ZXC: High-Performance Asymmetric Lossless Compression

ZXC is a high-performance, lossless, asymmetric compression library optimized for Content Delivery and Embedded Systems (Game Assets, Firmware, App Bundles). It is designed to be "Write Once, Read Many.". Unlike codecs like LZ4, ZXC trades compression speed (build-time) for maximum decompression throughput (run-time).

Key Result: ZXC outperforms LZ4 decompression by >+40% on Apple Silicon, >+20% on Cloud ARM (Google Axion), and >+7% on x86_64 with better compression ratios, accepting slower compression speed as the strategic trade-off.

Verified: ZXC has been officially merged into the lzbench master branch. You can now verify these results independently using the industry-standard benchmark suite.

ZXC Design Philosophy

Traditional codecs often force a trade-off between symmetric speed (LZ4) and archival density (Zstd).

ZXC focuses on Asymmetric Efficiency.

Designed for the "Write-Once, Read-Many" reality of software distribution, ZXC utilizes a computationally intensive encoder to generate a bitstream specifically structured to maximize decompression throughput. By performing heavy analysis upfront, the encoder produces a layout optimized for the instruction pipelining and branch prediction capabilities of modern CPUs, particularly ARMv8, effectively offloading complexity from the decoder to the encoder.

• Build Time: You generally compress only once (on CI/CD).
• Run Time: You decompress millions of times (on every user's device). ZXC respects this asymmetry.

👉 Read the Technical Whitepaper

Benchmarks

To ensure consistent performance, benchmarks are automatically executed on every commit via GitHub Actions. We monitor metrics on both x86_64 (Linux) and ARM64 (Apple Silicon M1/M2) runners to track compression speed, decompression speed, and ratios.

(See the latest benchmark logs)

1. Mobile & Client: Apple Silicon (M2)

Scenario: Game Assets loading, App startup.

Target	ZXC vs Competitor	Decompression Speed	Ratio	Verdict
1. Max Speed	ZXC -1 vs LZ4 --fast	11,175 MB/s vs 5,654 MB/s 1.98x Faster	61.2 vs 62.2 Smaller (-1.5%)	ZXC leads in raw throughput.
2. Standard	ZXC -3 vs LZ4 Default	6,888 MB/s vs 4,801 MB/s 1.43x Faster	46.5 vs 47.6 Smaller (-2.4%)	ZXC outperforms LZ4 in read speed and ratio.
3. High Density	ZXC -5 vs Zstd --fast 1	6,023 MB/s vs 2,158 MB/s 2.79x Faster	40.7 vs 41.0 Equivalent (-0.9%)	ZXC outperforms Zstd in decoding speed.

2. Cloud Server: Google Axion (ARM Neoverse V2)

Scenario: High-throughput Microservices, ARM Cloud Instances.

Target	ZXC vs Competitor	Decompression Speed	Ratio	Verdict
1. Max Speed	ZXC -1 vs LZ4 --fast	8,378 MB/s vs 4,860 MB/s 1.72x Faster	61.2 vs 62.2 Smaller (-1.5%)	ZXC leads in raw throughput.
2. Standard	ZXC -3 vs LZ4 Default	5,181 MB/s vs 4,181 MB/s 1.24x Faster	46.5 vs 47.6 Smaller (-2.4%)	ZXC outperforms LZ4 in read speed and ratio.
3. High Density	ZXC -5 vs Zstd --fast 1	4,485 MB/s vs 1,756 MB/s 2.55x Faster	40.7 vs 41.0 Equivalent (-0.9%)	ZXC outperforms Zstd in decoding speed.

3. Build Server: x86_64 (AMD EPYC 7763)

Scenario: CI/CD Pipelines compatibility.

