Cleanup: pass gasmix by value

In a previous commit, the get_gasmix_* functions were changed to
return by value. For consistency, also pass gasmix by value.

Note that on common 64-bit platforms struct gasmix is the size
of a pointer [2 * 32 bit vs. 64 bit] and therefore uses the
same space on the stack. On 32-bit platforms, the stack use
is probably doubled, but in return a dereference is avoided.

Supporting arbitrary gas-mixes (H2, Ar, ...) will be such an
invasive change that going back to pointers is probably the
least of our worries.

This commit is a step in const-ifying input parameters (passing
by value is the ultimate way of signaling that the input parameter
will not be changed [unless there are references to said parameter]).

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

28 files changed, 214 insertions, 215 deletions

diff --git a/core/deco.c b/core/deco.c
index e8bafd426..2990edd7d 100644
--- a/core/deco.c
+++ b/core/deco.c
@@ -479,7 +479,7 @@ void calc_crushing_pressure(struct deco_state *ds, double pressure)
 }
 
 /* add period_in_seconds at the given pressure and gas to the deco calculation */
-void add_segment(struct deco_state *ds, double pressure, const struct gasmix *gasmix, int period_in_seconds, int ccpo2, enum divemode_t divemode, int sac)
+void add_segment(struct deco_state *ds, double pressure, struct gasmix gasmix, int period_in_seconds, int ccpo2, enum divemode_t divemode, int sac)
 {
 	UNUSED(sac);
 	int ci;
diff --git a/core/dive.c b/core/dive.c
index 0cf0df780..2e79baf96 100644
--- a/core/dive.c
+++ b/core/dive.c
@@ -1021,7 +1021,7 @@ static void update_min_max_temperatures(struct dive *dive, temperature_t tempera
 int gas_volume(cylinder_t *cyl, pressure_t p)
 {
 	double bar = p.mbar / 1000.0;
-	double z_factor = gas_compressibility_factor(&cyl->gasmix, bar);
+	double z_factor = gas_compressibility_factor(cyl->gasmix, bar);
 	return lrint(cyl->type.size.mliter * bar_to_atm(bar) / z_factor);
 }
 
@@ -1082,7 +1082,7 @@ void update_setpoint_events(struct dive *dive, struct divecomputer *dc)
 				gasmix = get_gasmix_from_event(dive, ev);
 				next = get_next_event(ev, "gaschange");
 			}
-			fill_pressures(&pressures, calculate_depth_to_mbar(dc->sample[i].depth.mm, dc->surface_pressure, 0), &gasmix ,0, dc->divemode);
+			fill_pressures(&pressures, calculate_depth_to_mbar(dc->sample[i].depth.mm, dc->surface_pressure, 0), gasmix ,0, dc->divemode);
 			if (abs(dc->sample[i].setpoint.mbar - (int)(1000 * pressures.o2)) <= 50)
 				dc->sample[i].setpoint.mbar = 0;
 		}
@@ -1112,7 +1112,7 @@ void sanitize_gasmix(struct gasmix *mix)
 		if (!o2)
 			return;
 		/* 20.8% to 21% O2 is just air */
-		if (gasmix_is_air(mix)) {
+		if (gasmix_is_air(*mix)) {
 			mix->o2.permille = 0;
 			return;
 		}
@@ -1231,7 +1231,7 @@ static void sanitize_cylinder_info(struct dive *dive)
  * Output:     i) The icd_data stucture is filled with the delta_N2 and delta_He numbers (as permille).
  *            ii) Function returns a boolean indicating an exceeding of the rule-of-fifths. False = no icd problem.
  */
-bool isobaric_counterdiffusion(struct gasmix *oldgasmix, struct gasmix *newgasmix, struct icd_data *results)
+bool isobaric_counterdiffusion(struct gasmix oldgasmix, struct gasmix newgasmix, struct icd_data *results)
 {
 	if (!prefs.show_icd)
 		return false;
@@ -1608,7 +1608,7 @@ static void fixup_dive_pressures(struct dive *dive, struct divecomputer *dc)
 	simplify_dc_pressures(dc);
 }
 
-int find_best_gasmix_match(struct gasmix *mix, cylinder_t array[], unsigned int used)
+int find_best_gasmix_match(struct gasmix mix, cylinder_t array[], unsigned int used)
 {
 	int i;
 	int best = -1, score = INT_MAX;
@@ -1622,7 +1622,7 @@ int find_best_gasmix_match(struct gasmix *mix, cylinder_t array[], unsigned int
 		match = array + i;
 		if (cylinder_nodata(match))
 			continue;
-		distance = gasmix_distance(mix, &match->gasmix);
+		distance = gasmix_distance(mix, match->gasmix);
 		if (distance >= score)
 			continue;
 		best = i;
@@ -1640,14 +1640,14 @@ static bool validate_gaschange(struct dive *dive, struct event *event)
 	int o2, he, value;
 
 	/* We'll get rid of the per-event gasmix, but for now sanitize it */
-	if (gasmix_is_air(&event->gas.mix))
+	if (gasmix_is_air(event->gas.mix))
 		event->gas.mix.o2.permille = 0;
 
 	/* Do we already have a cylinder index for this gasmix? */
 	if (event->gas.index >= 0)
 		return true;
 
-	index = find_best_gasmix_match(&event->gas.mix, dive->cylinder, 0);
+	index = find_best_gasmix_match(event->gas.mix, dive->cylinder, 0);
 	if (index < 0)
 		return false;
 
@@ -1656,8 +1656,8 @@ static bool validate_gaschange(struct dive *dive, struct event *event)
 	event->gas.mix = dive->cylinder[index].gasmix;
 
 	/* Convert to odd libdivecomputer format */
-	o2 = get_o2(&event->gas.mix);
-	he = get_he(&event->gas.mix);
+	o2 = get_o2(event->gas.mix);
+	he = get_he(event->gas.mix);
 
 	o2 = (o2 + 5) / 10;
 	he = (he + 5) / 10;
@@ -1980,7 +1980,7 @@ static int sort_event(struct event *a, struct event *b)
 static int same_gas(struct event *a, struct event *b)
 {
 	if (a->type == b->type && a->flags == b->flags && a->value == b->value && !strcmp(a->name, b->name) &&
-			same_gasmix(&a->gas.mix, &b->gas.mix)) {
+			same_gasmix(a->gas.mix, b->gas.mix)) {
 		return true;
 	}
 	return false;
@@ -2078,7 +2078,7 @@ extern int get_cylinder_idx_by_use(struct dive *dive, enum cylinderuse cylinder_
 	return -1; // negative number means cylinder_use_type not found in list of cylinders
 }
 
-int gasmix_distance(const struct gasmix *a, const struct gasmix *b)
+int gasmix_distance(struct gasmix a, struct gasmix b)
 {
 	int a_o2 = get_o2(a), b_o2 = get_o2(b);
 	int a_he = get_he(a), b_he = get_he(b);
@@ -2099,7 +2099,7 @@ int gasmix_distance(const struct gasmix *a, const struct gasmix *b)
  *			divemode = the dive mode pertaining to this point in the dive profile.
  * This function called by: calculate_gas_information_new() in profile.c; add_segment() in deco.c.
  */
-extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, enum divemode_t divemode)
+extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, struct gasmix mix, double po2, enum divemode_t divemode)
 {
 	if ((divemode != OC) && po2) {	// This is a rebreather dive where pressures->o2 is defined
 		if (po2 >= amb_pressure) {
@@ -2204,20 +2204,20 @@ void cylinder_renumber(struct dive *dive, int mapping[])
 		dc_cylinder_renumber(dive, dc, mapping);
 }
 
-int same_gasmix(struct gasmix *a, struct gasmix *b)
+int same_gasmix(struct gasmix a, struct gasmix b)
 {
 	if (gasmix_is_air(a) && gasmix_is_air(b))
 		return 1;
-	return a->o2.permille == b->o2.permille && a->he.permille == b->he.permille;
+	return a.o2.permille == b.o2.permille && a.he.permille == b.he.permille;
 }
 
 int same_gasmix_cylinder(cylinder_t *cyl, int cylid, struct dive *dive, bool check_unused)
 {
-	struct gasmix *mygas = &cyl->gasmix;
+	struct gasmix mygas = cyl->gasmix;
 	for (int i = 0; i < MAX_CYLINDERS; i++) {
 		if (i == cylid || cylinder_none(&dive->cylinder[i]))
 			continue;
-		struct gasmix *gas2 = &dive->cylinder[i].gasmix;
+		struct gasmix gas2 = dive->cylinder[i].gasmix;
 		if (gasmix_distance(mygas, gas2) == 0 && (is_cylinder_used(dive, i) || check_unused))
 			return i;
 	}
@@ -2253,7 +2253,7 @@ static int match_cylinder(cylinder_t *cyl, struct dive *dive, unsigned int avail
 		if (!(available & (1u << i)))
 			continue;
 		target = dive->cylinder + i;
-		if (!same_gasmix(&cyl->gasmix, &target->gasmix))
+		if (!same_gasmix(cyl->gasmix, target->gasmix))
 			continue;
 		if (cyl->cylinder_use != target->cylinder_use)
 			continue;
@@ -4062,10 +4062,10 @@ fraction_t best_he(depth_t depth, struct dive *dive)
 	return fhe;
 }
 
-bool gasmix_is_air(const struct gasmix *gasmix)
+bool gasmix_is_air(struct gasmix gasmix)
 {
-	int o2 = gasmix->o2.permille;
-	int he = gasmix->he.permille;
+	int o2 = gasmix.o2.permille;
+	int he = gasmix.he.permille;
 	return (he == 0) && (o2 == 0 || ((o2 >= O2_IN_AIR - 1) && (o2 <= O2_IN_AIR + 1)));
 }
 
@@ -4148,7 +4148,7 @@ int mbar_to_depth(int mbar, struct dive *dive)
 }
 
 /* MOD rounded to multiples of roundto mm */
-depth_t gas_mod(struct gasmix *mix, pressure_t po2_limit, struct dive *dive, int roundto)
+depth_t gas_mod(struct gasmix mix, pressure_t po2_limit, struct dive *dive, int roundto)
 {
 	depth_t rounded_depth;
 
@@ -4158,7 +4158,7 @@ depth_t gas_mod(struct gasmix *mix, pressure_t po2_limit, struct dive *dive, int
 }
 
 /* Maximum narcotic depth rounded to multiples of roundto mm */
-depth_t gas_mnd(struct gasmix *mix, depth_t end, struct dive *dive, int roundto)
+depth_t gas_mnd(struct gasmix mix, depth_t end, struct dive *dive, int roundto)
 {
 	depth_t rounded_depth;
 	pressure_t ppo2n2;
@@ -4287,7 +4287,7 @@ int dive_has_gps_location(struct dive *dive)
 	return dive_site_has_gps_location(get_dive_site_by_uuid(dive->dive_site_uuid));
 }
 
