re pull request https://github.com/Unidata/netcdf-c/pull/405
re pull request https://github.com/Unidata/netcdf-c/pull/446
Notes:
1. This branch is a cleanup of the magic.dmh branch.
2. magic.dmh was originally merged, but caused problems with parallel IO.
It was re-issued as pull request https://github.com/Unidata/netcdf-c/pull/446.
3. This branch + pull request replace any previous pull requests and magic.dmh branch.
Given an otherwise valid netCDF file that has a corrupted header,
the netcdf library currently crashes. Instead, it should return
NC_ENOTNC.
Additionally, the NC_check_file_type code does not do the
forward search required by hdf5 files. It currently only looks
at file position 0 instead of 512, 1024, 2048,... Also, it turns
out that the HDF4 magic number is assumed to always be at the
beginning of the file (unlike HDF5).
The change is localized to libdispatch/dfile.c See
https://support.hdfgroup.org/release4/doc/DSpec_html/DS.pdf
Also, it turns out that the code in NC_check_file_type is duplicated
(mostly) in the function libsrc4/nc4file.c#nc_check_for_hdf.
This branch does the following.
1. Make NC_check_file_type return NC_ENOTNC instead of crashing.
2. Remove nc_check_for_hdf and centralize all file format checking
NC_check_file_type.
3. Add proper forward search for HDF5 files (but not HDF4 files)
to look for the magic number at offsets of 0, 512, 1024...
4. Add test tst_hdf5_offset.sh. This tests that hdf5 files with
an offset are properly recognized. It does so by prefixing
a legal file with some number of zero bytes: 512, 1024, etc.
5. Off-topic: Added -N flag to ncdump to force a specific output dataset name.
2. Factored out the parameter string parsing for ncgen and nccopy
int libdispatch/dfilter.c + include/ncfilter.h
3. Allow a parameter string to use constant types other than
unsigned int. See docs/filters.md for details.
4. Moved the old content of include/netcdf_filter.h into include/netcdf.h
and removed include/netcdf_filter.h as no longer needed.
5. Force the test filter (bzip2) in nc_test4/filter_test to
be built using BUILT_SOURCES.
to docs/filter.md
2. Moved location of filter.md in documentation
3. Add a template file as the basis for building new filters.
4. Did some test case cleanup
1. Allow nccopy to apply filters, especially on the output file.
This provides a third way to do this other than using ncgen or
programatically
2. Make sure that even if the filter code is not available, it is
possible to see the filter id and parameters for variables using
e.g ncdump -hs.
3. Fix bug in nccopy so that the input file does
not necessarily have to be netcdf-4.
4. At last minute decided to change to using a
single "_Filter" attribute for ncgen
5. Added a test to tst_filter.sh to generate C code using ncgen.
This relies on the HDF5 capability to
dynamically load compression filters.
Note that a compression filter is just
a subcase of filters.
The primary user-visible changes are as follows:
1. Add a standard header "netcdf_filter.h" that defines
the necessary API extensions
2. Modify ncgen to support two new special attributes
"_Filter_ID" and "_Filter_Parameters" so that compression
can be turned on when creating a file using ncgen.
4. Add a detailed description of filtering support
to the user's guide; see the file filters.md
5. Add a test case directory for this: nc_test4/filter_test.
It is fragile and a ./configure flags (-enable-filter-test)
is defined (default disabled) to shut this off this test
to avoid spurious 'make check' failures.
Note that the HDF5 documentation is not up-to-date, so
much of what is encoded here comes from examining the
actual code in the file H5PL.c in the HDF5 source code.
1. When running under windows (as opposed to cygwin)
we need to make sure to not user /cygdrive/ file paths.
This was ocurring in libdap4/d4read.c, but may occur
elsewhere.
2. Shell scripts in the git repo are not being checked-out
with the executable mode set. Had core.filemode set to false.
Was a major hassle to fix.
Specific changes:
1. Add dap4 code: libdap4 and dap4_test.
Note that until the d4ts server problem is solved, dap4 is turned off.
2. Modify various files to support dap4 flags:
configure.ac, Makefile.am, CMakeLists.txt, etc.
3. Add nc_test/test_common.sh. This centralizes
the handling of the locations of various
things in the build tree: e.g. where is
ncgen.exe located. See nc_test/test_common.sh
for details.
4. Modify .sh files to use test_common.sh
5. Obsolete separate oc2 by moving it to be part of
netcdf-c. This means replacing code with netcdf-c
equivalents.
5. Add --with-testserver to configure.ac to allow
override of the servers to be used for --enable-dap-remote-tests.
6. There were multiple versions of nctypealignment code. Try to
centralize in libdispatch/doffset.c and include/ncoffsets.h
7. Add a unit test for the ncuri code because of its complexity.
8. Move the findserver code out of libdispatch and into
a separate, self contained program in ncdap_test and dap4_test.
9. Move the dispatch header files (nc{3,4}dispatch.h) to
.../include because they are now shared by modules.
10. Revamp the handling of TOPSRCDIR and TOPBUILDDIR for shell scripts.
11. Make use of MREMAP if available
12. Misc. minor changes e.g.
- #include <config.h> -> #include "config.h"
- Add some no-install headers to /include
- extern -> EXTERNL and vice versa as needed
- misc header cleanup
- clean up checking for misc. unix vs microsoft functions
13. Change copyright decls in some files to point to LICENSE file.
14. Add notes to RELEASENOTES.md
re: github netcdf-c issue #271
This occurs for several reasons, including:
1. using H5Aopen_name instead of H5Aexists to test if attribute exists.
2. using H5Eset_auto instead of H5Eset_auto2.
There are probably others that will have to be extinguished as encountered.
p.s Hope I did not overdo this and kill too much.
The hash field for phony dimensions was not being set
(in nc4hdf.c). Also added test case (nc_test4/?).
Note that I searched for other similar failures and
did not find any, but I may have missed them.
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.
The count and start arrays are dimensioned to NC_MAX_DIMS even though the maximum size should be NDIMS which is set to 3; possibly, the maximum size could be 2 since only indices 0 and 1 are used to access both start and count. I left it at NDIMS since that matches the number of items in the initialization and is consistent with other uses in the file.
The constant NC_MAX_DIMS is used to dimension the `dimids` arrays which are use to retrieve the dimension ids corresponding to the variables dimensions. By definition, the maximum number of dimension ids is `NC_MAX_VAR_DIMS` as is documented in the `nc_inq_var` documentation:
http://www.unidata.ucar.edu/software/netcdf/netcdf-4/newdocs/netcdf-c/nc_005finq_005fvar.html
dimids Returned vector of *ndimsp dimension IDs corresponding to the variable dimensions. The caller must allocate enough space for a vector of at least *ndimsp integers to be returned. The maximum possible number of dimensions for a variable is given by the predefined constant NC_MAX_VAR_DIMS.
Although the default or standard values of NC_MAX_DIMS and NC_MAX_VAR_DIMS are the same, the correct value to be used here is NC_MAX_VAR_DIMS and not NC_MAX_DIMS. Even though this currently works, it could fail if either NC_MAX_VAR_DIMS or NC_MAX_DIMS is changed and it can also provide an incorrect function usage example that may mislead developers trying to determine the correct usage of the function.
1. Added check to libsrc4/nc4var.nc_def_var_extra to
check that the no specified chunks size is greater than
the dimension size.
2. Added test to nc_test4/tst_chunks.c
