Now it can generate chars until UINT_MAX

main.c

@@ -4,6 +4,9 @@
 #include "sodium.h"
 #include "strtoui.h"
 
+/**
+ * Maps a number that is between i_min and i_max to the range o_min and o_max
+ */
 int map(int i, int i_min, int i_max, int o_min, int o_max) {
     double r = (double)(o_max - o_min) / (double)(i_max - i_min);
     int j = (double) (i - i_min) * r + o_min;
@@ -11,32 +14,35 @@ int map(int i, int i_min, int i_max, int o_min, int o_max) {
 }
 
 int main(int argc, char *argv[]) {
+    //if doesnt have any argument just show a usage info
     if(argc == 1) {
-        puts("Usage: chars [length]");
-        puts("       Max length is 1024");
+        puts("Usage:\tchars [length]");
+        puts("\t0 > lenght > UINT_MAX");
+        puts("Description:");
+        puts("\t Generates a random string with the specified length");
         exit(EXIT_SUCCESS);
     }
 
+    //read the length argument and parse it to a an unsigned int
     unsigned int len;
     enum strtoui_error error = strtoui(&len, argv[1], 10);
-    if(error != STRTOUI_SUCCESS){
-        fputs("Bad input\n", stderr);
+    if(error == STRTOUI_OVERFLOW){
+        fputs("The input is too big\n", stderr);
         exit(EXIT_FAILURE);
-    }else if (len > 1024) {
-        fputs("The length is to big\n", stderr);
+    }else if(error == STRTOUI_UNDERFLOW) {
+        fputs("The input must be bigger than 0\n", stderr);
+        exit(EXIT_FAILURE);
+    }else if(error == STRTOUI_INCONVERTIBLE) {
+        fputs("The input isn't valid\n", stderr);
         exit(EXIT_FAILURE);
     }
 
-    char lower_range = 0x20;
-    char upper_range= 0x7e;
-
-    char data[len];
-    randombytes_buf(data, sizeof len);
-
+    //prints random numbers in the bounds specified as chars
+    char lower_bound = 0x20;
+    char upper_bound= 0x7e;
     for(int i = 0; i < len; i++) {
-        int random = randombytes_uniform(upper_range);
-        data[i] = map(random, 0, upper_range, lower_range, upper_range);
-        printf("%c", data[i]);
+        int random = randombytes_uniform(upper_bound);
+        printf("%c", map(random, 0, upper_bound, lower_bound, upper_bound));
     }
     printf("\n");