micula

Brotli codec in Java.

Micula is Latin for “small crumb”; brotli is German for a small piece of bread. This library is a pure-Java, production-grade encoder and decoder for the RFC 7932 Brotli compressed data format.

Features

• Pure Java — no JNI, no native libraries
• NIO-first — ByteBuffer only; no InputStream / OutputStream
• Event-driven — push compressed bytes via receive(ByteBuffer); receive reconstructed output and optional LZ77 command events through a handler
• Incremental — chunk-invariant decoding; resume mid-symbol across buffer boundaries
• RFC 7932 — raw Brotli streams (not Google’s large-window extensions)

Decoding

BrotliDecoder decoder = new BrotliDecoder();
decoder.setHandler(new BrotliDefaultHandler() {
    @Override
    public void content(ByteBuffer data, boolean end) throws BrotliException {
        // data is valid only during this call
    }
});

ByteBuffer buffer = ByteBuffer.allocate(8192);
while (channel.read(buffer) > 0) {
    buffer.flip();
    decoder.receive(buffer);
    buffer.compact();
}
decoder.close();

Encoding

BrotliEncoder encoder = new BrotliEncoder(new ChannelBrotliSink(outChannel));
encoder.setQuality(1);   // 0 = uncompressed metablocks; 1–2 = LZ77 + Huffman
encoder.setWindowBits(22);
encoder.receive(uncompressed);
encoder.close();

Build

ant build
ant test

Requires JDK 21+.

Documentation

• Javadoc (GitHub Pages)

License

GNU Lesser General Public License version 2.1 (see LICENSE).