From 3d5091d232ea991a6a991c86e9fb000f5a9009a0 Mon Sep 17 00:00:00 2001 From: René Scharfe Date: Fri, 18 Jul 2025 11:39:14 +0200 Subject: prio-queue: add prio_queue_replace() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a function to replace the top element of the queue that basically does the same as prio_queue_get() followed by prio_queue_put(), but without the work by prio_queue_get() to rebalance the heap. It can be used to optimize loops that get one element and then immediately add another one. That's common e.g., with commit history traversal, where we get out a commit and then put in its parents. Signed-off-by: René Scharfe Signed-off-by: Junio C Hamano --- t/unit-tests/u-prio-queue.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 't/unit-tests') diff --git a/t/unit-tests/u-prio-queue.c b/t/unit-tests/u-prio-queue.c index 145e689c9c..63e58114ae 100644 --- a/t/unit-tests/u-prio-queue.c +++ b/t/unit-tests/u-prio-queue.c @@ -13,6 +13,7 @@ static int intcmp(const void *va, const void *vb, void *data UNUSED) #define STACK -3 #define GET -4 #define REVERSE -5 +#define REPLACE -6 static int show(int *v) { @@ -51,6 +52,15 @@ static void test_prio_queue(int *input, size_t input_size, case REVERSE: prio_queue_reverse(&pq); break; + case REPLACE: + peek = prio_queue_peek(&pq); + cl_assert(i + 1 < input_size); + cl_assert(input[i + 1] >= 0); + cl_assert(j < result_size); + cl_assert_equal_i(result[j], show(peek)); + j++; + prio_queue_replace(&pq, &input[++i]); + break; default: prio_queue_put(&pq, &input[i]); break; @@ -81,6 +91,13 @@ void test_prio_queue__empty(void) ((int []){ 1, 2, MISSING, 1, 2, MISSING })); } +void test_prio_queue__replace(void) +{ + TEST_INPUT(((int []){ REPLACE, 6, 2, 4, REPLACE, 5, 7, GET, + REPLACE, 1, DUMP }), + ((int []){ MISSING, 2, 4, 5, 1, 6, 7 })); +} + void test_prio_queue__stack(void) { TEST_INPUT(((int []){ STACK, 8, 1, 5, 4, 6, 2, 3, DUMP }), @@ -92,3 +109,9 @@ void test_prio_queue__reverse_stack(void) TEST_INPUT(((int []){ STACK, 1, 2, 3, 4, 5, 6, REVERSE, DUMP }), ((int []){ 1, 2, 3, 4, 5, 6 })); } + +void test_prio_queue__replace_stack(void) +{ + TEST_INPUT(((int []){ STACK, 8, 1, 5, REPLACE, 4, 6, 2, 3, DUMP }), + ((int []){ 5, 3, 2, 6, 4, 1, 8 })); +} -- cgit v1.2.3