diff --git a/core/deco.cpp b/core/deco.cpp
index 7cb550f12..c203ea934 100644
--- a/core/deco.cpp
+++ b/core/deco.cpp
@@ -13,8 +13,6 @@
  * set_gf()		- set Buehlmann gradient factors
  * set_vpmb_conservatism() - set VPM-B conservatism value
  * clear_deco()
- * cache_deco_state()
- * restore_deco_state()
  * dump_tissues()
  */
 #include <stdlib.h>
@@ -522,19 +520,17 @@ extern "C" void clear_deco(struct deco_state *ds, double surface_pressure, bool
 	ds->ci_pointing_to_guiding_tissue = -1;
 }
 
-extern "C" void cache_deco_state(struct deco_state *src, struct deco_state **cached_datap)
+void deco_state_cache::cache(const struct deco_state *src)
 {
-	struct deco_state *data = *cached_datap;
-
-	if (!data) {
-		data = (deco_state *)malloc(sizeof(struct deco_state));
-		*cached_datap = data;
-	}
+	if (!data)
+		data = std::make_unique<deco_state>();
 	*data = *src;
 }
 
-extern "C" void restore_deco_state(struct deco_state *data, struct deco_state *target, bool keep_vpmb_state)
+void deco_state_cache::restore(struct deco_state *target, bool keep_vpmb_state) const
 {
+	if (!data)
+		return;
 	if (keep_vpmb_state) {
 		int ci;
 		for (ci = 0; ci < 16; ci++) {
@@ -547,7 +543,6 @@ extern "C" void restore_deco_state(struct deco_state *data, struct deco_state *t
 		data->max_bottom_ceiling_pressure = target->max_bottom_ceiling_pressure;
 	}
 	*target = *data;
-
 }
 
 extern "C" int deco_allowed_depth(double tissues_tolerance, double surface_pressure, const struct dive *dive, bool smooth)
diff --git a/core/deco.h b/core/deco.h
index cea87158e..f550aefe3 100644
--- a/core/deco.h
+++ b/core/deco.h
@@ -56,8 +56,6 @@ extern void clear_deco(struct deco_state *ds, double surface_pressure, bool in_p
 extern void dump_tissues(struct deco_state *ds);
 extern void set_gf(short gflow, short gfhigh);
 extern void set_vpmb_conservatism(short conservatism);
-extern void cache_deco_state(struct deco_state *source, struct deco_state **datap);
-extern void restore_deco_state(struct deco_state *data, struct deco_state *target, bool keep_vpmb_state);
 extern void nuclear_regeneration(struct deco_state *ds, double time);
 extern void vpmb_start_gradient(struct deco_state *ds);
 extern void vpmb_next_gradient(struct deco_state *ds, double deco_time, double surface_pressure, bool in_planner);
@@ -74,6 +72,21 @@ extern void update_regression(struct deco_state *ds, const struct dive *dive);
 
 #ifdef __cplusplus
 }
+
+// C++ only functions
+
+#include <memory>
+struct deco_state_cache {
+	// Test if there is cached data
+	operator bool () {
+		return !!data;
+	}
+	void cache(const struct deco_state *source);
+	void restore(struct deco_state *target, bool keep_vpmb_state) const;
+private:
+	std::unique_ptr<deco_state> data;
+};
+
 #endif
 
 #endif // DECO_H
diff --git a/core/planner.cpp b/core/planner.cpp
index 926d976b8..7b3105f44 100644
--- a/core/planner.cpp
+++ b/core/planner.cpp
@@ -111,7 +111,7 @@ static void interpolate_transition(struct deco_state *ds, struct dive *dive, dur
 }
 
