diff options
| author | Derrick Stolee <stolee@gmail.com> | 2018-11-01 16:46:17 +0300 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2018-11-02 06:14:21 +0300 |
| commit | aca4240f6a32423df5f95de6a9354b524fe57ec5 (patch) | |
| tree | 06a2b1efc6f6d9d0a66088e13965238bfb36e86b /prio-queue.h | |
| parent | 2d3b1c576c85b7f5db1f418907af00ab88e0c303 (diff) | |
prio-queue: add 'peek' operation
When consuming a priority queue, it can be convenient to inspect
the next object that will be dequeued without actually dequeueing
it. Our existing library did not have such a 'peek' operation, so
add it as prio_queue_peek().
Add a reference-level comparison in t/helper/test-prio-queue.c
so this method is exercised by t0009-prio-queue.sh. Further, add
a test that checks the behavior when the compare function is NULL
(i.e. the queue becomes a stack).
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'prio-queue.h')
| -rw-r--r-- | prio-queue.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/prio-queue.h b/prio-queue.h index d030ec9dd6..682e51867a 100644 --- a/prio-queue.h +++ b/prio-queue.h @@ -46,6 +46,12 @@ extern void prio_queue_put(struct prio_queue *, void *thing); */ extern void *prio_queue_get(struct prio_queue *); +/* + * Gain access to the "thing" that would be returned by + * prio_queue_get, but do not remove it from the queue. + */ +extern void *prio_queue_peek(struct prio_queue *); + extern void clear_prio_queue(struct prio_queue *); /* Reverse the LIFO elements */ |