1 files changed, 8 insertions, 0 deletions
diff --git a/dive.h b/dive.h
index da4cb07e0..2594f548a 100644
--- a/dive.h
+++ b/dive.h
@@ -118,6 +118,14 @@ static inline bool gasmix_is_air(const struct gasmix *gasmix)
 	return is_air(gasmix->o2.permille, gasmix->he.permille);
 }
 
+/* in the planner we use a null gasmix to indicate that we keep using the gas as before
+ * this is BAD as a null gasmix can also be interpreted as air.
+ * DANGER DANGER DANGER */
+static inline bool gasmix_is_null(const struct gasmix *gasmix)
+{
+	return gasmix->he.permille == 0 && gasmix->o2.permille == 0;
+}
+
 /* Linear interpolation between 'a' and 'b', when we are 'part'way into the 'whole' distance from a to b */
 static inline int interpolate(int a, int b, int part, int whole)
 {