osobhandClaude Opus 5.5
ca81c3ebfa
A parser often learns where the next structures are (a node's children, a structure's body once its prefix gives its length) before it reads them one at a time. Over openUrl's restartable reader a structure only reached after a miss costs a pass, and a round trip, of its own. - clawhdf5-format: `Storage::hint(offset, len)`, "about to be read by this operation". Default: nothing (every backend that reads when asked); `&T`, `Box`, `Arc` and the facade's `FileData` forward it (shifted past a user block, clamped to the file). - clawhdf5-wasm `LazyStorage` records hinted blocks it lacks. A pass that misses nothing ignores them (a hint never adds a round trip); a pass that misses also asks for them, in file order, while the pass stays within what is left of the operation's `maxFetch` budget (a hint never makes a call fail). At most 1 MiB (or a block) per hint and 65536 blocks per pass are recorded, whatever a file makes a parser hint. `Operation::attempt` follows hints; the plain `LazyStorage::attempt` does not. `run_blocking` and the browser's driver use the former. `LazyStats::hinted_blocks` counts them. No parser hints yet: results, passes and requests are unchanged. Tests: hinted blocks come with a miss and never alone (cached ones skipped, a plain attempt ignores them), and stay within the fetch budget, a hint past the end or longer than the file harmless. 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