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Index: head/sys/sys/tree.h
===================================================================
--- head/sys/sys/tree.h
+++ head/sys/sys/tree.h
@@ -307,38 +307,60 @@
(root)->rbh_root = NULL; \
} while (/*CONSTCOND*/ 0)
-#define RB_BLACK 0
-#define RB_RED 1
#define RB_ENTRY(type) \
struct { \
struct type *rbe_left; /* left element */ \
struct type *rbe_right; /* right element */ \
struct type *rbe_parent; /* parent element */ \
- int rbe_color; /* node color */ \
}
#define RB_LEFT(elm, field) (elm)->field.rbe_left
#define RB_RIGHT(elm, field) (elm)->field.rbe_right
-#define RB_PARENT(elm, field) (elm)->field.rbe_parent
-#define RB_COLOR(elm, field) (elm)->field.rbe_color
-#define RB_ISRED(elm, field) ((elm) != NULL && RB_COLOR(elm, field) == RB_RED)
+
+/*
+ * With the expectation that any object of struct type has an
+ * address that is a multiple of 4, and that therefore the
+ * 2 least significant bits of a pointer to struct type are
+ * always zero, this implementation sets those bits to indicate
+ * that the left or right child of the tree node is "red".
+ */
+#define RB_UP(elm, field) (elm)->field.rbe_parent
+#define RB_BITS(elm, field) *(__uintptr_t *)&RB_UP(elm, field)
+#define RB_RED_L (__uintptr_t)1
+#define RB_RED_R (__uintptr_t)2
+#define RB_RED_MASK (__uintptr_t)3
+#define RB_FLIP_LEFT(elm, field) (RB_BITS(elm, field) ^= RB_RED_L)
+#define RB_FLIP_RIGHT(elm, field) (RB_BITS(elm, field) ^= RB_RED_R)
+#define RB_RED_LEFT(elm, field) ((RB_BITS(elm, field) & RB_RED_L) != 0)
+#define RB_RED_RIGHT(elm, field) ((RB_BITS(elm, field) & RB_RED_R) != 0)
+#define RB_PARENT(elm, field) ((__typeof(RB_UP(elm, field))) \
+ (RB_BITS(elm, field) & ~RB_RED_MASK))
+
+/*
+ * This header may appear in user code where 'bool' is not defined,
+ * so it defines its own boolean type to avoid breaking that code.
+ */
+#define RB_BOOL int
+#define RB_TRUE 1
+#define RB_FALSE 0
+
#define RB_ROOT(head) (head)->rbh_root
#define RB_EMPTY(head) (RB_ROOT(head) == NULL)
#define RB_SET_PARENT(dst, src, field) do { \
- RB_PARENT(dst, field) = src; \
+ RB_BITS(dst, field) &= RB_RED_MASK; \
+ RB_BITS(dst, field) |= (__uintptr_t)src; \
} while (/*CONSTCOND*/ 0)
#define RB_SET(elm, parent, field) do { \
- RB_SET_PARENT(elm, parent, field); \
+ RB_UP(elm, field) = parent; \
RB_LEFT(elm, field) = RB_RIGHT(elm, field) = NULL; \
- RB_COLOR(elm, field) = RB_RED; \
} while (/*CONSTCOND*/ 0)
-#define RB_SET_BLACKRED(black, red, field) do { \
- RB_COLOR(black, field) = RB_BLACK; \
- RB_COLOR(red, field) = RB_RED; \
-} while (/*CONSTCOND*/ 0)
+#define RB_COLOR(elm, field) (RB_PARENT(elm, field) == NULL ? RB_FALSE : \
+ RB_LEFT(RB_PARENT(elm, field), field) == elm ? \
+ RB_RED_LEFT(RB_PARENT(elm, field), field) : \
