avoid undefined behaviour adding integers

tonycoz · Feb 21, 2013 · 91fb86b · 91fb86b
1 parent 5e84d11
commit 91fb86b
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Showing 2 changed files with 2 additions and 1 deletion.
diff --git a/bmp.c b/bmp.c
@@ -741,7 +741,7 @@ read_1bit_bmp(io_glue *ig, int xsize, int ysize, int clr_used,
     return NULL;
   }
 
-  if (xsize + 8 < xsize) { /* if there was overflow */
+  if ((i_img_dim)((i_img_dim_u)xsize + 8) < xsize) { /* if there was overflow */
     /* we check with 8 because we allocate that much for the decoded 
        line buffer */
     i_push_error(0, "integer overflow during memory allocation");

diff --git a/imdatatypes.h b/imdatatypes.h
@@ -41,6 +41,7 @@ May be larger than int on some platforms.
 */
 
 typedef ptrdiff_t i_img_dim;
+typedef size_t i_img_dim_u;
 
 /*
 =item i_color
-Original file line number
+Diff line change
@@ Expand Up / @@ -41,6 +41,7 @@ May be larger than int on some platforms. @@
     */
     typedef ptrdiff_t i_img_dim;
+    typedef size_t i_img_dim_u;
     /*
     =item i_color
@@ Expand Down @@