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(this project is no longer maintained, please move to http://github.com/richox/orz)

libzling

fast and lightweight compression library and utility.

Introduction

Libzling is an improved lightweight compression utility and library. libzling uses fast order-1 ROLZ (16MB block size and 10MB dictionary size) followed with Huffman encoding, making it 3 times as fast as gzip on compressing, while still getting much better compression ratio and decompression speed.

Simple benchmark with enwik8(100,000,000 bytes), also on Large Text Compression Benchmark (thanks to Matt Mahoney)

CPU: Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz
MEM: 65726592 kB
OS:  Linux 2.6.32.43-tlinux-1.0.14-default
Tool Encode Decode Compressed Size status
xz 1m23.838s 0m2.265s 26375764 PASS
bzip2 0m10.680s 0m4.633s 29008758 PASS
libzling e4 0m4.058s 0m0.989s 29721410 PASS
libzling e3 0m3.383s 0m1.007s 29999672 PASS
libzling e2 0m2.860s 0m1.021s 30477912 PASS
libzling e1 0m2.504s 0m1.021s 30855731 PASS
libzling e0 0m2.208s 0m1.043s 31456189 PASS
gzip 0m6.502s 0m1.089s 36518322 PASS

Build & Install

You can build and install libzling automatically by cmake with the following command:

cd ./build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/path/to/install
make
make install

Usage

Libling provides simple and lightweight interface. here is a simple program showing the basic usage of libzling. (compiled with g++ -Wall -O3 zling_sample.cpp -o zling_sample -lzling)

#include "libzling/libzling.h"

int main() {
    // compress
    {
        const int level = 0;  // valid levels: 0, 1, 2, 3, 4
        FILE* fin = fopen("./1.txt", "rb");
        FILE* fout = fopen("./1.txt.zlng", "wb");

        baidu::zling::FileInputter  inputter(fin);
        baidu::zling::FileOutputter outputter(fout);

        baidu::zling::Encode(&inputter, &outputter, level);
        fclose(fin);
        fclose(fout);
    }

    // decompress
    {
        FILE* fin = fopen("./1.txt.zlng", "rb");
        FILE* fout = fopen("./2.txt", "wb");

        baidu::zling::FileInputter  inputter(fin);
        baidu::zling::FileOutputter outputter(fout);

        baidu::zling::Decode(&inputter, &outputter);
        fclose(fin);
        fclose(fout);
    }
    return 0;
}

However libzling supports more complicated interface, see ./demo/zling.cpp for details.