-static inline
-void estack_init(struct estack *stack)
-{
- stack->top = -1;
-}
-
-static inline
-struct estack_entry *estack_ax(struct estack *stack)
-{
- assert(stack->top >= 0);
- return &stack->e[stack->top];
-}
-
-static inline
-struct estack_entry *estack_bx(struct estack *stack)
-{
- assert(stack->top >= 1);
- return &stack->e[stack->top - 1];
-}
-
-static inline
-void estack_push(struct estack *stack)
-{
- assert(stack->top < FILTER_STACK_LEN - 1);
- ++stack->top;
-}
-
-static inline
-void estack_pop(struct estack *stack)
-{
- assert(stack->top >= 0);
- stack->top--;
-}
+#define estack_ax_v ax
+#define estack_bx_v bx
+
+#define estack_ax(stack, top) \
+ ({ \
+ assert((top) > FILTER_STACK_EMPTY); \
+ &(stack)->e[top]; \
+ })
+
+#define estack_bx(stack, top) \
+ ({ \
+ assert((top) > FILTER_STACK_EMPTY + 1); \
+ &(stack)->e[(top) - 1]; \
+ })
+
+#define estack_push(stack, top, ax, bx) \
+ do { \
+ assert((top) < FILTER_STACK_LEN - 1); \
+ (stack)->e[(top) - 1].u.v = (bx); \
+ (bx) = (ax); \
+ ++(top); \
+ } while (0)
+
+#define estack_pop(stack, top, ax, bx) \
+ do { \
+ assert((top) > FILTER_STACK_EMPTY); \
+ (ax) = (bx); \
+ (bx) = (stack)->e[(top) - 2].u.v; \
+ (top)--; \
+ } while (0)