/src/hpn-ssh/openbsd-compat/sys-tree.h
Line  | Count  | Source  | 
1  |  | /*  $OpenBSD: tree.h,v 1.13 2011/07/09 00:19:45 pirofti Exp $ */  | 
2  |  | /*  | 
3  |  |  * Copyright 2002 Niels Provos <provos@citi.umich.edu>  | 
4  |  |  * All rights reserved.  | 
5  |  |  *  | 
6  |  |  * Redistribution and use in source and binary forms, with or without  | 
7  |  |  * modification, are permitted provided that the following conditions  | 
8  |  |  * are met:  | 
9  |  |  * 1. Redistributions of source code must retain the above copyright  | 
10  |  |  *    notice, this list of conditions and the following disclaimer.  | 
11  |  |  * 2. Redistributions in binary form must reproduce the above copyright  | 
12  |  |  *    notice, this list of conditions and the following disclaimer in the  | 
13  |  |  *    documentation and/or other materials provided with the distribution.  | 
14  |  |  *  | 
15  |  |  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR  | 
16  |  |  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES  | 
17  |  |  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  | 
18  |  |  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,  | 
19  |  |  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT  | 
20  |  |  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,  | 
21  |  |  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY  | 
22  |  |  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT  | 
23  |  |  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF  | 
24  |  |  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  | 
25  |  |  */  | 
26  |  |  | 
27  |  | /* OPENBSD ORIGINAL: sys/sys/tree.h */  | 
28  |  |  | 
29  |  | #include "config.h"  | 
30  |  | #ifdef NO_ATTRIBUTE_ON_RETURN_TYPE  | 
31  |  | # define __attribute__(x)  | 
32  |  | #endif  | 
33  |  |  | 
34  |  | #ifndef _SYS_TREE_H_  | 
35  |  | #define _SYS_TREE_H_  | 
36  |  |  | 
37  |  | /*  | 
38  |  |  * This file defines data structures for different types of trees:  | 
39  |  |  * splay trees and red-black trees.  | 
40  |  |  *  | 
41  |  |  * A splay tree is a self-organizing data structure.  Every operation  | 
42  |  |  * on the tree causes a splay to happen.  The splay moves the requested  | 
43  |  |  * node to the root of the tree and partly rebalances it.  | 
44  |  |  *  | 
45  |  |  * This has the benefit that request locality causes faster lookups as  | 
46  |  |  * the requested nodes move to the top of the tree.  On the other hand,  | 
47  |  |  * every lookup causes memory writes.  | 
48  |  |  *  | 
49  |  |  * The Balance Theorem bounds the total access time for m operations  | 
50  |  |  * and n inserts on an initially empty tree as O((m + n)lg n).  The  | 
51  |  |  * amortized cost for a sequence of m accesses to a splay tree is O(lg n);  | 
52  |  |  *  | 
53  |  |  * A red-black tree is a binary search tree with the node color as an  | 
54  |  |  * extra attribute.  It fulfills a set of conditions:  | 
55  |  |  *  - every search path from the root to a leaf consists of the  | 
56  |  |  *    same number of black nodes,  | 
57  |  |  *  - each red node (except for the root) has a black parent,  | 
58  |  |  *  - each leaf node is black.  | 
59  |  |  *  | 
60  |  |  * Every operation on a red-black tree is bounded as O(lg n).  | 
61  |  |  * The maximum height of a red-black tree is 2lg (n+1).  | 
62  |  |  */  | 
63  |  |  | 
64  |  | #define SPLAY_HEAD(name, type)            \  | 
65  |  | struct name {               \ | 
66  |  |   struct type *sph_root; /* root of the tree */     \  | 
67  |  | }  | 
68  |  |  | 
69  |  | #define SPLAY_INITIALIZER(root)           \  | 
70  |  |   { NULL } | 
71  |  |  | 
72  |  | #define SPLAY_INIT(root) do {           \ | 
73  |  |   (root)->sph_root = NULL;          \  | 
74  |  | } while (0)  | 
75  |  |  | 
76  |  | #define SPLAY_ENTRY(type)           \  | 
77  |  | struct {                \ | 
78  |  |   struct type *spe_left; /* left element */     \  | 
79  |  |   struct type *spe_right; /* right element */     \  | 
80  |  | }  | 
81  |  |  | 
82  |  | #define SPLAY_LEFT(elm, field)    (elm)->field.spe_left  | 
83  |  | #define SPLAY_RIGHT(elm, field)   (elm)->field.spe_right  | 
84  |  | #define SPLAY_ROOT(head)    (head)->sph_root  | 
85  |  | #define SPLAY_EMPTY(head)   (SPLAY_ROOT(head) == NULL)  | 
86  |  |  | 
87  |  | /* SPLAY_ROTATE_{LEFT,RIGHT} expect that tmp hold SPLAY_{RIGHT,LEFT} */ | 
88  |  | #define SPLAY_ROTATE_RIGHT(head, tmp, field) do {     \ | 
89  |  |   SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(tmp, field);  \  | 
90  |  |   SPLAY_RIGHT(tmp, field) = (head)->sph_root;     \  | 
91  |  |   (head)->sph_root = tmp;           \  | 
92  |  | } while (0)  | 
93  |  |     | 
94  |  | #define SPLAY_ROTATE_LEFT(head, tmp, field) do {      \ | 
95  |  |   SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(tmp, field);  \  | 
96  |  |   SPLAY_LEFT(tmp, field) = (head)->sph_root;      \  | 
97  |  |   (head)->sph_root = tmp;           \  | 
