go-compressions

compress codec

compress(1) .Z reader

the LZW the standard library's compress/lzw cannot read, because .Z has its own header and a code width that grows. Eight .Z streams are committed, each verified to round-trip through the reference tool, and the corpus asserts its own premise: that some stream actually widened and some did not, since a corpus that never widens tests nothing.

bzip2 codec

bzip2 ENCODER (NewWriter)

the half the standard library does not have — compress/bzip2 only reads. Every archive the tests produce is read back by two decoders this project did not write: compress/bzip2, and the reference bzip2 binary under `bzip2 -t`, which verifies rather than merely parses. Named honestly: 13 123 bytes where `bzip2 -9` writes 11 526 (+13.9%).

lzip codec

lzip (.lz) reader

LZMA with lzip's own framing and CRC. Every .lz in testdata was written by the real GNU lzip 1.26 and plzip 1.13 rather than hand-assembled from the specification, and the generator asserts its own premise: `lzip -dc` must read a file back before it is allowed to become a fixture.

lzo codec

LZO1X decoder + lzop (.lzo) container

written from a published prose description of the bytestream, because liblzo2 is GPL-2.0 and this is BSD-3-Clause: no liblzo2 code was read, ported or adapted. Decoder only, and the README says so rather than leaving it to be discovered.

adc codec

Apple Data Compression (ADC) decoder

the UDCO flavour of a UDIF disk image. The fixtures come off streams Apple wrote — `hdiutil convert -format UDCO` — with the ADC run lifted out of the resulting blkx table, so nothing here is checked against an encoder of ours.

lz4 libcodec

LZ4 block codec (CompressBlock / DecompressBlock)

SIMD on all 6 arches (match extension via matchlen)

wire-compatible with pierrec/lz4 — beats it on compression ratio (text ~4.6% smaller) and now decodes at parity with its hand-written arm64-asm decoder (~1.0-1.4x on real files, beating it on ooffice/sao); honestly slower on encode speed. Match extension delegates to matchlen's SIMD common-prefix kernel.

lz4c clicodec

LZ4 CLI (compress / decompress)

pure-Go CLI (rides the lz4 lib's SIMD)

single static-binary CLI over the lz4 library — stdin/stdout by default, -d decompress, -o output, -v summary (ratio + timing). Pure Go, no C toolchain. The reference CLI for the lz4 lib.

lzfse libcodec

Apple LZFSE / LZVN codec (Compress / Decompress)

pure-Go (scalar)

byte-compatible with the reference liblzfse: LZFSE = LZVN + FSE entropy stage. Auto-picks LZVN for ≤4 KiB inputs, LZFSE V1/V2 for larger; round-trips against Apple's C reference. Ratio within ~1-3% of Apple; decode now within ~1.6-2.1x of Apple's -O3 C reference (was ~2-3x).

lzfsec clicodec

LZFSE CLI (compress / decompress)

pure-Go (scalar)

single static-binary CLI over lzfse — stdin/stdout by default, optional -v summary (ratio + timing). Pure Go, no C toolchain.

deflate libcodec

DEFLATE / RFC 1951 codec (Deflate / Inflate, Writer / Reader)

match extension via matchlen (SIMD common-prefix kernel)

bidirectionally wire-compatible with the standard library's compress/flate — flate decodes every stream our Writer produces and we decode every stream flate.NewWriter produces (differential-fuzzed both ways). All three block types (stored / fixed / dynamic Huffman), 32 KiB sliding window, typed errors on every malformed-input path. The LZ77 parse delegates match extension to matchlen's SIMD common-prefix kernel. Correctness-first: competitive encode on text, honestly slower decode than stdlib flate.

appleoracle liboracle

macOS libcompression as a test oracle

cgo on macOS; refuses elsewhere

nothing here is a codec. It asks the platform what the bytes should be, so a test can judge an implementation against Apple's own LZFSE/LZVN/LZ4 rather than against bytes the code under test produced. The stub on every other platform REFUSES rather than returning a plausible empty answer, because libcompression returns 0 for failure, for incompressible input and for empty input alike. Replaced 84 lines of cgo in lzfse with a 21-line relay, and gave lz4 the oracle it never had.

blake3 libhash

BLAKE3 cryptographic hash (Sum256 / Sum512 / XOF)

SIMD mix4 on all 6 arches (VSX / vector facility)

pure-Go, cgo-free BLAKE3, verified against the official test vectors; the mix4 core runs go-asmgen SIMD on all 6 of Go's 64-bit targets. Streaming hash.Hash-style API plus arbitrary-length extendable output (XOF). All three BLAKE3 modes ship: unkeyed hashing, keyed hashing (MAC, via NewKeyed) and key derivation (NewDeriveKey / KDF).

b3sum clihash

BLAKE3 checksum CLI (print / verify)

SIMD on all 6 arches (via blake3)

pure-Go, cgo-free b3sum — output compatible with the reference Rust b3sum (<hex> <name>). Hashes files/stdin, --check verification, --length / --no-names. Single static binary.