diff --git a/src/util/ReusableArray.hxx b/src/util/ReusableArray.hxx
index 6e7e0dc4d..e5541a88f 100644
--- a/src/util/ReusableArray.hxx
+++ b/src/util/ReusableArray.hxx
@@ -66,6 +66,10 @@ public:
 		delete[] buffer;
 	}
 
+	size_t GetCapacity() const {
+		return capacity;
+	}
+
 	/**
 	 * Free resources allocated by this object.  This invalidates
 	 * the buffer returned by Get().