netcdf-c/libhdf4/hdf4dispatch.c
Dennis Heimbigner 3ffe7be446 Enhance/Fix filter support
re: Discussion https://github.com/Unidata/netcdf-c/discussions/2214

The primary change is to support so-called "standard filters".
A standard filter is one that is defined by the following
netcdf-c API:
````
int nc_def_var_XXX(int ncid, int varid, size_t nparams, unsigned* params);
int nc_inq_var_XXXX(int ncid, int varid, int* usefilterp, unsigned* params);
````
So for example, zstandard would be a standard filter by defining
the functions *nc_def_var_zstandard* and *nc_inq_var_zstandard*.

In order to define these functions, we need a new dispatch function:
````
int nc_inq_filter_avail(int ncid, unsigned filterid);
````
This function, combined with the existing filter API can be used
to implement arbitrary standard filters using a simple code pattern.
Note that I would have preferred that this function return a list
of all available filters, but HDF5 does not support that functionality.

So this PR implements the dispatch function and implements
the following standard functions:
    + bzip2
    + zstandard
    + blosc
Specific test cases are also provided for HDF5 and NCZarr.
Over time, other specific standard filters will be defined.

## Primary Changes
* Add nc_inq_filter_avail() to netcdf-c API.
* Add standard filter implementations to test use of *nc_inq_filter_avail*.
* Bump the dispatch table version number and add to all the relevant
   dispatch tables (libsrc, libsrcp, etc).
* Create a program to invoke nc_inq_filter_avail so that it is accessible
  to shell scripts.
* Cleanup szip support to properly support szip
  when HDF5 is disabled. This involves detecting
  libsz separately from testing if HDF5 supports szip.
* Integrate shuffle and fletcher32 into the existing
  filter API. This means that, for example, nc_def_var_fletcher32
  is now a wrapper around nc_def_var_filter.
* Extend the Codec defaulting to allow multiple default shared libraries.

## Misc. Changes
* Modify configure.ac/CMakeLists.txt to look for the relevant
  libraries implementing standard filters.
* Modify libnetcdf.settings to list available standard filters
  (including deflate and szip).
* Add CMake test modules to locate libbz2 and libzstd.
* Cleanup the HDF5 memory manager function use in the plugins.
* remove unused file include//ncfilter.h
* remove tests for the HDF5 memory operations e.g. H5allocate_memory.
* Add flag to ncdump to force use of _Filter instead of _Deflate
  or _Shuffle or _Fletcher32. Used for testing.
2022-03-14 12:39:37 -06:00

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C

/* Copyright 2018, UCAR/Unidata See netcdf/COPYRIGHT file for copying
* and redistribution conditions.*/
/**
* @file
* @internal Dispatch code for HDF4. HDF4 access is read-only, for
* HDF4 SD files only.
*
* @author Ed Hartnett
*/
#include "config.h"
#include <stdlib.h>
#include "hdf4dispatch.h"
#include "nc4dispatch.h"
#include "hdf5dispatch.h"
#include "netcdf_filter.h"
/* This is the dispatch object that holds pointers to all the
* functions that make up the HDF4 dispatch interface. */
static const NC_Dispatch HDF4_dispatcher = {
NC_FORMATX_NC_HDF4,
NC_DISPATCH_VERSION,
NC_RO_create,
NC_HDF4_open,
NC_RO_redef,
NC_RO__enddef,
NC_RO_sync,
NC_HDF4_abort,
NC_HDF4_close,
NC_RO_set_fill,
NC_HDF4_inq_format,
NC_HDF4_inq_format_extended,
NC4_inq,
NC4_inq_type,
NC_RO_def_dim,
NC4_inq_dimid,
HDF5_inq_dim,
NC4_inq_unlimdim,
NC_RO_rename_dim,
NC4_inq_att,
NC4_inq_attid,
NC4_inq_attname,
NC_RO_rename_att,
NC_RO_del_att,
NC4_get_att,
NC_RO_put_att,
NC_RO_def_var,
NC4_inq_varid,
NC_RO_rename_var,
NC_HDF4_get_vara,
NC_RO_put_vara,
NCDEFAULT_get_vars,
NCDEFAULT_put_vars,
NCDEFAULT_get_varm,
NCDEFAULT_put_varm,
NC4_inq_var_all,
NC_NOTNC4_var_par_access,
NC_RO_def_var_fill,
NC4_show_metadata,
NC4_inq_unlimdims,
NC4_inq_ncid,
NC4_inq_grps,
NC4_inq_grpname,
NC4_inq_grpname_full,
NC4_inq_grp_parent,
NC4_inq_grp_full_ncid,
NC4_inq_varids,
NC4_inq_dimids,
NC4_inq_typeids,
NC4_inq_type_equal,
NC_NOTNC4_def_grp,
NC_NOTNC4_rename_grp,
NC4_inq_user_type,
NC4_inq_typeid,
NC_NOTNC4_def_compound,
NC_NOTNC4_insert_compound,
NC_NOTNC4_insert_array_compound,
NC_NOTNC4_inq_compound_field,
NC_NOTNC4_inq_compound_fieldindex,
NC_NOTNC4_def_vlen,
NC_NOTNC4_put_vlen_element,
NC_NOTNC4_get_vlen_element,
NC_NOTNC4_def_enum,
NC_NOTNC4_insert_enum,
NC_NOTNC4_inq_enum_member,
NC_NOTNC4_inq_enum_ident,
NC_NOTNC4_def_opaque,
NC_NOTNC4_def_var_deflate,
NC_NOTNC4_def_var_fletcher32,
NC_NOTNC4_def_var_chunking,
NC_NOTNC4_def_var_endian,
NC_NOTNC4_def_var_filter,
NC_NOTNC4_set_var_chunk_cache,
NC_NOTNC4_get_var_chunk_cache,
NC_NOOP_inq_var_filter_ids,
NC_NOOP_inq_var_filter_info,
NC_NOTNC4_def_var_quantize,
NC_NOTNC4_inq_var_quantize,
NC_NOOP_inq_filter_avail,
};
const NC_Dispatch *HDF4_dispatch_table = NULL;
/**
* @internal Initialize HDF4 dispatch layer.
*
* @return ::NC_NOERR No error.
* @author Ed Hartnett
*/
int
NC_HDF4_initialize(void)
{
HDF4_dispatch_table = &HDF4_dispatcher;
return NC_NOERR;
}
/**
* @internal Finalize HDF4 dispatch layer.
*
* @return ::NC_NOERR No error.
* @author Ed Hartnett
*/
int
NC_HDF4_finalize(void)
{
return NC_NOERR;
}