[gimp/gimp-2-6] file-gif-load: ensure return value of LZWReadByte() is <= 255 (cherry picked from commit b1a3de76136

[Nils Philippsen <nphilipp src gnome org>]

commit 0eae221c7c6eb84591d718587a17ea90c8852d5b
Author: Nils Philippsen <nils redhat com>
Date:   Thu Aug 4 12:47:44 2011 +0200

    file-gif-load: ensure return value of LZWReadByte() is <= 255
    (cherry picked from commit b1a3de761362db982c0ddfaff60ab4a3c4267f32)

 plug-ins/common/file-gif-load.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/plug-ins/common/file-gif-load.c b/plug-ins/common/file-gif-load.c
index 9a0720b..a4d98fc 100644
--- a/plug-ins/common/file-gif-load.c
+++ b/plug-ins/common/file-gif-load.c
@@ -743,11 +743,11 @@ LZWReadByte (FILE *fd,
         }
       while (firstcode == clear_code);
 
-      return firstcode;
+      return firstcode & 255;
     }
 
   if (sp > stack)
-    return *--sp;
+    return (*--sp) & 255;
 
   while ((code = GetCode (fd, code_size, FALSE)) >= 0)
     {
@@ -770,7 +770,7 @@ LZWReadByte (FILE *fd,
           sp            = stack;
           firstcode     = oldcode = GetCode (fd, code_size, FALSE);
 
-          return firstcode;
+          return firstcode & 255;
         }
       else if (code == end_code)
         {
@@ -826,10 +826,10 @@ LZWReadByte (FILE *fd,
       oldcode = incode;
 
       if (sp > stack)
-        return *--sp;
+        return (*--sp) & 255;
     }
 
-  return code;
+  return code & 255;
 }
 
 static gint32