v0.10

Added

• Native builds now compile with ZSTD_MULTITHREAD, making
  ZstdCompressParameter.NB_WORKERS (plus JOB_SIZE and OVERLAP_LOG)
  functional instead of a silent no-op. Workers engage above zstd's 512 KiB
  job-size minimum; multithreaded frames are format-valid but not
  byte-identical to single-threaded output. A context that compressed with
  workers holds its native worker threads until close() — reset() does
  not release them, so give such contexts a dedicated owner (never pool
  them). See ADR 0015, which
  supersedes ADR 0014.
  (#80)

v0.9

Added

• Native builds now decode legacy zstd frame formats v0.4-v0.7
  (ZSTD_LEGACY_SUPPORT=4, matching zstd-jni's default). v0.1-v0.3 stay
  unsupported — they predate zstd's 1.0 stabilization and are essentially
  never seen in practice. Verified against a real fixture of five concatenated
  legacy frames extracted from zstd's own test suite. (#73)

Changed

• linux-x86_64/osx-x86_64/windows-x86_64 native builds now include
  zstd's hand-written BMI2 Huffman-decode assembly (previously disabled). It
  is a no-op on non-x86_64 targets and only activates via zstd's own runtime
  CPU detection; benchmarked as throughput-neutral on this project's
  synthetic workload but carries no measured downside either.
  (#71)
• aarch64 native builds now target an ARMv8-A + CRC baseline
  (-mcpu=generic+crc, zig's spelling of -march=armv8-a+crc), instead of
  the fully generic baseline. Measured +6.9% compress / +12-14% decompress
  throughput on Apple Silicon. (#71)

Security

• linux-x86_64/linux-aarch64 native builds now link with full RELRO and
  immediate binding (-Wl,-z,relro,-z,now), closing off the classic
  GOT-overwrite exploit primitive. Verified with llvm-readelf.
  (#71)
• windows-x86_64/windows-aarch64 native builds now export only zstd's
  public API (ZSTD_*/ZDICT_*) from the DLL, via -DZSTD_DLL_EXPORT=1
  (the PE analogue of the -fvisibility=hidden surface already used on
  ELF/Mach-O), instead of dumping every internal symbol
  (FSE_*/HUF_*/COVER_*/...) into the export table via
  --export-all-symbols. Cut the windows-x86_64 export table from 576 to
  185 symbols. (#79)

Fixed

• Building the native library from source on Windows was silently broken:
  Maven's exec plugin tried to execute build-zstd.sh directly, which only
  works via a shebang on macOS/Linux. Windows builds now invoke it through
  bash explicitly. A second latent bug this surfaced — unrecognized/Windows
  host OS detection crashed the build script under set -u — is fixed
  alongside it. (#75)
• Native library compilation now runs every translation unit through a real
  parallel work queue (xargs -P) instead of a fixed-size batch-then-wait
  loop, and aborts immediately if any zig cc invocation fails. Previously a
  failed compile under &/wait was invisible to set -e — it could
  silently produce no .o and only surface later as a cryptic link error, or
  worse, a link that "succeeded" against a stale .o left over from a
  previous run. (#78)

Investigated and rejected as part of the same effort (see
#70 for full benchmark data):
LTO (real compress regression on x86_64, unsupported on macOS entirely — zig's
Mach-O linker has no LTO support, tracked in
#77) and an x86-64-v3
baseline (mixed result, hurts compress more than it helps decompress). Both
would have traded away this project's existing compress-side edge over
zstd-jni for a smaller decompress-side gain.

v0.8

Added

• module-info.java: zstd now ships as a named JPMS module
  (module io.github.dfa1.zstd), exporting the single public API package.
  Module-path consumers grant --enable-native-access=io.github.dfa1.zstd
  instead of ALL-UNNAMED; classpath consumers are unaffected. See
  ADR 0011.

v0.7

Changed

• Breaking: renamed public types to spell out abbreviations, matching the
  Zstd<Compress|Decompress><Stream|Parameter> family and zstd's own prose
  ("compression context", "dictionary"): ZstdCompressCtx → ZstdCompressContext,
  ZstdDecompressCtx → ZstdDecompressContext, ZstdCompressDict →
  ZstdCompressDictionary, ZstdDecompressDict → ZstdDecompressDictionary.