-struct gasmix get_gasmix(struct dive *dive, struct divecomputer *dc, int time, struct event **evp, struct gasmix *gasmix)
+struct gasmix get_gasmix(struct dive *dive, struct divecomputer *dc, int time, struct event **evp, struct gasmix gasmix)
 {
 	struct event *ev = *evp;
 	struct gasmix res;
@@ -4298,7 +4298,7 @@ struct gasmix get_gasmix(struct dive *dive, struct divecomputer *dc, int time, s
 		res = dive->cylinder[cyl].gasmix;
 		ev = dc ? get_next_event(dc->events, "gaschange") : NULL;
 	} else {
-		res = *gasmix;
+		res = gasmix;
 	}
 
 	while (ev && ev->time.seconds < time) {
@@ -4314,5 +4314,5 @@ struct gasmix get_gasmix_at_time(struct dive *d, struct divecomputer *dc, durati
 {
 	struct event *ev = NULL;
 	struct gasmix gasmix = { 0 };
-	return get_gasmix(d, dc, time.seconds, &ev, &gasmix);
+	return get_gasmix(d, dc, time.seconds, &ev, gasmix);
 }
diff --git a/core/dive.h b/core/dive.h
index a1cc3ab6d..5bc041ac8 100644
--- a/core/dive.h
+++ b/core/dive.h
@@ -71,7 +71,7 @@ struct icd_data { // This structure provides communication between function isob
 	int dHe;      // The change in fraction (permille) of helium during the change
 };
 
-extern bool isobaric_counterdiffusion(struct gasmix *oldgasmix, struct gasmix *newgasmix, struct icd_data *results);
+extern bool isobaric_counterdiffusion(struct gasmix oldgasmix, struct gasmix newgasmix, struct icd_data *results);
 
 /*
  * Events are currently based straight on what libdivecomputer gives us.
@@ -114,32 +114,32 @@ extern int units_to_sac(double volume);
 
 /* Volume in mliter of a cylinder at pressure 'p' */
 extern int gas_volume(cylinder_t *cyl, pressure_t p);
-extern double gas_compressibility_factor(struct gasmix *gas, double bar);
-extern double isothermal_pressure(struct gasmix *gas, double p1, int volume1, int volume2);
-extern double gas_density(struct gasmix *gas, int pressure);
-extern int same_gasmix(struct gasmix *a, struct gasmix *b);
+extern double gas_compressibility_factor(struct gasmix gas, double bar);
+extern double isothermal_pressure(struct gasmix gas, double p1, int volume1, int volume2);
+extern double gas_density(struct gasmix gas, int pressure);
+extern int same_gasmix(struct gasmix a, struct gasmix b);
 
-static inline int get_o2(const struct gasmix *mix)
+static inline int get_o2(struct gasmix mix)
 {
-	return mix->o2.permille ?: O2_IN_AIR;
+	return mix.o2.permille ?: O2_IN_AIR;
 }
 
-static inline int get_he(const struct gasmix *mix)
+static inline int get_he(struct gasmix mix)
 {
-	return mix->he.permille;
+	return mix.he.permille;
 }
 
 struct gas_pressures {
 	double o2, n2, he;
 };
 
-extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, const struct gasmix *mix, double po2, enum divemode_t dctype);
+extern void fill_pressures(struct gas_pressures *pressures, const double amb_pressure, struct gasmix mix, double po2, enum divemode_t dctype);
 
 extern void sanitize_gasmix(struct gasmix *mix);
-extern int gasmix_distance(const struct gasmix *a, const struct gasmix *b);
-extern int find_best_gasmix_match(struct gasmix *mix, cylinder_t array[], unsigned int used);
+extern int gasmix_distance(struct gasmix a, struct gasmix b);
+extern int find_best_gasmix_match(struct gasmix mix, cylinder_t array[], unsigned int used);
 
-extern bool gasmix_is_air(const struct gasmix *gasmix);
+extern bool gasmix_is_air(struct gasmix gasmix);
 
 /* 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)
@@ -152,8 +152,8 @@ static inline int interpolate(int a, int b, int part, int whole)
 	return (a+b)/2;
 }
 
-void get_gas_string(const struct gasmix *gasmix, char *text, int len);
-const char *gasname(const struct gasmix *gasmix);
+void get_gas_string(struct gasmix gasmix, char *text, int len);
+const char *gasname(struct gasmix gasmix);
 
 #define MAX_SENSORS 2
 struct sample                         // BASE TYPE BYTES  UNITS    RANGE               DESCRIPTION
@@ -396,8 +396,8 @@ extern double depth_to_bar(int depth, struct dive *dive);
 extern double depth_to_atm(int depth, struct dive *dive);
 extern int rel_mbar_to_depth(int mbar, struct dive *dive);
 extern int mbar_to_depth(int mbar, struct dive *dive);
-extern depth_t gas_mod(struct gasmix *mix, pressure_t po2_limit, struct dive *dive, int roundto);
-extern depth_t gas_mnd(struct gasmix *mix, depth_t end, struct dive *dive, int roundto);
+extern depth_t gas_mod(struct gasmix mix, pressure_t po2_limit, struct dive *dive, int roundto);
+extern depth_t gas_mnd(struct gasmix mix, depth_t end, struct dive *dive, int roundto);
 
 #define SURFACE_THRESHOLD 750 /* somewhat arbitrary: only below 75cm is it really diving */
 
@@ -663,7 +663,7 @@ struct deco_state {
 	bool icd_warning;
 };
 
-extern void add_segment(struct deco_state *ds, double pressure, const struct gasmix *gasmix, int period_in_seconds, int setpoint, enum divemode_t divemode, int sac);
+extern void add_segment(struct deco_state *ds, double pressure, struct gasmix gasmix, int period_in_seconds, int setpoint, enum divemode_t divemode, int sac);
 extern void clear_deco(struct deco_state *ds, double surface_pressure);
 extern void dump_tissues(struct deco_state *ds);
 extern void set_gf(short gflow, short gfhigh);
@@ -722,7 +722,7 @@ extern struct event *get_next_event(struct event *event, const char *name);
  * 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);
+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);
diff --git a/core/divelist.c b/core/divelist.c
index 12382d896..18e9b1ae3 100644
--- a/core/divelist.c
+++ b/core/divelist.c
@@ -94,8 +94,8 @@ void get_dive_gas(struct dive *dive, int *o2_p, int *he_p, int *o2max_p)
 
 	for (i = 0; i < MAX_CYLINDERS; i++) {
 		cylinder_t *cyl = dive->cylinder + i;
-		int o2 = get_o2(&cyl->gasmix);
-		int he = get_he(&cyl->gasmix);
+		int o2 = get_o2(cyl->gasmix);
+		int he = get_he(cyl->gasmix);
 
 		if (!is_cylinder_used(dive, i))
 			continue;
@@ -135,7 +135,7 @@ int total_weight(struct dive *dive)
 static int active_o2(struct dive *dive, struct divecomputer *dc, duration_t time)
 {
 	struct gasmix gas = get_gasmix_at_time(dive, dc, time);
-	return get_o2(&gas);
+	return get_o2(gas);
 }
 
 /* calculate OTU for a dive - this only takes the first divecomputer into account */
@@ -420,8 +420,8 @@ static void add_dive_to_deco(struct deco_state *ds, struct dive *dive)
 
 		for (j = t0; j < t1; j++) {
 			int depth = interpolate(psample->depth.mm, sample->depth.mm, j - t0, t1 - t0);
-			gasmix = get_gasmix(dive, dc, j, &ev, &gasmix);
-			add_segment(ds, depth_to_bar(depth, dive), &gasmix, 1, sample->setpoint.mbar,
+			gasmix = get_gasmix(dive, dc, j, &ev, gasmix);
+			add_segment(ds, depth_to_bar(depth, dive), gasmix, 1, sample->setpoint.mbar,
 				get_current_divemode(&dive->dc, j, &evd, &current_divemode), dive->sac);
 		}
 	}
@@ -576,7 +576,7 @@ int init_decompression(struct deco_state *ds, struct dive *dive)
 #endif
 				return surface_time;
 			}
-			add_segment(ds, surface_pressure, &air, surface_time, 0, dive->dc.divemode, prefs.decosac);
+			add_segment(ds, surface_pressure, air, surface_time, 0, dive->dc.divemode, prefs.decosac);
 #if DECO_CALC_DEBUG & 2
 			printf("Tissues after surface intervall of %d:%02u:\n", FRACTION(surface_time, 60));
 			dump_tissues(ds);
@@ -614,7 +614,7 @@ int init_decompression(struct deco_state *ds, struct dive *dive)
 #endif
 			return surface_time;
 		}
-		add_segment(ds, surface_pressure, &air, surface_time, 0, dive->dc.divemode, prefs.decosac);
+		add_segment(ds, surface_pressure, air, surface_time, 0, dive->dc.divemode, prefs.decosac);
 #if DECO_CALC_DEBUG & 2
 		printf("Tissues after surface intervall of %d:%02u:\n", FRACTION(surface_time, 60));
 		dump_tissues(ds);
diff --git a/core/equipment.c b/core/equipment.c
index 53e4c273f..62e8dcb70 100644
--- a/core/equipment.c
+++ b/core/equipment.c
@@ -81,7 +81,7 @@ bool cylinder_none(void *_data)
 	return cylinder_nodata(cyl) && cylinder_nosamples(cyl);
 }
 
-void get_gas_string(const struct gasmix *gasmix, char *text, int len)
+void get_gas_string(struct gasmix gasmix, char *text, int len)
 {
 	if (gasmix_is_air(gasmix))
 		snprintf(text, len, "%s", translate("gettextFromC", "air"));
@@ -94,7 +94,7 @@ void get_gas_string(const struct gasmix *gasmix, char *text, int len)
 }
 
 /* Returns a static char buffer - only good for immediate use by printf etc */
-const char *gasname(const struct gasmix *gasmix)
+const char *gasname(struct gasmix gasmix)
 {
 	static char gas[64];
 	get_gas_string(gasmix, gas, sizeof(gas));
@@ -216,7 +216,7 @@ void reset_cylinders(struct dive *dive, bool track_gas)
 		if (cylinder_none(cyl))
 			continue;
 		if (cyl->depth.mm == 0) /* if the gas doesn't give a mod, calculate based on prefs */
-			cyl->depth = gas_mod(&cyl->gasmix, decopo2, dive, M_OR_FT(3,10));
+			cyl->depth = gas_mod(cyl->gasmix, decopo2, dive, M_OR_FT(3,10));
 		if (track_gas)
 			cyl->start.mbar = cyl->end.mbar = cyl->type.workingpressure.mbar;
 		cyl->gas_used.mliter = 0;
diff --git a/core/gas-model.c b/core/gas-model.c
index 49c677967..7fb9ce111 100644
--- a/core/gas-model.c
+++ b/core/gas-model.c
@@ -26,7 +26,7 @@
  * NOTE! Helium coefficients are a linear mix operation between the
  * 323K and one for 273K isotherms, to make everything be at 300K.
  */
-double gas_compressibility_factor(struct gasmix *gas, double bar)
+double gas_compressibility_factor(struct gasmix gas, double bar)
 {
 	static const double o2_coefficients[3] = {
 		-7.18092073703e-04,
@@ -69,15 +69,15 @@ double gas_compressibility_factor(struct gasmix *gas, double bar)
 /* Compute the new pressure when compressing (expanding) volome v1 at pressure p1 bar to volume v2
  * taking into account the compressebility (to first order) */
 
