Add CLAMP() macro
#define ARRAY_LEN(a) (sizeof(a) / sizeof(a[0]))
#define MIN(X,Y) (X) < (Y) ? (X) : (Y)
#define MAX(X,Y) (X) > (Y) ? (X) : (Y)
+#define CLAMP(V,X,Y) MIN( MAX((V),(X)), (Y) )
#define container_of(ptr, type, member) \
((type *) (((char *) (ptr)) - offsetof(type, member)))