98  |  | } while (0)  | 
99  |  |  | 
100  |  | #define SPLAY_LINKLEFT(head, tmp, field) do {       \ | 
101  |  |   SPLAY_LEFT(tmp, field) = (head)->sph_root;      \  | 
102  |  |   tmp = (head)->sph_root;           \  | 
103  |  |   (head)->sph_root = SPLAY_LEFT((head)->sph_root, field);   \  | 
104  |  | } while (0)  | 
105  |  |  | 
106  |  | #define SPLAY_LINKRIGHT(head, tmp, field) do {        \ | 
107  |  |   SPLAY_RIGHT(tmp, field) = (head)->sph_root;     \  | 
108  |  |   tmp = (head)->sph_root;           \  | 
109  |  |   (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field);  \  | 
110  |  | } while (0)  | 
111  |  |  | 
112  |  | #define SPLAY_ASSEMBLE(head, node, left, right, field) do {   \ | 
113  |  |   SPLAY_RIGHT(left, field) = SPLAY_LEFT((head)->sph_root, field); \  | 
114  |  |   SPLAY_LEFT(right, field) = SPLAY_RIGHT((head)->sph_root, field);\  | 
115  |  |   SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(node, field); \  | 
116  |  |   SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(node, field); \  | 
117  |  | } while (0)  | 
118  |  |  | 
119  |  | /* Generates prototypes and inline functions */  | 
120  |  |  | 
121  |  | #define SPLAY_PROTOTYPE(name, type, field, cmp)       \  | 
122  |  | void name##_SPLAY(struct name *, struct type *);      \  | 
123  |  | void name##_SPLAY_MINMAX(struct name *, int);       \  | 
124  |  | struct type *name##_SPLAY_INSERT(struct name *, struct type *);   \  | 
125  |  | struct type *name##_SPLAY_REMOVE(struct name *, struct type *);   \  | 
126  |  |                   \  | 
127  |  | /* Finds the node with the same key as elm */       \  | 
128  |  | static __inline struct type *           \  | 
129  |  | name##_SPLAY_FIND(struct name *head, struct type *elm)      \  | 
130  |  | {                 \ | 
131  |  |   if (SPLAY_EMPTY(head))            \  | 
132  |  |     return(NULL);           \  | 
133  |  |   name##_SPLAY(head, elm);          \  | 
134  |  |   if ((cmp)(elm, (head)->sph_root) == 0)        \  | 
135  |  |     return (head->sph_root);        \  | 
136  |  |   return (NULL);              \  | 
137  |  | }                 \  | 
138  |  |                   \  | 
139  |  | static __inline struct type *           \  | 
140  |  | name##_SPLAY_NEXT(struct name *head, struct type *elm)      \  | 
141  |  | {                 \ | 
142  |  |   name##_SPLAY(head, elm);          \  | 
143  |  |   if (SPLAY_RIGHT(elm, field) != NULL) {        \ | 
144  |  |     elm = SPLAY_RIGHT(elm, field);        \  | 
145  |  |     while (SPLAY_LEFT(elm, field) != NULL) {    \ | 
146  |  |       elm = SPLAY_LEFT(elm, field);     \  | 
147  |  |     }             \  | 
148  |  |   } else                \  | 
149  |  |     elm = NULL;           \  | 
150  |  |   return (elm);             \  | 
151  |  | }                 \  | 
152  |  |                   \  | 
153  |  | static __inline struct type *           \  | 
154  |  | name##_SPLAY_MIN_MAX(struct name *head, int val)      \  | 
155  |  | {                 \ | 
156  |  |   name##_SPLAY_MINMAX(head, val);         \  | 
157  |  |         return (SPLAY_ROOT(head));          \  | 
158  |  | }  | 
159  |  |  | 
160  |  | /* Main splay operation.  | 
161  |  |  * Moves node close to the key of elm to top  | 
162  |  |  */  | 
163  |  | #define SPLAY_GENERATE(name, type, field, cmp)        \  | 
164  |  | struct type *               \  | 
165  |  | name##_SPLAY_INSERT(struct name *head, struct type *elm)    \  | 
166  |  | {                 \ | 
167  |  |     if (SPLAY_EMPTY(head)) {            \ | 
168  |  |       SPLAY_LEFT(elm, field) = SPLAY_RIGHT(elm, field) = NULL;  \  | 
169  |  |     } else {                \ | 
170  |  |       int __comp;             \  | 
171  |  |       name##_SPLAY(head, elm);          \  | 
172  |  |       __comp = (cmp)(elm, (head)->sph_root);      \  | 
173  |  |       if(__comp < 0) {            \ | 
174  |  |         SPLAY_LEFT(elm, field) = SPLAY_LEFT((head)->sph_root, field);\  | 
175  |  |         SPLAY_RIGHT(elm, field) = (head)->sph_root;   \  | 
176  |  |         SPLAY_LEFT((head)->sph_root, field) = NULL;   \  | 
177  |  |       } else if (__comp > 0) {          \ | 
178  |  |         SPLAY_RIGHT(elm, field) = SPLAY_RIGHT((head)->sph_root, field);\  | 
179  |  |         SPLAY_LEFT(elm, field) = (head)->sph_root;    \  | 
180  |  |         SPLAY_RIGHT((head)->sph_root, field) = NULL;  \  | 
181  |  |       } else              \  | 
182  |  |         return ((head)->sph_root);        \  | 
183  |  |     }                 \  | 
184  |  |     (head)->sph_root = (elm);           \  | 
185  |  |     return (NULL);              \  | 
186  |  | }                 \  | 
187  |  |                   \  | 
188  |  | struct type *               \  | 
189  |  | name##_SPLAY_REMOVE(struct name *head, struct type *elm)    \  | 
190  |  | {                 \ | 
191  |  |   struct type *__tmp;           \  | 
192  |  |   if (SPLAY_EMPTY(head))            \  | 
193  |  |     return (NULL);            \  | 
