Core: remove MAX_CYLINDERS restriction

Instead of using fixed size arrays, use a new cylinder_table structure.
The code copies the weightsystem code, but is significantly more complex
because cylinders are such an integral part of the core.

Two functions to access the cylinders were added:
get_cylinder() and get_or_create_cylinder()
The former does a simple array access and supposes that the cylinder
exists. The latter is used by the parser(s) and if a cylinder with
the given id does not exist, cylinders up to that id are generated.

One point will make C programmers cringe: the cylinder structure is
passed by value. This is due to the way the table-macros work. A
refactoring of the table macros is planned. It has to be noted that
the size of a cylinder_t is 64 bytes, i.e. 8 long words on a 64-bit
architecture, so passing on the stack is probably not even significantly
slower than passing as reference.

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

6 files changed, 85 insertions, 97 deletions

diff --git a/qt-models/cylindermodel.cpp b/qt-models/cylindermodel.cpp
index 3a2b6e536..f64cc213a 100644
--- a/qt-models/cylindermodel.cpp
+++ b/qt-models/cylindermodel.cpp
@@ -131,10 +131,10 @@ static QVariant percent_string(fraction_t fraction)
 
 QVariant CylindersModel::data(const QModelIndex &index, int role) const
 {
-	if (!index.isValid() || index.row() >= MAX_CYLINDERS)
+	if (!index.isValid() || index.row() >= rows)
 		return QVariant();
 
-	const cylinder_t *cyl = &displayed_dive.cylinder[index.row()];
+	const cylinder_t *cyl = &displayed_dive.cylinders.cylinders[index.row()];
 
 	switch (role) {
 	case Qt::BackgroundRole: {
@@ -259,7 +259,7 @@ QVariant CylindersModel::data(const QModelIndex &index, int role) const
 
 cylinder_t *CylindersModel::cylinderAt(const QModelIndex &index)
 {
-	return &displayed_dive.cylinder[index.row()];
+	return &displayed_dive.cylinders.cylinders[index.row()];
 }
 
 // this is our magic 'pass data in' function that allows the delegate to get
@@ -420,16 +420,14 @@ int CylindersModel::rowCount(const QModelIndex&) const
 
 void CylindersModel::add()
 {
-	if (rows >= MAX_CYLINDERS) {
-		return;
-	}
-
 	int row = rows;
-	fill_default_cylinder(&displayed_dive, row);
-	displayed_dive.cylinder[row].start = displayed_dive.cylinder[row].type.workingpressure;
-	displayed_dive.cylinder[row].manually_added = true;
-	displayed_dive.cylinder[row].cylinder_use = OC_GAS;
+	cylinder_t cyl = { 0 };
+	fill_default_cylinder(&displayed_dive, &cyl);
+	cyl.start = cyl.type.workingpressure;
+	cyl.manually_added = true;
+	cyl.cylinder_use = OC_GAS;
 	beginInsertRows(QModelIndex(), row, row);
+	add_to_cylinder_table(&displayed_dive.cylinders, row, cyl);
 	rows++;
 	changed = true;
 	endInsertRows();
@@ -446,12 +444,12 @@ void CylindersModel::clear()
 
 static bool show_cylinder(struct dive *dive, int i)
 {
-	cylinder_t *cyl = dive->cylinder + i;
-
+	if (i < 0 || i >= dive->cylinders.nr)
+		return false;
 	if (is_cylinder_used(dive, i))
 		return true;
-	if (cylinder_none(cyl))
-		return false;
+
+	cylinder_t *cyl = dive->cylinders.cylinders + i;
 	if (cyl->start.mbar || cyl->sample_start.mbar ||
 	    cyl->end.mbar || cyl->sample_end.mbar)
 		return true;
@@ -467,34 +465,18 @@ static bool show_cylinder(struct dive *dive, int i)
 