v0.6

Added

• ZstdCompressCtx.refPrefix(MemorySegment) / ZstdDecompressCtx.refPrefix(...)
  — reference native content as a single-use prefix (raw-content dictionary) for
  the next frame only: the building block for delta compression (compress a new
  version against a similar previous one). The prefix is referenced, not copied
  or digested, and writes no dictionary ID; the decompressor must reference the
  same prefix to decode. Binds ZSTD_CCtx_refPrefix / ZSTD_DCtx_refPrefix.
  Segment-only by design — heap callers that need a copy should use
  loadDictionary instead.
• Zstd.dictId(byte[]) / Zstd.dictId(MemorySegment) — read the dictionary id
  stamped in raw dictionary bytes without wrapping them in a ZstdDictionary.
  Binds ZSTD_getDictID_fromDict.
• ZstdDictionaryId value type — a record wrapping the 32-bit dictionary id
  with an unsigned value(), isPresent(), and the NONE sentinel for "no id".
• ZstdFrame.decompressedSize(byte[]) / ZstdFrame.decompressedSize(MemorySegment)
  — the exact combined decompressed size of all concatenated frames, summed from
  each frame header (throws if any frame does not record its size). Complements
  decompressedBound (upper bound). Binds ZSTD_findDecompressedSize.
• ZstdFrame.headerSize(byte[]) / ZstdFrame.headerSize(MemorySegment) — the size
  of a frame's header computed from just its leading bytes (as few as 5), without a
  full parse. Binds ZSTD_frameHeaderSize.
• ZstdFrame.decompressionMargin(byte[]) / ZstdFrame.decompressionMargin(MemorySegment)
  — the extra room needed to decompress a frame in place (output buffer overlaps
  the compressed input at its tail), sized decompressedSize + margin. Binds
  ZSTD_decompressionMargin.
• ZstdDictionary.compressDict(int) / compressDict() / decompressDict() —
  factories for digested dictionaries, e.g. dict.compressDict(19) instead of
  new ZstdCompressDict(dict, 19). They signal that the result is AutoCloseable
  and are for sharing one digest across contexts via refDictionary; a single
  context should prefer the context-owned loadDictionary.

Changed

• Every dictionary-id accessor now returns ZstdDictionaryId instead of int:
  ZstdDictionary.id(), ZstdCompressDict.id(), ZstdDecompressDict.id(),
  ZstdFrame.dictId(...), and ZstdFrameHeader.dictId(). The 0 sentinel is now
  ZstdDictionaryId.NONE, and the id reads as unsigned via value().
• Zstd.decompress(byte[]) now throws ZstdException (instead of letting a raw
  ArithmeticException escape) when a frame declares a content size larger than a
  Java array can hold. The size comes from the untrusted frame header; use
  decompress(byte[], int) to bound output for untrusted input.

v0.5

Added

• ZstdCompressCtx.reset(ZstdResetDirective) / ZstdDecompressCtx.reset(...) —
  recycle a context's native state between frames without freeing and recreating
  it. SESSION_ONLY keeps the level, parameters, and dictionary; PARAMETERS /
  SESSION_AND_PARAMETERS restore the defaults. Binds ZSTD_CCtx_reset /
  ZSTD_DCtx_reset.
  (3dfd5b8)
• ZstdCompressCtx.loadDictionary(...) / ZstdDecompressCtx.loadDictionary(...)
  (a ZstdDictionary or a native MemorySegment) and refDictionary(...) (a
  pre-digested ZstdCompressDict / ZstdDecompressDict, attached by reference,
  no copy). A sticky dictionary on the context lets compression combine a
  dictionary with the advanced parameters (checksum, window log, long-distance
  matching) — impossible through the per-call compress(src, dict) overloads,
  which route the legacy dictionary path. A parameter reset(...) clears it.
  Binds ZSTD_CCtx_loadDictionary / ZSTD_DCtx_loadDictionary (now on contexts,
  not just streams), ZSTD_CCtx_refCDict, ZSTD_DCtx_refDDict.
  (3dfd5b8)

