+ const char *info, *flags;
+ unsigned int flag, last_flag;
+ char *filename_new, *dir;
+ char flag_map[128];
+ int flags_in_map = 0;
+ unsigned int i;
+ char *s;
+
+ memset (flag_map, 0, sizeof (flag_map));
+
+ info = strstr (filename, ":2,");
+
+ if (info == NULL) {
+ info = filename + strlen(filename);
+ } else {
+ flags = info + 3;
+
+ /* Loop through existing flags in filename. */
+ for (flags = info + 3, last_flag = 0;
+ *flags;
+ last_flag = flag, flags++)
+ {
+ flag = *flags;
+
+ /* Original flags not in ASCII order. Abort. */
+ if (flag < last_flag)
+ return NULL;
+
+ /* Non-ASCII flag. Abort. */
+ if (flag > sizeof(flag_map) - 1)
+ return NULL;
+
+ /* Repeated flag value. Abort. */
+ if (flag_map[flag])
+ return NULL;
+
+ flag_map[flag] = 1;
+ flags_in_map++;
+ }
+ }
+
+ /* Then set and clear our flags from tags. */
+ for (flags = flags_to_set; *flags; flags++) {
+ flag = *flags;
+ if (flag_map[flag] == 0) {
+ flag_map[flag] = 1;
+ flags_in_map++;
+ }
+ }
+
+ for (flags = flags_to_clear; *flags; flags++) {
+ flag = *flags;
+ if (flag_map[flag]) {
+ flag_map[flag] = 0;
+ flags_in_map--;
+ }
+ }
+
+ filename_new = (char *) talloc_size (ctx,
+ info - filename +
+ strlen (":2,") + flags_in_map + 1);
+ if (unlikely (filename_new == NULL))
+ return NULL;
+
+ strncpy (filename_new, filename, info - filename);
+ filename_new[info - filename] = '\0';
+
+ strcat (filename_new, ":2,");
+
+ s = filename_new + strlen (filename_new);
+ for (i = 0; i < sizeof (flag_map); i++)
+ {
+ if (flag_map[i]) {
+ *s = i;
+ s++;
+ }