Unzipping a file to disk using libzip

Question

I'm trying to unzip an executable file using c++ and the libzip library. Starting with the answer by rodrigo on a similar question, I come to this sample code:

#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, "file.txt", 0);
    zip_fread(f, contents, st.size);
    zip_fclose(f);

    //And close the archive
    zip_close(z);
}

from what I understand, this code does work to unzip a file, but I do not know how to write that file to the disk, much like extracting a zip file would so using a tool like winzip does. Having the unzipped data in memory doesn't help me, but I've been unable to figure out how to actually get the files onto the disk.

Answer 1

Something like this should do it:

if(!std::ofstream("file1.txt").write(contents, st.size))
{
    std::cerr << "Error writing file" << '\n';
    return EXIT_FAILURE;
}

Look up std::ofstream.

Of course you should check all your zip file functions to see if they returned errors before proceeding.