netcdf-c/libsrc
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
..
attr.m4 Separate out the --ansi comment fixes. 2018-12-12 13:23:09 -07:00
CMakeLists.txt Changes to make it possible to nest this project inside of another CMake 2019-11-07 14:00:53 -07:00
depend
dim.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
ffio.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
httpio.c This PR adds EXPERIMENTAL support for accessing data in the 2020-06-28 18:02:47 -06:00
lookup3.c Follow-up trivial typos 2018-04-26 23:04:01 -04:00
Makefile.am Master merge, conflict resolution, cleanup 2019-02-24 16:54:13 -07:00
memio.c This PR adds EXPERIMENTAL support for accessing data in the 2020-06-28 18:02:47 -06:00
mmapio.c Fix typo in mmapio.c 2019-05-04 21:09:59 -06:00
nc3dispatch.c Support no-op dispatch functions 2020-04-15 14:44:58 -06:00
nc3internal.c windows: detect Windows using the correct define name 2019-11-07 07:55:47 -05:00
ncFile.c windows: detect Windows using the correct define name 2019-11-07 07:55:47 -05:00
ncio.c Master merge, conflict resolution, cleanup 2019-02-24 16:54:13 -07:00
ncio.h Provide byte-range reading of remote datasets 2019-01-01 18:27:36 -07:00
ncstdio.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
ncstdio.h More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
ncx_cray.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
ncx.h More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
ncx.m4 re: github issues 2018-10-30 20:48:12 -06:00
posixio.c Spelling fixes 2019-09-18 08:03:01 -06:00
pstdint.h windows: detect Windows using the correct define name 2019-11-07 07:55:47 -05:00
putget.m4 took RELAX_COORD_BOUND out of libsrc code 2019-11-26 06:29:27 -07:00
t_ncio.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
t_ncio.in
t_ncxx.m4 More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
test_nc.sav
v1hpg.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
var.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
winceio.c More synchronization of copyright stanzas. 2018-12-06 14:34:40 -07:00
XGetopt.c Fix undefined references when using Visual Studio 2020-05-18 19:36:28 -06:00