Using H5S_MAX_RANK rather than hard coded 32?

[Kurt Schwehr]

In r39202, there is mention of 32 and H5S_MAX_RANK. Is it too hard to actually use the H5S_MAX_RANK from H5Spublic.h? e.g.

                    int nDims = CSLCount(papszTokens) - 2;
                    if( nDims >= 32 )
                    {
                        // The number of dimensions in a netCDFv4 file is
                        // limited by #define H5S_MAX_RANK    32
                        // but libnetcdf doesn't check that...
                        CPLDebug("netCDF",
                                 "nc_def_var(%s) failed: too many dimensions",
                                 pszVarName);
                        CSLDestroy(papszTokens);
                        continue;
                    }

Should be something like:

                    int nDims = CSLCount(papszTokens) - 2;
                    if( nDims >= H5S_MAX_RANK )
                    {
                        // The number of dimensions in a netCDFv4 file is
                        // limited by H5S_MAX_RANK,
                        // but libnetcdf doesn't check that...
                        CPLDebug("netCDF",
                                 "nc_def_var(%s) failed: too many dimensions",
                                 pszVarName);
                        CSLDestroy(papszTokens);
                        continue;
                    }

e.g. (UNTESTED!)

netcdfdataset.cpp

@@ -60 +60 @@
 #include "gdal.h"
 #include "gdal_frmts.h"
 #include "gdal_version.h"
+#include "hdf5.h"
 #include "ogr_core.h"
 #include "ogr_srs_api.h"
 
@@ -5841 +5842 @@
 #endif
 
                     int nDims = CSLCount(papszTokens) - 2;
-                    if( nDims >= 32 )
+                    if( nDims >= H5S_MAX_RANK )
                     {
                         // The number of dimensions in a netCDFv4 file is
-                        // limited by #define H5S_MAX_RANK    32
-                        // but libnetcdf doesn't check that...
+                        // limited by H5S_MAX_RANK to 32,
+                        // but libnetcdf doesn't check that.
                         CPLDebug("netCDF",
                                  "nc_def_var(%s) failed: too many dimensions",
                                  pszVarName);

[Even Rouault]

Actually, I wanted to make a bug report to libnetcdf. They should validate that and refuse to create variables with more than 32 dimensions for a netCDF v4 file.

[Even Rouault]

Upstream issue reported as ​https://github.com/Unidata/netcdf-c/issues/433