 void CylindersModel::updateDive()
 {
-	clear();
-	rows = 0;
 #ifdef DEBUG_CYL
 	dump_cylinders(&displayed_dive, true);
 #endif
-	for (int i = 0; i < MAX_CYLINDERS; i++) {
-		if (show_cylinder(&displayed_dive, i))
-			rows = i + 1;
-	}
-	if (rows > 0) {
-		beginInsertRows(QModelIndex(), 0, rows - 1);
-		endInsertRows();
-	}
-}
-
-void CylindersModel::copyFromDive(dive *d)
-{
-	if (!d)
-		return;
+	beginResetModel();
+	// TODO: this is fundamentally broken - it assumes that unused cylinders are at
+	// the end. Fix by using a QSortFilterProxyModel.
 	rows = 0;
-	for (int i = 0; i < MAX_CYLINDERS; i++) {
-		if (show_cylinder(d, i))
-			rows = i + 1;
-	}
-	if (rows > 0) {
-		beginInsertRows(QModelIndex(), 0, rows - 1);
-		endInsertRows();
+	for (int i = 0; i < displayed_dive.cylinders.nr; ++i) {
+		if (show_cylinder(&displayed_dive, i))
+			++rows;
 	}
+	endResetModel();
 }
 
 Qt::ItemFlags CylindersModel::flags(const QModelIndex &index) const
@@ -506,7 +488,6 @@ Qt::ItemFlags CylindersModel::flags(const QModelIndex &index) const
 
 void CylindersModel::remove(const QModelIndex &index)
 {
-	std::vector<int> mapping(MAX_CYLINDERS);
 
 	if (index.column() == USE) {
 		cylinder_t *cyl = cylinderAt(index);
@@ -518,48 +499,53 @@ void CylindersModel::remove(const QModelIndex &index)
 		dataChanged(index, index);
 		return;
 	}
-	if (index.column() != REMOVE) {
+
+	if (index.column() != REMOVE)
 		return;
-	}
 
 	if ((in_planner() && DivePlannerPointsModel::instance()->tankInUse(index.row())) ||
 		(!in_planner() && is_cylinder_prot(&displayed_dive, index.row())))
 			return;
 
-	beginRemoveRows(QModelIndex(), index.row(), index.row()); // yah, know, ugly.
+	beginRemoveRows(QModelIndex(), index.row(), index.row());
 	rows--;
-
 	remove_cylinder(&displayed_dive, index.row());
-	for (int i = 0; i < index.row(); i++)
-		mapping[i] = i;
-	// No mapping for removed gas, set to -1
+	changed = true;
+	endRemoveRows();
+
+	// Create a mapping of cylinder indexes:
+	// 1) Fill mapping[0]..mapping[index-1] with 0..index
+	// 2) Set mapping[index] to -1
+	// 3) Fill mapping[index+1]..mapping[end] with index..
+	std::vector<int> mapping(displayed_dive.cylinders.nr + 1);
+	std::iota(mapping.begin(), mapping.begin() + index.row(), 0);
 	mapping[index.row()] = -1;
-	for (int i = index.row() + 1; i < MAX_CYLINDERS; i++)
-		mapping[i] = i - 1;
+	std::iota(mapping.begin() + index.row() + 1, mapping.end(), index.row());
 
 	cylinder_renumber(&displayed_dive, &mapping[0]);
 	if (in_planner())
 		DivePlannerPointsModel::instance()->cylinderRenumber(&mapping[0]);
 	changed = true;
-	endRemoveRows();
-	dataChanged(index, index);
 }
 
 void CylindersModel::moveAtFirst(int cylid)
 {
-	std::vector<int> mapping(MAX_CYLINDERS);
 	cylinder_t temp_cyl;
 
