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Add two new macros, SLIST_CONCAT and LIST_CONCAT 

Add two new macros, SLIST_CONCAT and LIST_CONCAT. Note in both the
queue.h header file and in the queue.3 manual page that they are O(n) so
should be used only in low-usage paths with short lists (otherwise an
STAILQ or TAILQ should be used).

Reviewed by: kib
This commit is contained in:
mckusick 2017-04-04 12:00:28 +02:00 committed by Corinna Vinschen
parent 218c5e7d72
commit 9998bd4b7c
1 changed files with 36 additions and 2 deletions
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38
newlib/libc/include/sys/queue.h
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@ -76,6 +76,10 @@
*
* For details on the use of these macros, see the queue(3) manual page.
*
* Below is a summary of implemented functions where:
* + means the macro is available
* - means the macro is not available
* s means the macro is available but is slow (runs in O(n) time)
*
* SLIST LIST STAILQ TAILQ
* _HEAD + + + +
@ -101,10 +105,10 @@
* _INSERT_BEFORE - + - +
* _INSERT_AFTER + + + +
* _INSERT_TAIL - - + +
* _CONCAT - - + +
* _CONCAT s s + +
* _REMOVE_AFTER + - + -
* _REMOVE_HEAD + - + -
* _REMOVE + + + +
* _REMOVE s + s +
* _SWAP + + + +
*
*/
@ -183,6 +187,19 @@ struct { \
/*
* Singly-linked List functions.
*/
#define SLIST_CONCAT(head1, head2, type, field) do { \
QUEUE_TYPEOF(type) *curelm = SLIST_FIRST(head1); \
if (curelm == NULL) { \
if ((SLIST_FIRST(head1) = SLIST_FIRST(head2)) != NULL) \
SLIST_INIT(head2); \
} else if (SLIST_FIRST(head2) != NULL) { \
while (SLIST_NEXT(curelm, field) != NULL) \
curelm = SLIST_NEXT(curelm, field); \
SLIST_NEXT(curelm, field) = SLIST_FIRST(head2); \
SLIST_INIT(head2); \
} \
} while (0)
#define SLIST_EMPTY(head) ((head)->slh_first == NULL)
#define SLIST_FIRST(head) ((head)->slh_first)
@ -452,6 +469,23 @@ struct { \
#define QMD_LIST_CHECK_PREV(elm, field)
#endif /* (_KERNEL && INVARIANTS) */
#define LIST_CONCAT(head1, head2, type, field) do { \
QUEUE_TYPEOF(type) *curelm = LIST_FIRST(head1); \
if (curelm == NULL) { \
if ((LIST_FIRST(head1) = LIST_FIRST(head2)) != NULL) { \
LIST_FIRST(head2)->field.le_prev = \
&LIST_FIRST((head1)); \
LIST_INIT(head2); \
} \
} else if (LIST_FIRST(head2) != NULL) { \
while (LIST_NEXT(curelm, field) != NULL) \
curelm = LIST_NEXT(curelm, field); \
LIST_NEXT(curelm, field) = LIST_FIRST(head2); \
LIST_FIRST(head2)->field.le_prev = &LIST_NEXT(curelm, field); \
LIST_INIT(head2); \
} \
} while (0)
#define LIST_EMPTY(head) ((head)->lh_first == NULL)
#define LIST_FIRST(head) ((head)->lh_first)