bootutil: Provide flash_area_to_image

The flash_area_id_to_image has been replaced with flash_area_to_image
that moves flash_area_get_id inside the flash_area_id_to_image
and changes the logic so that it is now independent from
image numbers and should not require updates when BOOT_IMAGE_NUMBER
gets increased.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>

boot/bootutil/src/bootutil_public.c

@@ -458,18 +458,18 @@ boot_swap_type_multi(int image_index)
  return BOOT_SWAP_TYPE_NONE;
 }
 
-static int flash_area_id_to_image(int id)
+static int flash_area_to_image(const struct flash_area *fa)
 {
-#if BOOT_IMAGE_NUMBER > 2
-#error "BOOT_IMAGE_NUMBER > 2 requires change to flash_area_id_to_image"
-#elif BOOT_IMAGE_NUMBER > 1
- if (FLASH_AREA_IMAGE_PRIMARY(1) == id || (FLASH_AREA_IMAGE_SECONDARY(1) == id)) {
- return 1;
+ int i = 0;
+ int id = flash_area_get_id(fa);
+
+ while (BOOT_IMAGE_NUMBER > 1 && i < BOOT_IMAGE_NUMBER) {
+ if (FLASH_AREA_IMAGE_PRIMARY(i) == id || (FLASH_AREA_IMAGE_SECONDARY(i) == id)) {
+ break;
+ }
+ ++i;
  }
-#else
- (void)id;
-#endif
- return 0;
+ return i;
 }
 
 int
@@ -517,8 +517,7 @@ boot_set_next(const struct flash_area *fa, bool active, bool confirm)
  } else {
  swap_type = BOOT_SWAP_TYPE_TEST;
  }
- rc = boot_write_swap_info(fa, swap_type,
- flash_area_id_to_image(flash_area_get_id(fa)));
+ rc = boot_write_swap_info(fa, swap_type, flash_area_to_image(fa));
  }
  }
  break;