Priority queue clear

awslabs · Oct 25, 2023 · 6d04fa8 · 6d04fa8
1 parent 9134018
commit 6d04fa8
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diff --git a/include/aws/common/priority_queue.h b/include/aws/common/priority_queue.h
@@ -162,6 +162,12 @@ int aws_priority_queue_remove(struct aws_priority_queue *queue, void *item, cons
 AWS_COMMON_API
 int aws_priority_queue_top(const struct aws_priority_queue *queue, void **item);
 
+/**
+ * Removes all elements from the queue, but does not free internal memory.
+ */
+AWS_COMMON_API
+void aws_priority_queue_clear(struct aws_priority_queue *queue);
+
 /**
  * Current number of elements in the queue
  */

diff --git a/source/priority_queue.c b/source/priority_queue.c
@@ -401,6 +401,22 @@ size_t aws_priority_queue_capacity(const struct aws_priority_queue *queue) {
     return aws_array_list_capacity(&queue->container);
 }
 
+void aws_priority_queue_clear(struct aws_priority_queue *queue) {
+    AWS_PRECONDITION(aws_priority_queue_is_valid(queue));
+    size_t backpointer_count = aws_array_list_length(&queue->backpointers);
+    for (size_t i = 0; i < backpointer_count; ++i) {
+        struct aws_priority_queue_node *node = NULL;
+        aws_array_list_get_at(&queue->backpointers, &node, i);
+        if (node != NULL) {
+            node->current_index = SIZE_MAX;
+        }
+    }
+
+    aws_array_list_clear(&queue->backpointers);
+    aws_array_list_clear(&queue->container);
+    AWS_PRECONDITION(aws_priority_queue_is_valid(queue));
+}
+
 void aws_priority_queue_node_init(struct aws_priority_queue_node *node) {
     node->current_index = SIZE_MAX;
 }

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
@@ -94,6 +94,7 @@ add_test_case(priority_queue_remove_root_test)
 add_test_case(priority_queue_remove_leaf_test)
 add_test_case(priority_queue_remove_interior_sift_up_test)
 add_test_case(priority_queue_remove_interior_sift_down_test)
+add_test_case(priority_queue_clear_backpointers_test)
 
 add_test_case(linked_list_push_back_pop_front)
 add_test_case(linked_list_push_front_pop_back)

diff --git a/tests/priority_queue_test.c b/tests/priority_queue_test.c
@@ -451,10 +451,45 @@ static int s_test_remove_interior_sift_down(struct aws_allocator *allocator, voi
     return 0;
 }
 
+static int s_priority_queue_clear_backpointers_test(struct aws_allocator *allocator, void *ctx) {
+    (void)ctx;
+
+    struct aws_priority_queue queue;
+
+    ASSERT_SUCCESS(aws_priority_queue_init_dynamic(&queue, allocator, 16, sizeof(int), s_compare_ints));
+
+    const size_t NODE_COUNT = 16;
+    struct aws_priority_queue_node queue_nodes[NODE_COUNT];
+
+    for (size_t i = 0; i < NODE_COUNT; ++i) {
+        aws_priority_queue_node_init(&queue_nodes[i]);
+    }
+
+    for (int i = 0; i < NODE_COUNT; i++) {
+        aws_priority_queue_push_ref(&queue, &i, &queue_nodes[i]);
+    }
+
+    for (size_t i = 0; i < NODE_COUNT; ++i) {
+        ASSERT_TRUE(aws_priority_queue_node_is_in_queue(&queue_nodes[i]));
+    }
+
+    aws_priority_queue_clear(&queue);
+    ASSERT_INT_EQUALS(0, aws_priority_queue_size(&queue));
+
+    for (size_t i = 0; i < NODE_COUNT; ++i) {
+        ASSERT_FALSE(aws_priority_queue_node_is_in_queue(&queue_nodes[i]));
+    }
+
+    aws_priority_queue_clean_up(&queue);
+
+    return 0;
+}
+
 AWS_TEST_CASE(priority_queue_remove_interior_sift_down_test, s_test_remove_interior_sift_down);
 AWS_TEST_CASE(priority_queue_remove_interior_sift_up_test, s_test_remove_interior_sift_up);
 AWS_TEST_CASE(priority_queue_remove_leaf_test, s_test_remove_leaf);
 AWS_TEST_CASE(priority_queue_remove_root_test, s_test_remove_root);
 AWS_TEST_CASE(priority_queue_push_pop_order_test, s_test_priority_queue_preserves_order);
 AWS_TEST_CASE(priority_queue_random_values_test, s_test_priority_queue_random_values);
 AWS_TEST_CASE(priority_queue_size_and_capacity_test, s_test_priority_queue_size_and_capacity);
+AWS_TEST_CASE(priority_queue_clear_backpointers_test, s_priority_queue_clear_backpointers_test);