ZMat: a fast compression/decompr​ession lib for MATALB/Octave

ZMat: A MATLAB/Octave toolbox for zlib/gzip/lzma/lz4/zstd/blosc2 memory compression and base64 encoding

ZMat 1.0.0 — "Foxy the Fantastic Mr. Fox"

Release date: 2026-04-15

• Copyright: (C) 2019–2026 Qianqian Fang <q.fang at neu.edu>
• License: GNU General Public License v3 (GPL v3)
• URL: https://neurojson.org/zmat
• GitHub: https://github.com/NeuroJSON/zmat
• PyPI: https://pypi.org/project/zmat
• Acknowledgement: This project is part of the NeuroJSON project supported by US National Institutes of Health (NIH) grant U24-NS124027

Download

• Please download zmat by filling out a brief registration form
• The pre-compiled Octave mex file can only be used with Octave 10+ on Windows and MacOS (on Linux, the Octave mex file supports all Octave versions). The MATLAB mex files can run across a wide range of MATLAB versions.

Highlights

ZMat reaches its first stable release after seven years of development. This release adds a Python binding, updates all bundled compression libraries to their latest versions, and fixes long-standing memory and safety issues in the core C library.

New Features

• Python binding — pip install zmat provides compress, decompress, encode,decode, and a low-level zmat interface; supports all compression methods(zlib, gzip, lzma, lzip, lz4, lz4hc, zstd, blosc2 variants, base64)
• NumPy array round-trip — compress(arr, info=True) returns an info dict;decompress(data, info=info) restores the original dtype, shape, and memory order(mirrors the MATLAB [ss,info]=zmat(arr) / zmat(ss,info) pattern)
• Octave 10+ compatibility — special matrix types (diagonal, permutation, etc.)are now handled correctly
• Apple Silicon support — the blosc2 backend now automatically detects SSE2availability on Apple Silicon (M-series) Macs
• New Linux MEX binaries — pre-compiled MEX files for Linux are now includedin the private folder alongside the existing macOS and Windows binaries
• macOS — .mex extension is now recognized so packages built against newerOctave run on older releases as well
• Project webpage — https://neurojson.org/zmat

Bug Fixes

• Fixed safety, memory, and efficiency issues throughout zmatlib.c
• Fixed memory leaks in easylzma (lloyd/easylzma#4, lloyd/easylzma#7, closes #11)
• Fixed missing header file causing build failures

Build & CI

• Static linking hardened for macOS (gcc-12) and Linux
• CI runners updated; added Ubuntu 24.04 and Apple Silicon (arm64) targets
• Windows MEX and Python wheel builds fixed for MSYS2/MinGW toolchain

Acknowledgement

AI coding assistant Claude has been used in the development of this release.

Quick StartMATLAB / Octave

% Compress and decompress a numeric array (restoring size and type)

orig = single(rand(5));

[compressed, info] = zmat(orig, 1, 'lzma');

restored = zmat(compressed, info);

% Base64 encode and decode a string

encoded = zmat('zmat toolbox', 1, 'base64');

decoded = char(zmat(encoded, 0, 'base64'));

Python Examples

import numpy as np

import zmat

# Compress and decompress bytes

data = b"hello zmat"

compressed = zmat.compress(data, method='zlib')

restored = zmat.decompress(compressed, method='zlib')

# NumPy array round-trip (preserves dtype, shape, memory order)

arr = np.random.rand(4, 5).astype(np.float32)

compressed, info = zmat.compress(arr, method='lz4', info=True)

restored = zmat.decompress(compressed, info=info)

# Base64 encoding

encoded = zmat.encode(b"zmat toolbox", method='base64')

decoded = zmat.decode(encoded, method='base64')

C Examples

#include "zmatlib.h"

#include <string.h>

#include <stdlib.h>

int main(void) {

const char *input = "hello zmat";

unsigned char *compressed = NULL, *decompressed = NULL;

size_t complen = 0, decomplen = 0;

int status = 0;

union TZMatFlags flags = {1}; /* 1 = compress */

/* compress */

zmat_run(strlen(input), (unsigned char *)input,

&complen, &compressed, zmZlib, &status, flags.iscompress);

/* decompress */

flags.iscompress = 0;

zmat_run(complen, compressed,

&decomplen, &decompressed, zmZlib, &status, flags.iscompress);

free(compressed);

free(decompressed);

return 0;

}

Link with: -lzmat -lz -lpthread

Full Changelog

2026-04-15 [1954707] [mex] add Linux mex binaries

2026-04-15 [1558336] [doc] bump version to 1.0, add webpage

2026-04-12 [4310bb1] [macos] allow .mex for octave run older octave

2026-04-11 [5e079a0] [deploy] macos build still hardcode liboctmex full path

2026-04-11 [42518ff] [deploy] remove absolute path to liboctmex.1 on mac

2026-04-11 [41812bb] [ci] statically link gcc on macos, python build show dylib

2026-04-11 [03e0efc] [test] print benchmark output

2026-04-10 [c1eb247] [deploy] build zmat with static gcc

2026-04-10 [9fa6f02] [ci] fix windows python build

2026-04-10 [343e4fb] [bug] add missing header file

2026-04-10 [b993b31] [blosc2] update blosc2 to 2.23.1, zstd to 1.5.7

2026-04-10 [92fa19c] [miniz] update miniz to v3.1.1

2026-04-10 [99d1ddb] [lz4] update lz4 to 1.10.0

2026-04-10 [2c40056] [mex] update linux mex files

2026-03-07 [aea6ad4] [ci] bump python version to 0.9.10 to use latest package

2026-03-07 [6ad3773] [ci] add the missing README, update setup.py to use manylinux

2026-03-07 [4f85fba] [doc] add README for python module

2026-03-07 [f05e962] [feat] support special matrices in octave 10+

2026-03-07 [b440935] [bug] fix various python module building issues

2026-03-07 [9dde248] [feat] add python binding

2026-03-07 [a3e9ddb] [ci] fix MW_MINGW64_LOC again

2026-03-06 [baeccf5] [blosc] automatically detect sse2 on apple silicon

2026-03-05 [a986c56] fix safety, memory, and efficiency issues throughout zmatlib.c

2025-09-21 [1b2cb0f] [ci] update all retired runners

2025-01-18 [6f92b49] [feat] allow to build with miniz without lzma

2024-09-14 [c6a6ce1] [ci] disable upx on macos

2024-08-18 [26b1147] [example] revert sample code back to zlib from lzma test

2024-08-18 [7c3b09b] [deploy] update all build-in mex files after fixing #11

2024-08-18 [ca52abd] [ci] fix github macos-12 runner gcc version

2024-08-18 [66c8e88] [bug] fix memory leakage lloyd/easylzma#4 and lloyd/easylzma#7, close #11

2024-07-18 [d756c37] [ci] debug ubuntu 24.04 octave-dev installation

2024-07-18 [6149af3] [ci] add ubuntu 24.04

2024-06-14 [980b445] [mac] add arm64 apple silicon precompiled mex files

2024-03-30 [b810d29] [package] remove cmake cache file found by debian packaging