re: https://github.com/Unidata/netcdf-c/issues/1584
Support has been added for multiple filters per variable. This
affects a number of components in netcdf. The new APIs are
documented in NUG/filters.md.
The primary changes are:
* A set of new functions are provided (see __include/netcdf_filter.h__).
- Obtain a list of the filters associated with a variable
- Obtain the parameters for a specific filter.
* The existing __nc_inq_var_filter__ function now returns info
about the first defined filter.
* The utilities (ncgen, ncdump, and nccopy) now support
an extended format for specifying a sequence of filters.
The general form is __<filter>|<filter>..._.
* The ncdump **_Filter** attribute now dumps a list of all the
filters associated with a variable using the above new format.
* Filter specifications can now use a filter name instead of number
for filters known to the netcdf library, which in turn is taken
from the HDF5 filter registration page.
* New errors are defined: NC_EFILTER and NC_ENOFILTER. The latter
is returned if an attempt is made to access an unknown filter.
* Internally, the dispatch table has been extended to add a function
to handle all of the filter functions.
* New, filter-related, tests were added to nc_test4.
* A new plugin was added to the plugins directory to help with testing.
Notes:
1. The shuffle and fletcher32 filters are not part of the multifilter system.
Misc. changes:
1. A debug module was added to libhdf5 to help catch error locations.
re: https://github.com/Unidata/netcdf-c/issues/972
The current szip plugin code in the HDF5 library has some
unexpected behaviors that require some changes to how
nc_inq_var_szip is implemented and to the corresponding tests:
nc_test4/{test_szip,tst_vars3}.
Specifically, the following can happen:
1. The number of parameters provided by the user will be two,
but the number of parameters returned by nc_inq_var_filter
will be four because the HDF5 code (H5Zszip) will add two
extra parameters for internal use. It turns out that the two
parameters provided when calling nc_def_var_filter correspond
to the first two parameters of the four parameters returned
by nc_inq_var_filter.
2. The nc_inq_var_szip values corresponding to the ones provided
by the caller may be different than those provided by
nc_def_var_filter. The value of the options_mask argument is
known to add additional flag bits, and the pixels_per_block
parameter may be modified.
The in-memory files can be made persistent if nc_create is called with
NC_DISKLESS|NC_WRITE flags set. Initial test case also included.
- Modified ncio mechanism to support
multiple ncio packages; this is so we
can have posixio and memio operating
at the same time.
- cleanup up a bunch of lint issues (unused variables, etc).
