1 files changed, 23 insertions, 0 deletions
diff --git a/oid-array.h b/oid-array.h
index 6a22c0ac94..72bca78b7d 100644
--- a/oid-array.h
+++ b/oid-array.h
@@ -1,6 +1,8 @@
 #ifndef OID_ARRAY_H
 #define OID_ARRAY_H
 
+#include "hash.h"
+
 /**
  * The API provides storage and manipulation of sets of object identifiers.
  * The emphasis is on storage and processing efficiency, making them suitable
@@ -111,4 +113,25 @@ void oid_array_filter(struct oid_array *array,
  */
 void oid_array_sort(struct oid_array *array);
 
+/**
+ * Find the next unique oid in the array after position "cur".
+ * The array must be sorted for this to work. You can iterate
+ * over unique elements like this:
+ *
+ *   size_t i;
+ *   oid_array_sort(array);
+ *   for (i = 0; i < array->nr; i = oid_array_next_unique(array, i))
+ *	printf("%s", oid_to_hex(array->oids[i]);
+ *
+ * Non-unique iteration can just increment with "i++" to visit each element.
+ */
+static inline size_t oid_array_next_unique(struct oid_array *array, size_t cur)
+{
+	do {
+		cur++;
+	} while (cur < array->nr &&
+		 oideq(array->oid + cur, array->oid + cur - 1));
+	return cur;
+}
+
 #endif /* OID_ARRAY_H */