Add fix_empty_font_ids() to replace empty Font ids with a dummy string.

1 files changed, 17 insertions, 0 deletions

diff --git a/src/util.cc b/src/util.cc
index c6313b4c..533ee466 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -410,3 +410,20 @@ dcp::day_greater_than_or_equal (struct tm a, LocalTime b)
 
 	return a.tm_mday >= b.day();
 }
+
+/** Try quite hard to find a string which starts with \ref base and is
+ *  not in \ref existing.
+ */
+string
+dcp::unique_string (list<string> existing, string base)
+{
+	int const max_tries = existing.size() + 1;
+	for (int i = 0; i < max_tries; ++i) {
+		string trial = String::compose("%1%2", base, i);
+		if (find(existing.begin(), existing.end(), trial) == existing.end()) {
+			return trial;
+		}
+	}
+
+	DCP_ASSERT (false);
+}