Filter support has three goals:
1. Use the existing HDF5 filter implementations,
2. Allow filter metadata to be stored in the NumCodecs metadata format used by Zarr,
3. Allow filters to be used even when HDF5 is disabled
Detailed usage directions are define in docs/filters.md.
For now, the existing filter API is left in place. So filters
are defined using ''nc_def_var_filter'' using the HDF5 style
where the id and parameters are unsigned integers.
This is a big change since filters affect many parts of the code.
In the following, the terms "compressor" and "filter" and "codec" are generally
used synonomously.
### Filter-Related Changes:
* In order to support dynamic loading of shared filter libraries, a new library was added in the libncpoco directory; it helps to isolate dynamic loading across multiple platforms.
* Provide a json parsing library for use by plugins; this is created by merging libdispatch/ncjson.c with include/ncjson.h.
* Add a new _Codecs attribute to allow clients to see what codecs are being used; let ncdump -s print it out.
* Provide special headers to help support compilation of HDF5 filters when HDF5 is not enabled: netcdf_filter_hdf5_build.h and netcdf_filter_build.h.
* Add a number of new test to test the new nczarr filters.
* Let ncgen parse _Codecs attribute, although it is ignored.
### Plugin directory changes:
* Add support for the Blosc compressor; this is essential because it is the most common compressor used in Zarr datasets. This also necessitated adding a CMake FindBlosc.cmake file
* Add NCZarr support for the big-four filters provided by HDF5: shuffle, fletcher32, deflate (zlib), and szip
* Add a Codec defaulter (see docs/filters.md) for the big four filters.
* Make plugins work with windows by properly adding __declspec declaration.
### Misc. Non-Filter Changes
* Replace most uses of USE_NETCDF4 (deprecated) with USE_HDF5.
* Improve support for caching
* More fixes for path conversion code
* Fix misc. memory leaks
* Add new utility -- ncdump/ncpathcvt -- that does more or less the same thing as cygpath.
* Add a number of new test to test the non-filter fixes.
* Update the parsers
* Convert most instances of '#ifdef _MSC_VER' to '#ifdef _WIN32'
Primary fixes to get -ansi to work.
1. Convert all '//' C++ style comments to /*...*/ or to use #if 0...#endif
2. It turns out that when -ansi is specified, then a number of
functions no longer are defined in the header -- but they are still
in the .so file.<br>
The big example is strdup(). So, added code to include/ncconfig.h to define
externs for those missing functions that occur in more than one place.
These are enabled if !_WIN32 && __STDC__ == 1 (__STDC__ is supposed to
be the equivalent compile time flag to -ansi). Note that this requires
config.h (which references ncconfig.h) to be included in files where it is
currently not included. Single uses will be only in the file that uses them.
3. Added mmap test for the MAP_ANONYMOUS flag to configure.ac. Apparently
this is not always defined with -ansi.
4. fix some large integer constants in nc_test4/tst_atts3.c and nc_test4/tst_filterparser.c
to avoid compiler complaints.
5. fix a double constant in nc_test4/tst_filterparser.c to avoid compiler complaints.
[Note I suspect #4 and #5 will be a problem on big-endian machines, but we have no way to test]
Misc. Changes:
1. convert more instances of _MSC_VER to _WIN32.
2. added some debugging code to include/nctestserver.h
3. added comment about libdispatch/drc.c always being compiled.
4. modify parser generation in ncgen to remove unneeded files.
https://github.com/Unidata/netcdf-c/issues/1168https://github.com/Unidata/netcdf-c/issues/1163https://github.com/Unidata/netcdf-c/issues/1162
This PR partially fixes memory leaks in the netcdf-c library,
in the ncdump utility, and in some test cases.
The netcdf-c library now runs memory clean with the assumption
that the --disable-utilities option is used. The primary remaining
problem is ncgen. Once that is fixed, I believe the netcdf-c library
will run memory clean with no limitations.
Notes
-----------
1. Memory checking was performed using gcc -fsanitize=address.
Valgrind-based testing has yet to be performed.
2. The pnetcdf, hdf4, and examples code has not been tested.
Misc. Non-leak changes
1. Make tst_diskless2 only run when netcdf4 is enabled (issue 1162)
2. Fix CmakeLists.txt to turn off logging if ENABLE_NETCDF_4 is OFF
3. Isolated all my debug scripts into a single top-level directory
called debug
4. Fix some USE_NETCDF4 dependencies in nc_test and nc_test4 Makefile.am
re: https://github.com/Unidata/netcdf-c/issues/1154
Inadvertently, the behavior of NC_DISKLESS with nc_create() was
changed in release 4.6.1. Previously, the NC_WRITE flag needed
to be explicitly used with NC_DISKLESS in order to cause the
created file to be persisted to disk.