 /* returns the tissue tolerance at the end of this (partial) dive */
-static int tissue_at_end(struct deco_state *ds, struct dive *dive, struct deco_state **cached_datap)
+static int tissue_at_end(struct deco_state *ds, struct dive *dive, deco_state_cache &cache)
 {
 	struct divecomputer *dc;
 	struct sample *sample, *psample;
@@ -123,11 +123,11 @@ static int tissue_at_end(struct deco_state *ds, struct dive *dive, struct deco_s
 
 	if (!dive)
 		return 0;
-	if (*cached_datap) {
-		restore_deco_state(*cached_datap, ds, true);
+	if (cache) {
+		cache.restore(ds, true);
 	} else {
 		surface_interval = init_decompression(ds, dive, true);
-		cache_deco_state(ds, cached_datap);
+		cache.cache(ds);
 	}
 	dc = &dive->dc;
 	if (!dc->samples)
@@ -544,12 +544,12 @@ static bool trial_ascent(struct deco_state *ds, int wait_time, int trial_depth,
 {
 
 	bool clear_to_ascend = true;
-	struct deco_state *trial_cache = NULL;
+	deco_state_cache trial_cache;
 
 	// For consistency with other VPM-B implementations, we should not start the ascent while the ceiling is
 	// deeper than the next stop (thus the offgasing during the ascent is ignored).
 	// However, we still need to make sure we don't break the ceiling due to on-gassing during ascent.
-	cache_deco_state(ds, &trial_cache);
+	trial_cache.cache(ds);
 	if (wait_time)
 		add_segment(ds, depth_to_bar(trial_depth, dive),
 			    gasmix,
@@ -558,8 +558,7 @@ static bool trial_ascent(struct deco_state *ds, int wait_time, int trial_depth,
 		double tolerance_limit = tissue_tolerance_calc(ds, dive, depth_to_bar(stoplevel, dive), true);
 		update_regression(ds, dive);
 		if (deco_allowed_depth(tolerance_limit, surface_pressure, dive, 1) > stoplevel) {
-			restore_deco_state(trial_cache, ds, false);
-			free(trial_cache);
+			trial_cache.restore(ds, false);
 			return false;
 		}
 	}
@@ -582,8 +581,7 @@ static bool trial_ascent(struct deco_state *ds, int wait_time, int trial_depth,
 		}
 		trial_depth -= deltad;
 	}
-	restore_deco_state(trial_cache, ds, false);
-	free(trial_cache);
+	trial_cache.restore(ds, false);
 	return clear_to_ascend;
 }
 
@@ -654,7 +652,7 @@ static void average_max_depth(struct diveplan *dive, int *avg_depth, int *max_de
 		*avg_depth = *max_depth = 0;
 }
 
-extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, int timestep, struct decostop *decostoptable, struct deco_state **cached_datap, bool is_planner, bool show_disclaimer)
+bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, int timestep, struct decostop *decostoptable, deco_state_cache &cache, bool is_planner, bool show_disclaimer)
 {
 
 	int bottom_depth;
@@ -663,7 +661,7 @@ extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct di
 	bool is_final_plan = true;
 	int bottom_time;
 	int previous_deco_time;
-	struct deco_state *bottom_cache = NULL;
+	deco_state_cache bottom_cache;
 	struct sample *sample;
 	int po2;
 	int transitiontime, gi;
@@ -782,7 +780,7 @@ extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct di
 	gi = gaschangenr - 1;
 
 	/* Set tissue tolerance and initial vpmb gradient at start of ascent phase */
-	diveplan->surface_interval = tissue_at_end(ds, dive, cached_datap);
+	diveplan->surface_interval = tissue_at_end(ds, dive, cache);
 	nuclear_regeneration(ds, clock);
 	vpmb_start_gradient(ds);
 	if (decoMode(true) == RECREATIONAL) {
@@ -850,7 +848,7 @@ extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct di
 	}
 
