+gboolean no_cylinders(cylinder_t *cyl)
+{
+ int i;
+
+ for (i = 0; i < MAX_CYLINDERS; i++)
+ if (!cylinder_none(cyl + i))
+ return FALSE;
+ return TRUE;
+}
+
+/* descriptions are equal if they are both NULL or both non-NULL
+ and the same text */
+gboolean description_equal(const char *desc1, const char *desc2)
+{
+ return ((! desc1 && ! desc2) ||
+ (desc1 && desc2 && strcmp(desc1, desc2) == 0));
+}
+
+/* when checking for the same cylinder we want the size and description to match
+ but don't compare the start and end pressures, nor the Nitrox/He values */
+static gboolean one_cylinder_equal(cylinder_t *cyl1, cylinder_t *cyl2)
+{
+ return cyl1->type.size.mliter == cyl2->type.size.mliter &&
+ cyl1->type.workingpressure.mbar == cyl2->type.workingpressure.mbar &&
+ description_equal(cyl1->type.description, cyl2->type.description);
+}
+
+gboolean cylinders_equal(cylinder_t *cyl1, cylinder_t *cyl2)
+{
+ int i;
+
+ for (i = 0; i < MAX_CYLINDERS; i++)
+ if (!one_cylinder_equal(cyl1 + i, cyl2 + i))
+ return FALSE;
+ return TRUE;
+}
+
+/* copy size and description of all cylinders from cyl1 to cyl2 */
+void copy_cylinders(cylinder_t *cyl1, cylinder_t *cyl2)
+{
+ int i;
+
+ for (i = 0; i < MAX_CYLINDERS; i++) {
+ cyl2[i].type.size.mliter = cyl1[i].type.size.mliter;
+ cyl2[i].type.workingpressure.mbar = cyl1[i].type.workingpressure.mbar;
+ if (cyl1[i].type.description)
+ cyl2[i].type.description = strdup(cyl1[i].type.description);
+ else
+ cyl2[i].type.description = NULL;
+ }
+}
+
+static gboolean weightsystem_none(void *_data)
+{
+ weightsystem_t *ws = _data;
+ return !ws->weight.grams && !ws->description;
+}
+
+gboolean no_weightsystems(weightsystem_t *ws)
+{
+ int i;
+
+ for (i = 0; i < MAX_WEIGHTSYSTEMS; i++)
+ if (!weightsystem_none(ws + i))
+ return FALSE;
+ return TRUE;
+}
+
+static gboolean one_weightsystem_equal(weightsystem_t *ws1, weightsystem_t *ws2)
+{
+ return ws1->weight.grams == ws2->weight.grams &&
+ description_equal(ws1->description, ws2->description);
+}
+
+gboolean weightsystems_equal(weightsystem_t *ws1, weightsystem_t *ws2)
+{
+ int i;
+
+ for (i = 0; i < MAX_WEIGHTSYSTEMS; i++)
+ if (!one_weightsystem_equal(ws1 + i, ws2 + i))
+ return FALSE;
+ return TRUE;
+}
+
+static void set_one_cylinder(void *_data, GtkListStore *model, GtkTreeIter *iter)
+{
+ cylinder_t *cyl = _data;
+ unsigned int start, end;
+
+ start = cyl->start.mbar ? : cyl->sample_start.mbar;
+ end = cyl->end.mbar ? : cyl->sample_end.mbar;
+ gtk_list_store_set(model, iter,
+ CYL_DESC, cyl->type.description ? : "",
+ CYL_SIZE, cyl->type.size.mliter,
+ CYL_WORKP, cyl->type.workingpressure.mbar,
+ CYL_STARTP, start,
+ CYL_ENDP, end,
+ CYL_O2, cyl->gasmix.o2.permille,
+ CYL_HE, cyl->gasmix.he.permille,
+ -1);
+}
+
+static void set_one_weightsystem(void *_data, GtkListStore *model, GtkTreeIter *iter)
+{
+ weightsystem_t *ws = _data;
+
+ gtk_list_store_set(model, iter,
+ WS_DESC, ws->description ? : "unspecified",
+ WS_WEIGHT, ws->weight.grams,
+ -1);
+}
+
+static void *cyl_ptr(struct dive *dive, int idx)