Cleanup: unify get_gas_at_time() and get_gasmix()

There were two functions for getting gas-mixes at a certain timestamp:
- get_gasmix() for repeated queries.
- get_gas_at_time() for a single query.
Since the latter is a special case of the former, simply call
the former in the latter. Moreover, rename to get_gasmix_at_time()
for consistency.

Replace on get_gasmix() call, which was outside of a loop by the
corresponding get_gasmix_at_time() call.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

core/dive.c

@@ -4308,3 +4308,11 @@ struct gasmix get_gasmix(struct dive *dive, struct divecomputer *dc, int time, s
 	*evp = ev;
 	return res;
 }
+
+/* get the gas at a certain time during the dive */
+struct gasmix get_gasmix_at_time(struct dive *d, struct divecomputer *dc, duration_t time)
+{
+	struct event *ev = NULL;
+	struct gasmix gasmix = { 0 };
+	return get_gasmix(d, dc, time.seconds, &ev, &gasmix);
+}

core/dive.h

@@ -718,12 +718,15 @@ extern void printdecotable(struct decostop *table);
 
 extern struct event *get_next_event(struct event *event, const char *name);
 
-/* Get gasmix at increasing timestamps.
+/* Get gasmixes at increasing timestamps.
  * In "evp", pass a pointer to a "struct event *" which is NULL-initialized on first invocation.
  * On subsequent calls, pass the same "evp" and the "gasmix" from previous calls.
  */
 extern struct gasmix get_gasmix(struct dive *dive, struct divecomputer *dc, int time, struct event **evp, struct gasmix *gasmix);
 
+/* Get gasmix at a given time */
+extern struct gasmix get_gasmix_at_time(struct dive *dive, struct divecomputer *dc, duration_t time);
+
 /* these structs holds the information that
  * describes the cylinders / weight systems.
  * they are global variables initialized in equipment.c

core/divelist.c

@@ -134,8 +134,7 @@ int total_weight(struct dive *dive)
 
 static int active_o2(struct dive *dive, struct divecomputer *dc, duration_t time)
 {
-	struct gasmix gas;
+	struct gasmix gas = get_gasmix_at_time(dive, dc, time);
-	get_gas_at_time(dive, dc, time, &gas);
 	return get_o2(&gas);
 }
 

core/planner.c

@@ -81,22 +81,6 @@ bool diveplan_empty(struct diveplan *diveplan)
 	return true;
 }
 
-/* get the gas at a certain time during the dive */
-void get_gas_at_time(struct dive *dive, struct divecomputer *dc, duration_t time, struct gasmix *gas)
-{
-	// we always start with the first gas, so that's our gas
-	// unless an event tells us otherwise
-	struct event *event = dc->events;
-	*gas = dive->cylinder[0].gasmix;
-	while (event && event->time.seconds <= time.seconds) {
-		if (!strcmp(event->name, "gaschange")) {
-			int cylinder_idx = get_cylinder_index(dive, event);
-			*gas = dive->cylinder[cylinder_idx].gasmix;
-		}
-		event = event->next;
-	}
-}
-
 /* get the cylinder index at a certain time during the dive */
 int get_cylinderid_at_time(struct dive *dive, struct divecomputer *dc, duration_t time)
 {
@@ -164,7 +148,7 @@ int tissue_at_end(struct deco_state *ds, struct dive *dive, struct deco_state **
 			setpoint = sample[0].setpoint;
 
 		t1 = sample->time;
-		get_gas_at_time(dive, dc, t0, &gas);
+		gas = get_gasmix_at_time(dive, dc, t0);
 		if (i > 0)
 			lastdepth = psample->depth;
 

core/planner.h

@@ -17,7 +17,6 @@ extern void set_verbatim(bool verbatim);
 extern void set_display_runtime(bool display);
 extern void set_display_duration(bool display);
 extern void set_display_transitions(bool display);
-extern void get_gas_at_time(struct dive *dive, struct divecomputer *dc, duration_t time, struct gasmix *gas);
 extern int get_cylinderid_at_time(struct dive *dive, struct divecomputer *dc, duration_t time);
 extern int get_gasidx(struct dive *dive, struct gasmix *mix);
 extern bool diveplan_empty(struct diveplan *diveplan);

profile-widget/profilewidget2.cpp

@@ -758,8 +758,7 @@ void ProfileWidget2::plotDive(struct dive *d, bool force, bool doClearPictures)
 	qDeleteAll(eventItems);
 	eventItems.clear();
 	struct event *event = currentdc->events;
-	struct event *ev;
+	struct gasmix lastgasmix = get_gasmix_at_time(&displayed_dive, current_dc, duration_t{1});
-	struct gasmix lastgasmix = get_gasmix(&displayed_dive, current_dc, 1, &ev, NULL);
 
 	while (event) {
 #ifndef SUBSURFACE_MOBILE