194  |  |   name##_SPLAY(head, elm);          \  | 
195  |  |   if ((cmp)(elm, (head)->sph_root) == 0) {      \ | 
196  |  |     if (SPLAY_LEFT((head)->sph_root, field) == NULL) {  \ | 
197  |  |       (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field);\  | 
198  |  |     } else {            \ | 
199  |  |       __tmp = SPLAY_RIGHT((head)->sph_root, field); \  | 
200  |  |       (head)->sph_root = SPLAY_LEFT((head)->sph_root, field);\  | 
201  |  |       name##_SPLAY(head, elm);      \  | 
202  |  |       SPLAY_RIGHT((head)->sph_root, field) = __tmp; \  | 
203  |  |     }             \  | 
204  |  |     return (elm);           \  | 
205  |  |   }               \  | 
206  |  |   return (NULL);              \  | 
207  |  | }                 \  | 
208  |  |                   \  | 
209  |  | void                  \  | 
210  |  | name##_SPLAY(struct name *head, struct type *elm)     \  | 
211  |  | {                 \ | 
212  |  |   struct type __node, *__left, *__right, *__tmp;      \  | 
213  |  |   int __comp;             \  | 
214  |  | \  | 
215  |  |   SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = NULL;\  | 
216  |  |   __left = __right = &__node;         \  | 
217  |  | \  | 
218  |  |   while ((__comp = (cmp)(elm, (head)->sph_root))) {   \ | 
219  |  |     if (__comp < 0) {         \ | 
220  |  |       __tmp = SPLAY_LEFT((head)->sph_root, field);  \  | 
221  |  |       if (__tmp == NULL)        \  | 
222  |  |         break;          \  | 
223  |  |       if ((cmp)(elm, __tmp) < 0){     \ | 
224  |  |         SPLAY_ROTATE_RIGHT(head, __tmp, field); \  | 
225  |  |         if (SPLAY_LEFT((head)->sph_root, field) == NULL)\  | 
226  |  |           break;        \  | 
227  |  |       }           \  | 
228  |  |       SPLAY_LINKLEFT(head, __right, field);   \  | 
229  |  |     } else if (__comp > 0) {        \ | 
230  |  |       __tmp = SPLAY_RIGHT((head)->sph_root, field); \  | 
231  |  |       if (__tmp == NULL)        \  | 
232  |  |         break;          \  | 
233  |  |       if ((cmp)(elm, __tmp) > 0){     \ | 
234  |  |         SPLAY_ROTATE_LEFT(head, __tmp, field);  \  | 
235  |  |         if (SPLAY_RIGHT((head)->sph_root, field) == NULL)\  | 
236  |  |           break;        \  | 
237  |  |       }           \  | 
238  |  |       SPLAY_LINKRIGHT(head, __left, field);   \  | 
239  |  |     }             \  | 
240  |  |   }               \  | 
241  |  |   SPLAY_ASSEMBLE(head, &__node, __left, __right, field);    \  | 
242  |  | }                 \  | 
243  |  |                   \  | 
244  |  | /* Splay with either the minimum or the maximum element     \  | 
245  |  |  * Used to find minimum or maximum element in tree.     \  | 
246  |  |  */                 \  | 
247  |  | void name##_SPLAY_MINMAX(struct name *head, int __comp) \  | 
248  |  | {                 \ | 
249  |  |   struct type __node, *__left, *__right, *__tmp;      \  | 
250  |  | \  | 
251  |  |   SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = NULL;\  | 
252  |  |   __left = __right = &__node;         \  | 
253  |  | \  | 
254  |  |   while (1) {             \ | 
255  |  |     if (__comp < 0) {         \ | 
256  |  |       __tmp = SPLAY_LEFT((head)->sph_root, field);  \  | 
257  |  |       if (__tmp == NULL)        \  | 
258  |  |         break;          \  | 
259  |  |       if (__comp < 0){        \ | 
260  |  |         SPLAY_ROTATE_RIGHT(head, __tmp, field); \  | 
261  |  |         if (SPLAY_LEFT((head)->sph_root, field) == NULL)\  | 
262  |  |           break;        \  | 
263  |  |       }           \  | 
264  |  |       SPLAY_LINKLEFT(head, __right, field);   \  | 
265  |  |     } else if (__comp > 0) {        \ | 
266  |  |       __tmp = SPLAY_RIGHT((head)->sph_root, field); \  | 
267  |  |       if (__tmp == NULL)        \  | 
268  |  |         break;          \  | 
269  |  |       if (__comp > 0) {       \ | 
270  |  |         SPLAY_ROTATE_LEFT(head, __tmp, field);  \  | 
271  |  |         if (SPLAY_RIGHT((head)->sph_root, field) == NULL)\  | 
272  |  |           break;        \  | 
273  |  |       }           \  | 
274  |  |       SPLAY_LINKRIGHT(head, __left, field);   \  | 
275  |  |     }             \  | 
276  |  |   }               \  | 
277  |  |   SPLAY_ASSEMBLE(head, &__node, __left, __right, field);    \  | 
278  |  | }  | 
279  |  |  | 
280  |  | #define SPLAY_NEGINF  -1  | 
281  |  | #define SPLAY_INF 1  | 
282  |  |  | 
283  |  | #define SPLAY_INSERT(name, x, y)  name##_SPLAY_INSERT(x, y)  | 
284  |  | #define SPLAY_REMOVE(name, x, y)  name##_SPLAY_REMOVE(x, y)  | 
285  |  | #define SPLAY_FIND(name, x, y)    name##_SPLAY_FIND(x, y)  | 
286  |  | #define SPLAY_NEXT(name, x, y)    name##_SPLAY_NEXT(x, y)  | 
287  |  | #define SPLAY_MIN(name, x)    (SPLAY_EMPTY(x) ? NULL  \  | 
288  |  |           : name##_SPLAY_MIN_MAX(x, SPLAY_NEGINF))  | 
289  |  | #define SPLAY_MAX(name, x)    (SPLAY_EMPTY(x) ? NULL  \  | 
290  |  |           : name##_SPLAY_MIN_MAX(x, SPLAY_INF))  | 
291  |  |  | 
