Be more careful about dive computer selection

The selection logic was a bit random: some places would return NULL if
the dive computer index was out of range, others would return the
primary dive computer, and actually moving between dive computers would
just blindly increment and decrement the number.

This always selects the primary computer if the index is out of bounds,
and makes sure we stay in bound when switching beteen dive computers
(but switching between dives can then turn an in-bound number into an
out-of-bounds one)

Fixes #464

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/display.h b/display.h
index 35fa3749f..5af5c5612 100644
--- a/display.h
+++ b/display.h
@@ -32,7 +32,7 @@ typedef enum {
 	SC_PRINT
 } scale_mode_t;
 
-extern struct divecomputer *select_dc(struct divecomputer *main);
+extern struct divecomputer *select_dc(struct dive *);
 
 struct options {
 	enum {
@@ -46,7 +46,7 @@ struct options {
 	int profile_height, notes_height, tanks_height;
 };
 
-extern char dc_number;
+extern unsigned int dc_number;
 
 extern unsigned int amount_selected;