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https://github.com/Unidata/netcdf-c.git
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3ffe7be446
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.
197 lines
3.6 KiB
C
Executable File
197 lines
3.6 KiB
C
Executable File
/*********************************************************************
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* Copyright 1993, UCAR/Unidata
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* See netcdf/COPYRIGHT file for copying and redistribution conditions.
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* Derived from poco library from Boost Software: see nccpoco/LICENSE file.
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*********************************************************************/
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#include "config.h"
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#ifdef HAVE_DLFCN_H
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#include <dlfcn.h>
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#endif
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#ifdef USE_MUTEX
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#include <pthread.h>
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#endif
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#include "netcdf.h"
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#include "ncpoco.h"
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#include "ncpathmgr.h"
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#undef DEBUG
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/* Note: cygwin is missing RTLD_LOCAL, set it to 0 */
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#if !defined(RTLD_LOCAL)
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#define RTLD_LOCAL 0
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#endif
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#if !defined(RTLD_GLOBAL)
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#define RTLD_GLOBAL 0
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#endif
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#if !defined(RTLD_LAZY)
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#define RTLD_LAZY 1
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#endif
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#if !defined(RTLD_NOW)
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#define RTLD_NOW 2
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#endif
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#ifdef USE_MUTEX
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static pthread_mutex_t mutex;
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#endif
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static void
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ncperr(const char* fcn, NCPSharedLib* lib)
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{
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const char* msg = dlerror();
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lib->err.msg[0] = '\0';
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if(msg != NULL) {
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strlcat(lib->err.msg,fcn,sizeof(lib->err.msg));
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strlcat(lib->err.msg,": ",sizeof(lib->err.msg));
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strlcat(lib->err.msg,msg,sizeof(lib->err.msg));
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#ifdef DEBUG
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fprintf(stderr,">>> %s\n",lib->err.msg);
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#endif
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}
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}
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int
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ncp_unix_initialize(void)
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{
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int ret = 1;
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#ifdef USE_MUTEX
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pthread_mutexattr_t attr;
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pthread_mutexattr_init(&attr);
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pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
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if(pthread_mutex_init(&mutex, &attr)) {
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fprintf(stderr,"cp_unix: Cannot create mutext\n");
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ret = 1;
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}
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pthread_mutexattr_destroy(&attr);
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#endif
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return ret;
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}
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int
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ncp_unix_finalize(void)
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{
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#ifdef USE_MUTEX
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pthread_mutex_destroy(&mutex);
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#endif
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return 1;
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}
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/**************************************************/
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#ifdef USE_MUTEX
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static void lock(void) {pthread_mutex_lock(&mutex);}
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#else
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#define lock()
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#endif
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#ifdef USE_MUTEX
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static void unlock(void) {pthread_mutex_unlock(&mutex);}
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#else
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#define unlock()
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#endif
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/**************************************************/
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static int
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init(NCPSharedLib* lib)
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{
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int ret = NC_NOERR;
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return ret;
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}
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static int
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reclaim(NCPSharedLib* lib)
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{
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int ret = NC_NOERR;
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return ret;
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}
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static int
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load(NCPSharedLib* lib , const char* path0, int flags)
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{
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int ret = NC_NOERR;
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int realflags = RTLD_LAZY; /* versus RTLD_NOW which does not appear to work */
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char* path = NULL;
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if((path = NCpathcvt(path0))==NULL) {ret = NC_ENOMEM; goto done;}
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lock();
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if(lib->state.handle != NULL)
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{ret = NC_EEXIST; goto ldone;}
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lib->path = nulldup(path);
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lib->flags = flags;
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if(flags & NCP_LOCAL)
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realflags |= RTLD_LOCAL;
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else
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realflags |= RTLD_GLOBAL;
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lib->state.flags = realflags;
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lib->state.handle = dlopen(lib->path, lib->state.flags);
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if(lib->state.handle == NULL) {
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ncperr("dlopen",lib);
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ret = NC_ENOTFOUND;
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goto ldone;
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}
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ldone:
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unlock();
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done:
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nullfree(path);
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return ret;
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}
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static int
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unload(NCPSharedLib* lib)
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{
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int ret = NC_NOERR;
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lock();
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if(lib->state.handle != NULL) {
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dlclose(lib->state.handle);
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lib->state.handle = NULL;
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}
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unlock();
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return ret;
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}
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static int
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isLoaded(NCPSharedLib* lib)
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{
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return lib->state.handle != NULL;
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}
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static void*
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getsymbol(NCPSharedLib* lib, const char* name)
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{
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void* result = NULL;
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lock();
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if(lib->state.handle != NULL) {
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result = dlsym(lib->state.handle, name);
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if(result == NULL) {
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ncperr("dlsym",lib);
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}
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}
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unlock();
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return result;
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}
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static const char*
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getpath(NCPSharedLib* lib)
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{
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return lib->path;
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}
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struct NCPAPI ncp_unix_api = {
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init,
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reclaim,
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load,
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unload,
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isLoaded,
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getsymbol,
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getpath,
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};
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