brotli_fast 1.0.0

Fast, pure Dart Brotli (RFC 7932) encoder and decoder with no native dependencies. Works on the VM, AOT, Flutter, and the web (JS and Wasm), with one-shot functions, a dart:convert codec and streaming.

1.0.0

First release: a fast, pure Dart Brotli (RFC 7932) encoder and decoder, with no dependencies.

• API: brotliEncode / brotliDecode, the dart:convert codec brotli (BrotliCodec, BrotliEncoder, BrotliDecoder) with chunked stream conversion, BrotliDictionary for shared dictionaries, and BrotliException with typed BrotliErrorCodes.
• Encoder: qualities 0–11 and window sizes 10–24 bits, plus the large-window format (25–30). Qualities 0–5 use a fast tier; 6–11 add context modeling, block splitting, distance-parameter search and, at 10–11, cost-guided parsing.
• Decoder: one-shot and streaming, with a decompression-bomb limit, compound and serialized shared dictionaries, and large-window streams on opt-in.
• Platforms: VM, AOT, Flutter and the web (dart2js and dart2wasm). The encoder produces byte-identical output on all of them.
• Interoperability: CI cross-checks against the reference brotli CLI in both directions.
• License: Apache 2.0. The bundled google/brotli dictionary, tables and test corpus keep their MIT notice in NOTICE.

Inspired by brotli_neo (MIT), as a full rewrite. Compared with it:

• Fixes four decoder bugs that rejected or silently misdecoded valid streams on the VM and WASM:
  • long literal runs and long copies (10–24 extra bits) were read without refilling the bit window;
  • a meta-block that exactly filled the ring buffer wrapped its position before the ring could grow;
  • with small windows (10–17 bits), the one-shot fast path mistook distances past the wrapped ring position for dictionary references, and read copy sources that wrapped the ring end from past the window;
  • concurrent decoders (two streams through brotli.decoder, or a stream and a one-shot decode) shared one pooled ring buffer and corrupted each other.
• Streamed decoding now rejects trailing data after the end of the stream, like one-shot decoding, however the input is chunked (it was ignored when it arrived in a later chunk).
• Fixes an encoder crash (RangeError) at qualities 2–5 on random-looking input.
• The fast tier's hash is now exact under dart2js, so web output matches the VM.
• Faster encoding with byte-identical output. Against brotli_neo 0.2.0 on the same machine (AOT): text q5 1.7× (858 vs 502 MB/s), text q9 2.2× (93 vs 43 MB/s), binary q0–q5 +24–41%. See benchmark/HISTORY.md.
• Web-motivated code has per-platform implementations, so the VM, AOT and dart2wasm no longer pay for dart2js limits: unaligned reads and 8-byte match-length comparison use ByteData there, while dart2js keeps its 32-bit-safe paths.