add parsing cli interface using getopt

kpack_c.c

@@ -1,4 +1,9 @@
 #include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <string.h>
+#include <stdbool.h>
 
 /*
 TODO
@@ -8,7 +13,67 @@ kpack [--nologo / -n] [--kernel / -k] [--unpack / -u] <infile> [<outfile>]
 
 */
 
+static const char* str_usage = "Usage: %s [--nologo / -n] [--kernel / -k] [--unpack / -u] <infile> [<outfile>]\n";
+
 int main(int argc, char *argv[])
 {
-    printf("Abobaa!");
+    bool nologo = false;
+    bool kernel = false;
+    bool unpack = false;
+    char *infile = NULL;
+    char *outfile = NULL;
+    int opt;
+    static struct option long_options[] = {
+        {"nologo", no_argument, NULL, 'n'},
+        {"kernel", no_argument, NULL, 'k'},
+        {"unpack", no_argument, NULL, 'u'},
+        {0, 0, 0, 0} // must be zeros here
+    };
+    while ((opt = getopt_long(argc, argv, "nku", long_options, NULL)) != -1) {
+        switch (opt) {
+            case 'n':
+                nologo = true;
+                break;
+            case 'k':
+                kernel = true;
+                break;
+            case 'u':
+                unpack = true;
+                break;
+            default: // '?'
+                fprintf(stderr, str_usage, argv[0]);
+                return 1;
+        }
+    }
+    // Check for required infile
+    if (optind >= argc) {
+        fprintf(stderr, "Error: Input file is required.\n");
+        fprintf(stderr, str_usage, argv[0]);
+        return 1;
+    }
+    infile = argv[optind];
+
+    // Optional outfile
+    if (optind + 1 < argc) {
+        outfile = argv[optind + 1];
+        optind++;
+    }
+
+    // printf("argc = %d, optind = %d\n", argc - 1, optind);
+    if (argc - 1 > optind) {
+        fprintf(stderr, "Error: too many arguments\n");
+        fprintf(stderr, str_usage, argv[0]);
+        return 1;
+    }
+
+    // for debug: print parsed options and args
+    printf("nologo: %s\n", nologo ? "true" : "false");
+    printf("kernel: %s\n", kernel ? "true" : "false");
+    printf("unpack: %s\n", unpack ? "true" : "false");
+    printf("infile: %s\n", infile);
+    printf("outfile: %s\n", outfile ? outfile : "Not specified");
+
+    // TODO logic here
+
+    return 0;
 }