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May 8, 2026 • 6 min read

OxiArc 0.2.8 Released — Hardware-Accelerated Checksums, ISO 9660 Reading, and Zero-Copy Append

Pure Rust archive and compression gets faster and broader. OxiArc 0.2.8 adds SIMD CRC32 via aarch64 PMULL and Snappy CRC32C via SSE4.2, ISO 9660 read support with Joliet filenames, byte-for-byte raw-preserve append for ZIP/LZH, progress/cancel builders for LZ4/Zstd/LZMA, and a per-entry memory limit. ~58k SLoC, 1,281 tests, 12 crates.

release oxiarc archive compression iso9660 simd crc32 zip lzh pure-rust

The data archiving and compression foundation of the COOLJAPAN ecosystem just got faster, broader, and leaner.

Today we released OxiArc 0.2.8 — hardware-accelerated checksums, a new disc-image format to read, and append that copies bytes instead of recompressing them.

No C. No Fortran. No zlib. No libarchive. No external shared libraries.
No FFI overhead. No build hell.
Just clean, memory-safe, blazing-fast archiving and compression that compiles to a single static binary and runs everywhere, including WASM.

Why 0.2.8 matters: speed, reach, and discipline

Three headline changes define this release.

Hardware-accelerated checksums. CRC is on the critical path of nearly every archive format, so OxiArc now reaches for the silicon. On Apple Silicon and other aarch64 chips, oxiarc-core computes SIMD CRC32 using PMULL instructions — and the result is bitwise-identical to the scalar path. On x86_64, oxiarc-snappy gains Snappy CRC32C via SSE4.2 (_mm_crc32_u64), with runtime feature dispatch through a OnceLock. No flags, no configuration — the fast path is chosen automatically.

ISO 9660 reading. OxiArc can now read .iso disc images. A new IsoReader parses the Primary Volume Descriptor and decodes Joliet UCS-2 filenames, with format detection via magic bytes at LBA 16. ISO 9660 joins the read-only family alongside 7z and CAB — it’s a read format, not a new write target.

Zero-copy, raw-preserve append. The oxiarc add command introduced in 0.2.7 now preserves ZIP and LZH entries byte-for-byte when appending, eliminating the decompress→recompress round-trip entirely. New low-level building blocks make this possible: ZipWriter::add_file_raw, LzhReader::read_raw_method_data, and LzhWriter::add_file_raw.

OxiArc remains API-stable as of v0.2.8: ~58,356 lines of pure Rust across 12 crates, with 1,281 tests passing.

What’s new

As always: zero clippy warnings (-D warnings), zero rustdoc warnings, and full COOLJAPAN policy compliance.

Technical Deep Dive: bit-identical SIMD and lossless append

The CRC work is the kind of optimization that has to be invisible to be useful. The carry-less multiply approach used by the aarch64 PMULL path folds the input in parallel, but it computes the exact same polynomial remainder as the scalar table-driven code — so existing archives validate identically and there is no “fast mode” caveat. The Snappy CRC32C path on x86_64 takes the analogous route through the dedicated _mm_crc32_u64 instruction, gated behind a OnceLock that probes the CPU once and caches the decision.

Raw-preserve append is the other half of the story. When you oxiarc add into a ZIP or LZH archive, OxiArc no longer needs to understand the content of the existing entries — only their boundaries. LzhReader::read_raw_method_data hands back the already-compressed method data, and ZipWriter::add_file_raw / LzhWriter::add_file_raw splice it into the output untouched. The payoff is that appending to an archive full of large, already-compressed entries is fast and lossless: no CPU spent recompressing data that was already compressed.

IsoReader rounds out the read-only container family in oxiarc-archive, sitting next to the 7z and CAB readers and wiring into the same CLI verbs.

Getting Started

Install the CLI:

cargo install oxiarc-cli

Inspect a disc image, cap memory on an untrusted archive, and append losslessly:

oxiarc list disk.iso
oxiarc extract data.tar.gz -o output/ --memory-limit 100M
oxiarc add archive.zip newfile.txt

For the library, add the archive crate plus the codec you need:

cargo add oxiarc-archive
cargo add oxiarc-deflate

use oxiarc_deflate::{deflate, inflate};
use oxiarc_archive::ZipReader;
use std::fs::File;

let compressed = deflate(b"Hello, World!", 6)?;
let decompressed = inflate(&compressed)?;

let file = File::open("archive.zip")?;
let mut zip = ZipReader::new(file)?;
for entry in zip.entries() {
    println!("{}: {} bytes", entry.name, entry.size);
}

What’s New in 0.2.8

Tips

This is the foundation

OxiArc is the sovereign archiving and compression backend for the wider COOLJAPAN stack, and faster checksums plus lossless append directly benefit the pipelines that depend on it:

Repository: https://github.com/cool-japan/oxiarc

Star the repo if you want high-performance archiving and compression — now with hardware-accelerated checksums and zero-copy append — and none of the traditional native toolchain headaches.

The era of “just use zlib” or “link libarchive” is coming to an end.

— KitaSan at COOLJAPAN OÜ May 8, 2026

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