Additional analyis indicated that the current NC_DISKLESS
implementation was seriously flawed.
This PR attempts to clean up and regularize the situation with
respect to NC_DISKLESS control. One important aspect of diskless
operation is that there are two different notions of write.
1. The file is read-write vs read-only when using the netcdf API.
2. The file is persisted or not to disk at nc_close().
Previously, these two were conflated. The rules now are
as follows.
1. NC_DISKLESS + NC_WRITE means that the file is read/write using the netcdf API
2. NC_DISKLESS + NC_PERSIST means that the file is persisted to a disk file at nc_close.
3. NC_DISKLESS + NC_PERSIST + NC_WRITE means both 1 and 2.
The NC_PERSIST flag is new and takes over the obsolete NC_MPIPOSIX flag.
NC_MPIPOSIX is still defined, but is now an alias for the NC_MPIIO flag.
It is also now the case that for netcdf-4, NC_DISKLESS is independent
of NC_INMEMORY and in fact it is an error to specify both flags
simultaneously.
Finally, the MMAP code was fixed to use NC_PERSIST as well.
Also marked MMAP as deprecated.
Also added a test case to test various combinations of NC_DISKLESS,
NC_PERSIST, and NC_WRITE.
This PR affects a number of files and especially test cases
that used NC_DISKLESS.
Misc. Unrelated fixes
1. fixed some warnings in ncdump/dumplib.c
After a long discussion, I implemented the rules at the end of that issue.
They are documented in nccopy.1.
Additionally, I added a new, per-variable, -c flag that allows
for the direct setting of the chunking parameters for a variable.
The form is
-c var:c1,c2,...ck
where var is the name of the variable (possibly a fully qualified name)
and the ci are the chunksizes for that variable. It must be the case
that the rank of the variable is k. If the new form is used as well
as the old form, then the new form overrides the old form for the
specified variable. Note that multiple occurrences of the new form
-c flag may be specified.
Misc. Other fixes
1. Added -M <size> option to nccopy to specify the minimum
allowable chunksize.
2. Removed the unused variables from bigmeta.c
(Issue https://github.com/Unidata/netcdf-c/issues/1079)
3. Fixed failure of nc_test4/tst_filter.sh by using the new -M
flag (#1) to allow filter test on a small chunk size.
Modified provenance code to allocate the minimal space
needed for _NCProperties attribute in file. Basically
required using malloc in the provenance code and in ncdump.
Otherwise should cause no externally visible effects.
Also removed the ENABLE_FILEINFO from configure.ac since
the provenance code is no longer optional.
This consists of a persistent attribute named
_NCProperties plus two computed attributes
_IsNetcdf4 and _SuperblockVersion.
See the 'Provenance Attributes' section
of docs/attribute_conventions.md for details.
should be under ENABLE_DAP_REMOTE_TESTS.
Fixed to make sure that this is so.
Also attempted to fix ncdap_test/CMakeLists.txt,
but probably got it wrong.
HT to Nico Schlomer.
2. Attempted to reduce the number of conversion errors
when -Wconversion is set. Fixed oc2, but
rest of netcdf remains to be done.
HT to Nico Schlomer.
3. When doing #2, I discovered an error in ncgen.y
that has remained hidden. This required some other
test case fixes.
error occurs after an "exit:" label.
Corrected a dozen Coverity errors (mainly allocation issues, along with a few
other things):
711711, 711802, 711803, 711905, 970825, 996123, 996124, 1025787,
1047274, 1130013, 1130014, 1139538
Refactored internal fill-value code to correctly handle string types, and
especially to allow NULL pointers and null strings (ie. "") to be
distinguished. The code now avoids partially aliasing the two together
(which only happened on the 'write' side of things and wasn't reflected on
the 'read' side, adding to the previous confusion).
Probably still weak on handling fill-values of variable-length and compound
datatypes.
Refactored the recursive metadata reads a bit more, to process HDF5 named
datatypes and datasets immediately, avoiding chewing up memory for those
types of objects, etc.
Finished uncommenting and updating the nc_test4/tst_fills2.c code (as I'm
proceeding alphabetically through the nc_test4 code files).
enhancements, based on contributed code from Martin van Driel, to
support -v, -g, -V, and -G options for selecting groups and variables
in output. Fix all clang warnings from nccopy and ncdump sources, as
well as a few other cleanup changes to testing code.
