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* [newlib-cygwin] RB_REMOVE invokes RB_REMOVE_COLOR either when
@ 2020-10-26 13:32 Sebastian Huber
0 siblings, 0 replies; only message in thread
From: Sebastian Huber @ 2020-10-26 13:32 UTC (permalink / raw)
To: newlib-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=640a96a231140f377d77fc2699c604d1b65011ce
commit 640a96a231140f377d77fc2699c604d1b65011ce
Author: dougm <dougm@FreeBSD.org>
Date: Sat May 30 01:48:12 2020 +0000
RB_REMOVE invokes RB_REMOVE_COLOR either when
child is red or child is null. In the first case, RB_REMOVE_COLOR just changes
the child to black and returns. With this change, RB_REMOVE handles that case,
and drops the child argument to RB_REMOVE_COLOR, since that value is always
null.
RB_REMOVE_COLOR is changed to remove a couple of unneeded tests, and
to eliminate some deep indentation.
RB_ISRED is defined to combine a null check with a test for redness,
to replace that combination in several places.
Reviewed by: markj
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D25032
Diff:
---
newlib/libc/include/sys/tree.h | 137 +++++++++++++++++++----------------------
1 file changed, 65 insertions(+), 72 deletions(-)
diff --git a/newlib/libc/include/sys/tree.h b/newlib/libc/include/sys/tree.h
index b1e5e23a7..d5adfdd4e 100644
--- a/newlib/libc/include/sys/tree.h
+++ b/newlib/libc/include/sys/tree.h
@@ -321,6 +321,7 @@ struct { \
#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)
#define RB_ROOT(head) (head)->rbh_root
#define RB_EMPTY(head) (RB_ROOT(head) == NULL)
@@ -396,7 +397,7 @@ struct { \
#define RB_PROTOTYPE_INSERT_COLOR(name, type, attr) \
attr void name##_RB_INSERT_COLOR(struct name *, struct type *)
#define RB_PROTOTYPE_REMOVE_COLOR(name, type, attr) \
- attr void name##_RB_REMOVE_COLOR(struct name *, struct type *, struct type *)
+ attr void name##_RB_REMOVE_COLOR(struct name *, struct type *)
#define RB_PROTOTYPE_REMOVE(name, type, attr) \
attr struct type *name##_RB_REMOVE(struct name *, struct type *)
#define RB_PROTOTYPE_INSERT(name, type, attr) \
@@ -439,12 +440,11 @@ attr void \
name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
{ \
struct type *parent, *gparent, *tmp; \
- while ((parent = RB_PARENT(elm, field)) != NULL && \
- RB_COLOR(parent, field) == RB_RED) { \
+ 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 (tmp && RB_COLOR(tmp, field) == RB_RED) { \
+ if (RB_ISRED(tmp, field)) { \
RB_COLOR(tmp, field) = RB_BLACK; \
RB_SET_BLACKRED(parent, gparent, field);\
elm = gparent; \
@@ -460,7 +460,7 @@ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
RB_ROTATE_RIGHT(head, gparent, tmp, field); \
} else { \
tmp = RB_LEFT(gparent, field); \
- if (tmp && RB_COLOR(tmp, field) == RB_RED) { \
+ if (RB_ISRED(tmp, field)) { \
RB_COLOR(tmp, field) = RB_BLACK; \
RB_SET_BLACKRED(parent, gparent, field);\
elm = gparent; \
@@ -481,11 +481,11 @@ name##_RB_INSERT_COLOR(struct name *head, struct type *elm) \
#define RB_GENERATE_REMOVE_COLOR(name, type, field, attr) \
attr void \