Target	ZXC vs Competitor	Decompression Speed	Ratio	Verdict
1. Max Speed	ZXC -1 vs LZ4 --fast	5,962 MB/s vs 4,116 MB/s 1.45x Faster	61.2 vs 62.2 Smaller (-1.5%)	ZXC achieves higher throughput.
2. Standard	ZXC -3 vs LZ4 Default	3,863 MB/s vs 3,557 MB/s 1.09x Faster	46.5 vs 47.6 Smaller (-2.4%)	ZXC offers improved speed and ratio.
3. High Density	ZXC -5 vs Zstd --fast 1	3,498 MB/s vs 1,573 MB/s 2.22x Faster	40.7 vs 41.0 Equivalent (-0.9%)	ZXC provides faster decoding.

(Benchmark Graph ARM64 : Decompression Throughput & Storage Ratio (Normalized to LZ4))

Benchmark ARM64 (Apple Silicon)

Benchmarks were conducted using lzbench 2.2.1 (from @inikep), compiled with Clang 17.0.0 using MOREFLAGS="-march=native" on macOS Sequoia 15.7.2 (Build 24G325). The reference hardware is an Apple M2 processor (ARM64). All performance metrics reflect single-threaded execution on the standard Silesia Corpus.

Compressor name	Compression	Decompress.	Compr. size	Ratio	Filename
memcpy	52791 MB/s	52860 MB/s	211938580	100.00	12 files
zxc 0.7.0 -1	908 MB/s	11175 MB/s	129770958	61.23	12 files
zxc 0.7.0 -2	605 MB/s	9091 MB/s	115921778	54.70	12 files
zxc 0.7.0 -3	180 MB/s	6888 MB/s	98472307	46.46	12 files
zxc 0.7.0 -4	125 MB/s	6544 MB/s	92027546	43.42	12 files
zxc 0.7.0 -5	65.5 MB/s	6023 MB/s	86177811	40.66	12 files
lz4 1.10.0	813 MB/s	4801 MB/s	100880147	47.60	12 files
lz4 1.10.0 --fast -17	1345 MB/s	5654 MB/s	131723524	62.15	12 files
lz4hc 1.10.0 -12	14.1 MB/s	4544 MB/s	77262399	36.46	12 files
zstd 1.5.7 -1	642 MB/s	1623 MB/s	73229468	34.55	12 files
zstd 1.5.7 --fast --1	722 MB/s	2158 MB/s	86932028	41.02	12 files
brotli 1.2.0 -0	536 MB/s	418 MB/s	78306095	36.95	12 files
snappy 1.2.2	880 MB/s	3264 MB/s	101352257	47.82	12 files

Benchmark ARM64 (Google Axion)

Benchmarks were conducted using lzbench 2.2.1 (from @inikep), compiled with GCC 12.2.0 using MOREFLAGS="-march=native" on Linux 64-bits Debian GNU/Linux 12 (bookworm). The reference hardware is a Google Neoverse-V2 processor (ARM64). All performance metrics reflect single-threaded execution on the standard Silesia Corpus.

Compressor name	Compression	Decompress.	Compr. size	Ratio	Filename
memcpy	24630 MB/s	24706 MB/s	211938580	100.00	12 files
zxc 0.7.0 -1	812 MB/s	8378 MB/s	129770958	61.23	12 files
zxc 0.7.0 -2	542 MB/s	6972 MB/s	115921778	54.70	12 files
zxc 0.7.0 -3	160 MB/s	5181 MB/s	98472307	46.46	12 files
zxc 0.7.0 -4	112 MB/s	4941 MB/s	92027546	43.42	12 files
zxc 0.7.0 -5	58.3 MB/s	4485 MB/s	86177811	40.66	12 files
lz4 1.10.0	740 MB/s	4181 MB/s	100880147	47.60	12 files
lz4 1.10.0 --fast -17	1291 MB/s	4860 MB/s	131723524	62.15	12 files
lz4hc 1.10.0 -12	12.5 MB/s	3799 MB/s	77262399	36.46	12 files
zstd 1.5.7 -1	520 MB/s	1368 MB/s	73229468	34.55	12 files
zstd 1.5.7 --fast --1	603 MB/s	1756 MB/s	86932028	41.02	12 files
brotli 1.2.0 -0	424 MB/s	386 MB/s	78306095	36.95	12 files
snappy 1.2.2	750 MB/s	1839 MB/s	101352257	47.82	12 files