 	// VPM-B or Buehlmann Deco
-	tissue_at_end(ds, dive, cached_datap);
+	tissue_at_end(ds, dive, cache);
 	if ((divemode == CCR || divemode == PSCR) && prefs.dobailout) {
 		divemode = OC;
 		po2 = 0;
@@ -864,7 +862,7 @@ extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct di
 	}
 	previous_deco_time = 100000000;
 	ds->deco_time = 10000000;
-	cache_deco_state(ds, &bottom_cache);  // Lets us make several iterations
+	bottom_cache.cache(ds);  // Lets us make several iterations
 	bottom_depth = depth;
 	bottom_gi = gi;
 	bottom_gas = gas;
@@ -878,7 +876,7 @@ extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct di
 			vpmb_next_gradient(ds, ds->deco_time, diveplan->surface_pressure / 1000.0, true);
 
 		previous_deco_time = ds->deco_time;
-		restore_deco_state(bottom_cache, ds, true);
+		bottom_cache.restore(ds, true);
 
 		depth = bottom_depth;
 		gi = bottom_gi;
@@ -1124,7 +1122,6 @@ extern "C" bool plan(struct deco_state *ds, struct diveplan *diveplan, struct di
 
 	free(stoplevels);
 	free(gaschanges);
-	free(bottom_cache);
 	return decodive;
 }
 
diff --git a/core/planner.h b/core/planner.h
index 127f51fa8..cf08fa152 100644
--- a/core/planner.h
+++ b/core/planner.h
@@ -36,6 +36,8 @@ struct diveplan {
 	int surface_interval;
 };
 
+struct deco_state_cache;
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -58,9 +60,10 @@ struct decostop {
 	int depth;
 	int time;
 };
-extern bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, int timestep, struct decostop *decostoptable, struct deco_state **cached_datap, bool is_planner, bool show_disclaimer);
 
 #ifdef __cplusplus
 }
+
+extern bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, int timestep, struct decostop *decostoptable, deco_state_cache &cache, bool is_planner, bool show_disclaimer);
 #endif
 #endif // PLANNER_H
diff --git a/core/profile.cpp b/core/profile.cpp
index b38eaca09..fb93245b2 100644
--- a/core/profile.cpp
+++ b/core/profile.cpp
@@ -943,11 +943,11 @@ static void calculate_deco_information(struct deco_state *ds, const struct deco_
 		ds->deco_time = planner_ds->deco_time;
 		ds->first_ceiling_pressure = planner_ds->first_ceiling_pressure;
 	}
-	struct deco_state *cache_data_initial = NULL;
+	deco_state_cache cache_data_initial;
 	lock_planner();
 	/* For VPM-B outside the planner, cache the initial deco state for CVA iterations */
 	if (decoMode(in_planner) == VPMB) {
-		cache_deco_state(ds, &cache_data_initial);
+		cache_data_initial.cache(ds);
 	}
 	/* For VPM-B outside the planner, iterate until deco time converges (usually one or two iterations after the initial)
 	 * Set maximum number of iterations to 10 just in case */
@@ -1078,14 +1078,13 @@ static void calculate_deco_information(struct deco_state *ds, const struct deco_
 				last_ndl_tts_calc_time = entry->sec;
 
 				/* 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);
+				deco_state_cache cache_data;
+				cache_data.cache(ds);
 				calculate_ndl_tts(ds, dive, entry, gasmix, surface_pressure, current_divemode, in_planner);
 				if (decoMode(in_planner) == VPMB && !in_planner && i == pi->nr - 1)
 					final_tts = entry->tts_calc;
 				/* Restore "real" deco state for next real time step */
-				restore_deco_state(cache_data, ds, decoMode(in_planner) == VPMB);
-				free(cache_data);
+				cache_data.restore(ds, decoMode(in_planner) == VPMB);
 			}
 		}
 		if (decoMode(in_planner) == VPMB && !in_planner) {
@@ -1107,7 +1106,7 @@ static void calculate_deco_information(struct deco_state *ds, const struct deco_
 			first_iteration = false;
 			count_iteration ++;
 			this_deco_time = ds->deco_time;
-			restore_deco_state(cache_data_initial, ds, true);
+			cache_data_initial.restore(ds, true);
 			ds->deco_time = this_deco_time;
 		} else {
 			// With Buhlmann iterating isn't needed.  This makes the while condition false.
@@ -1115,7 +1114,6 @@ static void calculate_deco_information(struct deco_state *ds, const struct deco_
 		}
 	}
 
