Don't show tanks that aren't used during a dive

Some dive computers will always download all tanks that they store, not
just the ones used in a dive. Most people only want to see the tanks that
they actually used during the dive (and for the others there's an option
to go back to the old behavior, just in case).

All this is only in memory / during runtime. If the dive computer provided
the extra data we will not throw it away.

Fixes #373

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

9 files changed, 48 insertions, 2 deletions

diff --git a/dive.c b/dive.c
index 5a10af595..1a9bdd97a 100644
--- a/dive.c
+++ b/dive.c
@@ -594,6 +594,32 @@ static struct event *find_previous_event(struct divecomputer *dc, struct event *
 	return previous;
 }
 
+/* mark all tanks that we switch to in this dive computer's data as used */
+static void mark_used_tanks(struct dive *dive, struct divecomputer *dc)
+{
+	struct event *ev = get_next_event(dc->events, "gaschange");
+	// unless there is a gas change in the first 30 seconds we can
+	// always mark the first cylinder as used
+	if (!ev || ev->time.seconds > 30)
+		dive->cylinder[0].used = true;
+	while (ev) {
+		int idx = get_cylinder_index(dive, ev);
+		dive->cylinder[idx].used = true;
+		ev = get_next_event(ev->next, "gaschange");
+	}
+}
+
+/* walk all divecomputers to find the unused tanks in this dive */
+static void check_for_unused_tanks(struct dive *dive)
+{
+	int i;
+	struct divecomputer *dc;
+
+	for_each_dc(dive, dc) {
+		mark_used_tanks(dive, dc);
+	}
+}
+
 static void fixup_surface_pressure(struct dive *dive)
 {
 	struct divecomputer *dc;
@@ -879,7 +905,7 @@ struct dive *fixup_dive(struct dive *dive)
 	fixup_duration(dive);
 	fixup_watertemp(dive);
 	fixup_airtemp(dive);
-
+	check_for_unused_tanks(dive);
 	for (i = 0; i < MAX_CYLINDERS; i++) {
 		cylinder_t *cyl = dive->cylinder + i;
 		add_cylinder_description(&cyl->type);
diff --git a/dive.h b/dive.h
index ccba7a09f..2b69c949c 100644
--- a/dive.h
+++ b/dive.h
@@ -145,6 +145,7 @@ typedef struct {
 	struct gasmix gasmix;
 	pressure_t start, end, sample_start, sample_end;
 	depth_t depth;
+	bool used;
 } cylinder_t;
 
 typedef struct {
diff --git a/pref.h b/pref.h
index 37beb8faa..e3f0a545a 100644
--- a/pref.h
+++ b/pref.h
@@ -37,6 +37,7 @@ struct preferences {
 	short unit_system;
 	struct units units;
 	short show_sac;
+	bool display_unused_tanks;
 };
 enum unit_system_values { METRIC, IMPERIAL, PERSONALIZE };
 
diff --git a/qt-ui/mainwindow.cpp b/qt-ui/mainwindow.cpp
index c24e2733e..acbd13046 100644
--- a/qt-ui/mainwindow.cpp
+++ b/qt-ui/mainwindow.cpp
@@ -57,6 +57,7 @@ MainWindow::MainWindow() : helpView(0)
 	connect(PreferencesDialog::instance(), SIGNAL(settingsChanged()), ui.InfoWidget, SLOT(updateDiveInfo()));
 	connect(PreferencesDialog::instance(), SIGNAL(settingsChanged()), ui.divePlanner, SLOT(settingsChanged()));
 	connect(PreferencesDialog::instance(), SIGNAL(settingsChanged()), ui.divePlannerWidget, SLOT(settingsChanged()));
+	connect(PreferencesDialog::instance(), SIGNAL(settingsChanged()), TankInfoModel::instance(), SLOT(update()));
 