 	beginMoveRows(QModelIndex(), cylid, cylid, QModelIndex(), 0);
-	memmove(&temp_cyl, &displayed_dive.cylinder[cylid], sizeof(temp_cyl));
-	for (int i = cylid - 1; i >= 0; i--) {
-		memmove(&displayed_dive.cylinder[i + 1], &displayed_dive.cylinder[i], sizeof(temp_cyl));
-		mapping[i] = i + 1;
-	}
-	memmove(&displayed_dive.cylinder[0], &temp_cyl, sizeof(temp_cyl));
+	memmove(&temp_cyl, &displayed_dive.cylinders.cylinders[cylid], sizeof(temp_cyl));
+	for (int i = cylid - 1; i >= 0; i--)
+		memmove(&displayed_dive.cylinders.cylinders[i + 1], &displayed_dive.cylinders.cylinders[i], sizeof(temp_cyl));
+	memmove(&displayed_dive.cylinders.cylinders[0], &temp_cyl, sizeof(temp_cyl));
+
+	// Create a mapping of cylinder indexes:
+	// 1) Fill mapping[0]..mapping[cyl] with 0..index
+	// 2) Set mapping[cyl] to 0
+	// 3) Fill mapping[cyl+1]..mapping[end] with cyl..
+	std::vector<int> mapping(displayed_dive.cylinders.nr);
+	std::iota(mapping.begin(), mapping.begin() + cylid, 1);
 	mapping[cylid] = 0;
-	for (int i = cylid + 1; i < MAX_CYLINDERS; i++)
-		mapping[i] = i;
+	std::iota(mapping.begin() + (cylid + 1), mapping.end(), cylid);
 	cylinder_renumber(&displayed_dive, &mapping[0]);
 	if (in_planner())
 		DivePlannerPointsModel::instance()->cylinderRenumber(&mapping[0]);
@@ -571,28 +557,28 @@ void CylindersModel::updateDecoDepths(pressure_t olddecopo2)
 {
 	pressure_t decopo2;
 	decopo2.mbar = prefs.decopo2;
-	for (int i = 0; i < MAX_CYLINDERS; i++) {
-		cylinder_t *cyl = &displayed_dive.cylinder[i];
+	for (int i = 0; i < displayed_dive.cylinders.nr; i++) {
+		cylinder_t *cyl = &displayed_dive.cylinders.cylinders[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));
 		}
 	}
-	emit dataChanged(createIndex(0, 0), createIndex(MAX_CYLINDERS - 1, COLUMNS - 1));
+	emit dataChanged(createIndex(0, 0), createIndex(displayed_dive.cylinders.nr - 1, COLUMNS - 1));
 }
 
 void CylindersModel::updateTrashIcon()
 {
-	emit dataChanged(createIndex(0, 0), createIndex(MAX_CYLINDERS - 1, 0));
+	emit dataChanged(createIndex(0, 0), createIndex(displayed_dive.cylinders.nr - 1, 0));
 }
 
 bool CylindersModel::updateBestMixes()
 {
 	// Check if any of the cylinders are best mixes, update if needed
 	bool gasUpdated = false;
-	for (int i = 0; i < MAX_CYLINDERS; i++) {
-		cylinder_t *cyl = &displayed_dive.cylinder[i];
+	for (int i = 0; i < displayed_dive.cylinders.nr; i++) {
+		cylinder_t *cyl = &displayed_dive.cylinders.cylinders[i];
 		if (cyl->bestmix_o2) {
 			cyl->gasmix.o2 = best_o2(displayed_dive.maxdepth, &displayed_dive);
 			// fO2 + fHe must not be greater than 1
@@ -614,7 +600,7 @@ bool CylindersModel::updateBestMixes()
 	/* This slot is called when the bottom pO2 and END preferences are updated, we want to
 	 * emit dataChanged so MOD and MND are refreshed, even if the gas mix hasn't been changed */
 	if (gasUpdated)
-		emit dataChanged(createIndex(0, 0), createIndex(MAX_CYLINDERS - 1, COLUMNS - 1));
+		emit dataChanged(createIndex(0, 0), createIndex(displayed_dive.cylinders.nr - 1, COLUMNS - 1));
 	return gasUpdated;
 }
 
@@ -626,7 +612,7 @@ void CylindersModel::cylindersReset(const QVector<dive *> &dives)
 		return;
 
 	// Copy the cylinders from the current dive to the displayed dive.
-	copy_cylinders(current_dive, &displayed_dive, false);
+	copy_cylinders(&current_dive->cylinders, &displayed_dive.cylinders);
 
 	// And update the model..
 	updateDive();
diff --git a/qt-models/cylindermodel.h b/qt-models/cylindermodel.h
index 58d11e971..0def53ba9 100644
--- a/qt-models/cylindermodel.h
+++ b/qt-models/cylindermodel.h
@@ -37,7 +37,6 @@ public:
 	void add();
 	void clear();
 	void updateDive();
-	void copyFromDive(struct dive *d);
 	void updateDecoDepths(pressure_t olddecopo2);
 	void updateTrashIcon();
 	void moveAtFirst(int cylid);
diff --git a/qt-models/diveplannermodel.cpp b/qt-models/diveplannermodel.cpp
index 537bf278f..8d19afcfb 100644
--- a/qt-models/diveplannermodel.cpp
+++ b/qt-models/diveplannermodel.cpp
@@ -152,29 +152,32 @@ void DivePlannerPointsModel::loadFromDive(dive *d)
 // setup the cylinder widget accordingly
 void DivePlannerPointsModel::setupCylinders()
 {
-	int i;
+	clear_cylinder_table(&displayed_dive.cylinders);
 	if (mode == PLAN && current_dive) {
 		// take the displayed cylinders from the selected dive as starting point
-		CylindersModel::instance()->copyFromDive(current_dive);
-		copy_cylinders(current_dive, &displayed_dive, !prefs.display_unused_tanks);
+		copy_used_cylinders(current_dive, &displayed_dive, !prefs.display_unused_tanks);
 		reset_cylinders(&displayed_dive, true);
 
