netcdf-c/ncdump/ncdump.h
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.
* $Header: /upc/share/CVS/netcdf-3/ncdump/ncdump.h,v 1.34 2009/12/02 20:03:43 russ Exp $
*********************************************************************/
#ifndef _NCDUMP_H_
#define _NCDUMP_H_
typedef
enum {LANG_C, LANG_F} Nclang;
typedef struct { /* specification for how to format dump */
char *name; /* name specified with -n or derived from
* file name */
bool_t header_only; /* if true, don't print any variable data */
bool_t coord_vals; /* if true, print header and coordinate
* dimension values (values of variables
* that are also dimensions), but no other
* variable data */
bool_t brief_data_cmnts; /* if true, put // comments in data section
* identifying variable and indices, useful
* for navigating through large
* multi-dimensional data lists. */
bool_t full_data_cmnts; /* if true, put // comments in data section
* identifying every value, useful for
* navigating through large
* multi-dimensional data lists. */
bool_t string_times; /* if true, output date-time values as
* human-readable strings. */
bool_t iso_separator; /* if true, use 'T' separator between
* date and time components of
* human-readable strings, otherwise
* use ' ' */
bool_t special_atts; /* if true, output special attributes
* for optimization characteristics:
* _Compression, _Chunking,
* _Endianness, _Format, _Checksum,
* _NoFill, _NetCDF4 */
bool_t filter_atts; /* if true, output filters using _Filter in place of
* _Fletcher32, _Shuffle, and _Deflate. */
Nclang data_lang; /* Specifies index conventions used in data
* comments, either LANG_C (C, 0-based,
* column major) or LANG_F (Fortran,
* 1-based, row major) */
bool_t with_cache; /* For DAP URLs, get data with client-side
* caching when each variable is first accessed */
int nlvars; /* Number of variables specified with -v
* option on command line */
char** lvars; /* list of variable names specified with -v
* option on command line */
int nlgrps; /* Number of groups specified with -g
* option on command line */
char** lgrps; /* list of group names specified with -g
* option on command line */
idnode_t* grpids; /* list of grpids matching list specified with -g option */
int nc_kind; /* kind of netCDF file named on
* command line, 1 (classic), 2
* (64-bit offset), 3 (netCDF-4), 4
* (netCDF-4 classic model), 5 (64-bit data)
*/
int nc_extended; /* extended format info fornetCDF file named
* on command line.
*/
int nc_mode; /* mode as reported by inq_format_extended */
int xopt_inmemory; /* Use in-memory option; testing only */
int xopt_props ; /* 1=>Unconditionally Suppress properties attribute */
} fspec_t;
#endif /*_NCDUMP_H_ */