1 files changed, 109 insertions, 0 deletions
diff --git a/rdns_scan/zmap4rdns/lib/queue.c b/rdns_scan/zmap4rdns/lib/queue.c
new file mode 100644
index 0000000..bf91d78
--- /dev/null
+++ b/rdns_scan/zmap4rdns/lib/queue.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2021 Regents of the University of Michigan
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "queue.h"
+
+#include "xalloc.h"
+
+#include <pthread.h>
+
+zqueue_t *queue_init()
+{
+	zqueue_t *p = xmalloc(sizeof(zqueue_t));
+	p->front = NULL;
+	p->back = NULL;
+	p->size = 0;
+
+	pthread_mutex_init(&p->lock, NULL);
+	pthread_cond_init(&p->empty, NULL);
+	return p;
+}
+
+int is_empty(zqueue_t *queue) { return queue->size == 0; }
+
+void push_back(char *data, zqueue_t *queue)
+{
+	znode_t *new_node = xmalloc(sizeof(znode_t));
+	new_node->prev = NULL;
+	new_node->next = NULL;
+	new_node->data = strdup(data);
+
+	pthread_mutex_lock(&queue->lock);
+	if (is_empty(queue)) {
+		queue->front = new_node;
+		queue->back = new_node;
+	} else {
+		queue->back->next = new_node;
+		new_node->prev = queue->back;
+		queue->back = new_node;
+	}
+	queue->size++;
+	pthread_cond_signal(&queue->empty);
+	pthread_mutex_unlock(&queue->lock);
+}
+
+znode_t *pop_front(zqueue_t *queue)
+{
+	pthread_mutex_lock(&queue->lock);
+
+	while (is_empty(queue)) {
+		pthread_cond_wait(&queue->empty, &queue->lock);
+	}
+	znode_t *temp = pop_front_unsafe(queue);
+	pthread_mutex_unlock(&queue->lock);
+	return temp;
+}
+
+znode_t *pop_front_unsafe(zqueue_t *queue)
+{
+	znode_t *temp = queue->front;
+	queue->front = temp->next;
+	if (queue->front != NULL) {
+		queue->front->prev = NULL;
+	}
+	queue->size--;
+	return temp;
+}
+
+znode_t *get_front(zqueue_t *queue)
+{
+	pthread_mutex_lock(&queue->lock);
+
+	while (is_empty(queue)) {
+		pthread_cond_wait(&queue->empty, &queue->lock);
+	}
+
+	znode_t *temp = xmalloc(sizeof(znode_t));
+	temp = queue->front;
+	pthread_mutex_unlock(&queue->lock);
+	return temp;
+}
+
+znode_t *get_back(zqueue_t *queue)
+{
+	pthread_mutex_lock(&queue->lock);
+
+	while (is_empty(queue)) {
+		pthread_cond_wait(&queue->empty, &queue->lock);
+	}
+
+	znode_t *temp = xmalloc(sizeof(znode_t));
+	temp = queue->back;
+	pthread_mutex_unlock(&queue->lock);
+	return temp;
+}
+
+size_t get_size(zqueue_t *queue) { return queue->size; }