-name##_RB_REMOVE_COLOR(struct name *head, struct type *parent, struct type *elm) \
+name##_RB_REMOVE_COLOR(struct name *head, struct type *parent) \
{ \
- struct type *tmp; \
- while ((elm == NULL || RB_COLOR(elm, field) == RB_BLACK) && \
- elm != RB_ROOT(head)) { \
+ struct type *elm, *tmp; \
+ elm = NULL; \
+ do { \
if (RB_LEFT(parent, field) == elm) { \
tmp = RB_RIGHT(parent, field); \
if (RB_COLOR(tmp, field) == RB_RED) { \
@@ -493,32 +493,29 @@ name##_RB_REMOVE_COLOR(struct name *head, struct type *parent, struct type *elm)
RB_ROTATE_LEFT(head, parent, tmp, field);\
tmp = RB_RIGHT(parent, field); \
} \
- if ((RB_LEFT(tmp, field) == NULL || \
- RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&\
- (RB_RIGHT(tmp, field) == NULL || \
- RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {\
+ if (!RB_ISRED(RB_LEFT(tmp, field), field) && \
+ !RB_ISRED(RB_RIGHT(tmp, field), field)) { \
RB_COLOR(tmp, field) = RB_RED; \
elm = parent; \
parent = RB_PARENT(elm, field); \
- } else { \
- if (RB_RIGHT(tmp, field) == NULL || \
- RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK) {\
- struct type *oleft; \
- if ((oleft = RB_LEFT(tmp, field)) \
- != NULL) \
- RB_COLOR(oleft, field) = RB_BLACK;\
- RB_COLOR(tmp, field) = RB_RED; \
- RB_ROTATE_RIGHT(head, tmp, oleft, field);\
- tmp = RB_RIGHT(parent, field); \
- } \
- RB_COLOR(tmp, field) = RB_COLOR(parent, field);\
- RB_COLOR(parent, field) = RB_BLACK; \
- if (RB_RIGHT(tmp, field)) \
- RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK;\
- RB_ROTATE_LEFT(head, parent, tmp, field);\
- elm = RB_ROOT(head); \
- break; \
+ continue; \
} \
+ if (!RB_ISRED(RB_RIGHT(tmp, field), field)) { \
+ struct type *oleft; \
+ if ((oleft = RB_LEFT(tmp, field)) \
+ != NULL) \
+ RB_COLOR(oleft, field) = RB_BLACK; \
+ RB_COLOR(tmp, field) = RB_RED; \
+ RB_ROTATE_RIGHT(head, tmp, oleft, field); \
+ tmp = RB_RIGHT(parent, field); \
+ } \
+ RB_COLOR(tmp, field) = RB_COLOR(parent, field); \
+ RB_COLOR(parent, field) = RB_BLACK; \
+ if (RB_RIGHT(tmp, field)) \
+ RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK; \
+ RB_ROTATE_LEFT(head, parent, tmp, field); \
+ elm = RB_ROOT(head); \
+ break; \
} else { \
tmp = RB_LEFT(parent, field); \
if (RB_COLOR(tmp, field) == RB_RED) { \
@@ -526,59 +523,54 @@ name##_RB_REMOVE_COLOR(struct name *head, struct type *parent, struct type *elm)
RB_ROTATE_RIGHT(head, parent, tmp, field);\
tmp = RB_LEFT(parent, field); \
} \
- if ((RB_LEFT(tmp, field) == NULL || \
- RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&\
- (RB_RIGHT(tmp, field) == NULL || \
- RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {\
+ if (!RB_ISRED(RB_LEFT(tmp, field), field) && \
+ !RB_ISRED(RB_RIGHT(tmp, field), field)) { \
RB_COLOR(tmp, field) = RB_RED; \
elm = parent; \
parent = RB_PARENT(elm, field); \
- } else { \
- if (RB_LEFT(tmp, field) == NULL || \
- RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) {\
- struct type *oright; \
- if ((oright = RB_RIGHT(tmp, field)) \
- != NULL) \
- RB_COLOR(oright, field) = RB_BLACK;\
- RB_COLOR(tmp, field) = RB_RED; \