-		for (i = 0; i < MAX_CYLINDERS; i++)
-			if (!cylinder_none(&(displayed_dive.cylinder[i])))
-				return;		// We have at least one cylinder
+		if (displayed_dive.cylinders.nr > 0) {
+			CylindersModel::instance()->updateDive();
+			return;		// We have at least one cylinder
+		}
 	}
 	if (!empty_string(prefs.default_cylinder)) {
-		fill_default_cylinder(&displayed_dive, 0);
-		displayed_dive.cylinder[0].start = displayed_dive.cylinder[0].type.workingpressure;
-	}
-	if (cylinder_none(&displayed_dive.cylinder[0])) {
+		cylinder_t cyl = { 0 };
+		fill_default_cylinder(&displayed_dive, &cyl);
+		cyl.start = cyl.type.workingpressure;
+		add_to_cylinder_table(&displayed_dive.cylinders, 0, cyl);
+	} else {
+		cylinder_t cyl = { 0 };
 		// roughly an AL80
-		displayed_dive.cylinder[0].type.description = copy_qstring(tr("unknown"));
-		displayed_dive.cylinder[0].type.size.mliter = 11100;
-		displayed_dive.cylinder[0].type.workingpressure.mbar = 207000;
+		cyl.type.description = copy_qstring(tr("unknown"));
+		cyl.type.size.mliter = 11100;
+		cyl.type.workingpressure.mbar = 207000;
+		add_to_cylinder_table(&displayed_dive.cylinders, 0, cyl);
 	}
 	reset_cylinders(&displayed_dive, false);
-	CylindersModel::instance()->copyFromDive(&displayed_dive);
+	CylindersModel::instance()->updateDive();
 }
 
 // Update the dive's maximum depth.  Returns true if max. depth changed
@@ -265,13 +268,13 @@ QVariant DivePlannerPointsModel::data(const QModelIndex &index, int role) const
 		case GAS:
 			/* Check if we have the same gasmix two or more times
 			 * If yes return more verbose string */
-			int same_gas = same_gasmix_cylinder(&displayed_dive.cylinder[p.cylinderid], p.cylinderid, &displayed_dive, true);
+			int same_gas = same_gasmix_cylinder(&displayed_dive.cylinders.cylinders[p.cylinderid], p.cylinderid, &displayed_dive, true);
 			if (same_gas == -1)
-				return get_gas_string(displayed_dive.cylinder[p.cylinderid].gasmix);
+				return get_gas_string(displayed_dive.cylinders.cylinders[p.cylinderid].gasmix);
 			else
-				return get_gas_string(displayed_dive.cylinder[p.cylinderid].gasmix) +
+				return get_gas_string(displayed_dive.cylinders.cylinders[p.cylinderid].gasmix) +
 					QString(" (%1 %2 ").arg(tr("cyl.")).arg(p.cylinderid + 1) +
-						displayed_dive.cylinder[p.cylinderid].type.description + ")";
+						displayed_dive.cylinders.cylinders[p.cylinderid].type.description + ")";
 		}
 	} else if (role == Qt::DecorationRole) {
 		switch (index.column()) {
@@ -333,7 +336,7 @@ bool DivePlannerPointsModel::setData(const QModelIndex &index, const QVariant &v
 				p.setpoint = po2;
 		} break;
 		case GAS:
-			if (value.toInt() >= 0 && value.toInt() < MAX_CYLINDERS)
+			if (value.toInt() >= 0)
 				p.cylinderid = value.toInt();
 			/* Did we change the start (dp 0) cylinder to another cylinderid than 0? */
 			if (value.toInt() != 0 && index.row() == 0)
@@ -890,8 +893,8 @@ void DivePlannerPointsModel::createTemporaryPlan()
 	// what does the cache do???
 	struct deco_state *cache = NULL;
 	struct divedatapoint *dp = NULL;
-	for (int i = 0; i < MAX_CYLINDERS; i++) {
-		cylinder_t *cyl = &displayed_dive.cylinder[i];
+	for (int i = 0; i < displayed_dive.cylinders.nr; i++) {
+		cylinder_t *cyl = &displayed_dive.cylinders.cylinders[i];
 		if (cyl->depth.mm && cyl->cylinder_use != NOT_USED) {
 			dp = create_dp(0, cyl->depth.mm, i, 0);
 			if (diveplan.dp) {
diff --git a/qt-models/diveplotdatamodel.cpp b/qt-models/diveplotdatamodel.cpp
index 164cd04a4..eed13c501 100644
--- a/qt-models/diveplotdatamodel.cpp
+++ b/qt-models/diveplotdatamodel.cpp
@@ -190,8 +190,8 @@ void DivePlotDataModel::setDive(dive *d, const plot_info &info)
 	pInfo = info;
 	pInfo.entry = (plot_data *)malloc(sizeof(plot_data) * pInfo.nr);
 	memcpy(pInfo.entry, info.entry, sizeof(plot_data) * pInfo.nr);
-	pInfo.pressures = (plot_pressure_data *)malloc(sizeof(plot_pressure_data) * MAX_CYLINDERS * pInfo.nr);
-	memcpy(pInfo.pressures, info.pressures, sizeof(plot_pressure_data) * MAX_CYLINDERS * pInfo.nr);
+	pInfo.pressures = (plot_pressure_data *)malloc(sizeof(plot_pressure_data) * pInfo.nr_cylinders * pInfo.nr);
+	memcpy(pInfo.pressures, info.pressures, sizeof(plot_pressure_data) * pInfo.nr_cylinders * pInfo.nr);
 	endResetModel();
 }
 
