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newlib-cygwin
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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
This commit is contained in:
trasz 2019-09-28 09:22:52 +00:00 committed by Sebastian Huber
parent 303c61925d
commit fd4cbaba7a
1 changed files with 24 additions and 2 deletions
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26
newlib/libc/include/sys/tree.h
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@ -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); \