RFC-HDFG-2026-001 v5 reverses the earlier "no on-disk format change"
decision: the verbatim key=value string passed to H5Pappend_filter is
now retained on the pipeline entry and written to the file, so it can be
recovered losslessly without loading the filter plugin.
H5O_PLINE_VERSION_3 appends [config_length:2][config] after each filter's
name. H5O_pline_set_version selects v3 only when a filter carries a
stored string and the file's high bound admits it; otherwise it stays at
v2 and the string is omitted, keeping string-free files byte-identical.
The new bound H5F_LIBVER_V300 (now H5F_LIBVER_LATEST) gates emission and
is mirrored in every *_ver_bounds[] table, H5trace, h5test, and the
Fortran/Java constants.
The string is threaded through the property machinery: H5Pappend_filter
retains it, H5Z_append/decode initialize it, H5O__pline copy/size/reset
and the H5Pencode/H5Pdecode pipeline enc/dec carry it, H5Z_modify
(H5Pmodify_filter) clears it, and H5Z_delete frees it.
H5Pget_filter_params_by_idx now returns the stored string first, falling
back to get_config then a cd_values listing; h5dump -p shows it for every
filter. H5Z_get_config_func_t's doc no longer frames cd_values packing
as normative (it is filter-private).
Tests (test/tfilter2.c) cover the verbatim round-trip recovered without
the plugin, the silent v2 downgrade when the libver bound is too low,
H5Pmodify_filter clearing, and survival through H5Pencode/H5Pdecode and
H5Ocopy. Updated the h5repack plugin_test_cfg reference to the verbatim
PARAMS_STRING.
FFM build requires Java 25, Jextract 25.
Generates FFM bindings during configure.
JNI is default when the requirements are not met or can be forced.
Presets added for maven and FFM - JNI is default selection.
Enhanced Maven options will work with either JNI or FFM
New Workflows for testing and maven uploads.
Extensive documentation changes for java.
Scot Breitenfeld
Allen Byrne