292  |  | #define SPLAY_FOREACH(x, name, head)          \  | 
293  |  |   for ((x) = SPLAY_MIN(name, head);       \  | 
294  |  |        (x) != NULL;           \  | 
295  |  |        (x) = SPLAY_NEXT(name, head, x))  | 
296  |  |  | 
297  |  | /* Macros that define a red-black tree */  | 
298  |  | #define RB_HEAD(name, type)           \  | 
299  |  | struct name {               \ | 
300  |  |   struct type *rbh_root; /* root of the tree */     \  | 
301  |  | }  | 
302  |  |  | 
303  |  | #define RB_INITIALIZER(root)            \  | 
304  |  |   { NULL } | 
305  |  |  | 
306  | 0  | #define RB_INIT(root) do {           \ | 
307  | 0  |   (root)->rbh_root = NULL;          \  | 
308  | 0  | } while (0)  | 
309  |  |  | 
310  | 0  | #define RB_BLACK  0  | 
311  | 0  | #define RB_RED    1  | 
312  |  | #define RB_ENTRY(type)              \  | 
313  |  | struct {                \ | 
314  |  |   struct type *rbe_left;    /* left element */    \  | 
315  |  |   struct type *rbe_right;   /* right element */   \  | 
316  |  |   struct type *rbe_parent;  /* parent element */    \  | 
317  |  |   int rbe_color;      /* node color */    \  | 
318  |  | }  | 
319  |  |  | 
320  | 0  | #define RB_LEFT(elm, field)   (elm)->field.rbe_left  | 
321  | 0  | #define RB_RIGHT(elm, field)    (elm)->field.rbe_right  | 
322  | 0  | #define RB_PARENT(elm, field)   (elm)->field.rbe_parent  | 
323  | 0  | #define RB_COLOR(elm, field)    (elm)->field.rbe_color  | 
324  | 0  | #define RB_ROOT(head)     (head)->rbh_root  | 
325  |  | #define RB_EMPTY(head)      (RB_ROOT(head) == NULL)  | 
326  |  |  | 
327  | 0  | #define RB_SET(elm, parent, field) do {         \ | 
328  | 0  |   RB_PARENT(elm, field) = parent;          \  | 
329  | 0  |   RB_LEFT(elm, field) = RB_RIGHT(elm, field) = NULL;    \  | 
330  | 0  |   RB_COLOR(elm, field) = RB_RED;         \  | 
331  | 0  | } while (0)  | 
332  |  |  | 
333  | 0  | #define RB_SET_BLACKRED(black, red, field) do {       \ | 
334  | 0  |   RB_COLOR(black, field) = RB_BLACK;       \  | 
335  | 0  |   RB_COLOR(red, field) = RB_RED;         \  | 
336  | 0  | } while (0)  | 
337  |  |  | 
338  |  | #ifndef RB_AUGMENT  | 
339  | 0  | #define RB_AUGMENT(x) do {} while (0) | 
340  |  | #endif  | 
341  |  |  | 
342  | 0  | #define RB_ROTATE_LEFT(head, elm, tmp, field) do {     \ | 
343  | 0  |   (tmp) = RB_RIGHT(elm, field);         \  | 
344  | 0  |   if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field))) {   \ | 
345  | 0  |     RB_PARENT(RB_LEFT(tmp, field), field) = (elm);   \  | 
346  | 0  |   }               \  | 
347  | 0  |   RB_AUGMENT(elm);            \  | 
348  | 0  |   if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field))) {   \ | 
349  | 0  |     if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) \  | 
350  | 0  |       RB_LEFT(RB_PARENT(elm, field), field) = (tmp); \  | 
351  | 0  |     else              \  | 
352  | 0  |       RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); \  | 
353  | 0  |   } else                \  | 
354  | 0  |     (head)->rbh_root = (tmp);       \  | 
355  | 0  |   RB_LEFT(tmp, field) = (elm);         \  | 
356  | 0  |   RB_PARENT(elm, field) = (tmp);         \  | 
357  | 0  |   RB_AUGMENT(tmp);            \  | 
358  | 0  |   if ((RB_PARENT(tmp, field)))          \  | 
359  | 0  |     RB_AUGMENT(RB_PARENT(tmp, field));      \  | 
360  | 0  | } while (0)  | 
361  |  |  | 
362  | 0  | #define RB_ROTATE_RIGHT(head, elm, tmp, field) do {     \ | 
363  | 0  |   (tmp) = RB_LEFT(elm, field);         \  | 
364  | 0  |   if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field))) {   \ | 
365  | 0  |     RB_PARENT(RB_RIGHT(tmp, field), field) = (elm);    \  | 
366  | 0  |   }               \  | 
367  | 0  |   RB_AUGMENT(elm);            \  | 
368  | 0  |   if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field))) {   \ | 
369  | 0  |     if ((elm) == RB_LEFT(RB_PARENT(elm, field), field)) \  | 
370  | 0  |       RB_LEFT(RB_PARENT(elm, field), field) = (tmp); \  | 
371  | 0  |     else              \  | 
372  | 0  |       RB_RIGHT(RB_PARENT(elm, field), field) = (tmp); \  | 
373  | 0  |   } else                \  | 
374  | 0  |     (head)->rbh_root = (tmp);       \  | 
375  | 0  |   RB_RIGHT(tmp, field) = (elm);         \  | 
376  | 0  |   RB_PARENT(elm, field) = (tmp);         \  | 
377  | 0  |   RB_AUGMENT(tmp);            \  | 
378  | 0  |   if ((RB_PARENT(tmp, field)))          \  | 
379  | 0  |     RB_AUGMENT(RB_PARENT(tmp, field));      \  | 
380  | 0  | } while (0)  | 
381  |  |  | 
382  |  | /* Generates prototypes and inline functions */  | 
383  |  | #define RB_PROTOTYPE(name, type, field, cmp)        \  | 
384  |  |   RB_PROTOTYPE_INTERNAL(name, type, field, cmp,)  | 
385  |  | #define RB_PROTOTYPE_STATIC(name, type, field, cmp)     \  | 
386  |  |   RB_PROTOTYPE_INTERNAL(name, type, field, cmp, __attribute__((__unused__)) static)  | 
387  |  | #define RB_PROTOTYPE_INTERNAL(name, type, field, cmp, attr)   \  | 
388  |  | attr void name##_RB_INSERT_COLOR(struct name *, struct type *);   \  | 
