1 #ifndef JEMALLOC_INTERNAL_QR_H
2 #define JEMALLOC_INTERNAL_QR_H
3 
4 /* Ring definitions. */
5 #define	qr(a_type)							\
6 struct {								\
7 	a_type	*qre_next;						\
8 	a_type	*qre_prev;						\
9 }
10 
11 /* Ring functions. */
12 #define	qr_new(a_qr, a_field) do {					\
13 	(a_qr)->a_field.qre_next = (a_qr);				\
14 	(a_qr)->a_field.qre_prev = (a_qr);				\
15 } while (0)
16 
17 #define	qr_next(a_qr, a_field) ((a_qr)->a_field.qre_next)
18 
19 #define	qr_prev(a_qr, a_field) ((a_qr)->a_field.qre_prev)
20 
21 #define	qr_before_insert(a_qrelm, a_qr, a_field) do {			\
22 	(a_qr)->a_field.qre_prev = (a_qrelm)->a_field.qre_prev;		\
23 	(a_qr)->a_field.qre_next = (a_qrelm);				\
24 	(a_qr)->a_field.qre_prev->a_field.qre_next = (a_qr);		\
25 	(a_qrelm)->a_field.qre_prev = (a_qr);				\
26 } while (0)
27 
28 #define	qr_after_insert(a_qrelm, a_qr, a_field)				\
29     do									\
30     {									\
31 	(a_qr)->a_field.qre_next = (a_qrelm)->a_field.qre_next;		\
32 	(a_qr)->a_field.qre_prev = (a_qrelm);				\
33 	(a_qr)->a_field.qre_next->a_field.qre_prev = (a_qr);		\
34 	(a_qrelm)->a_field.qre_next = (a_qr);				\
35     } while (0)
36 
37 #define	qr_meld(a_qr_a, a_qr_b, a_type, a_field) do {			\
38 	a_type *t;							\
39 	(a_qr_a)->a_field.qre_prev->a_field.qre_next = (a_qr_b);	\
40 	(a_qr_b)->a_field.qre_prev->a_field.qre_next = (a_qr_a);	\
41 	t = (a_qr_a)->a_field.qre_prev;					\
42 	(a_qr_a)->a_field.qre_prev = (a_qr_b)->a_field.qre_prev;	\
43 	(a_qr_b)->a_field.qre_prev = t;					\
44 } while (0)
45 
46 /*
47  * qr_meld() and qr_split() are functionally equivalent, so there's no need to
48  * have two copies of the code.
49  */
50 #define	qr_split(a_qr_a, a_qr_b, a_type, a_field)			\
51 	qr_meld((a_qr_a), (a_qr_b), a_type, a_field)
52 
53 #define	qr_remove(a_qr, a_field) do {					\
54 	(a_qr)->a_field.qre_prev->a_field.qre_next			\
55 	    = (a_qr)->a_field.qre_next;					\
56 	(a_qr)->a_field.qre_next->a_field.qre_prev			\
57 	    = (a_qr)->a_field.qre_prev;					\
58 	(a_qr)->a_field.qre_next = (a_qr);				\
59 	(a_qr)->a_field.qre_prev = (a_qr);				\
60 } while (0)
61 
62 #define	qr_foreach(var, a_qr, a_field)					\
63 	for ((var) = (a_qr);						\
64 	    (var) != NULL;						\
65 	    (var) = (((var)->a_field.qre_next != (a_qr))		\
66 	    ? (var)->a_field.qre_next : NULL))
67 
68 #define	qr_reverse_foreach(var, a_qr, a_field)				\
69 	for ((var) = ((a_qr) != NULL) ? qr_prev(a_qr, a_field) : NULL;	\
70 	    (var) != NULL;						\
71 	    (var) = (((var) != (a_qr))					\
72 	    ? (var)->a_field.qre_prev : NULL))
73 
74 #endif /* JEMALLOC_INTERNAL_QR_H */
75