-	free(cache_data_initial);
 #if DECO_CALC_DEBUG & 1
 	dump_tissues(ds);
 #endif
diff --git a/qt-models/diveplannermodel.cpp b/qt-models/diveplannermodel.cpp
index cd29b3198..5c51a2de4 100644
--- a/qt-models/diveplannermodel.cpp
+++ b/qt-models/diveplannermodel.cpp
@@ -1073,12 +1073,12 @@ void DivePlannerPointsModel::updateDiveProfile()
 	if (diveplan_empty(&diveplan))
 		return;
 
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 	struct decostop stoptable[60];
 	struct deco_state plan_deco_state;
 
 	memset(&plan_deco_state, 0, sizeof(struct deco_state));
-	plan(&plan_deco_state, &diveplan, d, DECOTIMESTEP, stoptable, &cache, isPlanner(), false);
+	plan(&plan_deco_state, &diveplan, d, DECOTIMESTEP, stoptable, cache, isPlanner(), false);
 	updateMaxDepth();
 
 	if (isPlanner() && shouldComputeVariations()) {
@@ -1103,8 +1103,6 @@ void DivePlannerPointsModel::updateDiveProfile()
 	emit calculatedPlanNotes(QString(d->notes));
 
 
-	// throw away the cache
-	free(cache);
 #if DEBUG_PLAN
 	save_dive(stderr, d);
 	dump_plan(&diveplan);
@@ -1196,13 +1194,13 @@ void DivePlannerPointsModel::computeVariations(struct diveplan *original_plan, c
 	struct dive *dive = alloc_dive();
 	copy_dive(d, dive);
 	struct decostop original[60], deeper[60], shallower[60], shorter[60], longer[60];
-	struct deco_state *cache = NULL, *save = NULL;
+	deco_state_cache cache, save;
 	struct diveplan plan_copy;
 	struct divedatapoint *last_segment;
 	struct deco_state ds = *previous_ds;
 
 	int my_instance = ++instanceCounter;
-	cache_deco_state(&ds, &save);
+	save.cache(&ds);
 
 	duration_t delta_time = { .seconds = 60 };
 	QString time_units = tr("min");
@@ -1222,43 +1220,43 @@ void DivePlannerPointsModel::computeVariations(struct diveplan *original_plan, c
 		goto finish;
 	if (my_instance != instanceCounter)
 		goto finish;
-	plan(&ds, &plan_copy, dive, 1, original, &cache, true, false);
+	plan(&ds, &plan_copy, dive, 1, original, cache, true, false);
 	free_dps(&plan_copy);
-	restore_deco_state(save, &ds, false);
+	save.restore(&ds, false);
 
 	last_segment = cloneDiveplan(original_plan, &plan_copy);
 	last_segment->depth.mm += delta_depth.mm;
 	last_segment->next->depth.mm += delta_depth.mm;
 	if (my_instance != instanceCounter)
 		goto finish;
-	plan(&ds, &plan_copy, dive, 1, deeper, &cache, true, false);
+	plan(&ds, &plan_copy, dive, 1, deeper, cache, true, false);
 	free_dps(&plan_copy);
-	restore_deco_state(save, &ds, false);
+	save.restore(&ds, false);
 
 	last_segment = cloneDiveplan(original_plan, &plan_copy);
 	last_segment->depth.mm -= delta_depth.mm;
 	last_segment->next->depth.mm -= delta_depth.mm;
 	if (my_instance != instanceCounter)
 		goto finish;
-	plan(&ds, &plan_copy, dive, 1, shallower, &cache, true, false);
+	plan(&ds, &plan_copy, dive, 1, shallower, cache, true, false);
 	free_dps(&plan_copy);
-	restore_deco_state(save, &ds, false);
+	save.restore(&ds, false);
 
 	last_segment = cloneDiveplan(original_plan, &plan_copy);
 	last_segment->next->time += delta_time.seconds;
 	if (my_instance != instanceCounter)
 		goto finish;
-	plan(&ds, &plan_copy, dive, 1, longer, &cache, true, false);
+	plan(&ds, &plan_copy, dive, 1, longer, cache, true, false);
 	free_dps(&plan_copy);
-	restore_deco_state(save, &ds, false);
+	save.restore(&ds, false);
 