Benchmark x86_64

Benchmarks were conducted using lzbench 2.2.1 (from @inikep), compiled with GCC 13.3.0 using MOREFLAGS="-march=native" on Linux 64-bits Ubuntu 24.04. The reference hardware is an AMD EPYC 7763 processor (x86_64). All performance metrics reflect single-threaded execution on the standard Silesia Corpus.

Compressor name	Compression	Decompress.	Compr. size	Ratio	Filename
memcpy	20177 MB/s	19960 MB/s	211938580	100.00	12 files
zxc 0.7.0 -1	608 MB/s	5962 MB/s	129770958	61.23	12 files
zxc 0.7.0 -2	403 MB/s	4871 MB/s	115921778	54.70	12 files
zxc 0.7.0 -3	127 MB/s	3863 MB/s	98472307	46.46	12 files
zxc 0.7.0 -4	89.3 MB/s	3718 MB/s	92027546	43.42	12 files
zxc 0.7.0 -5	47.3 MB/s	3498 MB/s	86177811	40.66	12 files
lz4 1.10.0	592 MB/s	3557 MB/s	100880147	47.60	12 files
lz4 1.10.0 --fast -17	1033 MB/s	4116 MB/s	131723524	62.15	12 files
lz4hc 1.10.0 -12	11.1 MB/s	3475 MB/s	77262399	36.46	12 files
zstd 1.5.7 -1	413 MB/s	1199 MB/s	73229468	34.55	12 files
zstd 1.5.7 --fast --1	455 MB/s	1573 MB/s	86932028	41.02	12 files
brotli 1.2.0 -0	354 MB/s	286 MB/s	78306095	36.95	12 files
snappy 1.2.2	612 MB/s	1590 MB/s	101464727	47.87	12 files

---

Installation

Option 1: Download Release (GitHub)

1. Go to the Releases page.

2. Download the archive matching your architecture:

   macOS:

   • zxc-macos-arm64.tar.gz (NEON optimizations included).

   Linux:

   • zxc-linux-aarch64.tar.gz (NEON optimizations included).
   • zxc-linux-x86_64.tar.gz (Runtime dispatch for AVX2/AVX512).

   Windows:

   • zxc-windows-x64.zip (Runtime dispatch for AVX2/AVX512).

3. Extract and install:

   tar -xzf zxc-linux-x86_64.tar.gz -C /usr/local

   Each archive contains:

   bin/zxc                          # CLI binary
   include/                         # C headers (zxc.h, zxc_buffer.h, ...)
   lib/libzxc.a                     # Static library
   lib/pkgconfig/zxc.pc             # pkg-config support
   lib/cmake/zxc/zxcConfig.cmake    # CMake find_package(zxc) support
   

4. Use in your project:

   CMake:

   find_package(zxc REQUIRED)
   target_link_libraries(myapp PRIVATE zxc::zxc_lib)

   pkg-config:

   cc myapp.c $(pkg-config --cflags --libs zxc) -o myapp

Option 2: Building from Source

Requirements: CMake (3.14+), C17 Compiler (Clang/GCC/MSVC).

git clone https://github.com/hellobertrand/zxc.git
cd zxc
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build --parallel