- RB_ROTATE_LEFT(head, tmp, oright, field);\
- tmp = RB_LEFT(parent, field); \
- } \
- RB_COLOR(tmp, field) = RB_COLOR(parent, field);\
- RB_COLOR(parent, field) = RB_BLACK; \
- if (RB_LEFT(tmp, field)) \
- RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK;\
- RB_ROTATE_RIGHT(head, parent, tmp, field);\
- elm = RB_ROOT(head); \
- break; \
+ continue; \
+ } \
+ if (!RB_ISRED(RB_LEFT(tmp, field), field)) { \
+ struct type *oright; \
+ if ((oright = RB_RIGHT(tmp, field)) \
+ != NULL) \
+ RB_COLOR(oright, field) = RB_BLACK; \
+ RB_COLOR(tmp, field) = RB_RED; \
+ RB_ROTATE_LEFT(head, tmp, oright, field); \
+ tmp = RB_LEFT(parent, field); \
} \
+ RB_COLOR(tmp, field) = RB_COLOR(parent, field); \
+ RB_COLOR(parent, field) = RB_BLACK; \
+ if (RB_LEFT(tmp, field)) \
+ RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK; \
+ RB_ROTATE_RIGHT(head, parent, tmp, field); \
+ elm = RB_ROOT(head); \
+ break; \
} \
- } \
- if (elm) \
- RB_COLOR(elm, field) = RB_BLACK; \
+ } while (!RB_ISRED(elm, field) && parent != NULL); \
+ RB_COLOR(elm, field) = RB_BLACK; \
}
#define RB_GENERATE_REMOVE(name, type, field, attr) \
attr struct type * \
name##_RB_REMOVE(struct name *head, struct type *elm) \
{ \
- struct type *child, *parent, *parent_old, *old = elm; \
+ struct type *child, *old, *parent, *parent_old, *right; \
int color; \
+ \
+ old = elm; \
parent_old = parent = RB_PARENT(elm, field); \
+ right = RB_RIGHT(elm, field); \
color = RB_COLOR(elm, field); \
- if (RB_LEFT(elm, field) == NULL) { \
- elm = child = RB_RIGHT(elm, field); \
- if (elm != NULL) \
- RB_PARENT(elm, field) = parent; \
- } else if (RB_RIGHT(elm, field) == NULL) { \
+ if (RB_LEFT(elm, field) == NULL) \
+ elm = child = right; \
+ else if (right == NULL) \
elm = child = RB_LEFT(elm, field); \
- RB_PARENT(elm, field) = parent; \
- } else { \
- elm = RB_RIGHT(old, field); \
- if ((child = RB_LEFT(elm, field)) == NULL) { \
- child = RB_RIGHT(elm, field); \
+ else { \
+ if ((child = RB_LEFT(right, field)) == NULL) { \
+ child = RB_RIGHT(right, field); \
RB_RIGHT(old, field) = child; \
- parent = elm; \
+ parent = elm = right; \
} else { \
do \
elm = child; \
@@ -586,8 +578,6 @@ name##_RB_REMOVE(struct name *head, struct type *elm) \
child = RB_RIGHT(elm, field); \
parent = RB_PARENT(elm, field); \
RB_LEFT(parent, field) = child; \
- if (child != NULL) \
- RB_PARENT(child, field) = parent; \
RB_PARENT(RB_RIGHT(old, field), field) = elm; \
} \
RB_PARENT(RB_LEFT(old, field), field) = elm; \
@@ -600,8 +590,11 @@ name##_RB_REMOVE(struct name *head, struct type *elm) \
RB_LEFT(parent_old, field) = elm; \
else \
RB_RIGHT(parent_old, field) = elm; \
- if (color == RB_BLACK) \
- name##_RB_REMOVE_COLOR(head, parent, child); \
+ if (child != NULL) { \
+ RB_PARENT(child, field) = parent; \
+ RB_COLOR(child, field) = RB_BLACK; \
+ } else if (color != RB_RED && parent != NULL) \
+ name##_RB_REMOVE_COLOR(head, parent); \
while (parent != NULL) { \
RB_AUGMENT(parent); \
parent = RB_PARENT(parent, field); \
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