Fix undefined behavior that blocks compiling with UBSan

Left shifts are not defined in C if they would cause signed overflow,
so these expressions get instrumented, which makes them unusable as
switch values and triggers compile errors when compiling with UBSan.

Change-Id: I0588d4be1e00ba1cfde0eac119ead368b20d10c9

1 files changed, 2 insertions, 1 deletions

diff --git a/lib/rbcodec/metadata/metadata_common.h b/lib/rbcodec/metadata/metadata_common.h
index 14115b745a..0f6fcb279c 100644
--- a/lib/rbcodec/metadata/metadata_common.h
+++ b/lib/rbcodec/metadata/metadata_common.h
@@ -30,7 +30,8 @@
 #define TAG_NAME_LENGTH             32
 #define TAG_VALUE_LENGTH            128
 
-#define FOURCC(a,b,c,d) (((a)<<24) | ((b) << 16) | ((c) << 8) | (d))
+#define FOURCC(a,b,c,d) ((((unsigned long)(a)) << 24) | (((unsigned long)(b)) << 16) | \
+                         (((unsigned long)(c)) <<  8) | ((unsigned long)(d)))
 
 enum tagtype { TAGTYPE_APE = 1, TAGTYPE_VORBIS };