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* [newlib-cygwin] Add RB_REINSERT(3), a low overhead alternative to
@ 2020-10-26 13:31 Sebastian Huber
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From: Sebastian Huber @ 2020-10-26 13:31 UTC (permalink / raw)
To: newlib-cvs
https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=fd4cbaba7aaf4a76082b480e1fbeadda0e0faa0c
commit fd4cbaba7aaf4a76082b480e1fbeadda0e0faa0c
Author: trasz <trasz@FreeBSD.org>
Date: Sat Sep 28 09:22:52 2019 +0000
Add RB_REINSERT(3), a low overhead alternative to
removing a node and reinserting it back with an updated key.
This is one of dependencies for the upcoming stats(3) code.
Reviewed by: cem
Obtained from: Netflix
MFC after: 2 weeks
Sponsored by: Klara Inc, Netflix
Differential Revision: https://reviews.freebsd.org/D21786
Diff:
---
newlib/libc/include/sys/tree.h | 26 ++++++++++++++++++++++++--
1 file changed, 24 insertions(+), 2 deletions(-)
diff --git a/newlib/libc/include/sys/tree.h b/newlib/libc/include/sys/tree.h
index fd66ceba1..0eacf951d 100644
--- a/newlib/libc/include/sys/tree.h
+++ b/newlib/libc/include/sys/tree.h
@@ -393,7 +393,8 @@ struct { \
RB_PROTOTYPE_NFIND(name, type, attr); \
RB_PROTOTYPE_NEXT(name, type, attr); \
RB_PROTOTYPE_PREV(name, type, attr); \
- RB_PROTOTYPE_MINMAX(name, type, attr);
+ RB_PROTOTYPE_MINMAX(name, type, attr); \
+ RB_PROTOTYPE_REINSERT(name, type, attr);
#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) \
@@ -412,6 +413,8 @@ struct { \
attr struct type *name##_RB_PREV(struct type *)
#define RB_PROTOTYPE_MINMAX(name, type, attr) \
attr struct type *name##_RB_MINMAX(struct name *, int)
+#define RB_PROTOTYPE_REINSERT(name, type, attr) \
+ attr struct type *name##_RB_REINSERT(struct name *, struct type *)
/* Main rb operation.
* Moves node close to the key of elm to top
@@ -429,7 +432,9 @@ struct { \
RB_GENERATE_NFIND(name, type, field, cmp, attr) \
RB_GENERATE_NEXT(name, type, field, attr) \
RB_GENERATE_PREV(name, type, field, attr) \
- RB_GENERATE_MINMAX(name, type, field, attr)
+ RB_GENERATE_MINMAX(name, type, field, attr) \
+ RB_GENERATE_REINSERT(name, type, field, cmp, attr)
+
#define RB_GENERATE_INSERT_COLOR(name, type, field, attr) \
attr void \
@@ -758,6 +763,22 @@ name##_RB_MINMAX(struct name *head, int val) \
return (parent); \
}
+#define RB_GENERATE_REINSERT(name, type, field, cmp, attr) \
+attr struct type * \
+name##_RB_REINSERT(struct name *head, struct type *elm) \
+{ \
+ struct type *cmpelm; \
+ if (((cmpelm = RB_PREV(name, head, elm)) != NULL && \
+ cmp(cmpelm, elm) >= 0) || \
+ ((cmpelm = RB_NEXT(name, head, elm)) != NULL && \
+ cmp(elm, cmpelm) >= 0)) { \
+ /* XXXLAS: Remove/insert is heavy handed. */ \
+ RB_REMOVE(name, head, elm); \
+ return (RB_INSERT(name, head, elm)); \
+ } \
+ return (NULL); \
+} \
+
#define RB_NEGINF -1
#define RB_INF 1
@@ -769,6 +790,7 @@ name##_RB_MINMAX(struct name *head, int val) \
#define RB_PREV(name, x, y) name##_RB_PREV(y)
#define RB_MIN(name, x) name##_RB_MINMAX(x, RB_NEGINF)
#define RB_MAX(name, x) name##_RB_MINMAX(x, RB_INF)
+#define RB_REINSERT(name, x, y) name##_RB_REINSERT(x, y)
#define RB_FOREACH(x, name, head) \
for ((x) = RB_MIN(name, head); \
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