+ for (auto i = last_underscore + 1; i < s.size(); ++i) {
+ if (!isdigit(s[i])) {
+ return string::npos;
+ }
+ }
+
+ return last_underscore;
+ };
+
+ /* Write fonts to _fonts, changing any duplicate IDs so that they are unique */
+ for (auto font: fonts) {
+ auto id = fix_id(font->id());
+ if (used_ids.find(id) == used_ids.end()) {
+ /* This ID is unique so we can just use it as-is */
+ _fonts.put(font, id);
+ used_ids.insert(id);
+ } else {
+ auto end = underscore_number_position(id);
+ if (end == string::npos) {
+ /* This string has no _N suffix, so add one */
+ id += "_0";
+ end = underscore_number_position(id);
+ }
+
+ ++end;
+
+ /* Increment the suffix until we find a unique one */
+ auto number = dcp::raw_convert<int>(id.substr(end));
+ while (used_ids.find(id) != used_ids.end()) {
+ ++number;
+ id = String::compose("%1_%2", id.substr(0, end - 1), number);
+ }
+ used_ids.insert(id);
+ }
+ _fonts.put(font, id);