From 83e710f3bb2cfc493a323035911bd90cd9d1ba3b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franti=C5=A1ek=20Boh=C3=A1=C4=8Dek?=
 <fandabohacek@gmail.com>
Date: Wed, 16 Jun 2021 10:51:17 +0200
Subject: [PATCH] fix: movement within border underflow of unsigned integer

---
 image-viewer/include/direction.h    | 2 +-
 image-viewer/include/image_viewer.h | 1 +
 image-viewer/src/cursor.c           | 2 +-
 image-viewer/src/direction.c        | 2 +-
 image-viewer/src/image.c            | 4 ++--
 image-viewer/src/image_viewer.c     | 4 +++-
 6 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/image-viewer/include/direction.h b/image-viewer/include/direction.h
index ad7b454..9b68122 100644
--- a/image-viewer/include/direction.h
+++ b/image-viewer/include/direction.h
@@ -10,6 +10,6 @@ typedef enum {
   RIGHT,
 } direction_t;
 
-void direction_move_xy(direction_t direction, uint16_t *x, uint16_t *y, int16_t amount);
+void direction_move_xy(direction_t direction, int32_t *x, int32_t *y, int16_t amount);
 
 #endif // __DIRECTION_H__
diff --git a/image-viewer/include/image_viewer.h b/image-viewer/include/image_viewer.h
index aa35867..4738942 100644
--- a/image-viewer/include/image_viewer.h
+++ b/image-viewer/include/image_viewer.h
@@ -11,6 +11,7 @@ typedef struct {
   image_t image;
   cursor_t cursor;
   image_region_t region;
+  image_region_t image_region;
   image_region_t display_region;
   image_error_t error;
 
diff --git a/image-viewer/src/cursor.c b/image-viewer/src/cursor.c
index 749fe31..c5ced6b 100644
--- a/image-viewer/src/cursor.c
+++ b/image-viewer/src/cursor.c
@@ -22,7 +22,7 @@ void cursor_center(cursor_t *cursor, image_region_t region) {
 }
 
 bool cursor_move(cursor_t *cursor, image_region_t region, direction_t direction, int16_t amount) {
-  uint16_t x = cursor->x, y = cursor->y;
+  int32_t x = cursor->x, y = cursor->y;
   direction_move_xy(direction, &x, &y, amount);
 
   if (x < region.x) {
diff --git a/image-viewer/src/direction.c b/image-viewer/src/direction.c
index 8ca6223..7c7410f 100644
--- a/image-viewer/src/direction.c
+++ b/image-viewer/src/direction.c
@@ -1,6 +1,6 @@
 #include "direction.h"
 
-void direction_move_xy(direction_t direction, uint16_t *x, uint16_t *y, int16_t amount) {
+void direction_move_xy(direction_t direction, int32_t *x, int32_t *y, int16_t amount) {
   switch (direction) {
   case LEFT:
     *x -= amount;
diff --git a/image-viewer/src/image.c b/image-viewer/src/image.c
index d70204a..a36a8f8 100644
--- a/image-viewer/src/image.c
+++ b/image-viewer/src/image.c
@@ -36,8 +36,8 @@ image_region_t image_region_create(uint16_t x, uint16_t y, uint16_t width,
 
 bool image_region_move_within(image_region_t *to_move, direction_t direction,
                               int amount, image_region_t *border) {
-  uint16_t x = to_move->x;
-  uint16_t y = to_move->y;
+  int32_t x = to_move->x;
+  int32_t y = to_move->y;
 
   if (x < border->x) {
     x = border->x;
diff --git a/image-viewer/src/image_viewer.c b/image-viewer/src/image_viewer.c
index 86d3af1..a3f37ba 100644
--- a/image-viewer/src/image_viewer.c
+++ b/image-viewer/src/image_viewer.c
@@ -19,13 +19,15 @@ image_viewer_t image_viewer_create(char *filename, display_t *display, logger_t
     .region = image_region_create(0, 0, 0, 0),
     .logger = logger,
     .display_region = image_region_create(0, 0, DISPLAY_WIDTH, DISPLAY_HEIGHT),
+    .image_region = image_region_create(0, 0, 0, 0),
     .scale_factor = 0
   };
 
   viewer.error = image_loader_load(&viewer.image);
 
   if (viewer.error == IMERR_SUCCESS) {
-    viewer.region = image_region_create(0, 0, viewer.image.width, viewer.image.height);
+    viewer.region = viewer.image_region =
+        image_region_create(0, 0, viewer.image.width, viewer.image.height);
     cursor_center(&viewer.cursor, viewer.display_region);
   }
 
-- 
2.48.1