I've spent the last few months working on this codec. It has the following characteristics: - SOTA decompression throughput in its ratio class - Decent ratios (comparable to LZ4 at…

misa77 is an LZ-based codec that targets the write-once, read-many niche. In particular, it aims to satisfy the following criteria: In addition, misa77 has a somewhat synergizing tendency to decompress highly compressed files faster, leading to the following results: This makes high-effort compression particularly attractive for misa77, and inspires some experimental compression modes (refer to src/experimental/) that aim to spend more effort at compression time to produce a compressed stream that is friendlier to the microarchitectures of most CPUs when decompressing said streams. Cross-Platform results for v0.1.0 (across Intel x86-64, AMD x86-64, ARM64) can be found here. Note that these are likely outdated at the time of you reading this. As misa77's performance is quite "spiky" (depending on the shape of the data being compressed), a file-level breakdown for the silesia corpus yields some interesting insights into its performance. At level 0, misa77 decodes faster than lz4 on all 12 files (some by huge margins). All other levels decode faster on 11/12 files. The exception is x-ray, which is highly incompressible (lz4 has a ratio of nearly 1.0 on this file and essentially devolves to a memcpy). On the compressible files, misa77 sits on the decode-throughput/ratio Pareto frontier: it decodes fastest while ~matching or beating the ratio of the other fast-LZ codecs. sao and x-ray are exceptions due to the reasons stated before. Note: On x86-64, AVX2/SSE2 are selected at runtime. Other architectures use a portable path that has no explicit intrinsics, but is easily auto-vectorizable by compilers (and from my testing, does auto-vectorize on Apple ARM at the very least).