Files
clawhdf5/crates/clawhdf5
osobhandClaude Opus 5.5 1ffd013de9 edit: delete a heap's huge-object B-tree with its last huge object
libhdf5 deletes a fractal heap's huge-object B-tree when the heap is
closed with no huge object left (H5HF__huge_term) and starts huge IDs
over. The editor left the empty tree, and a read-only libhdf5 then
failed to list the object's attributes: closing the heap tried to delete
the tree ("no write intent on file"), and h5dump failed the same way.

Replacing an object's last huge attribute (one above the heap's 4 KiB
managed limit) now deletes the tree (header and nodes freed), resets the
next huge ID and the wrapped flag, as libhdf5 does; a later huge
attribute creates a new tree. Bt2::delete frees a whole tree.

Found by the extended random-operation test; regression:
last_huge_attribute_replaced (fails before: h5dump, h5py listing), which
also compares the heap with libhdf5's after the same replacement.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
2026-09-26 17:11:36 -05:00
..

clawhdf5

crates.io docs.rs

Pure-Rust HDF5 reader/writer — no C dependencies.

Features

  • Read and write HDF5 files entirely in Rust
  • Memory-mapped I/O for large files (mmap feature, enabled by default)
  • Parallel chunk reads via Rayon (parallel feature)
  • 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