+int
+add_string (char ***argv, int *size, int *alloc, const char *str)
+{
+ char **new_argv;
+ char *new_str;
+
+ if (*size >= *alloc) {
+ *alloc += 64;
+ new_argv = realloc (*argv, *alloc * sizeof (char *));
+ if (new_argv == NULL) {
+ reply_with_perror ("realloc");
+ free_strings (*argv);
+ return -1;
+ }
+ *argv = new_argv;
+ }
+
+ if (str) {
+ new_str = strdup (str);
+ if (new_str == NULL) {
+ reply_with_perror ("strdup");
+ free_strings (*argv);
+ }
+ } else
+ new_str = NULL;
+
+ (*argv)[*size] = new_str;
+
+ (*size)++;
+ return 0;
+}
+
+int
+count_strings (char * const* const argv)
+{
+ int argc;
+
+ for (argc = 0; argv[argc] != NULL; ++argc)
+ ;
+ return argc;
+}
+
+static int
+compare (const void *vp1, const void *vp2)
+{
+ char * const *p1 = (char * const *) vp1;
+ char * const *p2 = (char * const *) vp2;
+ return strcmp (*p1, *p2);
+}
+
+void
+sort_strings (char **argv, int len)
+{
+ qsort (argv, len, sizeof (char *), compare);
+}
+
+void
+free_strings (char **argv)
+{
+ int argc;
+
+ for (argc = 0; argv[argc] != NULL; ++argc)
+ free (argv[argc]);
+ free (argv);
+}
+
+void
+free_stringslen (char **argv, int len)
+{
+ int i;
+
+ for (i = 0; i < len; ++i)
+ free (argv[i]);
+ free (argv);
+}
+