v0.1.0

First version: a safe-Rust Zstandard encoder byte-identical to zstd 1.5.7,
an independent RFC 8878 decoder, parallel compression, and a C ABI.

Compression

• Added Compressor with compress, compress_into, compress_to_slice
  and compress_to_uninit. One-shot output is byte-identical to
  ZSTD_compress2 with the same parameters.
• Added incremental sessions: EncoderSession, and EncoderSessionOwned
  with reinit and into_compressor. A session matches
  ZSTD_compressStream2 driven with the same chunks, output capacities and
  Continue/Flush/End operations, including the reference's direct
  compression of a final End and the content size it then records.
• Configuration in EncoderConfig:
  • levels -131072..=22 (Level), the explicit CompressionParams (window,
    chain, hash and search logs, minimum match, target length, Strategy);
  • long distance matching (LongDistanceMatching, LdmParams);
  • checksum and content-size flags, and a source size hint.
  • Out-of-range values fail with ConfigError::OutOfRange, which names the
    Parameter. Compressor::default() uses level 3.
• Added std::io adapters (EncoderReader, EncoderWriter, FinishError)
  and memory retention control (RetentionPolicy, trim,
  retained_bytes).
• The core ports zstd 1.5.7's encoder:
  • all nine strategies with their extDict variants, the row match finder
    and binary trees;
  • the optimal parser, including btultra2's first-block pass;
  • long distance matching;
  • the pre- and post-block splitters;
  • FSE and Huffman table selection;
  • streaming buffers and window wrap-around;
  • index overflow correction.

Decompression

• Added Decompressor with decompress, decompress_into and
  decompress_to_slice; DecoderSession and DecoderSessionOwned; the
  DecoderReader and DecoderWriter adapters. Concatenated and skippable
  frames are supported.
• DecodeLimits bound the window (default 2^27, up to 2^31), the input and
  the output. Failures are typed (DecodeError, InvalidDataKind).
• It is stricter than the reference in two places: Huffman streams must be
  consumed exactly, and offsets beyond the window are rejected in every API.
  Frames that need a dictionary fail with DictionaryUnsupported.

Parallel compression (std)

• Added compressor::parallel:
  • ParallelCompressor, with prepare_slice batches of caller-run tasks
    and streaming ParallelEncoderSessions with a ParallelTaskQueue;
  • segments that reach back into an overlap of the previous input;
  • frames independent of the task count and execution order;
  • panic-safe task completion.
• Parallel frames decode anywhere but are not byte-identical to the serial
  encoder or to zstd's multithreaded mode.

Tooling

• Added mzstd-ffi: mzstd_compress (byte-identical to ZSTD_compress),
  mzstd_decompress, mzstd_compress_bound, and include/mzstd.h.
• Added zstd-ffi, a test-only crate that builds the vendored zstd v1.5.7
  and provides safe oracle wrappers and corpora.
• Added AFL++ targets in fuzz/afl: differential_c, output_capacity,
  encoder_session, compressor_lifecycle, parallel,
  parameter_parsing, decompress, decode_streaming and
  decode_roundtrip. Each has committed regressions, a seed builder over
  upstream's test data, and a campaign script.
• Added Criterion benchmarks against zstd (compress, decompress, and
  mzstd-ffi's one_shot), CI workflows and architecture specifications.
• Measured with cargo bench --bench compress -- 'compress/(text-1MiB|binary-1MiB)/'
  and cargo bench --bench decompress -- 'decompress/(text-4MiB|binary-4MiB)/level-3'
  (--warm-up-time 1 --measurement-time 3, Apple M5 Pro, rustc 1.99).
  Output sizes are identical on both sides. Compression runs at 0.5–0.7×
  zstd's speed (text 1 MiB, level 3: 418 vs 775 MiB/s; level 19: 3.8 vs
  5.5 MiB/s). Decompression runs at 0.2–0.35× (text 4 MiB: 716 MiB/s vs
  2.19 GiB/s). Neither codec has SIMD yet.