+ RB_RED_RIGHT(RB_PARENT(elm, field), field))
/*
* Something to be invoked in a loop at the root of every modified subtree,
@@ -442,106 +464,123 @@
attr void \
name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
{ \
- struct type *parent, *gparent, *tmp; \
- while (RB_ISRED((parent = RB_PARENT(elm, field)), field)) { \
- gparent = RB_PARENT(parent, field); \
- if (parent == RB_LEFT(gparent, field)) { \
- tmp = RB_RIGHT(gparent, field); \
- if (RB_ISRED(tmp, field)) { \
- RB_COLOR(tmp, field) = RB_BLACK; \
- RB_SET_BLACKRED(parent, gparent, field);\
- elm = gparent; \
- continue; \
- } \
+ struct type *gparent, *parent; \
+ while ((parent = RB_PARENT(elm, field)) != NULL) { \
+ if (RB_LEFT(parent, field) == elm) \
+ RB_FLIP_LEFT(parent, field); \
+ else \
+ RB_FLIP_RIGHT(parent, field); \
+ if ((gparent = RB_PARENT(parent, field)) == NULL) \
+ break; \
+ if (RB_RED_LEFT(gparent, field) && \
+ RB_RED_RIGHT(gparent, field)) { \
+ RB_FLIP_LEFT(gparent, field); \
+ RB_FLIP_RIGHT(gparent, field); \
+ elm = gparent; \
+ continue; \
+ } \
+ if (RB_RED_LEFT(gparent, field) && \
+ parent == RB_LEFT(gparent, field)) { \
if (RB_RIGHT(parent, field) == elm) { \
- RB_ROTATE_LEFT(head, parent, tmp, field);\
- tmp = parent; \
+ RB_ROTATE_LEFT(head, parent, elm, field);\
+ RB_FLIP_RIGHT(parent, field); \
+ RB_FLIP_LEFT(elm, field); \
parent = elm; \
- elm = tmp; \
} \
- RB_SET_BLACKRED(parent, gparent, field); \
- RB_ROTATE_RIGHT(head, gparent, tmp, field); \
- } else { \
- tmp = RB_LEFT(gparent, field); \
- if (RB_ISRED(tmp, field)) { \
- RB_COLOR(tmp, field) = RB_BLACK; \
- RB_SET_BLACKRED(parent, gparent, field);\
- elm = gparent; \
- continue; \
- } \
+ RB_ROTATE_RIGHT(head, gparent, parent, field); \
+ RB_FLIP_LEFT(gparent, field); \
+ RB_FLIP_RIGHT(parent, field); \
+ } else if (RB_RED_RIGHT(gparent, field) && \
+ parent == RB_RIGHT(gparent, field)) { \
if (RB_LEFT(parent, field) == elm) { \
- RB_ROTATE_RIGHT(head, parent, tmp, field);\
- tmp = parent; \
+ RB_ROTATE_RIGHT(head, parent, elm, field);\
+ RB_FLIP_LEFT(parent, field); \
+ RB_FLIP_RIGHT(elm, field); \
parent = elm; \
- elm = tmp; \
} \
- RB_SET_BLACKRED(parent, gparent, field); \
- RB_ROTATE_LEFT(head, gparent, tmp, field); \
+ RB_ROTATE_LEFT(head, gparent, parent, field); \
+ RB_FLIP_RIGHT(gparent, field); \
+ RB_FLIP_LEFT(parent, field); \
} \
+ break; \
} \
- RB_COLOR(head->rbh_root, field) = RB_BLACK; \
}
#define RB_GENERATE_REMOVE_COLOR(name, type, field, attr) \
attr void \
-name##_RB_REMOVE_COLOR(struct name *head, struct type *parent) \
+name##_RB_REMOVE_COLOR(struct name *head, struct type *par) \
{ \
- struct type *elm, *tmp; \
- elm = NULL; \
+ struct type *gpr, *sib, *nec; \
+ RB_BOOL left_elm, left_par, red_gpr; \
+ left_par = (RB_LEFT(par, field) == NULL); \
