ReadAttrStr and HDF5DataSet::ReadString read every string as fixed-length,
sizing the buffer by H5Tget_size. For a variable-length string (what h5py
writes for a str, UTF-8) that size is a pointer, so the read put a char*
into the buffer and returned garbage. transformation_type then never equalled
"rotation", and an EIGER master whose goniometer attributes were written that
way (depends_on, transformation_type, units on /entry/sample/transformations)
was processed as stills although it holds a valid rotation sweep.
All string reads now go through one helper, ReadHDF5String, which handles both
fixed- and variable-length strings in either character set; ReadElement<string>
already handled the variable-length case and now uses the same helper.
Test: JFJochReader_Goniometer_VariableLengthStrings reads the rotation axis
from a master with fixed-length ASCII and with variable-length UTF-8 string
attributes and depends_on dataset.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SVmAWnzCmRKAXVUCdc4iNi
leonarski_fandClaude Opus 5.5
badd7360ca