1 files changed, 120 insertions, 0 deletions
diff --git a/lib/queue.c b/lib/queue.c
new file mode 100644
index 000000000..2e4c7ca62
--- /dev/null
+++ b/lib/queue.c
@@ -0,0 +1,120 @@
+/*
+ * Copyright (c) 2008, 2009 Nicira Networks.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <config.h>
+#include "queue.h"
+#include <assert.h>
+#include "compiler.h"
+#include "leak-checker.h"
+#include "ofpbuf.h"
+
+static void check_queue(struct ovs_queue *q);
+
+/* Initializes 'q' as an empty packet queue. */
+void
+queue_init(struct ovs_queue *q)
+{
+    q->n = 0;
+    q->head = NULL;
+    q->tail = NULL;
+}
+
+/* Destroys 'q' and all of the packets that it contains. */
+void
+queue_destroy(struct ovs_queue *q)
+{
+    struct ofpbuf *cur, *next;
+    for (cur = q->head; cur != NULL; cur = next) {
+        next = cur->next;
+        ofpbuf_delete(cur);
+    }
+}
+
+/* Removes and destroys all of the packets in 'q', rendering it empty. */
+void
+queue_clear(struct ovs_queue *q)
+{
+    queue_destroy(q);
+    queue_init(q);
+}
+
+/* Advances the first packet in 'q' from 'q->head' to 'next', which should be
+ * the second packet in the queue.
+ *
+ * The odd, unsafe interface here allows the first packet in the queue to be
+ * passed to a function for possible consumption (and destruction) and only
+ * dropped from the queue if that function actually accepts it. */
+void
+queue_advance_head(struct ovs_queue *q, struct ofpbuf *next)
+{
+    assert(q->n);
+    assert(q->head);
+    q->head = next;
+    if (q->head == NULL) {
+        q->tail = NULL;
+    }
+    q->n--;
+}
+
+/* Appends 'b' to the tail of 'q'. */
+void
+queue_push_tail(struct ovs_queue *q, struct ofpbuf *b)
+{
+    check_queue(q);
+    leak_checker_claim(b);
+
+    b->next = NULL;
+    if (q->n++) {
+        q->tail->next = b;
+    } else {
+        q->head = b;
+    }
+    q->tail = b;
+
+    check_queue(q);
+}
+
+/* Removes the first buffer from 'q', which must not be empty, and returns
+ * it.  The caller must free the buffer (with ofpbuf_delete()) when it is no
+ * longer needed. */
+struct ofpbuf *
+queue_pop_head(struct ovs_queue *q)
+{
+    struct ofpbuf *head = q->head;
+    queue_advance_head(q, head->next);
+    return head;
+}
+
+/* Checks the internal integrity of 'q'.  For use in debugging. */
+static void
+check_queue(struct ovs_queue *q UNUSED)
+{
+#if 0
+    struct ofpbuf *iter;
+    size_t n;
+
+    assert(q->n == 0
+           ? q->head == NULL && q->tail == NULL
+           : q->head != NULL && q->tail != NULL);
+
+    n = 0;
+    for (iter = q->head; iter != NULL; iter = iter->next) {
+        n++;
+        assert((iter->next != NULL) == (iter != q->tail));
+    }
+    assert(n == q->n);
+#endif
+}