Home

syc

A streaming archiver and compressor with its own LZ codecs, written from scratch in Free Pascal, with C and assembler for the hottest loops. Tuned for modest hardware.

v0.5.x, pre-release. Every release stays a pre-release until v1.0.0. Frozen formats never change; the others can change between versions.

Where things stand

part	state
sylz fast LZ codec	format v2 (frozen at v0.2.2) and v3 (-ec, Huffman-coded literals; frozen at v0.2.14), levels 0–10, safe decoder, x86-64 assembler and C beside a Pascal reference; the same bytes on every target
zpaq-std plugin	one file, two codecs: -ma:sylz (v2) and -ma:sylzec (v3); Linux x86-64/arm64, Windows x86-64/32-bit
command line	archives (a, x, l, i, t: versions, deduplication, metadata) and single-file streams (c, d); see Usage
archive and stream formats	.syc format 2 and .sylz version 4, frozen at v0.4.0; encrypted .syc format 3 and .sylz version 5 (v0.5.0), provisional; see syc encryption
platforms	Linux x86-64/arm64/x86, Windows x86-64/x86, macOS arm64; CI tests all of them on every push and checks they write the same bytes (Building)
Rust syc v0.1.x	frozen in legacy/rust/, see Legacy Rust syc

Pages

• sylz format — the block format, and why it is shaped that way
• Benchmarks — numbers against lz4, lz4hc, misa77, lizard, zxc, zstd, and how they are taken
• Building — Free Pascal build, every platform, cross-compiling, tests, CI
• zpaq-std plugin — sylz as -ma:sylz and -ma:sylzec in zpaq-std
• Free Pascal codegen notes — what makes FPC code fast or slow, measured
• Versioning and releases
• Roadmap
• Legacy Rust syc

Competitors

misa77, lz5-ex, lizard, zxc (fast LZ); zstd, lz6 (LZ + entropy coding); ultra-fast-lzma2 (high ratio).