 	ui.mainErrorMessage->hide();
 	initialUiSetup();
@@ -647,6 +648,7 @@ void MainWindow::readSettings()
 	GET_BOOL("gf_low_at_maxdepth", gf_low_at_maxdepth);
 	set_gf(prefs.gflow, prefs.gfhigh, prefs.gf_low_at_maxdepth);
 	GET_BOOL("show_sac", show_sac);
+	GET_BOOL("display_unused_tanks", display_unused_tanks);
 	s.endGroup();
 
 	s.beginGroup("GeneralSettings");
diff --git a/qt-ui/models.cpp b/qt-ui/models.cpp
index 4debafd9a..1e22f7da0 100644
--- a/qt-ui/models.cpp
+++ b/qt-ui/models.cpp
@@ -301,7 +301,8 @@ void CylindersModel::setDive(dive* d)
 		return;
 	rows = 0;
 	for(int i = 0; i < MAX_CYLINDERS; i++) {
-		if (!cylinder_none(&d->cylinder[i])) {
+		if (!cylinder_none(&d->cylinder[i]) &&
+		    (prefs.display_unused_tanks || d->cylinder[i].used)) {
 			rows = i+1;
 		}
 	}
diff --git a/qt-ui/models.h b/qt-ui/models.h
index 06dc66aa1..16818e407 100644
--- a/qt-ui/models.h
+++ b/qt-ui/models.h
@@ -47,6 +47,7 @@ public:
 	/*reimp*/ bool setData(const QModelIndex& index, const QVariant& value, int role = Qt::EditRole);
 	const QString& biggerString() const;
 	void clear();
+public slots:
 	void update();
 private:
 	int rows;
diff --git a/qt-ui/preferences.cpp b/qt-ui/preferences.cpp
index 382880a1f..67e2dfe8d 100644
--- a/qt-ui/preferences.cpp
+++ b/qt-ui/preferences.cpp
@@ -103,6 +103,7 @@ void PreferencesDialog::setUiFromPrefs()
 			ui.default_cylinder->setCurrentIndex(i);
 	}
 	ui.displayinvalid->setChecked(prefs.display_invalid_dives);
+	ui.display_unused_tanks->setChecked(prefs.display_unused_tanks);
 	ui.show_sac->setChecked(prefs.show_sac);
 	ui.vertical_speed_minutes->setChecked(prefs.units.vertical_speed_time == units::MINUTES);
 	ui.vertical_speed_seconds->setChecked(prefs.units.vertical_speed_time == units::SECONDS);
@@ -162,6 +163,7 @@ void PreferencesDialog::syncSettings()
 	s.setValue("gfhigh", ui.gfhigh->value());
 	SB("gf_low_at_maxdepth", ui.gf_low_at_maxdepth);
 	SB("show_sac", ui.show_sac);
+	SB("display_unused_tanks", ui.display_unused_tanks);
 	s.endGroup();
 
 	// Units
diff --git a/qt-ui/preferences.ui b/qt-ui/preferences.ui
index 283fbbb39..fb5a16abb 100644
--- a/qt-ui/preferences.ui
+++ b/qt-ui/preferences.ui
@@ -772,6 +772,17 @@
               </item>
              </layout>
             </item>
+            <item>
+             <layout class="QHBoxLayout" name="horizontalLayout_11c">
+              <item>
+               <widget class="QCheckBox" name="display_unused_tanks">
+                <property name="text">
+                 <string>unused tanks</string>
+                </property>
+               </widget>
+              </item>
+             </layout>
+            </item>
            </layout>
           </widget>
          </item>
diff --git a/subsurfacestartup.c b/subsurfacestartup.c
index 39da8e47c..0640333d0 100644
--- a/subsurfacestartup.c
+++ b/subsurfacestartup.c
@@ -29,6 +29,7 @@ struct preferences default_prefs = {
 	.font_size = 14.0,
 	.display_invalid_dives = FALSE,
 	.show_sac = FALSE,
+	.display_unused_tanks = FALSE
 };
 
 struct units *get_units()