do { \
- if (RB_LEFT(parent, field) == elm) { \
- tmp = RB_RIGHT(parent, field); \
- if (RB_COLOR(tmp, field) == RB_RED) { \
- RB_SET_BLACKRED(tmp, parent, field); \
- RB_ROTATE_LEFT(head, parent, tmp, field);\
- tmp = RB_RIGHT(parent, field); \
+ left_elm = left_par; \
+ if (left_elm ? \
+ !RB_RED_RIGHT(par, field) : \
+ !RB_RED_LEFT(par, field)) { \
+ gpr = RB_PARENT(par, field); \
+ left_par = gpr != NULL && \
+ RB_LEFT(gpr, field) == par; \
+ red_gpr = gpr == NULL ? \
+ RB_TRUE: RB_COLOR(par, field); \
+ } \
+ if (left_elm) { \
+ if (RB_RED_RIGHT(par, field)) { \
+ red_gpr = RB_TRUE; \
+ RB_ROTATE_LEFT(head, par, gpr, field); \
+ RB_FLIP_RIGHT(par, field); \
+ RB_FLIP_LEFT(gpr, field); \
} \
- if (RB_ISRED(RB_RIGHT(tmp, field), field)) \
- RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK; \
- else if (RB_ISRED(RB_LEFT(tmp, field), field)) { \
- struct type *oleft; \
- RB_ROTATE_RIGHT(head, tmp, oleft, field); \
- RB_COLOR(oleft, field) = RB_BLACK; \
- tmp = oleft; \
+ sib = RB_RIGHT(par, field); \
+ if (RB_RED_RIGHT(sib, field)) { \
+ if (RB_RED_LEFT(sib, field)) { \
+ RB_FLIP_LEFT(sib, field); \
+ RB_FLIP_RIGHT(par, field); \
+ } \
+ RB_FLIP_RIGHT(sib, field); \
+ } else if (RB_RED_LEFT(sib, field)) { \
+ RB_ROTATE_RIGHT(head, sib, nec, field); \
+ RB_FLIP_LEFT(sib, field); \
+ sib = nec; \
} else { \
- RB_COLOR(tmp, field) = RB_RED; \
- elm = parent; \
- parent = RB_PARENT(elm, field); \
+ RB_FLIP_RIGHT(par, field); \
+ par = gpr; \
continue; \
} \
- RB_COLOR(tmp, field) = RB_COLOR(parent, field); \
- RB_COLOR(parent, field) = RB_BLACK; \
- RB_ROTATE_LEFT(head, parent, tmp, field); \
- elm = RB_ROOT(head); \
- break; \
+ RB_ROTATE_LEFT(head, par, sib, field); \
+ return; \
} else { \
- tmp = RB_LEFT(parent, field); \
- if (RB_COLOR(tmp, field) == RB_RED) { \
- RB_SET_BLACKRED(tmp, parent, field); \
- RB_ROTATE_RIGHT(head, parent, tmp, field);\
- tmp = RB_LEFT(parent, field); \
+ if (RB_RED_LEFT(par, field)) { \
+ red_gpr = RB_TRUE; \
+ RB_ROTATE_RIGHT(head, par, gpr, field); \
+ RB_FLIP_LEFT(par, field); \
+ RB_FLIP_RIGHT(gpr, field); \
} \
- if (RB_ISRED(RB_LEFT(tmp, field), field)) \
- RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK; \
- else if (RB_ISRED(RB_RIGHT(tmp, field), field)) { \
- struct type *oright; \
- RB_ROTATE_LEFT(head, tmp, oright, field); \
- RB_COLOR(oright, field) = RB_BLACK; \
- tmp = oright; \
- } else if (!RB_ISRED(RB_LEFT(tmp, field), field)) { \
- RB_COLOR(tmp, field) = RB_RED; \
- elm = parent; \
- parent = RB_PARENT(elm, field); \
+ sib = RB_LEFT(par, field); \
+ if (RB_RED_LEFT(sib, field)) { \
+ if (RB_RED_RIGHT(sib, field)) { \
+ RB_FLIP_RIGHT(sib, field); \
+ RB_FLIP_LEFT(par, field); \
+ } \
+ RB_FLIP_LEFT(sib, field); \
+ } else if (RB_RED_RIGHT(sib, field)) { \
