using libzip to extract files

libzip_simple.c

/* Copyright (C) 2011 rocenting@gmail.com */
/* cc -o example.out libzip_simple.c -lzip */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <zip.h>
 
static void safe_create_dir(const char *dir)
{
	if (mkdir(dir, 0755) < 0) {
		if (errno != EEXIST) {
			perror(dir);
			exit(1);
		}
	}
}
 
int main(int argc, char *argv[])
{
	const char *archive; // File path
	struct zip *za; // Zip archive
	struct zip_file *zf; // Stores file to be extracted
	struct zip_stat sb; // Stores file info
	char buf[100]; // Buffer to write stuff
	int err; // Stores error code
	int i, len;
	FILE * fd; // Where file is extracted to
	long long sum; // How much file has been copied so far

	// Requires 1 argument (zip path)
	if (argc != 2) {
		fprintf(stderr, "Usage: %s archive.zip\n", argv[0]);
		return 1;
	}
 
	// Open the zip file
	archive = argv[1];
	if ((za = zip_open(archive, 0, &err)) == NULL) {
		zip_error_to_str(buf, sizeof(buf), err, errno);
		fprintf(stderr, "Can't open zip archive '%s'\n", archive);
		return 1;
	} 

	// Unpack zip
	for (i=0; i < zip_get_num_entries(za, 0); i++) { // Iterate through all files in zip
		if (zip_stat_index(za, i, 0, &sb) == 0) { // Tries to grab file info
			// Print file info
			printf("==================\n");
			printf("Name: [%s], ", sb.name);
			printf("Size: [%llu], ", sb.size);
			printf("mtime: [%u]\n", (unsigned int)sb.mtime);

			len = strlen(sb.name);
			if (sb.name[len - 1] == '/') { // Check if directory
				safe_create_dir(sb.name); // Create directory
			} else {
				zf = zip_fopen_index(za, i, 0); // Open file within zip
				if (!zf) {
					fprintf(stderr, "Unable to open file within zip\n");
					exit(100);
				}

				fd = fopen(sb.name, "wb"); // Create new file
				if (fd == NULL) {
					fprintf(stderr, "Unable to create destination file\n");
					exit(101);
				}

				sum = 0;
				while (sum != sb.size) { // Copy bytes to new file
					len = zip_fread(zf, buf, 100);
					if (len < 0) {
						fprintf(stderr, "Unable to extract file contents\n");
						exit(102);
					}
					fwrite(buf, 1, len, fd);
					sum += len;
				}
				// Finished copying file
				fclose(fd);
				zip_fclose(zf);
			}
        } else {
			printf("File[%s] Line[%d]\n", __FILE__, __LINE__);
		}
	}
 
	if (zip_close(za) == -1) {
		fprintf(stderr, "Can't close zip archive '%s'\n", archive);
		return 1;
	}
 
	return 0;
}

Removed duplicated includes; fixed \n in outputs; altered to use fopen, fclose and fwrite instead of using unistd; added comments and more helpful error messages for my own learning purposes.

Why did the tab size change to 8?