-double isothermal_pressure(struct gasmix *gas, double p1, int volume1, int volume2)
+double isothermal_pressure(struct gasmix gas, double p1, int volume1, int volume2)
 {
 	double p_ideal = p1 * volume1 / volume2 / gas_compressibility_factor(gas, p1);
 
 	return p_ideal * gas_compressibility_factor(gas, p_ideal);
 }
 
-inline double gas_density(struct gasmix *gas, int pressure) {
-	int density =  gas->he.permille * HE_DENSITY + gas->o2.permille * O2_DENSITY + (1000 - gas->he.permille - gas->o2.permille) * N2_DENSITY;
+inline double gas_density(struct gasmix gas, int pressure) {
+	int density =  gas.he.permille * HE_DENSITY + gas.o2.permille * O2_DENSITY + (1000 - gas.he.permille - gas.o2.permille) * N2_DENSITY;
 
 	return density * (double) pressure / gas_compressibility_factor(gas, pressure / 1000.0) / SURFACE_PRESSURE / 1000000.0;
 }
diff --git a/core/import-divinglog.c b/core/import-divinglog.c
index 4e205d661..3e2f396ba 100644
--- a/core/import-divinglog.c
+++ b/core/import-divinglog.c
@@ -137,7 +137,7 @@ extern int divinglog_profile(void *handle, int columns, char **data, char **colu
 			cur_sample->pressure[0].mbar = pressure * 100;
 			cur_sample->rbt.seconds = rbt;
 			if (oldcyl != tank) {
-				struct gasmix *mix = &cur_dive->cylinder[tank].gasmix;
+				struct gasmix mix = cur_dive->cylinder[tank].gasmix;
 				int o2 = get_o2(mix);
 				int he = get_he(mix);
 
diff --git a/core/parse-xml.c b/core/parse-xml.c
index ae779e1f8..681d05aa9 100644
--- a/core/parse-xml.c
+++ b/core/parse-xml.c
@@ -652,7 +652,7 @@ void add_gas_switch_event(struct dive *dive, struct divecomputer *dc, int second
 	if (idx < 0 || idx >= MAX_CYLINDERS)
 		return;
 	/* The gas switch event format is insane for historical reasons */
-	struct gasmix *mix = &dive->cylinder[idx].gasmix;
+	struct gasmix mix = dive->cylinder[idx].gasmix;
 	int o2 = get_o2(mix);
 	int he = get_he(mix);
 	struct event *ev;
@@ -665,7 +665,7 @@ void add_gas_switch_event(struct dive *dive, struct divecomputer *dc, int second
 	ev = add_event(dc, seconds, he ? SAMPLE_EVENT_GASCHANGE2 : SAMPLE_EVENT_GASCHANGE, 0, value, "gaschange");
 	if (ev) {
 		ev->gas.index = idx;
-		ev->gas.mix = *mix;
+		ev->gas.mix = mix;
 	}
 }
 
diff --git a/core/planner.c b/core/planner.c
index ec2436a70..673c2b6b7 100644
--- a/core/planner.c
+++ b/core/planner.c
@@ -95,12 +95,12 @@ int get_cylinderid_at_time(struct dive *dive, struct divecomputer *dc, duration_
 	return cylinder_idx;
 }
 
-int get_gasidx(struct dive *dive, struct gasmix *mix)
+int get_gasidx(struct dive *dive, struct gasmix mix)
 {
 	return find_best_gasmix_match(mix, dive->cylinder, 0);
 }
 
-void interpolate_transition(struct deco_state *ds, struct dive *dive, duration_t t0, duration_t t1, depth_t d0, depth_t d1, const struct gasmix *gasmix, o2pressure_t po2, enum divemode_t divemode)
+void interpolate_transition(struct deco_state *ds, struct dive *dive, duration_t t0, duration_t t1, depth_t d0, depth_t d1, struct gasmix gasmix, o2pressure_t po2, enum divemode_t divemode)
 {
 	int32_t j;
 
@@ -176,7 +176,7 @@ int tissue_at_end(struct deco_state *ds, struct dive *dive, struct deco_state **
 		}
 
 		divemode = get_current_divemode(&dive->dc, t0.seconds + 1, &evdm, &divemode);
-		interpolate_transition(ds, dive, t0, t1, lastdepth, sample->depth, &gas, setpoint, divemode);
+		interpolate_transition(ds, dive, t0, t1, lastdepth, sample->depth, gas, setpoint, divemode);
 		psample = sample;
 		t0 = t1;
 	}
@@ -211,7 +211,7 @@ void fill_default_cylinder(cylinder_t *cyl)
 			cyl->type.size.mliter = lrint(cuft_to_l(ti->cuft) * 1000 / bar_to_atm(psi_to_bar(ti->psi)));
 	}
 	// MOD of air
-	cyl->depth = gas_mod(&cyl->gasmix, pO2, &displayed_dive, 1);
+	cyl->depth = gas_mod(cyl->gasmix, pO2, &displayed_dive, 1);
 }
 
 /* calculate the new end pressure of the cylinder, based on its current end pressure and the
@@ -234,7 +234,7 @@ static void update_cylinder_pressure(struct dive *d, int old_depth, int new_dept
 	if (in_deco)
 		cyl->deco_gas_used.mliter += gas_used.mliter;
 	if (cyl->type.size.mliter) {
-		delta_p.mbar = lrint(gas_used.mliter * 1000.0 / cyl->type.size.mliter * gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0));
+		delta_p.mbar = lrint(gas_used.mliter * 1000.0 / cyl->type.size.mliter * gas_compressibility_factor(cyl->gasmix, cyl->end.mbar / 1000.0));
 		cyl->end.mbar -= delta_p.mbar;
 	}
 }
@@ -550,7 +550,7 @@ void track_ascent_gas(int depth, cylinder_t *cylinder, int avg_depth, int bottom
 }
 
 // Determine whether ascending to the next stop will break the ceiling.  Return true if the ascent is ok, false if it isn't.
-bool trial_ascent(struct deco_state *ds, int wait_time, int trial_depth, int stoplevel, int avg_depth, int bottom_time, struct gasmix *gasmix, int po2, double surface_pressure, struct dive *dive, enum divemode_t divemode)
+bool trial_ascent(struct deco_state *ds, int wait_time, int trial_depth, int stoplevel, int avg_depth, int bottom_time, struct gasmix gasmix, int po2, double surface_pressure, struct dive *dive, enum divemode_t divemode)
 {
 
 	bool clear_to_ascend = true;
@@ -615,7 +615,7 @@ bool enough_gas(int current_cylinder)
  * So we always test at the upper bundary, not in the middle!
  */
 
-int wait_until(struct deco_state *ds, struct dive *dive, int clock, int min, int leap, int stepsize, int depth, int target_depth, int avg_depth, int bottom_time, struct gasmix *gasmix, int po2, double surface_pressure, enum divemode_t divemode)
+int wait_until(struct deco_state *ds, struct dive *dive, int clock, int min, int leap, int stepsize, int depth, int target_depth, int avg_depth, int bottom_time, struct gasmix gasmix, int po2, double surface_pressure, enum divemode_t divemode)
 {
 	// When a deco stop exceeds two days, there is something wrong...
 	if (min >= 48 * 3600)
@@ -774,11 +774,11 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 		// How long can we stay at the current depth and still directly ascent to the surface?
 		do {
 			add_segment(ds, depth_to_bar(depth, dive),
-				    &dive->cylinder[current_cylinder].gasmix,
+				    dive->cylinder[current_cylinder].gasmix,
 				    timestep, po2, divemode, prefs.bottomsac);
 			update_cylinder_pressure(dive, depth, depth, timestep, prefs.bottomsac, &dive->cylinder[current_cylinder], false, divemode);
 			clock += timestep;
-		} while (trial_ascent(ds, 0, depth, 0, avg_depth, bottom_time, &dive->cylinder[current_cylinder].gasmix,
+		} while (trial_ascent(ds, 0, depth, 0, avg_depth, bottom_time, dive->cylinder[current_cylinder].gasmix,
 				      po2, diveplan->surface_pressure / 1000.0, dive, divemode) &&
 			 enough_gas(current_cylinder) && clock < 6 * 3600);
 
@@ -869,12 +869,12 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 		last_ascend_rate = ascent_velocity(depth, avg_depth, bottom_time);
 		/* Always prefer the best_first_ascend_cylinder if it has the right gasmix.
 		 * Otherwise take first cylinder from list with rightgasmix  */
-		if (same_gasmix(&gas, &dive->cylinder[best_first_ascend_cylinder].gasmix))
+		if (same_gasmix(gas, dive->cylinder[best_first_ascend_cylinder].gasmix))
 			current_cylinder = best_first_ascend_cylinder;
 		else
-			current_cylinder = get_gasidx(dive, &gas);
+			current_cylinder = get_gasidx(dive, gas);
 		if (current_cylinder == -1) {
-			report_error(translate("gettextFromC", "Can't find gas %s"), gasname(&gas));
+			report_error(translate("gettextFromC", "Can't find gas %s"), gasname(gas));
 			current_cylinder = 0;
 		}
 		reset_regression();
@@ -894,7 +894,7 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 					deltad = depth - stoplevels[stopidx];
 
 				add_segment(ds, depth_to_bar(depth, dive),
-								&dive->cylinder[current_cylinder].gasmix,
+								dive->cylinder[current_cylinder].gasmix,
 								TIMESTEP, po2, divemode, prefs.decosac);
 				last_segment_min_switch = false;
 				clock += TIMESTEP;
@@ -923,7 +923,7 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 				if (current_cylinder != gaschanges[gi].gasidx) {
 					if (!prefs.switch_at_req_stop ||
 							!trial_ascent(ds, 0, depth, stoplevels[stopidx - 1], avg_depth, bottom_time,
-							&dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, dive, divemode) || get_o2(&dive->cylinder[current_cylinder].gasmix) < 160) {
+							dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, dive, divemode) || get_o2(dive->cylinder[current_cylinder].gasmix) < 160) {
 						current_cylinder = gaschanges[gi].gasidx;
 						gas = dive->cylinder[current_cylinder].gasmix;
 #if DEBUG_PLAN & 16
@@ -931,9 +931,9 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 							(get_o2(&gas) + 5) / 10, (get_he(&gas) + 5) / 10, gaschanges[gi].depth / 1000.0);
 #endif
 						/* Stop for the minimum duration to switch gas unless we switch to o2 */
-						if (!last_segment_min_switch && get_o2(&dive->cylinder[current_cylinder].gasmix) != 1000) {
+						if (!last_segment_min_switch && get_o2(dive->cylinder[current_cylinder].gasmix) != 1000) {
 							add_segment(ds, depth_to_bar(depth, dive),
-								&dive->cylinder[current_cylinder].gasmix,
+								dive->cylinder[current_cylinder].gasmix,
 								prefs.min_switch_duration, po2, divemode, prefs.decosac);
 							clock += prefs.min_switch_duration;
 							last_segment_min_switch = true;
@@ -953,7 +953,7 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 			while (1) {
 				/* Check if ascending to next stop is clear, go back and wait if we hit the ceiling on the way */
 				if (trial_ascent(ds, 0, depth, stoplevels[stopidx], avg_depth, bottom_time,
-						&dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, dive, divemode)) {
+						dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, dive, divemode)) {
 					decostoptable[decostopcounter].depth = depth;
 					decostoptable[decostopcounter].time = 0;
 					decostopcounter++;
@@ -985,9 +985,9 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 						(get_o2(&gas) + 5) / 10, (get_he(&gas) + 5) / 10, gaschanges[gi + 1].depth / 1000.0);
 #endif
 					/* Stop for the minimum duration to switch gas unless we switch to o2 */
-					if (!last_segment_min_switch && get_o2(&dive->cylinder[current_cylinder].gasmix) != 1000) {
+					if (!last_segment_min_switch && get_o2(dive->cylinder[current_cylinder].gasmix) != 1000) {
 						add_segment(ds, depth_to_bar(depth, dive),
-							&dive->cylinder[current_cylinder].gasmix,
+							dive->cylinder[current_cylinder].gasmix,
 							prefs.min_switch_duration, po2, divemode, prefs.decosac);
 						clock += prefs.min_switch_duration;
 						last_segment_min_switch = true;
@@ -996,7 +996,7 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 				}
 
