the problem of
copying files that we have experienced. In any case, it will
serve as a place to stick additional plugins.
