netcdf-c/include/netcdf_aux.h
Dennis Heimbigner aeb3ac2809 Mostly revert the filter code to reduce its complexity of use.
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.
2020-09-27 12:43:46 -06:00

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2.4 KiB
C

/*********************************************************************
* Copyright 2018, UCAR/Unidata
* See netcdf/COPYRIGHT file for copying and redistribution conditions.
* $Id$
* $Header$
*********************************************************************/
/*
* In order to use any of the netcdf_XXX.h files, it is necessary
* to include netcdf.h followed by any netcdf_XXX.h files.
* Various things (like EXTERNL) are defined in netcdf.h
* to make them available for use by the netcdf_XXX.h files.
*/
#ifndef NCAUX_H
#define NCAUX_H
#define NCAUX_ALIGN_C 0
#define NCAUX_ALIGN_UNIFORM 1
#if defined(__cplusplus)
extern "C" {
#endif
/**
Reclaim the output tree of data from a call
to e.g. nc_get_vara or the input to e.g. nc_put_vara.
This recursively walks the top-level instances to
reclaim any nested data such as vlen or strings or such.
Assumes it is passed a pointer to count instances of xtype.
Reclaims any nested data.
WARNING: does not reclaim the top-level memory because
we do not know how it was allocated.
Should work for any netcdf format.
*/
EXTERNL int ncaux_reclaim_data(int ncid, int xtype, void* memory, size_t count);
EXTERNL int ncaux_begin_compound(int ncid, const char *name, int alignmode, void** tag);
EXTERNL int ncaux_end_compound(void* tag, nc_type* typeid);
EXTERNL int ncaux_abort_compound(void* tag);
EXTERNL int ncaux_add_field(void* tag, const char *name, nc_type field_type,
int ndims, const int* dimsizes);
/* Takes any type */
EXTERNL size_t ncaux_type_alignment(int xtype, int ncid);
/* Takes type classes only */
EXTERNL size_t ncaux_class_alignment(int ncclass);
/**************************************************/
/* Capture the id and parameters for a filter
using the HDF5 unsigned int format
*/
typedef struct NC_H5_Filterspec {
unsigned int filterid; /**< ID for arbitrary filter. */
size_t nparams; /**< nparams for arbitrary filter. */
unsigned int* params; /**< Params for arbitrary filter. */
} NC_H5_Filterspec;
EXTERNL int ncaux_h5filterspec_parse(const char* txt, unsigned int* idp, size_t* nparamsp, unsigned int** paramsp);
EXTERNL int ncaux_h5filterspec_parselist(const char* txt0, int* formatp, size_t* nspecsp, struct NC_H5_Filterspec*** vectorp);
EXTERNL void ncaux_h5filterspec_free(struct NC_H5_Filterspec* f);
EXTERNL void ncaux_h5filterspec_fix8(unsigned char* mem, int decode);
#if defined(__cplusplus)
}
#endif
#endif /*NCAUX_H*/