 				int new_clock = wait_until(ds, dive, clock, clock, laststoptime * 2 + 1, timestep, depth, stoplevels[stopidx], avg_depth,
-					bottom_time, &dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, divemode);
+					bottom_time, dive->cylinder[current_cylinder].gasmix, po2, diveplan->surface_pressure / 1000.0, divemode);
 				laststoptime = new_clock - clock;
 				/* Finish infinite deco */
 				if (laststoptime >= 48 * 3600 && depth >= 6000) {
@@ -1011,12 +1011,12 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 					 * backgas.  This could be customized if there were demand.
 					 */
 					if (break_cylinder == -1) {
-						if (get_o2(&dive->cylinder[best_first_ascend_cylinder].gasmix) <= 320)
+						if (get_o2(dive->cylinder[best_first_ascend_cylinder].gasmix) <= 320)
 							break_cylinder = best_first_ascend_cylinder;
 						else
 							break_cylinder = 0;
 					}
-					if (get_o2(&dive->cylinder[current_cylinder].gasmix) == 1000) {
+					if (get_o2(dive->cylinder[current_cylinder].gasmix) == 1000) {
 						if (laststoptime >= 12 * 60) {
 							laststoptime = 12 * 60;
 							new_clock = clock + laststoptime;
@@ -1043,7 +1043,7 @@ bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, i
 						}
 					}
 				}
-				add_segment(ds, depth_to_bar(depth, dive), &dive->cylinder[stop_cylinder].gasmix,
+				add_segment(ds, depth_to_bar(depth, dive), dive->cylinder[stop_cylinder].gasmix,
 					    laststoptime, po2, divemode, prefs.decosac);
 				last_segment_min_switch = false;
 				decostoptable[decostopcounter].depth = depth;
diff --git a/core/planner.h b/core/planner.h
index a96633b74..fb5338c8f 100644
--- a/core/planner.h
+++ b/core/planner.h
@@ -18,7 +18,7 @@ extern void set_display_runtime(bool display);
 extern void set_display_duration(bool display);
 extern void set_display_transitions(bool display);
 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 int get_gasidx(struct dive *dive, struct gasmix mix);
 extern bool diveplan_empty(struct diveplan *diveplan);
 extern void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_disclaimer, int error);
 
diff --git a/core/plannernotes.c b/core/plannernotes.c
index c7d443324..27742f2f9 100644
--- a/core/plannernotes.c
+++ b/core/plannernotes.c
@@ -42,7 +42,7 @@ static int diveplan_duration(struct diveplan *diveplan)
  *             5) Pointers to gas mixes in the gas change: gas-from and gas-to.
  * Returns:    The size of the output buffer that has been used after the new results have been added.
  */
-static void add_icd_entry(struct membuffer *b, struct icd_data *icdvalues, bool printheader, int time_seconds, int ambientpressure_mbar, struct gasmix *gas_from, struct gasmix *gas_to)
+static void add_icd_entry(struct membuffer *b, struct icd_data *icdvalues, bool printheader, int time_seconds, int ambientpressure_mbar, struct gasmix gas_from, struct gasmix gas_to)
 {
 	if (printheader) { // Create a table description and a table header if no icd data have been written yet.
 		put_format(b, "<div>%s:", translate("gettextFromC","Isobaric counterdiffusion information"));
@@ -179,8 +179,8 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 			nextdp = nextdp->next;
 		if (nextdp)
 			newgasmix = dive->cylinder[nextdp->cylinderid].gasmix;
-		gaschange_after = (nextdp && (gasmix_distance(&gasmix, &newgasmix)));
-		gaschange_before =  (gasmix_distance(&lastprintgasmix, &gasmix));
+		gaschange_after = (nextdp && (gasmix_distance(gasmix, newgasmix)));
+		gaschange_before =  (gasmix_distance(lastprintgasmix, gasmix));
 		rebreatherchange_after = (nextdp && (dp->setpoint != nextdp->setpoint || dp->divemode != nextdp->divemode));
 		rebreatherchange_before = lastprintsetpoint != dp->setpoint || lastdivemode != dp->divemode;
 		/* do we want to skip this leg as it is devoid of anything useful? */
@@ -215,7 +215,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
-							     gasname(&gasmix),
+							     gasname(gasmix),
 							     (double) dp->setpoint / 1000.0);
 					} else {
 						put_format_loc(&buf, translate("gettextFromC", "%s to %.*f %s in %d:%02d min - runtime %d:%02u on %s"),
@@ -223,7 +223,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
-							     gasname(&gasmix));
+							     gasname(gasmix));
 					}
 
 					put_string(&buf, "<br>");
@@ -237,14 +237,14 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
-							     gasname(&gasmix),
+							     gasname(gasmix),
 							     (double) dp->setpoint / 1000.0);
 					} else {
 						put_format_loc(&buf, translate("gettextFromC", "Stay at %.*f %s for %d:%02d min - runtime %d:%02u on %s %s"),
 							     decimals, depthvalue, depth_unit,
 							     FRACTION(dp->time - lasttime, 60),
 							     FRACTION(dp->time, 60),
-							     gasname(&gasmix),
+							     gasname(gasmix),
 							     translate("gettextFromC", divemode_text_ui[dp->divemode]));
 					}
 					put_string(&buf, "<br>");
@@ -308,16 +308,16 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 					if (dp->setpoint) {
 						asprintf_loc(&temp, translate("gettextFromC", "(SP = %.1fbar CCR)"), dp->setpoint / 1000.0);
 						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>",
-							gasname(&newgasmix), temp);
+							gasname(newgasmix), temp);
 						free(temp);
 					} else {
 						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>",
-							gasname(&newgasmix), lastdivemode == UNDEF_COMP_TYPE || lastdivemode == dp->divemode ? "" : translate("gettextFromC", divemode_text_ui[dp->divemode]));
-						if (isascent && (get_he(&lastprintgasmix) > 0)) { // For a trimix gas change on ascent, save ICD info if previous cylinder had helium
-							if (isobaric_counterdiffusion(&lastprintgasmix, &newgasmix, &icdvalues)) // Do icd calulations
+							gasname(newgasmix), lastdivemode == UNDEF_COMP_TYPE || lastdivemode == dp->divemode ? "" : translate("gettextFromC", divemode_text_ui[dp->divemode]));
+						if (isascent && (get_he(lastprintgasmix) > 0)) { // For a trimix gas change on ascent, save ICD info if previous cylinder had helium
+							if (isobaric_counterdiffusion(lastprintgasmix, newgasmix, &icdvalues)) // Do icd calulations
 								icdwarning = true;
 							if (icdvalues.dN2 > 0) { // If the gas change involved helium as well as an increase in nitrogen..
-								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &newgasmix); // .. then print calculations to buffer.
+								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), lastprintgasmix, newgasmix); // .. then print calculations to buffer.
 								icdtableheader = false;
 							}
 						}
@@ -330,16 +330,16 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 					// If a new gas has been used for this segment, now is the time to show it
 					if (dp->setpoint) {
 						asprintf_loc(&temp, translate("gettextFromC", "(SP = %.1fbar CCR)"), (double) dp->setpoint / 1000.0);
-						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>", gasname(&gasmix), temp);
+						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>", gasname(gasmix), temp);
 						free(temp);
 					} else {
-						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>", gasname(&gasmix),
+						put_format(&buf, "<td style='padding-left: 10px; color: red; float: left;'><b>%s %s</b></td>", gasname(gasmix),
 							   lastdivemode == UNDEF_COMP_TYPE || lastdivemode == dp->divemode ? "" : translate("gettextFromC", divemode_text_ui[dp->divemode]));
-						if (get_he(&lastprintgasmix) > 0) {  // For a trimix gas change, save ICD info if previous cylinder had helium
-							if (isobaric_counterdiffusion(&lastprintgasmix, &gasmix, &icdvalues))  // Do icd calculations
+						if (get_he(lastprintgasmix) > 0) {  // For a trimix gas change, save ICD info if previous cylinder had helium
+							if (isobaric_counterdiffusion(lastprintgasmix, gasmix, &icdvalues))  // Do icd calculations
 								icdwarning = true;
 							if (icdvalues.dN2 > 0) { // If the gas change involved helium as well as an increase in nitrogen..
-								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, lasttime, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &gasmix); // .. then print data to buffer.
+								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, lasttime, depth_to_mbar(dp->depth.mm, dive), lastprintgasmix, gasmix); // .. then print data to buffer.
 								icdtableheader = false;
 							}
 						}
@@ -362,14 +362,14 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 			if (plan_verbatim) {
 				if (lastsetpoint >= 0) {
 					if (nextdp && nextdp->setpoint) {
-						put_format_loc(&buf, translate("gettextFromC", "Switch gas to %s (SP = %.1fbar)"), gasname(&newgasmix), (double) nextdp->setpoint / 1000.0);
+						put_format_loc(&buf, translate("gettextFromC", "Switch gas to %s (SP = %.1fbar)"), gasname(newgasmix), (double) nextdp->setpoint / 1000.0);
 					} else {
-						put_format(&buf, translate("gettextFromC", "Switch gas to %s"), gasname(&newgasmix));
-						if ((isascent) && (get_he(&lastprintgasmix) > 0)) {          // For a trimix gas change on ascent:
-							if (isobaric_counterdiffusion(&lastprintgasmix, &newgasmix, &icdvalues)) // Do icd calculations
+						put_format(&buf, translate("gettextFromC", "Switch gas to %s"), gasname(newgasmix));
+						if ((isascent) && (get_he(lastprintgasmix) > 0)) {          // For a trimix gas change on ascent:
+							if (isobaric_counterdiffusion(lastprintgasmix, newgasmix, &icdvalues)) // Do icd calculations
 								icdwarning = true;
 							if (icdvalues.dN2 > 0) { // If the gas change involved helium as well as an increase in nitrogen..
-								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), &lastprintgasmix, &newgasmix); // ... then print data to buffer.
+								add_icd_entry(&icdbuf, &icdvalues, icdtableheader, dp->time, depth_to_mbar(dp->depth.mm, dive), lastprintgasmix, newgasmix); // ... then print data to buffer.
 								icdtableheader = false;
 							}
 						}
@@ -451,8 +451,8 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		volume = get_volume_units(cyl->gas_used.mliter, NULL, &unit);
 		deco_volume = get_volume_units(cyl->deco_gas_used.mliter, NULL, &unit);
 		if (cyl->type.size.mliter) {
-			int remaining_gas = lrint((double)cyl->end.mbar * cyl->type.size.mliter / 1000.0 / gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0));
-			double deco_pressure_mbar = isothermal_pressure(&cyl->gasmix, 1.0, remaining_gas + cyl->deco_gas_used.mliter,
+			int remaining_gas = lrint((double)cyl->end.mbar * cyl->type.size.mliter / 1000.0 / gas_compressibility_factor(cyl->gasmix, cyl->end.mbar / 1000.0));
+			double deco_pressure_mbar = isothermal_pressure(cyl->gasmix, 1.0, remaining_gas + cyl->deco_gas_used.mliter,
 				cyl->type.size.mliter) * 1000 - cyl->end.mbar;
 			deco_pressure = get_pressure_units(lrint(deco_pressure_mbar), &pressure_unit);
 			pressure = get_pressure_units(cyl->start.mbar - cyl->end.mbar, &pressure_unit);
@@ -464,7 +464,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 					translate("gettextFromC", "Warning:"),
 					translate("gettextFromC", "this is more gas than available in the specified cylinder!"));
 			else
-				if (cyl->end.mbar / 1000.0 * cyl->type.size.mliter / gas_compressibility_factor(&cyl->gasmix, cyl->end.mbar / 1000.0)
+				if (cyl->end.mbar / 1000.0 * cyl->type.size.mliter / gas_compressibility_factor(cyl->gasmix, cyl->end.mbar / 1000.0)
 				    < cyl->deco_gas_used.mliter)
 					snprintf(warning, sizeof(warning), "<br>&nbsp;&mdash; <span style='color: red;'>%s </span> %s",
 						translate("gettextFromC", "Warning:"),
@@ -481,7 +481,7 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 						* depth_to_bar(lastbottomdp->depth.mm, dive)
 						+ prefs.sacfactor / 100.0 * cyl->deco_gas_used.mliter);
 					/* Calculate minimum gas pressure for cyclinder. */
-					lastbottomdp->minimum_gas.mbar = lrint(isothermal_pressure(&cyl->gasmix, 1.0,
+					lastbottomdp->minimum_gas.mbar = lrint(isothermal_pressure(cyl->gasmix, 1.0,
 						mingasv.mliter, cyl->type.size.mliter) * 1000);
 					/* Translate all results into correct units */
 					mingas_volume = get_volume_units(mingasv.mliter, NULL, &unit);
@@ -513,18 +513,18 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 			/* Print the gas consumption for every cylinder here to temp buffer. */
 			if (lrint(volume) > 0) {
 				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s/%.0f%s in planned ascent)"),
-					     volume, unit, pressure, pressure_unit, gasname(&cyl->gasmix), deco_volume, unit, deco_pressure, pressure_unit);
+					     volume, unit, pressure, pressure_unit, gasname(cyl->gasmix), deco_volume, unit, deco_pressure, pressure_unit);
 			} else {
 				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s/%.0f%s of <span style='color: red;'><b>%s</b></span>"),
-					     volume, unit, pressure, pressure_unit, gasname(&cyl->gasmix));
+					     volume, unit, pressure, pressure_unit, gasname(cyl->gasmix));
 			}
 		} else {
 			if (lrint(volume) > 0) {
 				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s of <span style='color: red;'><b>%s</b></span> (%.0f%s during planned ascent)"),
-					     volume, unit, gasname(&cyl->gasmix), deco_volume, unit);
+					     volume, unit, gasname(cyl->gasmix), deco_volume, unit);
 			} else {
 				asprintf_loc(&temp, translate("gettextFromC", "%.0f%s of <span style='color: red;'><b>%s</b></span>"),
-					     volume, unit, gasname(&cyl->gasmix));
+					     volume, unit, gasname(cyl->gasmix));
 			}
 		}
 		/* Gas consumption: Now finally print all strings to output */
@@ -558,11 +558,11 @@ void add_plan_to_notes(struct diveplan *diveplan, struct dive *dive, bool show_d
 		while (dp) {
 			if (dp->time != 0) {
 				struct gas_pressures pressures;
-				struct gasmix *gasmix = &dive->cylinder[dp->cylinderid].gasmix;
+				struct gasmix gasmix = dive->cylinder[dp->cylinderid].gasmix;
 