+ RB_ROTATE_LEFT(head, sib, nec, field); \
+ RB_FLIP_RIGHT(sib, field); \
+ sib = nec; \
+ } else { \
+ RB_FLIP_LEFT(par, field); \
+ par = gpr; \
continue; \
} \
- RB_COLOR(tmp, field) = RB_COLOR(parent, field); \
- RB_COLOR(parent, field) = RB_BLACK; \
- RB_ROTATE_RIGHT(head, parent, tmp, field); \
- elm = RB_ROOT(head); \
- break; \
+ RB_ROTATE_RIGHT(head, par, sib, field); \
+ return; \
} \
- } while (!RB_ISRED(elm, field) && parent != NULL); \
- RB_COLOR(elm, field) = RB_BLACK; \
+ } while (!red_gpr); \
+ if (gpr == NULL); \
+ else if (left_par) \
+ RB_FLIP_LEFT(gpr, field); \
+ else \
+ RB_FLIP_RIGHT(gpr, field); \
}
#define RB_GENERATE_REMOVE(name, type, field, attr) \
@@ -549,12 +588,11 @@
name##_RB_REMOVE(struct name *head, struct type *elm) \
{ \
struct type *child, *old, *parent, *right; \
- int color; \
+ RB_BOOL red; \
\
old = elm; \
parent = RB_PARENT(elm, field); \
right = RB_RIGHT(elm, field); \
- color = RB_COLOR(elm, field); \
if (RB_LEFT(elm, field) == NULL) \
elm = child = right; \
else if (right == NULL) \
@@ -562,6 +600,9 @@
else { \
if ((child = RB_LEFT(right, field)) == NULL) { \
child = RB_RIGHT(right, field); \
+ red = RB_RED_RIGHT(old, field); \
+ if (red) \
+ RB_FLIP_RIGHT(old, field); \
RB_RIGHT(old, field) = child; \
parent = elm = right; \
} else { \
@@ -570,18 +611,27 @@
while ((child = RB_LEFT(elm, field)) != NULL); \
child = RB_RIGHT(elm, field); \
parent = RB_PARENT(elm, field); \
+ red = RB_RED_LEFT(parent, field); \
+ if (red) \
+ RB_FLIP_LEFT(parent, field); \
RB_LEFT(parent, field) = child; \
RB_SET_PARENT(RB_RIGHT(old, field), elm, field); \
} \
RB_SET_PARENT(RB_LEFT(old, field), elm, field); \
- color = RB_COLOR(elm, field); \
elm->field = old->field; \
} \
+ if (elm == child) { \
+ red = RB_COLOR(old, field); \
+ if (!red); \
+ else if (RB_LEFT(parent, field) == old) \
+ RB_FLIP_LEFT(parent, field); \
+ else \
+ RB_FLIP_RIGHT(parent, field); \
+ } \
RB_SWAP_CHILD(head, old, elm, field); \
- if (child != NULL) { \
+ if (child != NULL) \
RB_SET_PARENT(child, parent, field); \
- RB_COLOR(child, field) = RB_BLACK; \
- } else if (color != RB_RED && parent != NULL) \
+ else if (!red && parent != NULL) \
name##_RB_REMOVE_COLOR(head, parent); \
while (parent != NULL) { \
RB_AUGMENT(parent); \
@@ -610,13 +660,12 @@
return (tmp); \
} \
RB_SET(elm, parent, field); \
- if (parent != NULL) { \
- if (comp < 0) \
- RB_LEFT(parent, field) = elm; \
- else \
- RB_RIGHT(parent, field) = elm; \
- } else \
+ if (parent == NULL) \
RB_ROOT(head) = elm; \
+ else if (comp < 0) \
+ RB_LEFT(parent, field) = elm; \
+ else \
+ RB_RIGHT(parent, field) = elm; \
name##_RB_INSERT_COLOR(head, elm); \
while (elm != NULL) { \
RB_AUGMENT(elm); \

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