core: add remove_event_from_dc() function

We have a remove_event() function that
1) frees the event
2) works on the current divecomputer
3) compares the events because the profile has copies of events

However, for undo commands
1) we want to keep the event so that we can readd it later
2) we have to work on arbitrary divecomputers
3) we don't work with copies of events

Therefore, create a new remove_event_from_dc() function that
does all that. Moreover, make the event argument to remove_event()
const to (slightly) point out the difference in the API.

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

1 files changed, 15 insertions, 1 deletions

diff --git a/core/dive.c b/core/dive.c
index 25084a554..3ec9b1a82 100644
--- a/core/dive.c
+++ b/core/dive.c
@@ -205,7 +205,21 @@ static int same_event(const struct event *a, const struct event *b)
 	return !strcmp(a->name, b->name);
 }
 
-void remove_event(struct event *event)
+/* Remove given event from dive computer. Does *not* free the event. */
+void remove_event_from_dc(struct divecomputer *dc, struct event *event)
+{
+	for (struct event **ep = &dc->events; *ep; ep = &(*ep)->next) {
+		if (*ep == event) {
+			*ep = event->next;
+			event->next = NULL; // For good measure.
+			break;
+		}
+	}
+}
+
+/* Remove an event from current dive computer that is identical to the passed in event.
+ * Frees the event. */
+void remove_event(const struct event *event)
 {
 	struct event **ep = &current_dc->events;
 	while (ep && !same_event(*ep, event))