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Commit Graph

14 Commits

Author SHA1 Message Date
Dennis Heimbigner
59e04ae071 This PR adds EXPERIMENTAL support for accessing data in the
cloud using a variant of the Zarr protocol and storage
format. This enhancement is generically referred to as "NCZarr".

The data model supported by NCZarr is netcdf-4 minus the user-defined
types and the String type. In this sense it is similar to the CDF-5
data model.

More detailed information about enabling and using NCZarr is
described in the document NUG/nczarr.md and in a
[Unidata Developer's blog entry](https://www.unidata.ucar.edu/blogs/developer/en/entry/overview-of-zarr-support-in).

WARNING: this code has had limited testing, so do use this version
for production work. Also, performance improvements are ongoing.
Note especially the following platform matrix of successful tests:

Platform | Build System | S3 support
------------------------------------
Linux+gcc      | Automake     | yes
Linux+gcc      | CMake        | yes
Visual Studio  | CMake        | no

Additionally, and as a consequence of the addition of NCZarr,
major changes have been made to the Filter API. NOTE: NCZarr
does not yet support filters, but these changes are enablers for
that support in the future.  Note that it is possible
(probable?) that there will be some accidental reversions if the
changes here did not correctly mimic the existing filter testing.

In any case, previously filter ids and parameters were of type
unsigned int. In order to support the more general zarr filter
model, this was all converted to char*.  The old HDF5-specific,
unsigned int operations are still supported but they are
wrappers around the new, char* based nc_filterx_XXX functions.
This entailed at least the following changes:
1. Added the files libdispatch/dfilterx.c and include/ncfilter.h
2. Some filterx utilities have been moved to libdispatch/daux.c
3. A new entry, "filter_actions" was added to the NCDispatch table
   and the version bumped.
4. An overly complex set of structs was created to support funnelling
   all of the filterx operations thru a single dispatch
   "filter_actions" entry.
5. Move common code to from libhdf5 to libsrc4 so that it is accessible
   to nczarr.

Changes directly related to Zarr:
1. Modified CMakeList.txt and configure.ac to support both C and C++
   -- this is in support of S3 support via the awd-sdk libraries.
2. Define a size64_t type to support nczarr.
3. More reworking of libdispatch/dinfermodel.c to
   support zarr and to regularize the structure of the fragments
   section of a URL.

Changes not directly related to Zarr:
1. Make client-side filter registration be conditional, with default off.
2. Hack include/nc4internal.h to make some flags added by Ed be unique:
   e.g. NC_CREAT, NC_INDEF, etc.
3. cleanup include/nchttp.h and libdispatch/dhttp.c.
4. Misc. changes to support compiling under Visual Studio including:
   * Better testing under windows for dirent.h and opendir and closedir.
5. Misc. changes to the oc2 code to support various libcurl CURLOPT flags
   and to centralize error reporting.
6. By default, suppress the vlen tests that have unfixed memory leaks; add option to enable them.
7. Make part of the nc_test/test_byterange.sh test be contingent on remotetest.unidata.ucar.edu being accessible.

Changes Left TO-DO:
1. fix provenance code, it is too HDF5 specific.
2020-06-28 18:02:47 -06:00
Dennis Heimbigner
84c69afca7 Allow redefinition of variable filters
re: Github issue https://github.com/Unidata/netcdf-c/issues/1713

If nc_def_var_filter or nc_def_var_deflate or nc_def_var_szip is
called multiple times with the same filter id, but possibly with
different sets of parameters, then the first invocation is
sticky and later invocations are ignored. The desired behavior
is to have the last invocation be used.

This PR implements that desired behavior, with some special
cases.  If you call nc_def_var_deflate multiple times, then the
last invocation rule applies with respect to deflate. However,
the shuffle filter, if enabled, is always applied just before
applying deflate.

Misc unrelated changes:
1. Make client-side filters be disabled by default
2. Fix the definition of uintptr_t and use in oc2 and libdap4
3. Add some test cases
4. modify filter order tests to use plugin filters rather
   than client-side filters
2020-05-11 09:42:31 -06:00
Dennis Heimbigner
6f86660da8 Fix missing forward declarations
re: issue https://github.com/Unidata/netcdf-c/issues/1687

static functions are being used before decl and it causes
errors. Only occurs when BIG_ENDIAN is defined.
Solution is to add the forward declarations.
2020-04-03 20:15:34 -06:00
Edward Hartnett
7004bbc2d5 updated documentation 2020-03-06 09:54:26 -07:00
Dennis Heimbigner
44d0dcaad2 Add support for multiple filters per variable.
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.
2020-02-16 12:59:33 -07:00
Ed Hartnett
1d9f28fb70 changing USE_NETCDF4 to USE_HDF5 in dfilter.c 2019-05-22 07:36:22 -06:00
Dennis Heimbigner
8d0bced60d Allow in-line definition of filters
Priority: Low

re: issue https://github.com/Unidata/netcdf-c/issues/1329

HDF5 has the ability to programmatically define new filters,
as opposed to using HDF5_PLUGIN_PATH env variable.
This PR adds support for that feature.
Not clear how useful this is, though.
See docs/filters.md for details.
2019-03-21 11:33:27 -06:00
Dennis Heimbigner
8714066b18 Fix errors when building on big-endian machine
re: issue https://github.com/Unidata/netcdf-c/issues/1278
re: issue https://github.com/Unidata/netcdf-c/issues/876
re: issue https://github.com/Unidata/netcdf-c/issues/806

* Major change to the handling of 8-byte parameters for nc_def_var_filter.
  The old code was not well thought out.
  * The new algorithm is documented in docs/filters.md.
  * Added new utility file plugins/H5Zutil.c to support
  * Modified plugins/H5Zmisc.c to use new algorithm
  the new algorithm.
  * Renamed include/ncfilter.h to include/netcdf_filter.h
    and made it an installed header so clients can access the
    new algorithm utility.
  * Fixed nc_test4/tst_filterparser.c and nc_test4/test_filter_misc.c
    to use the new algorithm
* libdap4/ fixes:
  * d4swap.c has an error in the endian pre-processing such
    that record counts were not being swapped correctly.
  * d4data.c had an error in that checksums were being computed
    after endian swapping rather than before.
* ocinitialize() was never being called, so xxdr bigendian handling
  was never set correctly.
  * Required adding debug statements to occompile
* Found and fixed memory leak in ncdump.c

Not tested:
* HDF4
* Pnetcdf
* parallel HDF5
2019-01-31 21:13:06 -07:00
Ward Fisher
25417880f7 Updated libdispatch/ files with copyright notice. 2018-12-06 14:29:57 -07:00
Dennis Heimbigner
6633932fd4 re: GH Issue https://github.com/Unidata/netcdf-c/issues/806
Incorrect reference to byteswap8 in libdispatch/dfilter.c
Change byteswap8 -> NC_byteswap8.
2018-01-25 13:51:42 -07:00
Dennis Heimbigner
3e47f5f300 Rebuilt the filter parameter handling code to use a common
parser everywhere.
2018-01-23 16:00:11 -07:00
Ed Hartnett
a8d5323083 fixed leak in event of null paramter 2017-11-14 09:34:26 -07:00
Dennis Heimbigner
111248e067 Changed to make little-endian the standard for 64-bit parameters 2017-10-10 11:21:01 -06:00
Dennis Heimbigner
8fe67b79e6 forgot to add dfilter.c to git 2017-10-08 16:37:42 -06:00