S4 — Squished S3
Copyright 2026 abyo software 合同会社 (LLC)

This product includes software developed by abyo software 合同会社
and its contributors. Licensed under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

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Third-party components
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This product bundles or links to the following third-party components.
Each component remains under its own license:

1. ferro-compress (integrated at crates/s4-codec/src/ferro_compress/)
   - Origin: abyo software 合同会社 / FerroSearch project
   - License: Apache-2.0 OR MIT (dual-licensed)
   - Purpose: NVIDIA nvCOMP Rust binding for GPU compression backend
   - Status: Source physically integrated into s4-codec for crates.io
     distribution. Subset includes algo / error / nvcomp_sys (FFI) /
     nvcomp / nvcomp_hlif / bitcomp_device / slab_alloc and the
     nvcomp_hlif_shim.cpp C-ABI shim. Tantivy bitmap-op kernels and CPU
     codec features from upstream are NOT included.

2. s3s (https://github.com/Nugine/s3s)
   - License: Apache-2.0
   - Purpose: S3-compatible HTTP service framework

3. NVIDIA nvCOMP SDK (optional, when built with `--features nvcomp-gpu`)
   - License: NVIDIA Software License Agreement (proprietary, NOT redistributed
     by S4 — users must obtain from NVIDIA Developer)
   - Purpose: GPU-accelerated compression codecs (zstd, Bitcomp, gANS)
   - Distribution: BYO (bring-your-own) — set NVCOMP_HOME environment variable
     pointing to extracted nvCOMP redist tarball at build time. S4 binaries
     and Docker images do NOT bundle libnvcomp.

4. Rust crates from the Rust ecosystem
   - All under permissive licenses (MIT / Apache-2.0 / BSD)
   - See `Cargo.lock` for the full list and `cargo tree --format "{p} {l}"` to
     audit licenses

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Trademark notice
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"S4" and "Squished S3" are unregistered trademarks of abyo software 合同会社.
"Amazon S3" and "AWS" are trademarks of Amazon.com, Inc. or its affiliates.
S4 is not affiliated with, endorsed by, or sponsored by Amazon or AWS.
