osobhandClaude Opus 5.5
9ea44d473d
A type-1 (raw data chunk) B-tree key holds the chunk size, the filter mask and one offset per dimension, and those offsets are always 8 bytes: they are dataset coordinates, not file addresses. The reader used the superblock's size-of-offsets for them, so in a file with 4-byte offsets every key was misparsed. Unfiltered chunked datasets read as zeros (with stray bytes where a misread address landed on data) and filtered ones failed with "deflate: truncated stream". Only the sibling and child addresses follow size-of-offsets now. The unit-test B-tree builder wrote keys the same wrong way, which is why its tests passed; it now matches the format. Regression: h5py_four_byte_offsets_chunked_reads (h5py, set_sizes(4, 4) and (4, 8); 1-D and 2-D, unfiltered and gzip) and the unit test collect_chunks_with_four_byte_addresses. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
clawhdf5
Pure-Rust HDF5 reader/writer — no C dependencies.
Features
- Read and write HDF5 files entirely in Rust
- Memory-mapped I/O for large files (
mmapfeature, enabled by default) - Parallel chunk reads via Rayon (
parallelfeature) - Lazy dataset access for minimal memory usage
- h5py-compatible file output
Usage
use clawhdf5::File;
let file = File::open("data.h5").unwrap();
let dataset = file.dataset("/group/data").unwrap();
let values: Vec<f64> = dataset.read_1d().unwrap();
License
MIT