qt 调用zlib压缩与解压缩功能

Zlib是一种免费且通用的压缩库，由于Zlib压缩效果比LZW好，而且解压缩速度快，更重要的是商业软件中使用Zlib不需要缴纳版权费，所以很多游戏都使用Zlib压缩资源文件。

Zlib是由Jean-loup Gailly 和 Mark Adler共同编写完成的压缩库，Zlib是开源的，而且从Zlib的官方网站http://www.zlib.net/上可以下载到不同平台和编译器下的源代码实现。

Zlib联合使用LZ77算法和Huffman哈夫曼树来实现数据压缩和数据解压。

zlib源码http://download.csdn.net/detail/huangyuancao/7760901

void MainWindow::on_pushButton_clicked()
{
    FILE* File_src;
    FILE* File_compress;
    FILE* File_uncompress;
    unsigned long len_src;
    unsigned long len_compress;
    unsigned long len_uncompress = MaxBufferSize;
    unsigned char *buffer_src  = new unsigned char[MaxBufferSize];
    unsigned char *buffer_compress  = new unsigned char[MaxBufferSize];
    unsigned char *buffer_uncompress = new unsigned char[MaxBufferSize];
    File_src = fopen("src.txt","r");
    File_compress = fopen("compress.txt","w");
    File_uncompress = fopen("uncompress.txt","w");
    //compress
    len_src = fread(buffer_src,sizeof(char),MaxBufferSize-1,File_src);
    compress(buffer_compress,&len_compress,buffer_src,len_src);
    fwrite(buffer_compress,sizeof(char),len_compress,File_compress);
    qDebug() << "normal zlib:" ;
    qDebug() << "src:\n" << buffer_src << ",length:" << len_src ;
    qDebug() << "compress:\n" << buffer_compress << ",length:" << len_compress ;
    //uncompress
    uncompress(buffer_uncompress,&len_uncompress,buffer_compress,len_compress);
    fwrite(buffer_uncompress,sizeof(char),len_uncompress,File_uncompress);
    qDebug() << "uncompress:\n" << buffer_uncompress << ",length:" << len_uncompress;
    fclose(File_src);
    fclose(File_compress);
    fclose(File_uncompress);
}

void MainWindow::on_pushButton_2_clicked()
{
    QByteArray src;
    src.append("中华人民共和国,china mobile,123456 ");
    unsigned long len_compress;
    unsigned long len_uncompress;
    unsigned char *buffer_compress  = new unsigned char[MaxBufferSize];
    unsigned char *buffer_uncompress = new unsigned char[MaxBufferSize];
    compress(buffer_compress,&len_compress,(Bytef*)src.data(), src.length());
    uncompress(buffer_uncompress,&len_uncompress,buffer_compress,len_compress);
    qDebug() << "qt zlib:"  ;
    qDebug() << "src:\n" << src.data() << ",length:" << src.size() ;
    qDebug() << "compress:\n" << buffer_compress << ",length:" << len_compress ;
    qDebug() << "uncompress:\n" << buffer_uncompress << ",length:" << len_uncompress ;
}

执行效果：

参考http://www.cnblogs.com/chuncn/archive/2011/03/23/1992481.html

qt调用zlib实例http://download.csdn.net/detail/huangyuancao/7760919