[freetype2] master 22a0cccb4: * src/base/ftobjs.c (ft_open_face_internal): Properly guard `face_index`.

[Werner Lemberg]

branch: master
commit 22a0cccb4d9d002f33c1ba7a4b36812c7d4f46b5
Author: Werner Lemberg <wl@gnu.org>
Commit: Werner Lemberg <wl@gnu.org>

    * src/base/ftobjs.c (ft_open_face_internal): Properly guard `face_index`.
    
    We must ensure that the cast to `FT_Int` doesn't change the sign.
    
    Fixes #1139.
---
 src/base/ftobjs.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/base/ftobjs.c b/src/base/ftobjs.c
index 2c0f0e6c9..10952a6c6 100644
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -2527,6 +2527,15 @@
 #endif
 
 
+    /* only use lower 31 bits together with sign bit */
+    if ( face_index > 0 )
+      face_index &= 0x7FFFFFFFL;
+    else
+    {
+      face_index &= 0x7FFFFFFFL;
+      face_index  = -face_index;
+    }
+
 #ifdef FT_DEBUG_LEVEL_TRACE
     FT_TRACE3(( "FT_Open_Face: " ));
     if ( face_index < 0 )