 				current_divemode = get_current_divemode(&dive->dc, dp->time, &evd, &current_divemode);
 				amb = depth_to_atm(dp->depth.mm, dive);
-				fill_pressures(&pressures, amb, gasmix, (current_divemode == OC) ? 0.0 : amb * gasmix->o2.permille / 1000.0, current_divemode);
+				fill_pressures(&pressures, amb, gasmix, (current_divemode == OC) ? 0.0 : amb * gasmix.o2.permille / 1000.0, current_divemode);
 
 				if (pressures.o2 > (dp->entered ? prefs.bottompo2 : prefs.decopo2) / 1000.0) {
 					const char *depth_unit;
diff --git a/core/profile.c b/core/profile.c
index 56cc85aac..cfda49163 100644
--- a/core/profile.c
+++ b/core/profile.c
@@ -333,7 +333,7 @@ int get_cylinder_index(struct dive *dive, struct event *ev)
 	fprintf(stderr, "Still looking up cylinder based on gas mix in get_cylinder_index()!\n");
 
 	mix = get_gasmix_from_event(dive, ev);
-	best = find_best_gasmix_match(&mix, dive->cylinder, 0);
+	best = find_best_gasmix_match(mix, dive->cylinder, 0);
 	return best < 0 ? 0 : best;
 }
 
@@ -760,14 +760,14 @@ static void fill_sac(struct dive *dive, struct plot_info *pi, int idx, unsigned
 /*
  * Create a bitmap of cylinders that match our current gasmix
  */
-static unsigned int matching_gases(struct dive *dive, struct gasmix *gasmix)
+static unsigned int matching_gases(struct dive *dive, struct gasmix gasmix)
 {
 	int i;
 	unsigned int gases = 0;
 
 	for (i = 0; i < MAX_CYLINDERS; i++) {
 		cylinder_t *cyl = dive->cylinder + i;
-		if (same_gasmix(gasmix, &cyl->gasmix))
+		if (same_gasmix(gasmix, cyl->gasmix))
 			gases |= 1 << i;
 	}
 	return gases;
@@ -781,10 +781,10 @@ static void calculate_sac(struct dive *dive, struct divecomputer *dc, struct plo
 
 	for (int i = 0; i < pi->nr; i++) {
 		struct plot_data *entry = pi->entry + i;
-		struct gasmix newmix = get_gasmix(dive, dc, entry->sec, &ev, &gasmix);
-		if (!same_gasmix(&newmix, &gasmix)) {
+		struct gasmix newmix = get_gasmix(dive, dc, entry->sec, &ev, gasmix);
+		if (!same_gasmix(newmix, gasmix)) {
 			gasmix = newmix;
-			gases = matching_gases(dive, &newmix);
+			gases = matching_gases(dive, newmix);
 		}
 
 		fill_sac(dive, pi, i, gases);
@@ -907,7 +907,7 @@ static void setup_gas_sensor_pressure(struct dive *dive, struct divecomputer *dc
 
 #ifndef SUBSURFACE_MOBILE
 /* calculate DECO STOP / TTS / NDL */
-static void calculate_ndl_tts(struct deco_state *ds, struct dive *dive, struct plot_data *entry, struct gasmix *gasmix, double surface_pressure,enum divemode_t divemode)
+static void calculate_ndl_tts(struct deco_state *ds, struct dive *dive, struct plot_data *entry, struct gasmix gasmix, double surface_pressure,enum divemode_t divemode)
 {
 	/* FIXME: This should be configurable */
 	/* ascent speed up to first deco stop */
@@ -1026,7 +1026,7 @@ void calculate_deco_information(struct deco_state *ds, struct deco_state *planne
 			int time_stepsize = 20;
 
 			current_divemode = get_current_divemode(dc, entry->sec, &evd, &current_divemode);
-			gasmix = get_gasmix(dive, dc, t1, &ev, &gasmix);
+			gasmix = get_gasmix(dive, dc, t1, &ev, gasmix);
 			entry->ambpressure = depth_to_bar(entry->depth, dive);
 			entry->gfline = get_gf(ds, entry->ambpressure, dive) * (100.0 - AMB_PERCENTAGE) + AMB_PERCENTAGE;
 			if (t0 > t1) {
@@ -1040,7 +1040,7 @@ void calculate_deco_information(struct deco_state *ds, struct deco_state *planne
 			for (j = t0 + time_stepsize; j <= t1; j += time_stepsize) {
 				int depth = interpolate(entry[-1].depth, entry[0].depth, j - t0, t1 - t0);
 				add_segment(ds, depth_to_bar(depth, dive),
-					    &gasmix, time_stepsize, entry->o2pressure.mbar, current_divemode, entry->sac);
+					    gasmix, time_stepsize, entry->o2pressure.mbar, current_divemode, entry->sac);
 				entry->icd_warning = ds->icd_warning;
 				if ((t1 - j < time_stepsize) && (j < t1))
 					time_stepsize = t1 - j;
@@ -1115,7 +1115,7 @@ void calculate_deco_information(struct deco_state *ds, struct deco_state *planne
 				/* We are going to mess up deco state, so store it for later restore */
 				struct deco_state *cache_data = NULL;
 				cache_deco_state(ds, &cache_data);
-				calculate_ndl_tts(ds, dive, entry, &gasmix, surface_pressure, current_divemode);
+				calculate_ndl_tts(ds, dive, entry, gasmix, surface_pressure, current_divemode);
 				if (decoMode() == VPMB && !in_planner() && i == pi->nr - 1)
 					final_tts = entry->tts_calc;
 				/* Restore "real" deco state for next real time step */
@@ -1213,15 +1213,15 @@ static void calculate_gas_information_new(struct dive *dive, struct divecomputer
 		int fn2, fhe;
 		struct plot_data *entry = pi->entry + i;
 
-		gasmix = get_gasmix(dive, dc, entry->sec, &evg, &gasmix);
+		gasmix = get_gasmix(dive, dc, entry->sec, &evg, gasmix);
 		amb_pressure = depth_to_bar(entry->depth, dive);
 		current_divemode = get_current_divemode(dc, entry->sec, &evd, &current_divemode);
-		fill_pressures(&entry->pressures, amb_pressure, &gasmix, (current_divemode == OC) ? 0.0 : entry->o2pressure.mbar / 1000.0, current_divemode);
+		fill_pressures(&entry->pressures, amb_pressure, gasmix, (current_divemode == OC) ? 0.0 : entry->o2pressure.mbar / 1000.0, current_divemode);
 		fn2 = (int)(1000.0 * entry->pressures.n2 / amb_pressure);
 		fhe = (int)(1000.0 * entry->pressures.he / amb_pressure);
 		if (dc->divemode == PSCR) { // OC pO2 is calulated for PSCR with or without external PO2 monitoring.
-			struct gasmix gasmix2 = get_gasmix(dive, dc, entry->sec, &evg, &gasmix);
-			entry->scr_OC_pO2.mbar = (int) depth_to_mbar(entry->depth, dive) * get_o2(&gasmix2) / 1000;
+			struct gasmix gasmix2 = get_gasmix(dive, dc, entry->sec, &evg, gasmix);
+			entry->scr_OC_pO2.mbar = (int) depth_to_mbar(entry->depth, dive) * get_o2(gasmix2) / 1000;
 		}
 
