mirror/netcdf-c
2
0
Fork 0
mirror of https://github.com/Unidata/netcdf-c.git synced 2024-11-27 07:30:33 +08:00
Code Issues Packages Projects Releases Wiki Activity
942f756eae
netcdf-c/nczarr_test/ref_multi.cdl

18 lines
415 B
Plaintext
Raw Normal View History

Add filter support to NCZarr 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'
2021-09-03 07:04:26 +08:00
netcdf multifilter {
dimensions:
dim0 = 4 ;
dim1 = 4 ;
dim2 = 4 ;
dim3 = 4 ;
variables:
float var(dim0, dim1, dim2, dim3) ;
var:_Storage = "chunked" ;
var:_ChunkSizes = 4, 4, 4, 4 ;
var:_Filter = "307,9|1,2|40000" ;
Improve filter installation process to avoid use of an extra shell script re: https://github.com/Unidata/netcdf-c/issues/2338 re: https://github.com/Unidata/netcdf-c/issues/2294 In issue https://github.com/Unidata/netcdf-c/issues/2338, Ed Hartnett suggested a better way to install filters to a user defined location -- for Automake, anyway. This PR implements that suggestion. It turns out to be more complicated than it appears, so there are fair number of changes; mostly to shell scripts. Most of the change is in plugins/Makefile.am. NOTE: this PR still does NOT address the use of HDF5_PLUGIN_PATH as the default; this turns out to be complex when dealing with NCZarr. So this will be addressed in a subsequent post 4.9.0 PR. ## Misc. Changes 1. Record the occurrences of incomplete codecs in libnczarr so that they can be included in _Codecs attribute correctly. This allows users to see what missing filters are referenced in the Zarr file. Primarily affects libnczarr/zfilter.[ch]. Also required creating a new no-effect filter: H5Zunknown.c. 2. Move the unknown filter test to a separate test file. 3. Incorporates PR https://github.com/Unidata/netcdf-c/pull/2343
2022-05-15 06:05:48 +08:00
var:_Codecs = "[{\"id\": \"bz2\",\"level\": \"9\"},{\"id\": \"zlib\",\"level\": \"2\"},{\"id\": \"noop\"}]" ;
Add filter support to NCZarr 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'
2021-09-03 07:04:26 +08:00
var:_NoFill = "true" ;
// global attributes:
:_Format = "netCDF-4" ;
}
Reference in New Issue Copy Permalink