Don't use negative gas index

This shouldn't happen, but in case we run out of gases we shouldn't use
the negative gas index (which is the error return of get_gas_idx()) for
the array. Let's fall back to the (incorrect) first gas.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/planner.c b/planner.c
index 7a5f52945..5142b0e50 100644
--- a/planner.c
+++ b/planner.c
@@ -161,6 +161,10 @@ static int time_at_last_depth(struct dive *dive, int o2, int he, unsigned int ne
 	sample = &dive->dc.sample[dive->dc.samples - 1];
 	depth = sample->depth.mm;
 	gasidx = get_gasidx(dive, o2, he);
+	if (gasidx == -1) {
+		fprintf(stderr, "cannot find gas (%d/%d), using first gas\n", o2, he);
+		gasidx = 0;
+	}
 	while (deco_allowed_depth(tissue_tolerance, surface_pressure, dive, 1) > next_stop) {
 		wait++;
 		tissue_tolerance = add_segment(depth_to_mbar(depth, dive) / 1000.0,