Initial support for user-specified charsets

Added runtime switch parsing. This adds the -c,--capitalize;
-y,--symbols; -l,--lower; -i,--i18n; -n,--numerals; and -h,--help
switches. These allow the end user to customer the output.

Set default password length to 32 long. User can still specify with old
syntax. Also added some better error checking on the input string to
ensure the user specifies an int.

Added helptext (usage function). Updated README.

1 files changed, 60 insertions, 14 deletions

diff --git a/src/main.c b/src/main.c
index 6e28a85..c1836be 100644
--- a/src/main.c
+++ b/src/main.c
@@ -15,6 +15,7 @@
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <time.h>
 #include <locale.h>
 
@@ -74,7 +75,6 @@ int intrcat(unsigned int* arr, unsigned int rstart, unsigned int rend) {
 //
 // @return Size of the array contents
 int populate_intl_arr(unsigned int* out) {
-  out[0] = '\0';
   int count = 0;
 
   // Populate the array
@@ -106,34 +106,80 @@ void print_intl_arr(unsigned int* arr) {
 }
 
 
+void usage() {
+  printf(
+    "Upwgen is a password generator with international support. If no length\n"
+    "is specified, defaults to 32 characters output length\n\n"
+    "Usage:\n  upwgen [options] [length]\n\n"
+    "Options:\n"
+    "  -c,--capitalize Include at least one capital letter in output\n"
+    "  -l,--lower      Include at least one lower case letter in output\n"
+    "  -n,--numerals   Include at least one numeral in output\n"
+    "  -y,--symbols    Include at least one symbol in output\n"
+    "  -i,--i18n       Include at least one international letter in output\n"
+    "\n"
+    "  -h,--help       Print this help text\n"
+  );
+}
+
+
 int main(int argc, char* argv[]) {
-  char* passlen;      // Argv 1, user specified length of the password
-  int count;          // Number of international chars to choose from
   struct timespec ts; // Timespec for seeding rng
+  int count;          // Number of chars to choose from
   int len;            // Password length
+  int i;              // Arg index
   unsigned long seed; // Seed for the RNG (current seconds * nanoseconds)
   unsigned int chars[1024]; // Uint array to hold international chars
 
+  // Initialize
+  count    = 0;
+  len      = 32;
+  i        = 1;
+  chars[0] = '\0';
   setlocale(LC_ALL, "en_US.UTF-8");
 
-  if(argc == 1) {
-    printf("Password length required\n");
-    return 1;
+  while(i < argc) {
+    if(strcmp(argv[i], "-c") == 0 || strcmp(argv[i], "--capitals") == 0) {
+      count += intrcat(chars, 65, 90); // English uppercase
+    } else if(strcmp(argv[i], "-l") == 0 || strcmp(argv[i], "--lower") == 0) {
+      count += intrcat(chars, 97, 122); // English lower case
+    } else if(strcmp(argv[i], "-n") == 0 || strcmp(argv[i], "--numerals") == 0) {
+      count += intrcat(chars, 48, 57); // English numerals
+    } else if(strcmp(argv[i], "-y") == 0 || strcmp(argv[i], "--symbols") == 0) {
+      count += intrcat(chars, 33, 47);   // English symbols ! - /
+      count += intrcat(chars, 58, 64);   // English symbols : - @
+      count += intrcat(chars, 91, 96);   // English symbols [ - `
+      count += intrcat(chars, 123, 126); // English symbols { - ~
+    } else if(strcmp(argv[i], "-i") == 0 || strcmp(argv[i], "--i18n") == 0) {
+      count += populate_intl_arr(chars);
+    } else if(strcmp(argv[i], "-h") == 0 || strcmp(argv[i], "--help") == 0) {
+      usage();
+      return 0;
+    } else {
+      // If we reach this block, the user specified a custom length (or
+      // fatfingered something). Test for ability to convert from str to int
+      // and set length if possible.
+      if(atoi(argv[i]) == 0) {
+        printf("Invalid length \"%s\"\n", argv[i]);
+        return 1;
+      } else {
+        len = atoi(argv[i]);
+      }
+    }
+    i++;
   }
 
-  passlen = argv[1];
-
-  // Store supported chars here!
-  count = populate_intl_arr(chars);
-  //printf("%d international chars for use\n", count);
-  //print_intl_arr(chars);
-  //return 0;
+  // Ensure at least one character set was specified
+  if(chars[0] == '\0') {
+    printf("Must specify at least one character set\n");
+    return 0;
+  }
 
+  // Get the random data seed
   clock_gettime(CLOCK_REALTIME, &ts);
   seed = ts.tv_sec + ts.tv_nsec;
   srand((unsigned)seed);
 
-  len = atoi(passlen);
   while(len > 0) {
     int r = rand() % count;
     printf("%lc", chars[r]);