device: random screen-related fixes.

Signed-off-by: Gediminas Jakutis <gediminas@varciai.lt>

1 files changed, 4 insertions, 5 deletions

diff --git a/src/device/screen.cpp b/src/device/screen.cpp
index 2857161..3f1d215 100644
--- a/src/device/screen.cpp
+++ b/src/device/screen.cpp
@@ -9,8 +9,7 @@ void draw_lines(OLEDDisplay *screen, struct display_status *status);
 void update_lines(struct display_status *status);
 void init_msg(char *msg, size_t size);
 
-/* Effectively const. For type safety reasons. */
-static char NOTHING[] = {'\0'};
+static char empty_string[] = "";
 
 void display_status_init(OLEDDisplay *screen, struct display_status *status, char *msg)
 {
@@ -58,7 +57,7 @@ int display_update_scroll(struct display_status *status)
 		update_lines(status);
 		draw_lines(status->screen, status);
 	}
-	if (status->first_line == NOTHING && status->second_line == NOTHING) {
+	if (!(*status->first_line) && !(*(status->second_line))) {
 		return END_OF_MESSAGE;
 	} else {
 		return 0;
@@ -76,8 +75,8 @@ void update_lines(struct display_status *status)
 {
 	status->first_line = (status->line_cursor * SCREEN_MAX_CHARS < status->message_len)
 			? status->message + status->line_cursor * SCREEN_MAX_CHARS
-			: NOTHING;
+			: empty_string;
 	status->second_line = (status->line_cursor * SCREEN_MAX_CHARS < status->message_len)
 			? status->message + (status->line_cursor + 1) * SCREEN_MAX_CHARS
-			: NOTHING;
+			: empty_string;
 }