389  |  | attr void name##_RB_REMOVE_COLOR(struct name *, struct type *, struct type *);\  | 
390  |  | attr struct type *name##_RB_REMOVE(struct name *, struct type *); \  | 
391  |  | attr struct type *name##_RB_INSERT(struct name *, struct type *); \  | 
392  |  | attr struct type *name##_RB_FIND(struct name *, struct type *);   \  | 
393  |  | attr struct type *name##_RB_NFIND(struct name *, struct type *);  \  | 
394  |  | attr struct type *name##_RB_NEXT(struct type *);      \  | 
395  |  | attr struct type *name##_RB_PREV(struct type *);      \  | 
396  |  | attr struct type *name##_RB_MINMAX(struct name *, int);     \  | 
397  |  |                   \  | 
398  |  |  | 
399  |  | /* Main rb operation.  | 
400  |  |  * Moves node close to the key of elm to top  | 
401  |  |  */  | 
402  |  | #define RB_GENERATE(name, type, field, cmp)       \  | 
403  |  |   RB_GENERATE_INTERNAL(name, type, field, cmp,)  | 
404  |  | #define RB_GENERATE_STATIC(name, type, field, cmp)      \  | 
405  |  |   RB_GENERATE_INTERNAL(name, type, field, cmp, __attribute__((__unused__)) static)  | 
406  |  | #define RB_GENERATE_INTERNAL(name, type, field, cmp, attr)    \  | 
407  |  | attr void               \  | 
408  | 0  | name##_RB_INSERT_COLOR(struct name *head, struct type *elm)   \  | 
409  | 0  | {                 \ | 
410  | 0  |   struct type *parent, *gparent, *tmp;        \  | 
411  | 0  |   while ((parent = RB_PARENT(elm, field)) &&      \  | 
412  | 0  |       RB_COLOR(parent, field) == RB_RED) {     \ | 
413  | 0  |     gparent = RB_PARENT(parent, field);      \  | 
414  | 0  |     if (parent == RB_LEFT(gparent, field)) {   \ | 
415  | 0  |       tmp = RB_RIGHT(gparent, field);     \  | 
416  | 0  |       if (tmp && RB_COLOR(tmp, field) == RB_RED) { \ | 
417  | 0  |         RB_COLOR(tmp, field) = RB_BLACK; \  | 
418  | 0  |         RB_SET_BLACKRED(parent, gparent, field);\  | 
419  | 0  |         elm = gparent;        \  | 
420  | 0  |         continue;       \  | 
421  | 0  |       }           \  | 
422  | 0  |       if (RB_RIGHT(parent, field) == elm) {   \ | 
423  | 0  |         RB_ROTATE_LEFT(head, parent, tmp, field);\  | 
424  | 0  |         tmp = parent;       \  | 
425  | 0  |         parent = elm;       \  | 
426  | 0  |         elm = tmp;        \  | 
427  | 0  |       }           \  | 
428  | 0  |       RB_SET_BLACKRED(parent, gparent, field); \  | 
429  | 0  |       RB_ROTATE_RIGHT(head, gparent, tmp, field);  \  | 
430  | 0  |     } else {           \ | 
431  | 0  |       tmp = RB_LEFT(gparent, field);     \  | 
432  | 0  |       if (tmp && RB_COLOR(tmp, field) == RB_RED) { \ | 
433  | 0  |         RB_COLOR(tmp, field) = RB_BLACK; \  | 
434  | 0  |         RB_SET_BLACKRED(parent, gparent, field);\  | 
435  | 0  |         elm = gparent;        \  | 
436  | 0  |         continue;       \  | 
437  | 0  |       }           \  | 
438  | 0  |       if (RB_LEFT(parent, field) == elm) {   \ | 
439  | 0  |         RB_ROTATE_RIGHT(head, parent, tmp, field);\  | 
440  | 0  |         tmp = parent;       \  | 
441  | 0  |         parent = elm;       \  | 
442  | 0  |         elm = tmp;        \  | 
443  | 0  |       }           \  | 
444  | 0  |       RB_SET_BLACKRED(parent, gparent, field); \  | 
445  | 0  |       RB_ROTATE_LEFT(head, gparent, tmp, field);  \  | 
446  | 0  |     }             \  | 
447  | 0  |   }               \  | 
448  | 0  |   RB_COLOR(head->rbh_root, field) = RB_BLACK;     \  | 
449  | 0  | }                  \ Unexecuted instantiation: krl.c:revoked_serial_tree_RB_INSERT_COLOR Unexecuted instantiation: krl.c:revoked_key_id_tree_RB_INSERT_COLOR Unexecuted instantiation: krl.c:revoked_blob_tree_RB_INSERT_COLOR  | 
450  |  |                   \  | 
451  |  | attr void               \  | 
452  | 0  | name##_RB_REMOVE_COLOR(struct name *head, struct type *parent, struct type *elm) \  | 
453  | 0  | {                 \ | 
454  | 0  |   struct type *tmp;           \  | 
455  | 0  |   while ((elm == NULL || RB_COLOR(elm, field) == RB_BLACK) &&  \  | 
456  | 0  |       elm != RB_ROOT(head)) {         \ | 
457  | 0  |     if (RB_LEFT(parent, field) == elm) {     \ | 
458  | 0  |       tmp = RB_RIGHT(parent, field);      \  | 
459  | 0  |       if (RB_COLOR(tmp, field) == RB_RED) {   \ | 
460  | 0  |         RB_SET_BLACKRED(tmp, parent, field); \  | 
461  | 0  |         RB_ROTATE_LEFT(head, parent, tmp, field);\  | 
462  | 0  |         tmp = RB_RIGHT(parent, field);    \  | 
463  | 0  |       }           \  | 
464  | 0  |       if ((RB_LEFT(tmp, field) == NULL ||   \  | 
465  | 0  |           RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&\  | 
466  | 0  |           (RB_RIGHT(tmp, field) == NULL ||   \  | 
467  | 0  |           RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {\ | 
468  | 0  |         RB_COLOR(tmp, field) = RB_RED;   \  | 
469  | 0  |         elm = parent;       \  | 
470  | 0  |         parent = RB_PARENT(elm, field);   \  | 
471  | 0  |       } else {         \ | 
472  | 0  |         if (RB_RIGHT(tmp, field) == NULL || \  | 
