osobhandClaude Opus 5.5
2bc4cb46a6
A 256 x 256 hyperslab of a contiguous f32 dataset read at an eighth of h5py's speed: partial_read copied the bounding box out of the file, the extractor then walked it element by element (a recursive call and two bounds checks per element) into a second buffer, and read_f32_selection converted that into a third. Selections of contiguous data are now copied straight from the file, one memcpy per run of elements contiguous in the file (gather.rs: a block along the last dimension, touching blocks as one range, whole rows merged), with no zero-filled intermediate and no full copy for large selections. The typed selection readers copy into their Vec<T> directly when the dataset stores T natively (new data_read::read_selection_native and sealed NativeElement trait, which the read_as_* fast paths now share; read_as_u64 gains one) and convert as before otherwise. The general extractor used by the chunked paths runs on the same run walker, keeping its old handling of unvalidated selections. Checked against h5py (contiguous_read_interop.rs) for strided, blocked, adjacent-block and whole-row hyperslabs, points and empty selections of every 1-8-byte type in both byte orders, ranks 1-4. Also keeps the huge-page threshold constant out of no_std builds, where it was unused. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
clawhdf5-format
Pure-Rust HDF5 binary format parsing and writing — no C dependencies.
Features
- Zero-copy superblock, object header, and B-tree parsing
- Chunked dataset read/write with filter pipelines
no_stdsupport (disablestdfeature)- Optional parallel reads via Rayon
- SHA-256 provenance tracking
Usage
use clawhdf5_format::Superblock;
let data = std::fs::read("data.h5").unwrap();
let sb = Superblock::from_bytes(&data).unwrap();
println!("HDF5 version {}.{}", sb.version_major(), sb.version_minor());
License
MIT