 		/* Calculate MOD, EAD, END and EADD based on partial pressures calculated before
@@ -1229,7 +1229,7 @@ static void calculate_gas_information_new(struct dive *dive, struct divecomputer
 		 * END takes O₂ + N₂ (air) into account ("Narcotic" for trimix dives)
 		 * EAD just uses N₂ ("Air" for nitrox dives) */
 		pressure_t modpO2 = { .mbar = (int)(prefs.modpO2 * 1000) };
-		entry->mod = (double)gas_mod(&gasmix, modpO2, dive, 1).mm;
+		entry->mod = (double)gas_mod(gasmix, modpO2, dive, 1).mm;
 		entry->end = (entry->depth + 10000) * (1000 - fhe) / 1000.0 - 10000;
 		entry->ead = (entry->depth + 10000) * fn2 / (double)N2_IN_AIR - 10000;
 		entry->eadd = (entry->depth + 10000) *
@@ -1237,7 +1237,7 @@ static void calculate_gas_information_new(struct dive *dive, struct divecomputer
 				       entry->pressures.n2 / amb_pressure * N2_DENSITY +
 				       entry->pressures.he / amb_pressure * HE_DENSITY) /
 				      (O2_IN_AIR * O2_DENSITY + N2_IN_AIR * N2_DENSITY) * 1000 - 10000;
-		entry->density = gas_density(&gasmix, depth_to_mbar(entry->depth, dive));
+		entry->density = gas_density(gasmix, depth_to_mbar(entry->depth, dive));
 		if (entry->mod < 0)
 			entry->mod = 0;
 		if (entry->ead < 0)
@@ -1387,11 +1387,10 @@ static void plot_string(struct plot_info *pi, struct plot_data *entry, struct me
 	depthvalue = get_depth_units(entry->depth, NULL, &depth_unit);
 	put_format_loc(b, translate("gettextFromC", "@: %d:%02d\nD: %.1f%s\n"), FRACTION(entry->sec, 60), depthvalue, depth_unit);
 	for (cyl = 0; cyl < MAX_CYLINDERS; cyl++) {
-		struct gasmix *mix;
 		int mbar = GET_PRESSURE(entry, cyl);
 		if (!mbar)
 			continue;
-		mix = &displayed_dive.cylinder[cyl].gasmix;
+		struct gasmix mix = displayed_dive.cylinder[cyl].gasmix;
 		pressurevalue = get_pressure_units(mbar, &pressure_unit);
 		put_format_loc(b, translate("gettextFromC", "P: %d%s (%s)\n"), pressurevalue, pressure_unit, gasname(mix));
 	}
diff --git a/core/qthelper.cpp b/core/qthelper.cpp
index fd9a8212b..bddd5ed33 100644
--- a/core/qthelper.cpp
+++ b/core/qthelper.cpp
@@ -400,7 +400,7 @@ void selectedDivesGasUsed(QVector<QPair<QString, int> > &gasUsedOrdered)
 		get_gas_used(d, diveGases);
 		for (j = 0; j < MAX_CYLINDERS; j++)
 			if (diveGases[j].mliter) {
-				QString gasName = gasname(&d->cylinder[j].gasmix);
+				QString gasName = gasname(d->cylinder[j].gasmix);
 				gasUsed[gasName] += diveGases[j].mliter;
 			}
 	}
@@ -1228,8 +1228,8 @@ extern "C" char *picturedir_string()
 
 QString get_gas_string(struct gasmix gas)
 {
-	uint o2 = (get_o2(&gas) + 5) / 10, he = (get_he(&gas) + 5) / 10;
-	QString result = gasmix_is_air(&gas) ? gettextFromC::tr("AIR") : he == 0 ? (o2 == 100 ? gettextFromC::tr("OXYGEN") : QString("EAN%1").arg(o2, 2, 10, QChar('0'))) : QString("%1/%2").arg(o2).arg(he);
+	uint o2 = (get_o2(gas) + 5) / 10, he = (get_he(gas) + 5) / 10;
+	QString result = gasmix_is_air(gas) ? gettextFromC::tr("AIR") : he == 0 ? (o2 == 100 ? gettextFromC::tr("OXYGEN") : QString("EAN%1").arg(o2, 2, 10, QChar('0'))) : QString("%1/%2").arg(o2).arg(he);
 	return result;
 }
 
diff --git a/core/save-git.c b/core/save-git.c
index 7717a4b5f..2824b22ca 100644
--- a/core/save-git.c
+++ b/core/save-git.c
@@ -126,10 +126,10 @@ static void save_extra_data(struct membuffer *b, struct extra_data *ed)
 	}
 }
 
-static void put_gasmix(struct membuffer *b, struct gasmix *mix)
+static void put_gasmix(struct membuffer *b, struct gasmix mix)
 {
-	int o2 = mix->o2.permille;
-	int he = mix->he.permille;
+	int o2 = mix.o2.permille;
+	int he = mix.he.permille;
 
 	if (o2) {
 		put_format(b, " o2=%u.%u%%", FRACTION(o2, 10));
@@ -154,7 +154,7 @@ static void save_cylinder_info(struct membuffer *b, struct dive *dive)
 		put_pressure(b, cylinder->type.workingpressure, " workpressure=", "bar");
 		show_utf8(b, " description=", description, "");
 		strip_mb(b);
-		put_gasmix(b, &cylinder->gasmix);
+		put_gasmix(b, cylinder->gasmix);
 		put_pressure(b, cylinder->start, " start=", "bar");
 		put_pressure(b, cylinder->end, " end=", "bar");
 		if (cylinder->cylinder_use != OC_GAS)
@@ -385,7 +385,7 @@ static void save_one_event(struct membuffer *b, struct dive *dive, struct event
 		struct gasmix mix = get_gasmix_from_event(dive, ev);
 		if (ev->gas.index >= 0)
 			show_integer(b, ev->gas.index, "cylinder=", "");
-		put_gasmix(b, &mix);
+		put_gasmix(b, mix);
 	}
 	put_string(b, "\n");
 }
diff --git a/core/save-xml.c b/core/save-xml.c
index 7e2328e5c..fea2b1430 100644
--- a/core/save-xml.c
+++ b/core/save-xml.c
@@ -127,10 +127,10 @@ static void save_overview(struct membuffer *b, struct dive *dive)
 	show_utf8(b, dive->suit, "  <suit>", "</suit>\n", 0);
 }
 
-static void put_gasmix(struct membuffer *b, struct gasmix *mix)
+static void put_gasmix(struct membuffer *b, struct gasmix mix)
 {
-	int o2 = mix->o2.permille;
-	int he = mix->he.permille;
+	int o2 = mix.o2.permille;
+	int he = mix.he.permille;
 
 	if (o2) {
 		put_format(b, " o2='%u.%u%%'", FRACTION(o2, 10));
@@ -155,7 +155,7 @@ static void save_cylinder_info(struct membuffer *b, struct dive *dive)
 			put_milli(b, " size='", volume, " l'");
 		put_pressure(b, cylinder->type.workingpressure, " workpressure='", " bar'");
 		show_utf8(b, description, " description='", "'", 1);
-		put_gasmix(b, &cylinder->gasmix);
+		put_gasmix(b, cylinder->gasmix);
 		put_pressure(b, cylinder->start, " start='", " bar'");
 		put_pressure(b, cylinder->end, " end='", " bar'");
 		if (cylinder->cylinder_use != OC_GAS)
@@ -310,7 +310,7 @@ static void save_one_event(struct membuffer *b, struct dive *dive, struct event
 		struct gasmix mix = get_gasmix_from_event(dive, ev);
 		if (ev->gas.index >= 0)
 			show_integer(b, ev->gas.index, "cylinder='", "'");
-		put_gasmix(b, &mix);
+		put_gasmix(b, mix);
 	}
 	put_format(b, " />\n");
 }
diff --git a/core/statistics.c b/core/statistics.c
index 58d851611..bb32095cc 100644
--- a/core/statistics.c
+++ b/core/statistics.c
@@ -309,14 +309,14 @@ static void get_gas_parts(struct gasmix mix, volume_t vol, int o2_in_topup, volu
 {
 	volume_t air = {};
 
-	if (gasmix_is_air(&mix)) {
+	if (gasmix_is_air(mix)) {
 		o2->mliter = 0;
 		he->mliter = 0;
 		return;
 	}
 
-	air.mliter = lrint(((double)vol.mliter * (1000 - get_he(&mix) - get_o2(&mix))) / (1000 - o2_in_topup));
-	he->mliter = lrint(((double)vol.mliter * get_he(&mix)) / 1000.0);
+	air.mliter = lrint(((double)vol.mliter * (1000 - get_he(mix) - get_o2(mix))) / (1000 - o2_in_topup));
+	he->mliter = lrint(((double)vol.mliter * get_he(mix)) / 1000.0);
 	o2->mliter += vol.mliter - he->mliter - air.mliter;
 }
 
diff --git a/core/subsurface-qt/DiveObjectHelper.cpp b/core/subsurface-qt/DiveObjectHelper.cpp
index 15291554d..a69c73ddc 100644
--- a/core/subsurface-qt/DiveObjectHelper.cpp
+++ b/core/subsurface-qt/DiveObjectHelper.cpp
@@ -207,7 +207,7 @@ QString DiveObjectHelper::gas() const
 		gas = m_dive->cylinder[i].type.description;
 		if (!gas.isEmpty())
 			gas += QChar(' ');
-		gas += gasname(&m_dive->cylinder[i].gasmix);
+		gas += gasname(m_dive->cylinder[i].gasmix);
 		// if has a description and if such gas is not already present
 		if (!gas.isEmpty() && gases.indexOf(gas) == -1) {
 			if (!gases.isEmpty())
diff --git a/desktop-widgets/divelogexportdialog.cpp b/desktop-widgets/divelogexportdialog.cpp
index bf01b0e9f..93341dd20 100644
--- a/desktop-widgets/divelogexportdialog.cpp
+++ b/desktop-widgets/divelogexportdialog.cpp
@@ -351,10 +351,10 @@ void DiveLogExportDialog::export_TeX(const char *filename, const bool selected_o
 
 			if (is_cylinder_used(dive, i) || (prefs.display_unused_tanks && dive->cylinder[i].type.description)){
 				put_format(&buf, "\\def\\cyl%cdescription{%s}\n", 'a' + i, dive->cylinder[i].type.description);
-				put_format(&buf, "\\def\\cyl%cgasname{%s}\n", 'a' + i, gasname(&dive->cylinder[i].gasmix));
-				put_format(&buf, "\\def\\cyl%cmixO2{%.1f\\%%}\n", 'a' + i, get_o2(&dive->cylinder[i].gasmix)/10.0);
-				put_format(&buf, "\\def\\cyl%cmixHe{%.1f\\%%}\n", 'a' + i, get_he(&dive->cylinder[i].gasmix)/10.0);
-				put_format(&buf, "\\def\\cyl%cmixN2{%.1f\\%%}\n", 'a' + i, (100.0 - (get_o2(&dive->cylinder[i].gasmix)/10.0) - (get_he(&dive->cylinder[i].gasmix)/10.0)));
+				put_format(&buf, "\\def\\cyl%cgasname{%s}\n", 'a' + i, gasname(dive->cylinder[i].gasmix));
+				put_format(&buf, "\\def\\cyl%cmixO2{%.1f\\%%}\n", 'a' + i, get_o2(dive->cylinder[i].gasmix)/10.0);
+				put_format(&buf, "\\def\\cyl%cmixHe{%.1f\\%%}\n", 'a' + i, get_he(dive->cylinder[i].gasmix)/10.0);
+				put_format(&buf, "\\def\\cyl%cmixN2{%.1f\\%%}\n", 'a' + i, (100.0 - (get_o2(dive->cylinder[i].gasmix)/10.0) - (get_he(dive->cylinder[i].gasmix)/10.0)));
 				delta_p.mbar += dive->cylinder[i].start.mbar - dive->cylinder[i].end.mbar;
 				put_format(&buf, "\\def\\cyl%cstartpress{%.1f\\pressureunit}\n", 'a' + i, get_pressure_units(dive->cylinder[i].start.mbar, &unit)/1.0);
 				put_format(&buf, "\\def\\cyl%cendpress{%.1f\\pressureunit}\n", 'a' + i, get_pressure_units(dive->cylinder[i].end.mbar, &unit)/1.0);
diff --git a/desktop-widgets/tab-widgets/TabDiveInformation.cpp b/desktop-widgets/tab-widgets/TabDiveInformation.cpp
index 09f180cb1..a4f8f455f 100644
--- a/desktop-widgets/tab-widgets/TabDiveInformation.cpp
+++ b/desktop-widgets/tab-widgets/TabDiveInformation.cpp
@@ -62,7 +62,7 @@ void TabDiveInformation::updateData()
 		gaslist.append(separator); volumes.append(separator); SACs.append(separator);
 		separator = "\n";
 