# Run tests
ctest --test-dir build -C Release --output-on-failure

# CLI usage
./build/zxc --help

# Install library, headers, and CMake/pkg-config files
sudo cmake --install build

CMake Options

Option	Default	Description
BUILD_SHARED_LIBS	OFF	Build shared libraries instead of static (libzxc.so, libzxc.dylib, zxc.dll)
ZXC_NATIVE_ARCH	ON	Enable -march=native for maximum performance
ZXC_ENABLE_LTO	ON	Enable Link-Time Optimization (LTO)
ZXC_PGO_MODE	OFF	Profile-Guided Optimization mode (OFF, GENERATE, USE)
ZXC_BUILD_CLI	ON	Build command-line interface
ZXC_BUILD_TESTS	ON	Build unit tests
ZXC_ENABLE_COVERAGE	OFF	Enable code coverage generation (disables LTO/PGO)

# Build shared library
cmake -B build -DBUILD_SHARED_LIBS=ON

# Portable build (without -march=native)
cmake -B build -DZXC_NATIVE_ARCH=OFF

# Library only (no CLI, no tests)
cmake -B build -DZXC_BUILD_CLI=OFF -DZXC_BUILD_TESTS=OFF

# Code coverage build
cmake -B build -DZXC_ENABLE_COVERAGE=ON

---

Compression Levels

• Level 1, 2 (Fast): Optimized for real-time assets (Gaming, UI).
• Level 3, 4 (Balanced): A strong middle-ground offering efficient compression speed and a ratio superior to LZ4.
• Level 5 (Compact): The best choice for Embedded, Firmware, or Archival. Better compression than LZ4 and significantly faster decoding than Zstd.

---

Usage

1. CLI

The CLI is perfect for benchmarking or manually compressing assets.

# Basic Compression (Level 3 is default)
zxc -z input_file output_file

# High Compression (Level 5)
zxc -z -5 input_file output_file

# -z for compression can be omitted
zxc input_file output_file

# as well as output file; it will be automatically assigned to input_file.xc
zxc input_file

# Decompression
zxc -d compressed_file output_file

# Benchmark Mode (Testing speed on your machine)
zxc -b input_file

2. API

ZXC provides a thread-safe, stateless API with two usage patterns:

Buffer API (In-Memory)

#include "zxc.h"

// Compression
uint64_t bound = zxc_compress_bound(src_size);
size_t compressed_size = zxc_compress(src, src_size, dst, bound, level, checksum);

// Decompression
size_t decompressed_size = zxc_decompress(src, src_size, dst, dst_capacity, checksum);

Stream API (Files, Multi-Threaded)

#include "zxc.h"

// Compression
int64_t result = zxc_stream_compress(f_in, f_out, threads, level, checksum);

// Decompression
int64_t result = zxc_stream_decompress(f_in, f_out, threads, checksum);

Features:

• Caller-allocated buffers with explicit bounds
• Thread-safe (stateless)
• Multi-threaded streaming (auto-detects CPU cores)
• Optional checksum validation

See complete examples and advanced usage →

Language Bindings

Official wrappers maintained in this repository:

Language	Package Manager	Install Command	Documentation	Author
Rust	crates.io	cargo add zxc-compress	README	@hellobertrand
Python	PyPI	pip install zxc-compress	README	@nuberchardzer1

Community-maintained bindings:

Language	Package Manager	Install Command	Repository	Author
Go	pkg.go.dev	go get github.com/meysam81/go-zxc	https://github.com/meysam81/go-zxc	@meysam81

Safety & Quality

• Unit Tests: Comprehensive test suite with CTest integration.
• Continuous Fuzzing: Integrated with ClusterFuzzLite suites.
• Static Analysis: Checked with Cppcheck & Clang Static Analyzer.
• CodeQL Analysis: GitHub Advanced Security scanning for vulnerabilities.
• Code Coverage: Automated tracking with Codecov integration.
• Dynamic Analysis: Validated with Valgrind and ASan/UBSan in CI pipelines.
• Safe API: Explicit buffer capacity is required for all operations.

License & Credits

ZXC Copyright © 2025-2026, Bertrand Lebonnois and contributors. Licensed under the BSD 3-Clause License. See LICENSE for details.

Third-Party Components:

• rapidhash by Nicolas De Carli (MIT) - Used for high-speed, platform-independent checksums.