 	last_segment = cloneDiveplan(original_plan, &plan_copy);
 	last_segment->next->time -= delta_time.seconds;
 	if (my_instance != instanceCounter)
 		goto finish;
-	plan(&ds, &plan_copy, dive, 1, shorter, &cache, true, false);
+	plan(&ds, &plan_copy, dive, 1, shorter, cache, true, false);
 	free_dps(&plan_copy);
-	restore_deco_state(save, &ds, false);
+	save.restore(&ds, false);
 
 	char buf[200];
 	sprintf(buf, ", %s: %c %d:%02d /%s %c %d:%02d /min", qPrintable(tr("Stop times")),
@@ -1273,8 +1271,6 @@ void DivePlannerPointsModel::computeVariations(struct diveplan *original_plan, c
 finish:
 	free_dps(original_plan);
 	free(original_plan);
-	free(save);
-	free(cache);
 	free_dive(dive);
 }
 
@@ -1289,13 +1285,12 @@ void DivePlannerPointsModel::computeVariationsDone(QString variations)
 void DivePlannerPointsModel::createPlan(bool replanCopy)
 {
 	// Ok, so, here the diveplan creates a dive
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 	removeDeco();
 	createTemporaryPlan();
 
-	//TODO: C-based function here?
 	struct decostop stoptable[60];
-	plan(&ds_after_previous_dives, &diveplan, d, DECOTIMESTEP, stoptable, &cache, isPlanner(), true);
+	plan(&ds_after_previous_dives, &diveplan, d, DECOTIMESTEP, stoptable, cache, isPlanner(), true);
 
 	if (shouldComputeVariations()) {
 		struct diveplan *plan_copy;
@@ -1306,8 +1301,6 @@ void DivePlannerPointsModel::createPlan(bool replanCopy)
 		computeVariations(plan_copy, &ds_after_previous_dives);
 	}
 
-	free(cache);
-
 	// Fixup planner notes.
 	if (current_dive && d->id == current_dive->id) {
 		// Try to identify old planner output and remove only this part
diff --git a/tests/testplan.cpp b/tests/testplan.cpp
index b7c7ff57f..74448a1a1 100644
--- a/tests/testplan.cpp
+++ b/tests/testplan.cpp
@@ -15,7 +15,7 @@
 static struct dive dive = { 0 };
 static struct decostop stoptable[60];
 static struct deco_state test_deco_state;
-extern bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, int timestep, struct decostop *decostoptable, struct deco_state **cached_datap, bool is_planner, bool show_disclaimer);
+extern bool plan(struct deco_state *ds, struct diveplan *diveplan, struct dive *dive, int timestep, struct decostop *decostoptable, deco_state_cache &cache, bool is_planner, bool show_disclaimer);
 void setupPrefs()
 {
 	copy_prefs(&default_prefs, &prefs);
@@ -443,7 +443,7 @@ bool compareDecoTime(int actualRunTimeSeconds, int benchmarkRunTimeSeconds, int
 
 void TestPlan::testMetric()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefs();
 	prefs.unit_system = METRIC;
@@ -453,7 +453,7 @@ void TestPlan::testMetric()
 	struct diveplan testPlan = {};
 	setupPlan(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -484,7 +484,7 @@ void TestPlan::testMetric()
 
 void TestPlan::testImperial()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefs();
 	prefs.unit_system = IMPERIAL;
@@ -494,7 +494,7 @@ void TestPlan::testImperial()
 	struct diveplan testPlan = {};
 	setupPlan(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -525,7 +525,7 @@ void TestPlan::testImperial()
 
 void TestPlan::testVpmbMetric45m30minTx()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -534,7 +534,7 @@ void TestPlan::testVpmbMetric45m30minTx()
 	struct diveplan testPlan = {};
 	setupPlanVpmb45m30mTx(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -555,7 +555,7 @@ void TestPlan::testVpmbMetric45m30minTx()
 