-		gaslist.append(gasname(&displayed_dive.cylinder[i].gasmix));
+		gaslist.append(gasname(displayed_dive.cylinder[i].gasmix));
 		if (!gases[i].mliter)
 			continue;
 		volumes.append(get_volume_string(gases[i], true));
diff --git a/profile-widget/diveeventitem.cpp b/profile-widget/diveeventitem.cpp
index 875954b37..64de02436 100644
--- a/profile-widget/diveeventitem.cpp
+++ b/profile-widget/diveeventitem.cpp
@@ -51,7 +51,7 @@ struct event *DiveEventItem::getEvent()
 	return internalEvent;
 }
 
-void DiveEventItem::setEvent(struct event *ev, struct gasmix *lastgasmix)
+void DiveEventItem::setEvent(struct event *ev, struct gasmix lastgasmix)
 {
 	if (!ev)
 		return;
@@ -63,7 +63,7 @@ void DiveEventItem::setEvent(struct event *ev, struct gasmix *lastgasmix)
 	recalculatePos(true);
 }
 
-void DiveEventItem::setupPixmap(struct gasmix *lastgasmix)
+void DiveEventItem::setupPixmap(struct gasmix lastgasmix)
 {
 	const IconMetrics& metrics = defaultIconMetrics();
 #ifndef SUBSURFACE_MOBILE
@@ -94,13 +94,13 @@ void DiveEventItem::setupPixmap(struct gasmix *lastgasmix)
 	} else if (event_is_gaschange(internalEvent)) {
 		struct gasmix mix = get_gasmix_from_event(&displayed_dive, internalEvent);
 		struct icd_data icd_data;
-		bool icd = isobaric_counterdiffusion(lastgasmix, &mix, &icd_data);
+		bool icd = isobaric_counterdiffusion(lastgasmix, mix, &icd_data);
 		if (mix.he.permille) {
 			if (icd)
 				setPixmap(EVENT_PIXMAP_BIGGER(":gaschange-trimix-ICD-icon"));
 			else
 				setPixmap(EVENT_PIXMAP_BIGGER(":gaschange-trimix-icon"));
-		} else if (gasmix_is_air(&mix)) {
+		} else if (gasmix_is_air(mix)) {
 			if (icd)
 				setPixmap(EVENT_PIXMAP_BIGGER(":gaschange-air-ICD-icon"));
 			else
@@ -165,7 +165,7 @@ void DiveEventItem::setupPixmap(struct gasmix *lastgasmix)
 #undef EVENT_PIXMAP_BIGGER
 }
 
-void DiveEventItem::setupToolTipString(struct gasmix *lastgasmix)
+void DiveEventItem::setupToolTipString(struct gasmix lastgasmix)
 {
 	// we display the event on screen - so translate
 	QString name = gettextFromC::tr(internalEvent->name);
@@ -177,12 +177,12 @@ void DiveEventItem::setupToolTipString(struct gasmix *lastgasmix)
 		struct gasmix mix = get_gasmix_from_event(&displayed_dive, internalEvent);
 		struct membuffer mb = {};
 		name += ": ";
-		name += gasname(&mix);
+		name += gasname(mix);
 
 		/* Do we have an explicit cylinder index?  Show it. */
 		if (internalEvent->gas.index >= 0)
 			name += tr(" (cyl. %1)").arg(internalEvent->gas.index + 1);
-		bool icd = isobaric_counterdiffusion(lastgasmix, &mix, &icd_data);
+		bool icd = isobaric_counterdiffusion(lastgasmix, mix, &icd_data);
 		if (icd_data.dHe < 0) {
 			put_format(&mb, "\n%s %s:%+.3g%% %s:%+.3g%%%s%+.3g%%",
 				qPrintable(tr("ICD")),
@@ -192,7 +192,7 @@ void DiveEventItem::setupToolTipString(struct gasmix *lastgasmix)
 			name += QString::fromUtf8(mb.buffer, mb.len);
 			free_buffer(&mb);
 		}
-		*lastgasmix = mix;
+		lastgasmix = mix;
 	} else if (same_string(internalEvent->name, "modechange")) {
 		name += QString(": %1").arg(gettextFromC::tr(divemode_text_ui[internalEvent->value]));
 	} else if (value) {
diff --git a/profile-widget/diveeventitem.h b/profile-widget/diveeventitem.h
index a3535f8aa..6547fa716 100644
--- a/profile-widget/diveeventitem.h
+++ b/profile-widget/diveeventitem.h
@@ -13,7 +13,7 @@ class DiveEventItem : public DivePixmapItem {
 public:
 	DiveEventItem(QGraphicsItem *parent = 0);
 	~DiveEventItem();
-	void setEvent(struct event *ev, struct gasmix *lastgasmix);
+	void setEvent(struct event *ev, struct gasmix lastgasmix);
 	struct event *getEvent();
 	void eventVisibilityChanged(const QString &eventName, bool visible);
 	void setVerticalAxis(DiveCartesianAxis *axis);
@@ -25,8 +25,8 @@ slots:
 	void recalculatePos(bool instant = false);
 
 private:
-	void setupToolTipString(struct gasmix *lastgasmix);
-	void setupPixmap(struct gasmix *lastgasmix);
+	void setupToolTipString(struct gasmix lastgasmix);
+	void setupPixmap(struct gasmix lastgasmix);
 	DiveCartesianAxis *vAxis;
 	DiveCartesianAxis *hAxis;
 	DivePlotDataModel *dataModel;
diff --git a/profile-widget/diveprofileitem.cpp b/profile-widget/diveprofileitem.cpp
index 94fb787b1..5a359b3e8 100644
--- a/profile-widget/diveprofileitem.cpp
+++ b/profile-widget/diveprofileitem.cpp
@@ -413,8 +413,8 @@ void DivePercentageItem::paint(QPainter *painter, const QStyleOptionGraphicsItem
 			struct gasmix gasmix = { 0 };
 			struct event *ev = NULL;
 			int sec = dataModel->index(i, DivePlotDataModel::TIME).data().toInt();
-			gasmix = get_gasmix(&displayed_dive, displayed_dc, sec, &ev, &gasmix);
-			int inert = 1000 - get_o2(&gasmix);
+			gasmix = get_gasmix(&displayed_dive, displayed_dc, sec, &ev, gasmix);
+			int inert = 1000 - get_o2(gasmix);
 			mypen.setBrush(QBrush(ColorScale(value, inert)));
 			painter->setPen(mypen);
 			painter->drawLine(poly[i - 1], poly[i]);
diff --git a/profile-widget/profilewidget2.cpp b/profile-widget/profilewidget2.cpp
index 9371047bd..4ea1f36d2 100644
--- a/profile-widget/profilewidget2.cpp
+++ b/profile-widget/profilewidget2.cpp
@@ -781,7 +781,7 @@ void ProfileWidget2::plotDive(struct dive *d, bool force, bool doClearPictures)
 		item->setHorizontalAxis(timeAxis);
 		item->setVerticalAxis(profileYAxis);
 		item->setModel(dataModel);
-		item->setEvent(event, &lastgasmix);
+		item->setEvent(event, lastgasmix);
 		item->setZValue(2);
 		scene()->addItem(item);
 		eventItems.push_back(item);
@@ -1710,7 +1710,7 @@ void ProfileWidget2::changeGas()
 		tank = rx.cap(1).toInt() - 1; // we display the tank 1 based
 	} else {
 		qDebug() << "failed to parse tank number";
-		tank = get_gasidx(&displayed_dive, &gasmix);
+		tank = get_gasidx(&displayed_dive, gasmix);
 	}
 	// add this both to the displayed dive and the current dive
 	add_gas_switch_event(current_dive, current_dc, seconds, tank);
diff --git a/profile-widget/tankitem.cpp b/profile-widget/tankitem.cpp
index d1adae41c..5a8b8ca48 100644
--- a/profile-widget/tankitem.cpp
+++ b/profile-widget/tankitem.cpp
@@ -57,15 +57,15 @@ void TankItem::setData(DivePlotDataModel *model, struct plot_info *plotInfo, str
 	modelDataChanged();
 }
 
-void TankItem::createBar(qreal x, qreal w, struct gasmix *gas)
+void TankItem::createBar(qreal x, qreal w, struct gasmix gas)
 {
 	// pick the right gradient, size, position and text
 	QGraphicsRectItem *rect = new QGraphicsRectItem(x, 0, w, height, this);
 	if (gasmix_is_air(gas))
 		rect->setBrush(air);
-	else if (gas->he.permille)
+	else if (gas.he.permille)
 		rect->setBrush(trimix);
-	else if (gas->o2.permille == 1000)
+	else if (gas.o2.permille == 1000)
 		rect->setBrush(oxygen);
 	else
 		rect->setBrush(nitrox);
@@ -112,14 +112,14 @@ void TankItem::modelDataChanged(const QModelIndex&, const QModelIndex&)
 	while (ev && (int)ev->time.seconds < last_entry->sec) {
 		width = hAxis->posAtValue(ev->time.seconds) - hAxis->posAtValue(startTime);
 		left = hAxis->posAtValue(startTime);
-		createBar(left, width, &gasmix);
+		createBar(left, width, gasmix);
 		startTime = ev->time.seconds;
 		gasmix = get_gasmix_from_event(&displayed_dive, ev);
 		ev = get_next_event(ev->next, "gaschange");
 	}
 	width = hAxis->posAtValue(last_entry->sec) - hAxis->posAtValue(startTime);
 	left = hAxis->posAtValue(startTime);
-	createBar(left, width, &gasmix);
+	createBar(left, width, gasmix);
 }
 
 void TankItem::setHorizontalAxis(DiveCartesianAxis *horizontal)
diff --git a/profile-widget/tankitem.h b/profile-widget/tankitem.h
index 8ccfcb5bb..433b1444f 100644
--- a/profile-widget/tankitem.h
+++ b/profile-widget/tankitem.h
@@ -25,7 +25,7 @@ public slots:
 	void modelDataChanged(const QModelIndex &topLeft = QModelIndex(), const QModelIndex &bottomRight = QModelIndex());
 
 private:
-	void createBar(qreal x, qreal w, struct gasmix *gas);
+	void createBar(qreal x, qreal w, struct gasmix gas);
 	DivePlotDataModel *dataModel;
 	DiveCartesianAxis *hAxis;
 	struct dive diveCylinderStore;
diff --git a/qt-models/cylindermodel.cpp b/qt-models/cylindermodel.cpp
index 9a093112c..11d4595ee 100644
--- a/qt-models/cylindermodel.cpp
+++ b/qt-models/cylindermodel.cpp
@@ -100,7 +100,7 @@ static QVariant gas_volume_tooltip(cylinder_t *cyl, pressure_t p)
 	if (!vol)
 		return QVariant();
 
