Use bit tricks for HB_DIRECTION_IS_*

We already depend on the exact values of the direction enum
in HB_DIRECTION_REVERSE(), so we may as well use that.

diff --git a/src/hb-common.h b/src/hb-common.h
index cc673ad..f64d6cc 100644 (file)
--- a/src/hb-common.h
+++ b/src/hb-common.h
@@ -79,10 +79,10 @@ typedef enum _hb_direction_t {
   HB_DIRECTION_BTT
 } hb_direction_t;
 
-#define HB_DIRECTION_IS_HORIZONTAL(dir)        ((dir) == HB_DIRECTION_LTR || (dir) == HB_DIRECTION_RTL)
-#define HB_DIRECTION_IS_VERTICAL(dir)  ((dir) == HB_DIRECTION_TTB || (dir) == HB_DIRECTION_BTT)
-#define HB_DIRECTION_IS_FORWARD(dir)   ((dir) == HB_DIRECTION_LTR || (dir) == HB_DIRECTION_TTB)
-#define HB_DIRECTION_IS_BACKWARD(dir)  ((dir) == HB_DIRECTION_RTL || (dir) == HB_DIRECTION_BTT)
+#define HB_DIRECTION_IS_HORIZONTAL(dir)        ((((unsigned int) (dir)) & ~1U) == 0)
+#define HB_DIRECTION_IS_VERTICAL(dir)  ((((unsigned int) (dir)) & ~1U) == 2)
+#define HB_DIRECTION_IS_FORWARD(dir)   ((((unsigned int) (dir)) & ~2U) == 0)
+#define HB_DIRECTION_IS_BACKWARD(dir)  ((((unsigned int) (dir)) & ~2U) == 1)
 #define HB_DIRECTION_REVERSE(dir)      ((hb_direction_t) (((unsigned int) (dir)) ^ 1))