diff --git a/qt-models/divetripmodel.cpp b/qt-models/divetripmodel.cpp
index 30ab2175b..220d122d4 100644
--- a/qt-models/divetripmodel.cpp
+++ b/qt-models/divetripmodel.cpp
@@ -157,7 +157,7 @@ QVariant DiveTripModelBase::diveData(const struct dive *d, int column, int role)
 		case SUIT:
 			return QString(d->suit);
 		case CYLINDER:
-			return QString(d->cylinder[0].type.description);
+			return d->cylinders.nr > 0 ? QString(d->cylinders.cylinders[0].type.description) : QString();
 		case SAC:
 			return displaySac(d, prefs.units.show_units_table);
 		case OTU:
@@ -1410,7 +1410,9 @@ bool DiveTripModelList::lessThan(const QModelIndex &i1, const QModelIndex &i2) c
 	case SUIT:
 		return lessThanHelper(strCmp(d1->suit, d2->suit), row_diff);
 	case CYLINDER:
-		return lessThanHelper(strCmp(d1->cylinder[0].type.description, d2->cylinder[0].type.description), row_diff);
+		if (d1->cylinders.nr > 0 && d2->cylinders.nr > 0)
+			return lessThanHelper(strCmp(d1->cylinders.cylinders[0].type.description, d2->cylinders.cylinders[0].type.description), row_diff);
+		return d1->cylinders.nr - d2->cylinders.nr < 0;
 	case GAS:
 		return lessThanHelper(nitrox_sort_value(d1) - nitrox_sort_value(d2), row_diff);
 	case SAC:
diff --git a/qt-models/models.cpp b/qt-models/models.cpp
index f6b3e927f..ab80f95f0 100644
--- a/qt-models/models.cpp
+++ b/qt-models/models.cpp
@@ -26,10 +26,8 @@ GasSelectionModel *GasSelectionModel::instance()
 static QStringList getGasList()
 {
 	QStringList list;
-	for (int i = 0; i < MAX_CYLINDERS; i++) {
-		cylinder_t *cyl = &displayed_dive.cylinder[i];
-		if (cylinder_nodata(cyl))
-			break;
+	for (int i = 0; i < displayed_dive.cylinders.nr; i++) {
+		const cylinder_t *cyl = &displayed_dive.cylinders.cylinders[i];
 		/* Check if we have the same gasmix two or more times
 		 * If yes return more verbose string */
 		int same_gas = same_gasmix_cylinder(cyl, i, &displayed_dive, true);