C zip library for opening password protected files - c

Question

I am trying to use zlib and minizip. When I build 6 projects in one soltuion which are included in archive I downloaded everything works and project will create exe files (minizip and miniunz). Here is the problem, I don't know how to use miniunz and minizip source codes in my application and google isn't helping. Can somebody, who has experience with these libs, provide step by step tutorial how to include these lib in my application?
Or if you have other libraries to work with password protected files and can provide some tutorial how to include it in project that will help too, I tried to find something but there was no tutorial how to install them to projects
Thanks

Answer 1

Code based on minizip unzip.c.
include stdio.h zip.h unzip.h
First, create a zip with a file inside with a password.
The zip file must be in the same directory as the executable.
Run the program from a prompt in the directory of the generated program.
This example only extracts the first file!
/*-----------start-------------- */
/*Tries to open the zip in the current directory.*/
unzFile zfile = unzOpen("teste.zip");
if(zfile==NULL)
{
printf("Error!");
return;
}
printf("OK Zip teste.zip opened...\n");
int err = unzGoToFirstFile(zfile);/*go to first file in zip*/
if (err != UNZ_OK)
{
printf("error %d with zipfile in unzGoToFirstFile\n", err);
unzClose(zfile);/*close zip*/
}
/*At this point zfile points to the first file contained in the zip*/
char filename_inzip[256] = {0};/* The file name will be returned here */
unz_file_info file_info = {0};/*strcuture with info of the first file*/
err = unzGetCurrentFileInfo(zfile, &file_info, filename_inzip, sizeof(filename_inzip), NULL, 0, NULL, 0);
if (err != UNZ_OK)
{
printf("error %d with zipfile in unzGetCurrentFileInfo\n",err);
}
else
{
int len = 8192;/*size of chunk*/
char buffer[8192]={0};/*buffer used to save uncompressed data*/
printf("name of first file is :%s\n",filename_inzip);
printf("uncompressed_size = %d\n",file_info.uncompressed_size);
/*Use your password here, the same one used to create your zip */
err = unzOpenCurrentFilePassword(zfile, "yourpassword");
if (err != UNZ_OK)
printf("error %d with zipfile in unzOpenCurrentFilePassword\n", err);
else
printf("password ok\n");
FILE *fp = fopen(filename_inzip, "wb");/*file for data binary type*/
if (fp != NULL)
{
do
{/*read the current file returned by unzGoToFirstFile to buffer in chunks of the 8192*/
err = unzReadCurrentFile(zfile, &buffer, len );
if (err < 0)
{
printf("error %d with zipfile in unzReadCurrentFile\n", err);
break;
}
if (err == 0)
break;
/*Save the chunk read to the file*/
if (fwrite(&buffer, err, 1, fp) != 1)/*if error break*/
{
printf("error %d in writing extracted file\n", errno);
err = UNZ_ERRNO;
break;
}/*else continue*/
}
while (err > 0);
/*close file*/
fclose(fp);
}
}
unzClose(zfile);