From 71bab09c60e0d6c1043bebf97a83c41517562dde Mon Sep 17 00:00:00 2001
From: June McEnroe <june@causal.agency>
Date: Sun, 30 Jul 2017 14:08:56 -0400
Subject: Assert stable struct Tile field offsets

---
 torus.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/torus.h b/torus.h
index 23b4708..bb012f2 100644
--- a/torus.h
+++ b/torus.h
@@ -1,6 +1,7 @@
+#include <assert.h>
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
-#include <assert.h>
 
 #define ALIGNED(x) __attribute__((aligned(x)))
 
@@ -29,6 +30,8 @@ struct Tile {
     uint8_t colors[CELL_ROWS][CELL_COLS] ALIGNED(16);
 } ALIGNED(4096);
 static_assert(sizeof(struct Tile) == 4096, "struct Tile is page-sized");
+static_assert(offsetof(struct Tile, cells) == 16, "stable cells offset");
+static_assert(offsetof(struct Tile, colors) == 2016, "stable colors offset");
 
 #define TILE_ROWS (512)
 #define TILE_COLS (512)
-- 
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