 void TestPlan::testVpmbMetric60m10minTx()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -564,7 +564,7 @@ void TestPlan::testVpmbMetric60m10minTx()
 	struct diveplan testPlan = {};
 	setupPlanVpmb60m10mTx(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -585,7 +585,7 @@ void TestPlan::testVpmbMetric60m10minTx()
 
 void TestPlan::testVpmbMetric60m30minAir()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -594,7 +594,7 @@ void TestPlan::testVpmbMetric60m30minAir()
 	struct diveplan testPlan = {};
 	setupPlanVpmb60m30minAir(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -615,7 +615,7 @@ void TestPlan::testVpmbMetric60m30minAir()
 
 void TestPlan::testVpmbMetric60m30minEan50()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -624,7 +624,7 @@ void TestPlan::testVpmbMetric60m30minEan50()
 	struct diveplan testPlan = {};
 	setupPlanVpmb60m30minEan50(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -651,7 +651,7 @@ void TestPlan::testVpmbMetric60m30minEan50()
 
 void TestPlan::testVpmbMetric60m30minTx()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -660,7 +660,7 @@ void TestPlan::testVpmbMetric60m30minTx()
 	struct diveplan testPlan = {};
 	setupPlanVpmb60m30minTx(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -687,7 +687,7 @@ void TestPlan::testVpmbMetric60m30minTx()
 
 void TestPlan::testVpmbMetric100m60min()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -696,7 +696,7 @@ void TestPlan::testVpmbMetric100m60min()
 	struct diveplan testPlan = {};
 	setupPlanVpmb100m60min(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -729,7 +729,7 @@ void TestPlan::testVpmbMetric100m60min()
 
 void TestPlan::testMultipleGases()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -739,7 +739,7 @@ void TestPlan::testMultipleGases()
 
 	setupPlanSeveralGases(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -755,7 +755,7 @@ void TestPlan::testMultipleGases()
 
 void TestPlan::testVpmbMetricMultiLevelAir()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -764,7 +764,7 @@ void TestPlan::testVpmbMetricMultiLevelAir()
 	struct diveplan testPlan = {};
 	setupPlanVpmbMultiLevelAir(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -785,7 +785,7 @@ void TestPlan::testVpmbMetricMultiLevelAir()
 
 void TestPlan::testVpmbMetric100m10min()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -794,7 +794,7 @@ void TestPlan::testVpmbMetric100m10min()
 	struct diveplan testPlan = {};
 	setupPlanVpmb100m10min(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -831,7 +831,7 @@ void TestPlan::testVpmbMetric100m10min()
  */
 void TestPlan::testVpmbMetricRepeat()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefsVpmb();
 	prefs.unit_system = METRIC;
@@ -840,7 +840,7 @@ void TestPlan::testVpmbMetricRepeat()
 	struct diveplan testPlan = {};
 	setupPlanVpmb30m20min(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -861,7 +861,7 @@ void TestPlan::testVpmbMetricRepeat()
 	int firstDiveRunTimeSeconds = dive.dc.duration.seconds;
 
 	setupPlanVpmb100mTo70m30min(&testPlan);
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -898,7 +898,7 @@ void TestPlan::testVpmbMetricRepeat()
 	QVERIFY(compareDecoTime(dive.dc.duration.seconds, 127u * 60u + 20u, 127u * 60u + 20u));
 
 	setupPlanVpmb30m20min(&testPlan);
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, 1, 0);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, 1, 0);
 
 #if DEBUG
 	free(dive.notes);
@@ -925,7 +925,7 @@ void TestPlan::testVpmbMetricRepeat()
 
 void TestPlan::testCcrBailoutGasSelection()
 {
-	struct deco_state *cache = NULL;
+	deco_state_cache cache;
 
 	setupPrefs();
 	prefs.unit_system = METRIC;
@@ -937,7 +937,7 @@ void TestPlan::testCcrBailoutGasSelection()
 	struct diveplan testPlan = {};
 	setupPlanCcr(&testPlan);
 
-	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, &cache, true, false);
+	plan(&test_deco_state, &testPlan, &dive, 60, stoptable, cache, true, false);
 
 #if DEBUG
 	free(dive.notes);