473  | 0  |             RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK) {\ | 
474  | 0  |           struct type *oleft;   \  | 
475  | 0  |           if ((oleft = RB_LEFT(tmp, field)))\  | 
476  | 0  |             RB_COLOR(oleft, field) = RB_BLACK;\  | 
477  | 0  |           RB_COLOR(tmp, field) = RB_RED; \  | 
478  | 0  |           RB_ROTATE_RIGHT(head, tmp, oleft, field);\  | 
479  | 0  |           tmp = RB_RIGHT(parent, field);  \  | 
480  | 0  |         }         \  | 
481  | 0  |         RB_COLOR(tmp, field) = RB_COLOR(parent, field);\  | 
482  | 0  |         RB_COLOR(parent, field) = RB_BLACK; \  | 
483  | 0  |         if (RB_RIGHT(tmp, field))   \  | 
484  | 0  |           RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK;\  | 
485  | 0  |         RB_ROTATE_LEFT(head, parent, tmp, field);\  | 
486  | 0  |         elm = RB_ROOT(head);     \  | 
487  | 0  |         break;          \  | 
488  | 0  |       }           \  | 
489  | 0  |     } else {           \ | 
490  | 0  |       tmp = RB_LEFT(parent, field);      \  | 
491  | 0  |       if (RB_COLOR(tmp, field) == RB_RED) {   \ | 
492  | 0  |         RB_SET_BLACKRED(tmp, parent, field); \  | 
493  | 0  |         RB_ROTATE_RIGHT(head, parent, tmp, field);\  | 
494  | 0  |         tmp = RB_LEFT(parent, field);    \  | 
495  | 0  |       }           \  | 
496  | 0  |       if ((RB_LEFT(tmp, field) == NULL ||   \  | 
497  | 0  |           RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&\  | 
498  | 0  |           (RB_RIGHT(tmp, field) == NULL ||   \  | 
499  | 0  |           RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {\ | 
500  | 0  |         RB_COLOR(tmp, field) = RB_RED;   \  | 
501  | 0  |         elm = parent;       \  | 
502  | 0  |         parent = RB_PARENT(elm, field);   \  | 
503  | 0  |       } else {         \ | 
504  | 0  |         if (RB_LEFT(tmp, field) == NULL || \  | 
505  | 0  |             RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) {\ | 
506  | 0  |           struct type *oright;    \  | 
507  | 0  |           if ((oright = RB_RIGHT(tmp, field)))\  | 
508  | 0  |             RB_COLOR(oright, field) = RB_BLACK;\  | 
509  | 0  |           RB_COLOR(tmp, field) = RB_RED; \  | 
510  | 0  |           RB_ROTATE_LEFT(head, tmp, oright, field);\  | 
511  | 0  |           tmp = RB_LEFT(parent, field);  \  | 
512  | 0  |         }         \  | 
513  | 0  |         RB_COLOR(tmp, field) = RB_COLOR(parent, field);\  | 
514  | 0  |         RB_COLOR(parent, field) = RB_BLACK; \  | 
515  | 0  |         if (RB_LEFT(tmp, field))   \  | 
516  | 0  |           RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK;\  | 
517  | 0  |         RB_ROTATE_RIGHT(head, parent, tmp, field);\  | 
518  | 0  |         elm = RB_ROOT(head);     \  | 
519  | 0  |         break;          \  | 
520  | 0  |       }           \  | 
521  | 0  |     }             \  | 
522  | 0  |   }               \  | 
523  | 0  |   if (elm)             \  | 
524  | 0  |     RB_COLOR(elm, field) = RB_BLACK;     \  | 
525  | 0  | }                  \  | 
526  |  |                   \  | 
527  |  | attr struct type *              \  | 
528  | 0  | name##_RB_REMOVE(struct name *head, struct type *elm)     \  | 
529  | 0  | {                 \ | 
530  | 0  |   struct type *child, *parent, *old = elm;      \  | 
531  | 0  |   int color;              \  | 
532  | 0  |   if (RB_LEFT(elm, field) == NULL)       \  | 
533  | 0  |     child = RB_RIGHT(elm, field);       \  | 
534  | 0  |   else if (RB_RIGHT(elm, field) == NULL)       \  | 
535  | 0  |     child = RB_LEFT(elm, field);       \  | 
536  | 0  |   else {               \ | 
537  | 0  |     struct type *left;          \  | 
538  | 0  |     elm = RB_RIGHT(elm, field);       \  | 
539  | 0  |     while ((left = RB_LEFT(elm, field)))      \  | 
540  | 0  |       elm = left;         \  | 
541  | 0  |     child = RB_RIGHT(elm, field);       \  | 
542  | 0  |     parent = RB_PARENT(elm, field);       \  | 
543  | 0  |     color = RB_COLOR(elm, field);       \  | 
544  | 0  |     if (child)           \  | 
545  | 0  |       RB_PARENT(child, field) = parent;   \  | 
546  | 0  |     if (parent) {           \ | 
547  | 0  |       if (RB_LEFT(parent, field) == elm)   \  | 
548  | 0  |         RB_LEFT(parent, field) = child;   \  | 
549  | 0  |       else            \  | 
550  | 0  |         RB_RIGHT(parent, field) = child; \  | 
551  | 0  |       RB_AUGMENT(parent);       \  | 
552  | 0  |     } else              \  | 
553  | 0  |       RB_ROOT(head) = child;       \  | 
554  | 0  |     if (RB_PARENT(elm, field) == old)     \  | 
555  | 0  |       parent = elm;         \  | 
556  | 0  |     (elm)->field = (old)->field;        \  | 
557  | 0  |     if (RB_PARENT(old, field)) {       \ | 
558  | 0  |       if (RB_LEFT(RB_PARENT(old, field), field) == old)\  | 
559  | 0  |         RB_LEFT(RB_PARENT(old, field), field) = elm;\  | 
560  | 0  |       else            \  | 
561  | 0  |         RB_RIGHT(RB_PARENT(old, field), field) = elm;\  | 
