core: move get_dive_gas() to struct dive

It is unclear why this was declared in divelist.h.

Moreover, rename it to get_maximal_gas() to better reflect
what it does.

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

core/dive.cpp

@@ -2666,3 +2666,40 @@ temperature_t dive::dc_airtemp() const
 		return temperature_t();
 	return temperature_t{ static_cast<uint32_t>((sum + nr / 2) / nr) };
 }
+
+/*
+ * Get "maximal" dive gas for a dive.
+ * Rules:
+ *  - Trimix trumps nitrox (highest He wins, O2 breaks ties)
+ *  - Nitrox trumps air (even if hypoxic)
+ * These are the same rules as the inter-dive sorting rules.
+ */
+dive::get_maximal_gas_result dive::get_maximal_gas() const
+{
+	int maxo2 = -1, maxhe = -1, mino2 = 1000;
+
+	for (auto [i, cyl]: enumerated_range(cylinders)) {
+		int o2 = get_o2(cyl.gasmix);
+		int he = get_he(cyl.gasmix);
+
+		if (!is_cylinder_used(this, i))
+			continue;
+		if (cyl.cylinder_use == OXYGEN)
+			continue;
+		if (cyl.cylinder_use == NOT_USED)
+			continue;
+		if (o2 > maxo2)
+			maxo2 = o2;
+		if (o2 < mino2 && maxhe <= 0)
+			mino2 = o2;
+		if (he > maxhe) {
+			maxhe = he;
+			mino2 = o2;
+		}
+	}
+	/* All air? Show/sort as "air"/zero */
+	if ((!maxhe && maxo2 == O2_IN_AIR && mino2 == maxo2) ||
+			(maxo2 == -1 && maxhe == -1 && mino2 == 1000))
+		maxo2 = mino2 = 0;
+	return { mino2, maxhe, maxo2 };
+}

core/dive.h

@@ -85,6 +85,9 @@ struct dive {
 	temperature_t dc_airtemp() const;	/* average over divecomputers */
 	temperature_t dc_watertemp() const;	/* average over divecomputers */
 
+	struct get_maximal_gas_result { int o2_p; int he_p; int o2low_p; };
+	get_maximal_gas_result get_maximal_gas() const;
+
 	bool is_planned() const;
 	bool is_logged() const;
 	bool likely_same(const struct dive &b) const;

core/divelist.cpp

@@ -104,45 +104,6 @@ std::unique_ptr<dive> dive_table::default_dive()
 	return d;
 }
 
-/*
- * Get "maximal" dive gas for a dive.
- * Rules:
- *  - Trimix trumps nitrox (highest He wins, O2 breaks ties)
- *  - Nitrox trumps air (even if hypoxic)
- * These are the same rules as the inter-dive sorting rules.
- */
-void get_dive_gas(const struct dive *dive, int *o2_p, int *he_p, int *o2max_p)
-{
-	int maxo2 = -1, maxhe = -1, mino2 = 1000;
-
-	for (auto [i, cyl]: enumerated_range(dive->cylinders)) {
-		int o2 = get_o2(cyl.gasmix);
-		int he = get_he(cyl.gasmix);
-
-		if (!is_cylinder_used(dive, i))
-			continue;
-		if (cyl.cylinder_use == OXYGEN)
-			continue;
-		if (cyl.cylinder_use == NOT_USED)
-			continue;
-		if (o2 > maxo2)
-			maxo2 = o2;
-		if (o2 < mino2 && maxhe <= 0)
-			mino2 = o2;
-		if (he > maxhe) {
-			maxhe = he;
-			mino2 = o2;
-		}
-	}
-	/* All air? Show/sort as "air"/zero */
-	if ((!maxhe && maxo2 == O2_IN_AIR && mino2 == maxo2) ||
-			(maxo2 == -1 && maxhe == -1 && mino2 == 1000))
-		maxo2 = mino2 = 0;
-	*o2_p = mino2;
-	*he_p = maxhe;
-	*o2max_p = maxo2;
-}
-
 int total_weight(const struct dive *dive)
 {
 	int total_grams = 0;

core/divelist.h

@@ -51,8 +51,6 @@ private:
 /* this is used for both git and xml format */
 #define DATAFORMAT_VERSION 3
 
-extern void get_dive_gas(const struct dive *dive, int *o2_p, int *he_p, int *o2low_p);
-
 int get_min_datafile_version();
 void report_datafile_version(int version);
 void clear_dive_file_data();

core/profile.cpp

@@ -1250,13 +1250,12 @@ static void debug_print_profiledata(struct plot_info &pi)
  */
 struct plot_info create_plot_info_new(const struct dive *dive, const struct divecomputer *dc, const struct deco_state *planner_ds)
 {
-	int o2, he, o2max;
 	struct deco_state plot_deco_state;
 	bool in_planner = planner_ds != NULL;
 	divelog.dives.init_decompression(&plot_deco_state, dive, in_planner);
 	plot_info pi;
 	calculate_max_limits_new(dive, dc, pi, in_planner);
-	get_dive_gas(dive, &o2, &he, &o2max);
+	auto [o2, he, o2max ] = dive->get_maximal_gas();
 	if (dc->divemode == FREEDIVE) {
 		pi.dive_type = plot_info::FREEDIVING;
 	} else if (he > 0) {

core/string-format.cpp

@@ -259,8 +259,7 @@ QString formatDiveDateTime(const dive *d)
 
 QString formatDiveGasString(const dive *d)
 {
-	int o2, he, o2max;
+	auto [o2, he, o2max ] = d->get_maximal_gas();
-	get_dive_gas(d, &o2, &he, &o2max);
 	o2 = (o2 + 5) / 10;
 	he = (he + 5) / 10;
 	o2max = (o2max + 5) / 10;

qt-models/divetripmodel.cpp

@@ -28,8 +28,7 @@
 
 static int nitrox_sort_value(const struct dive *dive)
 {
-	int o2, he, o2max;
+	auto [o2, he, o2max ] = dive->get_maximal_gas();
-	get_dive_gas(dive, &o2, &he, &o2max);
 	return he * 1000 + o2;
 }
 

stats/statsvariables.cpp

@@ -216,7 +216,7 @@ bool StatsQuartiles::isValid() const
 // Define an ordering for gas types
 // invalid < air < ean (including oxygen) < trimix
 // The latter two are sorted by (helium, oxygen)
-// This is in analogy to the global get_dive_gas() function.
+// This is in analogy to the dive::get_maximal_gas() function.
 static bool operator<(const gas_bin_t &t1, const gas_bin_t &t2)
 {
 	if (t1.type != t2.type)