Changed

• NativeLibrary.classifier() now throws a clear UnsatisfiedLinkError naming
  the unsupported CPU arch instead of silently mapping it to x86_64 (which
  deferred failure to a cryptic dlopen error). Added an explicit amd64
  branch so Linux JVMs (which report os.arch=amd64) still resolve x86_64.
  (ea1ac84)

Fixed

• Native JARs are much smaller. The ELF shared library is now stripped at link
  time (-s), dropping debug info (libzstd.so 4.0M -> ~650K), and the
  multi-MB .pdb debug database and .lib import library that lld emits next
  to the Windows .dll are no longer bundled (neither is needed at runtime).
  Net: linux-x86_64 native jar 1.2M -> 285K, windows-x86_64 1.2M -> 372K.
  (ea1ac84)

v0.4

Added

• Zstd.versionNumber() — the linked zstd version as a single integer
  (MAJOR * 10000 + MINOR * 100 + PATCH, e.g. 10507 for 1.5.7), for
  programmatic version checks alongside version().

Changed

• ZstdSkippableContent is now a true immutable value: it defensively copies its
  bytes on the way in and out, and compares by content
  (equals / hashCode / toString over the payload, not array identity).
• Public methods fail fast with a named NullPointerException on null byte[],
  dictionary, or sample arguments, instead of an opaque failure deep in native
  code. Streams are documented as not thread-safe; digested dictionaries
  (ZstdCompressDict / ZstdDecompressDict) as immutable and safe to share.

Fixed

• A streaming wrapper that failed partway through construction (e.g. an invalid
  parameter or dictionary) leaked the native context. The context is now freed
  on every constructor error path.

Security

• The bundled library is extracted into a directory created owner-only
  (rwx------) atomically at creation, not just by default. The third-party
  setup-zig CI action is pinned to a full commit SHA.

v0.3

Changed

• zstd-platform is now an ordinary (empty) jar instead of a pom aggregator:
  depend on it like any other artifact — drop the <type>pom</type> you needed
  before. It still transitively pulls the bindings plus all six native libraries.

Security

• Native loading is bundled-only. Removed the -Dzstd.lib.path override —
  loading a caller-supplied native library is arbitrary native code execution in
  the JVM, so the loader now trusts only the artifact bundled on the classpath.
  The bundled library is extracted into a private, owner-only temp directory
  (closing a swap/symlink window in the shared temp root). To run a self-built
  libzstd, rebuild it into the native resource jar (see docs/how-to.md).

Fixed

• ZstdSkippableContent now compares by content: equals / hashCode /
  toString consider the payload bytes instead of array identity.

v0.2

Added

• zstd-platform aggregator artifact: one dependency pulls the bindings plus
  every platform's native library, so a build runs on any OS/arch without
  choosing a classifier.
• MemorySegment constructors on ZstdCompressDict / ZstdDecompressDict to
  digest a dictionary straight from off-heap memory (e.g. an mmap slice) with no
  heap byte[] copy.

v0.1

First release. Java 25 Foreign Function & Memory (FFM) bindings for
Zstandard 1.5.7, built hermetically from
vendored source with zig cc (no JNI, no prebuilt binaries). 68 of the public
zstd symbols are bound; see docs/supported.md.

Added

• One-shot compression/decompression over byte[] and zero-copy MemorySegment
  (Zstd, ZstdCompressCtx, ZstdDecompressCtx).
• Dictionaries: training (ZDICT_trainFromBuffer, COVER / fast-COVER optimisers,
  finalizeDictionary), digested ZstdCompressDict / ZstdDecompressDict,
  dictionary ids and header size.
• Streaming: ZstdOutputStream / ZstdInputStream (java.io) and a zero-copy
  MemorySegment driver (ZstdCompressStream / ZstdDecompressStream), with
  dictionaries, pledgedSrcSize, and live progress().
• All advanced parameters (ZstdCompressParameter / ZstdDecompressParameter)
  with bounds queries; checksum, long-distance matching, window log, etc.
• Frame inspection (ZstdFrame): header, content/compressed size, dictionary id,
  skippable frames.
• Typed errors (ZstdException.code() / ZstdErrorCode) and memory accounting
  (sizeOf(), Zstd.estimate*Size).
• Native artifacts for macOS, Linux and Windows on x86_64 and aarch64,
  cross-compiled from a single host with zig cc.
• Format-compatibility tests against the reference zstd-jni binding.