Improve tank handling for Cobalt

This isn't Cobalt specific, this is specific to dive computers that
indicate the first tank that's in use with a gaschange event that
coincides with the first sample.

We need to make sure that we suppress showing that gas change event
(regardless which cylinder it goes to) and instead set the correct
cylinder index from the very start of the dive.

This works with the test data I have and doesn't seem to break thing with
any of the files that I tried... but I'm worried that this is not the
right way to do things.

Fixes #742

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

1 files changed, 18 insertions, 0 deletions

diff --git a/profile.c b/profile.c
index f0b7041ee..4bc94220b 100644
--- a/profile.c
+++ b/profile.c
@@ -378,6 +378,19 @@ static int set_cylinder_index(struct plot_info *pi, int i, int cylinderindex, un
 	return i;
 }
 
+/* normally the first cylinder has index 0... if not, we need to fix this up here */
+static int set_first_cylinder_index(struct plot_info *pi, int i, int cylinderindex, unsigned int end)
+{
+	while (i < pi->nr) {
+		struct plot_data *entry = pi->entry + i;
+		if (entry->sec > end)
+			break;
+		entry->cylinderindex = cylinderindex;
+		i++;
+	}
+	return i;
+}
+
 static void check_gas_change_events(struct dive *dive, struct divecomputer *dc, struct plot_info *pi)
 {
 	int i = 0, cylinderindex = 0;
@@ -386,6 +399,11 @@ static void check_gas_change_events(struct dive *dive, struct divecomputer *dc,
 	if (!ev)
 		return;
 
+	// for dive computers that tell us their first gas as an event on the first sample
+	// we need to make sure things are setup correctly
+	if ((cylinderindex = explicit_first_cylinder(dive, dc)) != 0)
+		set_first_cylinder_index(pi, 0, cylinderindex, ~0u);
+
 	do {
 		i = set_cylinder_index(pi, i, cylinderindex, ev->time.seconds);
 		cylinderindex = get_cylinder_index(dive, ev);