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>

1 files changed, 5 insertions, 5 deletions

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)