562  | 0  |       RB_AUGMENT(RB_PARENT(old, field));    \  | 
563  | 0  |     } else              \  | 
564  | 0  |       RB_ROOT(head) = elm;       \  | 
565  | 0  |     RB_PARENT(RB_LEFT(old, field), field) = elm;   \  | 
566  | 0  |     if (RB_RIGHT(old, field))       \  | 
567  | 0  |       RB_PARENT(RB_RIGHT(old, field), field) = elm; \  | 
568  | 0  |     if (parent) {           \ | 
569  | 0  |       left = parent;          \  | 
570  | 0  |       do {           \ | 
571  | 0  |         RB_AUGMENT(left);     \  | 
572  | 0  |       } while ((left = RB_PARENT(left, field)));  \  | 
573  | 0  |     }             \  | 
574  | 0  |     goto color;           \  | 
575  | 0  |   }               \  | 
576  | 0  |   parent = RB_PARENT(elm, field);         \  | 
577  | 0  |   color = RB_COLOR(elm, field);         \  | 
578  | 0  |   if (child)             \  | 
579  | 0  |     RB_PARENT(child, field) = parent;     \  | 
580  | 0  |   if (parent) {             \ | 
581  | 0  |     if (RB_LEFT(parent, field) == elm)     \  | 
582  | 0  |       RB_LEFT(parent, field) = child;     \  | 
583  | 0  |     else              \  | 
584  | 0  |       RB_RIGHT(parent, field) = child;   \  | 
585  | 0  |     RB_AUGMENT(parent);         \  | 
586  | 0  |   } else                \  | 
587  | 0  |     RB_ROOT(head) = child;         \  | 
588  | 0  | color:                  \  | 
589  | 0  |   if (color == RB_BLACK)           \  | 
590  | 0  |     name##_RB_REMOVE_COLOR(head, parent, child);    \  | 
591  | 0  |   return (old);             \  | 
592  | 0  | }                  \  | 
593  |  |                   \  | 
594  |  | /* Inserts a node into the RB tree */         \  | 
595  |  | attr struct type *              \  | 
596  | 0  | name##_RB_INSERT(struct name *head, struct type *elm)     \  | 
597  | 0  | {                 \ | 
598  | 0  |   struct type *tmp;           \  | 
599  | 0  |   struct type *parent = NULL;         \  | 
600  | 0  |   int comp = 0;             \  | 
601  | 0  |   tmp = RB_ROOT(head);           \  | 
602  | 0  |   while (tmp) {             \ | 
603  | 0  |     parent = tmp;           \  | 
604  | 0  |     comp = (cmp)(elm, parent);        \  | 
605  | 0  |     if (comp < 0)           \  | 
606  | 0  |       tmp = RB_LEFT(tmp, field);     \  | 
607  | 0  |     else if (comp > 0)         \  | 
608  | 0  |       tmp = RB_RIGHT(tmp, field);     \  | 
609  | 0  |     else              \  | 
610  | 0  |       return (tmp);         \  | 
611  | 0  |   }               \  | 
612  | 0  |   RB_SET(elm, parent, field);         \  | 
613  | 0  |   if (parent != NULL) {           \ | 
614  | 0  |     if (comp < 0)           \  | 
615  | 0  |       RB_LEFT(parent, field) = elm;     \  | 
616  | 0  |     else              \  | 
617  | 0  |       RB_RIGHT(parent, field) = elm;     \  | 
618  | 0  |     RB_AUGMENT(parent);         \  | 
619  | 0  |   } else                \  | 
620  | 0  |     RB_ROOT(head) = elm;         \  | 
621  | 0  |   name##_RB_INSERT_COLOR(head, elm);        \  | 
622  | 0  |   return (NULL);              \  | 
623  | 0  | }                  \  | 
624  |  |                   \  | 
625  |  | /* Finds the node with the same key as elm */       \  | 
626  |  | attr struct type *              \  | 
627  | 0  | name##_RB_FIND(struct name *head, struct type *elm)     \  | 
628  | 0  | {                 \ | 
629  | 0  |   struct type *tmp = RB_ROOT(head);       \  | 
630  | 0  |   int comp;             \  | 
631  | 0  |   while (tmp) {             \ | 
632  | 0  |     comp = cmp(elm, tmp);         \  | 
633  | 0  |     if (comp < 0)           \  | 
634  | 0  |       tmp = RB_LEFT(tmp, field);     \  | 
635  | 0  |     else if (comp > 0)         \  | 
636  | 0  |       tmp = RB_RIGHT(tmp, field);     \  | 
637  | 0  |     else              \  | 
638  | 0  |       return (tmp);         \  | 
639  | 0  |   }               \  | 
640  | 0  |   return (NULL);             \  | 
641  | 0  | }                  \  | 
642  |  |                   \  | 
643  |  | /* Finds the first node greater than or equal to the search key */  \  | 
644  |  | attr struct type *              \  | 
645  | 0  | name##_RB_NFIND(struct name *head, struct type *elm)      \  | 
646  | 0  | {                 \ | 
647  | 0  |   struct type *tmp = RB_ROOT(head);       \  | 
648  | 0  |   struct type *res = NULL;          \  | 
649  | 0  |   int comp;             \  | 
650  | 0  |   while (tmp) {             \ | 
651  | 0  |     comp = cmp(elm, tmp);         \  | 
652  | 0  |     if (comp < 0) {           \ | 
653  | 0  |       res = tmp;          \  | 
654  | 0  |       tmp = RB_LEFT(tmp, field);     \  | 
655  | 0  |     }             \  | 
656  | 0  |     else if (comp > 0)         \  | 
657  | 0  |       tmp = RB_RIGHT(tmp, field);     \  | 
658  | 0  |     else              \  | 
659  | 0  |       return (tmp);         \  | 
660  | 0  |   }               \  | 
661  | 0  |   return (res);             \  | 