-	Z = gas_compressibility_factor(&cyl->gasmix, p.mbar / 1000.0);
+	Z = gas_compressibility_factor(cyl->gasmix, p.mbar / 1000.0);
 	return gas_volume_string(vol, "(Z=") + QString("%1)").arg(Z, 0, 'f', 3);
 }
 
@@ -212,14 +212,14 @@ QVariant CylindersModel::data(const QModelIndex &index, int role) const
 			} else {
 				pressure_t modpO2;
 				modpO2.mbar = prefs.bottompo2;
-				ret = get_depth_string(gas_mod(&cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(1,1)), true);
+				ret = get_depth_string(gas_mod(cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(1,1)), true);
 			}
 			break;
 		case MND:
 			if (cyl->bestmix_he)
 				ret = QString("*");
 			else
-				ret = get_depth_string(gas_mnd(&cyl->gasmix, prefs.bestmixend, &displayed_dive, M_OR_FT(1,1)), true);
+				ret = get_depth_string(gas_mnd(cyl->gasmix, prefs.bestmixend, &displayed_dive, M_OR_FT(1,1)), true);
 			break;
 		case USE:
 			ret = gettextFromC::tr(cylinderuse_text[cyl->cylinder_use]);
@@ -353,15 +353,15 @@ bool CylindersModel::setData(const QModelIndex &index, const QVariant &value, in
 		if (CHANGED()) {
 			cyl->gasmix.o2 = string_to_fraction(qPrintable(vString));
 			// fO2 + fHe must not be greater than 1
-			if (get_o2(&cyl->gasmix) + get_he(&cyl->gasmix) > 1000)
-				cyl->gasmix.he.permille = 1000 - get_o2(&cyl->gasmix);
+			if (get_o2(cyl->gasmix) + get_he(cyl->gasmix) > 1000)
+				cyl->gasmix.he.permille = 1000 - get_o2(cyl->gasmix);
 			pressure_t modpO2;
 			if (displayed_dive.dc.divemode == PSCR)
-				modpO2.mbar = prefs.decopo2 + (1000 - get_o2(&cyl->gasmix)) * SURFACE_PRESSURE *
+				modpO2.mbar = prefs.decopo2 + (1000 - get_o2(cyl->gasmix)) * SURFACE_PRESSURE *
 						prefs.o2consumption / prefs.decosac / prefs.pscr_ratio;
 			else
 				modpO2.mbar = prefs.decopo2;
-			cyl->depth = gas_mod(&cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(3, 10));
+			cyl->depth = gas_mod(cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(3, 10));
 			cyl->bestmix_o2 = false;
 			changed = true;
 		}
@@ -370,8 +370,8 @@ bool CylindersModel::setData(const QModelIndex &index, const QVariant &value, in
 		if (CHANGED()) {
 			cyl->gasmix.he = string_to_fraction(qPrintable(vString));
 			// fO2 + fHe must not be greater than 1
-			if (get_o2(&cyl->gasmix) + get_he(&cyl->gasmix) > 1000)
-				cyl->gasmix.o2.permille = 1000 - get_he(&cyl->gasmix);
+			if (get_o2(cyl->gasmix) + get_he(cyl->gasmix) > 1000)
+				cyl->gasmix.o2.permille = 1000 - get_he(cyl->gasmix);
 			cyl->bestmix_he = false;
 			changed = true;
 		}
@@ -395,7 +395,7 @@ bool CylindersModel::setData(const QModelIndex &index, const QVariant &value, in
 			}
 			pressure_t modpO2;
 			modpO2.mbar = prefs.decopo2;
-			cyl->depth = gas_mod(&cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(3, 10));
+			cyl->depth = gas_mod(cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(3, 10));
 			changed = true;
 		}
 		break;
@@ -588,8 +588,8 @@ void CylindersModel::updateDecoDepths(pressure_t olddecopo2)
 		cylinder_t *cyl = &displayed_dive.cylinder[i];
 		/* If the gas's deco MOD matches the old pO2, it will have been automatically calculated and should be updated.
 		 * If they don't match, we should leave the user entered depth as it is */
-		if (cyl->depth.mm == gas_mod(&cyl->gasmix, olddecopo2, &displayed_dive, M_OR_FT(3, 10)).mm) {
-			cyl->depth = gas_mod(&cyl->gasmix, decopo2, &displayed_dive, M_OR_FT(3, 10));
+		if (cyl->depth.mm == gas_mod(cyl->gasmix, olddecopo2, &displayed_dive, M_OR_FT(3, 10)).mm) {
+			cyl->depth = gas_mod(cyl->gasmix, decopo2, &displayed_dive, M_OR_FT(3, 10));
 		}
 	}
 	emit dataChanged(createIndex(0, 0), createIndex(MAX_CYLINDERS - 1, COLUMNS - 1));
@@ -609,18 +609,18 @@ bool CylindersModel::updateBestMixes()
 		if (cyl->bestmix_o2) {
 			cyl->gasmix.o2 = best_o2(displayed_dive.maxdepth, &displayed_dive);
 			// fO2 + fHe must not be greater than 1
-			if (get_o2(&cyl->gasmix) + get_he(&cyl->gasmix) > 1000)
-				cyl->gasmix.he.permille = 1000 - get_o2(&cyl->gasmix);
+			if (get_o2(cyl->gasmix) + get_he(cyl->gasmix) > 1000)
+				cyl->gasmix.he.permille = 1000 - get_o2(cyl->gasmix);
 			pressure_t modpO2;
 			modpO2.mbar = prefs.decopo2;
-			cyl->depth = gas_mod(&cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(3, 10));
+			cyl->depth = gas_mod(cyl->gasmix, modpO2, &displayed_dive, M_OR_FT(3, 10));
 			gasUpdated = true;
 		}
 		if (cyl->bestmix_he) {
 			cyl->gasmix.he = best_he(displayed_dive.maxdepth, &displayed_dive);
 			// fO2 + fHe must not be greater than 1
-			if (get_o2(&cyl->gasmix) + get_he(&cyl->gasmix) > 1000)
-				cyl->gasmix.o2.permille = 1000 - get_he(&cyl->gasmix);
+			if (get_o2(cyl->gasmix) + get_he(cyl->gasmix) > 1000)
+				cyl->gasmix.o2.permille = 1000 - get_he(cyl->gasmix);
 			gasUpdated = true;
 		}
 	}
diff --git a/smtk-import/smartrak.c b/smtk-import/smartrak.c
index 826ad6a9d..acc43e4f0 100644
--- a/smtk-import/smartrak.c
+++ b/smtk-import/smartrak.c
@@ -506,16 +506,16 @@ static void merge_cylinder_type(cylinder_type_t *src, cylinder_type_t *dst)
 	}
 }
 
-static void merge_cylinder_mix(struct gasmix *src, struct gasmix *dst)
+static void merge_cylinder_mix(struct gasmix src, struct gasmix *dst)
 {
 	if (!dst->o2.permille)
-		*dst = *src;
+		*dst = src;
 }
 
 static void merge_cylinder_info(cylinder_t *src, cylinder_t *dst)
 {
 	merge_cylinder_type(&src->type, &dst->type);
-	merge_cylinder_mix(&src->gasmix, &dst->gasmix);
+	merge_cylinder_mix(src->gasmix, &dst->gasmix);
 	MERGE_MAX(dst, dst, src, start.mbar);
 	MERGE_MIN(dst, dst, src, end.mbar);
 	if (!dst->cylinder_use)
diff --git a/tests/testplan.cpp b/tests/testplan.cpp
index d7413f31f..dd62aa777 100644
--- a/tests/testplan.cpp
+++ b/tests/testplan.cpp
@@ -58,8 +58,8 @@ void setupPlan(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(79, 260) * 60 / M_OR_FT(23, 75);
-	plan_add_segment(dp, 0, gas_mod(&ean36, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean36, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(79, 260), 0, 0, 1, OC);
 	plan_add_segment(dp, 30 * 60 - droptime, M_OR_FT(79, 260), 0, 0, 1, OC);
 }
@@ -86,8 +86,8 @@ void setupPlanVpmb45m30mTx(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(45, 150) * 60 / M_OR_FT(23, 75);
-	plan_add_segment(dp, 0, gas_mod(&ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(45, 150), 0, 0, 1, OC);
 	plan_add_segment(dp, 30 * 60 - droptime, M_OR_FT(45, 150), 0, 0, 1, OC);
 }
@@ -114,8 +114,8 @@ void setupPlanVpmb60m10mTx(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(60, 200) * 60 / M_OR_FT(23, 75);
-	plan_add_segment(dp, 0, gas_mod(&tx50_15, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(tx50_15, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(60, 200), 0, 0, 1, OC);
 	plan_add_segment(dp, 10 * 60 - droptime, M_OR_FT(60, 200), 0, 0, 1, OC);
 }
@@ -159,7 +159,7 @@ void setupPlanVpmb60m30minEan50(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(60, 200) * 60 / M_OR_FT(99, 330);
-	plan_add_segment(dp, 0, gas_mod(&ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(60, 200), 0, 0, 1, OC);
 	plan_add_segment(dp, 30 * 60 - droptime, M_OR_FT(60, 200), 0, 0, 1, OC);
 }
@@ -183,7 +183,7 @@ void setupPlanVpmb60m30minTx(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(60, 200) * 60 / M_OR_FT(99, 330);
-	plan_add_segment(dp, 0, gas_mod(&ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(60, 200), 0, 0, 1, OC);
 	plan_add_segment(dp, 30 * 60 - droptime, M_OR_FT(60, 200), 0, 0, 1, OC);
 }
@@ -231,8 +231,8 @@ void setupPlanVpmb100m60min(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(100, 330) * 60 / M_OR_FT(99, 330);
-	plan_add_segment(dp, 0, gas_mod(&ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(100, 330), 0, 0, 1, OC);
 	plan_add_segment(dp, 60 * 60 - droptime, M_OR_FT(100, 330), 0, 0, 1, OC);
 }
@@ -258,8 +258,8 @@ void setupPlanVpmb100m10min(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(100, 330) * 60 / M_OR_FT(99, 330);
-	plan_add_segment(dp, 0, gas_mod(&ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(100, 330), 0, 0, 1, OC);
 	plan_add_segment(dp, 10 * 60 - droptime, M_OR_FT(100, 330), 0, 0, 1, OC);
 }
@@ -307,9 +307,9 @@ void setupPlanVpmb100mTo70m30min(struct diveplan *dp)
 	free_dps(dp);
 
 	int droptime = M_OR_FT(100, 330) * 60 / M_OR_FT(18, 60);
-	plan_add_segment(dp, 0, gas_mod(&tx21_35, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
-	plan_add_segment(dp, 0, gas_mod(&oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 3, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(tx21_35, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 1, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(ean50, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 2, 0, 1, OC);
+	plan_add_segment(dp, 0, gas_mod(oxygen, po2, &displayed_dive, M_OR_FT(3, 10)).mm, 3, 0, 1, OC);
 	plan_add_segment(dp, droptime, M_OR_FT(100, 330), 0, 0, 1, OC);
 	plan_add_segment(dp, 20 * 60 - droptime, M_OR_FT(100, 330), 0, 0, 1, OC);
 	plan_add_segment(dp, 3 * 60, M_OR_FT(70, 230), 0, 0, 1, OC);