netcdf-c/ncgen/Makefile.am
Dennis Heimbigner 231ae96c4b Add support for Zarr string type to NCZarr
* re: https://github.com/Unidata/netcdf-c/pull/2278
* re: https://github.com/Unidata/netcdf-c/issues/2485
* re: https://github.com/Unidata/netcdf-c/issues/2474

This PR subsumes PR https://github.com/Unidata/netcdf-c/pull/2278.
Actually is a bit an omnibus covering several issues.

## PR https://github.com/Unidata/netcdf-c/pull/2278
Add support for the Zarr string type.
Zarr strings are restricted currently to be of fixed size.
The primary issue to be addressed is to provide a way for user to
specify the size of the fixed length strings. This is handled by providing
the following new attributes special:
1. **_nczarr_default_maxstrlen** —
This is an attribute of the root group. It specifies the default
maximum string length for string types. If not specified, then
it has the value of 64 characters.
2. **_nczarr_maxstrlen** —
This is a per-variable attribute. It specifies the maximum
string length for the string type associated with the variable.
If not specified, then it is assigned the value of
**_nczarr_default_maxstrlen**.

This PR also requires some hacking to handle the existing netcdf-c NC_CHAR
type, which does not exist in zarr. The goal was to choose numpy types for
both the netcdf-c NC_STRING type and the netcdf-c NC_CHAR type such that
if a pure zarr implementation read them, it would still work and an
NC_CHAR type would be handled by zarr as a string of length 1.

For writing variables and NCZarr attributes, the type mapping is as follows:
* "|S1" for NC_CHAR.
* ">S1" for NC_STRING && MAXSTRLEN==1
* ">Sn" for NC_STRING && MAXSTRLEN==n

Note that it is a bit of a hack to use endianness, but it should be ok since for
string/char, the endianness has no meaning.

For reading attributes with pure zarr (i.e. with no nczarr
atribute types defined), they will always be interpreted as of
type NC_CHAR.

## Issue: https://github.com/Unidata/netcdf-c/issues/2474
This PR partly fixes this issue because it provided more
comprehensive support for Zarr attributes that are JSON valued expressions.
This PR still does not address the problem in that issue where the
_ARRAY_DIMENSION attribute is incorrectly set. Than can only be
fixed by the creator of the datasets.

## Issue: https://github.com/Unidata/netcdf-c/issues/2485
This PR also fixes the scalar failure shown in this issue.
It generally cleans up scalar handling.
It also adds a note to the documentation describing that
NCZarr supports scalars while Zarr does not and also how
scalar interoperability is achieved.

## Misc. Other Changes
1. Convert the nczarr special attributes and keys to be all lower case. So "_NCZARR_ATTR" now used "_nczarr_attr. Support back compatibility for the upper case names.
2. Cleanup my too-clever-by-half handling of scalars in libnczarr.
2022-08-27 20:21:13 -06:00

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Makefile

## This is a automake file, part of Unidata's netCDF package.
# Copyright 2008, see the COPYRIGHT file for more information.
# This file builds and runs the ncgen program.
# Put together AM_CPPFLAGS and AM_LDFLAGS.
include $(top_srcdir)/lib_flags.am
LDADD = ${top_builddir}/liblib/libnetcdf.la
# Build ncgen from the listed sources.
bin_PROGRAMS = ncgen
ncgen_SOURCES = bindata.c bytebuffer.c cdata.c cvt.c data.c \
debug.c dump.c escapes.c f77data.c genbin.c \
genc.c genchar.c generate.c generr.c genf77.c \
genj.c genlib.c getfill.c jdata.c list.c \
main.c ncgeny.c semantics.c \
util.c bytebuffer.h data.h debug.h dump.h \
generate.h generr.h genlib.h includes.h list.h \
ncgen.h ncgeny.h util.h
# Obsolete
OBSOLETE = odom.c odom.h jdatastd.c jdatajni.c genjni.c cdfdata.c cmldata.c
# This is the man page.
man_MANS = ncgen.1
# These files all need to be distributed.
EXTRA_DIST = ncgen.y ncgen.l ncgenl.c $(man_MANS) internals.html \
c0.cdl c0_4.cdl ref_camrun.cdl \
ncf199.cdl CMakeLists.txt c5.cdl \
compound_datasize_test.cdl compound_datasize_test2.cdl \
tst_gattenum.cdl tst_usuffix.cdl
# This shell script causes ncgen to build a classic and a 64-bit
# offset file from a cdl file shipped with the distribution.
#if !BUILD_DLL
##
# Moved to ncdump as these tests rely on ncdump having been built.
##
#TESTS = run_tests.sh
#if USE_HDF5
#TESTS += run_nc4_tests.sh
#endif # USE_HDF5
#endif # !BUILD_DLL
CLEANFILES = c0.nc c0_64.nc c0_4.nc c0_4c.nc ref_camrun.c \
ncf199.nc c5.nc compound_datasize_test.nc compound_datasize_test2.nc \
tst_compound_datasize_test.cdl tst_compound_datasize_test2.cdl tst_ncf199.cdl \
tst_tst_gattenum.cdl tst_gattenum.nc \
tst_tst_usuffix.cdl tst_usuffix.nc \
tst_c0.cdl tst_c0_4.cdl tst_c0_4c.cdl tst_c0_64.cdl
# These rules are used if someone wants to rebuild ncgenl.c or ncgeny.c
# Otherwise never invoked, but records how to do it.
# BTW: note that renaming is essential because otherwise
# autoconf will forcibly delete files of the name *.tab.*
# Note also that this should be built under linux or cygwin
# using bison version 3 or later.
# Note also that this code is in a shell script if you do
# not want to other to ./configure.
makeparser::
rm -f ncgenl.c lex.ncg.c
flex -Pncg -8 ncgen.l
sed -e s/lex.ncg.c/ncgenl.c/g <lex.ncg.c >ncgenl.c
bison -pncg -t -d ncgen.y
rm -f ncgeny.c ncgeny.h
sed -e s/ncgen.tab.c/ncgeny.c/g -e s/ncgen.tab.h/ncgeny.h/g <ncgen.tab.c >ncgeny.c
sed -e s/ncgen.tab.c/ncgeny.c/g -e s/ncgen.tab.h/ncgeny.h/g <ncgen.tab.h >ncgeny.h
rm -f lex.ncg.c ncgen.tab.h ncgen.tab.c