Question

Is there a simple example of how to unzip a .zip file and extract the files to a directory? I am currently using zlib, and while I understand that zlib does not directly deal with zip files, there seems to be several additional things in zlibs’s “contrib” library. I noticed and read about “minizip”, and after reading some documents and looking at some of the code, I do not see a simple example of how to unzip a .zip file and extract the files to a directory.

I would like to find a platform independent way of doing so, but if that is not possible then I need to find a way for windows and mac.

Answer 1

zlib handles the deflate compression/decompression algorithm, but there is more than that in a ZIP file.

You can try libzip. It is free, portable and easy to use.

UPDATE: Here I attach quick’n’dirty example of libzip, with all the error controls ommited:

#include <zip.h>

int main()
{
    //Open the ZIP archive
    int err = 0;
    zip *z = zip_open("foo.zip", 0, &err);

    //Search for the file of given name
    const char *name = "file.txt";
    struct zip_stat st;
    zip_stat_init(&st);
    zip_stat(z, name, 0, &st);

    //Alloc memory for its uncompressed contents
    char *contents = new char[st.size];

    //Read the compressed file
    zip_file *f = zip_fopen(z, name, 0);
    zip_fread(f, contents, st.size);
    zip_fclose(f);

    //And close the archive
    zip_close(z);

    //Do something with the contents
    //delete allocated memory
    delete[] contents;
}