662  | 0  | }                  \ Unexecuted instantiation: krl.c:revoked_key_id_tree_RB_NFIND Unexecuted instantiation: krl.c:revoked_blob_tree_RB_NFIND  | 
663  |  |                   \  | 
664  |  | /* ARGSUSED */                \  | 
665  |  | attr struct type *              \  | 
666  | 0  | name##_RB_NEXT(struct type *elm)          \  | 
667  | 0  | {                 \ | 
668  | 0  |   if (RB_RIGHT(elm, field)) {         \ | 
669  | 0  |     elm = RB_RIGHT(elm, field);       \  | 
670  | 0  |     while (RB_LEFT(elm, field))       \  | 
671  | 0  |       elm = RB_LEFT(elm, field);     \  | 
672  | 0  |   } else {             \ | 
673  | 0  |     if (RB_PARENT(elm, field) &&       \  | 
674  | 0  |         (elm == RB_LEFT(RB_PARENT(elm, field), field)))  \  | 
675  | 0  |       elm = RB_PARENT(elm, field);     \  | 
676  | 0  |     else {             \ | 
677  | 0  |       while (RB_PARENT(elm, field) &&     \  | 
678  | 0  |           (elm == RB_RIGHT(RB_PARENT(elm, field), field)))\  | 
679  | 0  |         elm = RB_PARENT(elm, field);   \  | 
680  | 0  |       elm = RB_PARENT(elm, field);     \  | 
681  | 0  |     }             \  | 
682  | 0  |   }               \  | 
683  | 0  |   return (elm);             \  | 
684  | 0  | }                  \ Unexecuted instantiation: krl.c:revoked_blob_tree_RB_NEXT Unexecuted instantiation: krl.c:revoked_serial_tree_RB_NEXT Unexecuted instantiation: krl.c:revoked_key_id_tree_RB_NEXT  | 
685  |  |                   \  | 
686  |  | /* ARGSUSED */                \  | 
687  |  | attr struct type *              \  | 
688  | 0  | name##_RB_PREV(struct type *elm)          \  | 
689  | 0  | {                 \ | 
690  | 0  |   if (RB_LEFT(elm, field)) {         \ | 
691  | 0  |     elm = RB_LEFT(elm, field);       \  | 
692  | 0  |     while (RB_RIGHT(elm, field))       \  | 
693  | 0  |       elm = RB_RIGHT(elm, field);     \  | 
694  | 0  |   } else {             \ | 
695  | 0  |     if (RB_PARENT(elm, field) &&       \  | 
696  | 0  |         (elm == RB_RIGHT(RB_PARENT(elm, field), field)))  \  | 
697  | 0  |       elm = RB_PARENT(elm, field);     \  | 
698  | 0  |     else {             \ | 
699  | 0  |       while (RB_PARENT(elm, field) &&     \  | 
700  | 0  |           (elm == RB_LEFT(RB_PARENT(elm, field), field)))\  | 
701  | 0  |         elm = RB_PARENT(elm, field);   \  | 
702  | 0  |       elm = RB_PARENT(elm, field);     \  | 
703  | 0  |     }             \  | 
704  | 0  |   }               \  | 
705  | 0  |   return (elm);             \  | 
706  | 0  | }                  \ Unexecuted instantiation: krl.c:revoked_serial_tree_RB_PREV Unexecuted instantiation: krl.c:revoked_key_id_tree_RB_PREV Unexecuted instantiation: krl.c:revoked_blob_tree_RB_PREV  | 
707  |  |                   \  | 
708  |  | attr struct type *              \  | 
709  | 0  | name##_RB_MINMAX(struct name *head, int val)        \  | 
710  | 0  | {                 \ | 
711  | 0  |   struct type *tmp = RB_ROOT(head);       \  | 
712  | 0  |   struct type *parent = NULL;         \  | 
713  | 0  |   while (tmp) {             \ | 
714  | 0  |     parent = tmp;           \  | 
715  | 0  |     if (val < 0)           \  | 
716  | 0  |       tmp = RB_LEFT(tmp, field);     \  | 
717  | 0  |     else              \  | 
718  | 0  |       tmp = RB_RIGHT(tmp, field);     \  | 
719  | 0  |   }               \  | 
720  | 0  |   return (parent);            \  | 
721  | 0  | }  | 
722  |  |  | 
723  | 0  | #define RB_NEGINF -1  | 
724  |  | #define RB_INF  1  | 
725  |  |  | 
726  | 0  | #define RB_INSERT(name, x, y) name##_RB_INSERT(x, y)  | 
727  | 0  | #define RB_REMOVE(name, x, y) name##_RB_REMOVE(x, y)  | 
728  | 0  | #define RB_FIND(name, x, y) name##_RB_FIND(x, y)  | 
729  | 0  | #define RB_NFIND(name, x, y)  name##_RB_NFIND(x, y)  | 
730  | 0  | #define RB_NEXT(name, x, y) name##_RB_NEXT(y)  | 
731  | 0  | #define RB_PREV(name, x, y) name##_RB_PREV(y)  | 
732  | 0  | #define RB_MIN(name, x)   name##_RB_MINMAX(x, RB_NEGINF)  | 
733  |  | #define RB_MAX(name, x)   name##_RB_MINMAX(x, RB_INF)  | 
734  |  |  | 
735  |  | #define RB_FOREACH(x, name, head)         \  | 
736  | 0  |   for ((x) = RB_MIN(name, head);         \  | 
737  | 0  |        (x) != NULL;           \  | 
738  | 0  |        (x) = name##_RB_NEXT(x))  | 
739  |  |  | 
740  |  | #define RB_FOREACH_SAFE(x, name, head, y)       \  | 
741  | 0  |   for ((x) = RB_MIN(name, head);         \  | 
742  | 0  |       ((x) != NULL) && ((y) = name##_RB_NEXT(x), 1);    \  | 
743  | 0  |        (x) = (y))  | 
744  |  |  | 
745  |  | #define RB_FOREACH_REVERSE(x, name, head)       \  | 
746  |  |   for ((x) = RB_MAX(name, head);          \  | 
747  |  |        (x) != NULL;           \  | 
748  |  |        (x) = name##_RB_PREV(x))  | 
749  |  |  | 
750  |  | #define RB_FOREACH_REVERSE_SAFE(x, name, head, y)     \  | 
751  |  |   for ((x) = RB_MAX(name, head);          \  | 
752  |  |       ((x) != NULL) && ((y) = name##_RB_PREV(x), 1);    \  | 
753  |  |        (x) = (y))  | 
754  |  |  | 
755  |  | #endif  /* _SYS_TREE_H_ */  |