Cylinders: access cylinders with get_cylinder()

Instead of accessing the cylinder table directly, use the get_cylinder()
function. This gives less unwieldy expressions. But more importantly,
the function does bound checking. This is crucial for now as the code
hasn't be properly audited since the change to arbitrarily sized
cylinder tables. Accesses of invalid cylinder indexes may lead to
silent data-corruption that is sometimes not even noticed by
valgrind. Returning NULL instead of an invalid pointer will make
debugging much easier.

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

4 files changed, 4 insertions, 4 deletions

diff --git a/desktop-widgets/divelogexportdialog.cpp b/desktop-widgets/divelogexportdialog.cpp
index e093819dd..cf859e2b9 100644
--- a/desktop-widgets/divelogexportdialog.cpp
+++ b/desktop-widgets/divelogexportdialog.cpp
@@ -445,7 +445,7 @@ void DiveLogExportDialog::export_TeX(const char *filename, const bool selected_o
 		put_format(&buf, "\n%% Gas use information:\n");
 		qty_cyl = 0;
 		for (i = 0; i < dive->cylinders.nr; i++){
-			const cylinder_t &cyl = dive->cylinders.cylinders[i];
+			const cylinder_t &cyl = *get_cylinder(dive, i);
 			if (is_cylinder_used(dive, i) || (prefs.display_unused_tanks && cyl.type.description)){
 				put_format(&buf, "\\def\\%scyl%cdescription{%s}\n", ssrf, 'a' + i, cyl.type.description);
 				put_format(&buf, "\\def\\%scyl%cgasname{%s}\n", ssrf, 'a' + i, gasname(cyl.gasmix));
diff --git a/desktop-widgets/simplewidgets.cpp b/desktop-widgets/simplewidgets.cpp
index c49a9886b..5edc66e80 100644
--- a/desktop-widgets/simplewidgets.cpp
+++ b/desktop-widgets/simplewidgets.cpp
@@ -512,7 +512,7 @@ void DiveComponentSelection::buttonClicked(QAbstractButton *button)
 			text << tr("Cylinders:\n");
 			for (cyl = 0; cyl < displayed_dive.cylinders.nr; cyl++) {
 				if (is_cylinder_used(&displayed_dive, cyl))
-					text << displayed_dive.cylinders.cylinders[cyl].type.description << " " << gasname(displayed_dive.cylinders.cylinders[cyl].gasmix) << "\n";
+					text << get_cylinder(&displayed_dive, cyl)->type.description << " " << gasname(get_cylinder(&displayed_dive, cyl)->gasmix) << "\n";
 			}
 		}
 		if (what->weights) {
diff --git a/desktop-widgets/tab-widgets/TabDiveInformation.cpp b/desktop-widgets/tab-widgets/TabDiveInformation.cpp
index 6fabc3bb3..928627311 100644
--- a/desktop-widgets/tab-widgets/TabDiveInformation.cpp
+++ b/desktop-widgets/tab-widgets/TabDiveInformation.cpp
@@ -66,7 +66,7 @@ void TabDiveInformation::updateProfile()
 		gaslist.append(separator); volumes.append(separator); SACs.append(separator);
 		separator = "\n";
 
-		gaslist.append(gasname(current_dive->cylinders.cylinders[i].gasmix));
+		gaslist.append(gasname(get_cylinder(current_dive, i)->gasmix));
 		if (!gases[i].mliter)
 			continue;
 		volumes.append(get_volume_string(gases[i], true));
diff --git a/desktop-widgets/tab-widgets/maintab.cpp b/desktop-widgets/tab-widgets/maintab.cpp
index 4d3d7397d..e10575942 100644
--- a/desktop-widgets/tab-widgets/maintab.cpp
+++ b/desktop-widgets/tab-widgets/maintab.cpp
@@ -656,7 +656,7 @@ bool cylinders_equal(const dive *d1, const dive *d2)
 	if (d1->cylinders.nr != d2->cylinders.nr)
 		return false;
 	for (int i = 0; i < d1->cylinders.nr; ++i) {
-		if (!same_cylinder(d1->cylinders.cylinders[i], d2->cylinders.cylinders[i]))
+		if (!same_cylinder(*get_cylinder(d1, i), *get_cylinder(d2, i)))
 			return false;
 	}
 	return true;