1 files changed, 100 insertions, 0 deletions
diff --git a/bsd/freebsd/contrib/ntp/lib/isc/include/isc/queue.h b/bsd/freebsd/contrib/ntp/lib/isc/include/isc/queue.h
new file mode 100644
index 0000000..5bf84c5
--- /dev/null
+++ b/bsd/freebsd/contrib/ntp/lib/isc/include/isc/queue.h
@@ -0,0 +1,100 @@
+/*
+ * Copyright (C) 2011, 2012  Internet Systems Consortium, Inc. ("ISC")
+ *
+ * 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 ISC DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS.  IN NO EVENT SHALL ISC 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.
+ */
+
+/* $Id$ */
+
+/*
+ * This is a generic implementation of a two-lock concurrent queue.
+ * There are built-in mutex locks for the head and tail of the queue,
+ * allowing elements to be safely added and removed at the same time.
+ */
+
+#ifndef ISC_QUEUE_H
+#define ISC_QUEUE_H 1
+#include <isc/assertions.h>
+#include <isc/boolean.h>
+#include <isc/mutex.h>
+
+#ifdef ISC_QUEUE_CHECKINIT
+#define ISC_QLINK_INSIST(x) ISC_INSIST(x)
+#else
+#define ISC_QLINK_INSIST(x) (void)0
+#endif
+
+#define ISC_QLINK(type) struct { void *next; isc_boolean_t linked; }
+#define ISC_QLINK_INIT(elt, link) \
+	do { \
+		(elt)->link.next = (void *)(-1); \
+		(elt)->link.linked = ISC_FALSE; \
+	} while (0)
+#define ISC_QLINK_LINKED(elt, link) ((elt)->link.linked)
+
+#define ISC_QUEUE(type) struct { \
+	type headnode; \
+	type *head, *tail; \
+	isc_mutex_t headlock, taillock; \
+}
+
+#define ISC_QUEUE_INIT(queue, link) \
+	do { \
+		isc_mutex_init(&(queue).headlock); \
+		isc_mutex_init(&(queue).taillock); \
+		(queue).head = (void *) &((queue).headnode); \
+		(queue).tail = (void *) &((queue).headnode); \
+		ISC_QLINK_INIT((queue).head, link); \
+	} while (0)
+
+#define ISC_QUEUE_EMPTY(queue) ISC_TF((queue).head == (queue).tail)
+
+#define ISC_QUEUE_DESTROY(queue) \
+	do { \
+		ISC_QLINK_INSIST(ISC_QUEUE_EMPTY(queue)); \
+		isc_mutex_destroy(&(queue).headlock); \
+		isc_mutex_destroy(&(queue).taillock); \
+	} while (0)
+
+#define ISC_QUEUE_PUSH(queue, elt, link) \
+	do { \
+		ISC_QLINK_INSIST(!ISC_QLINK_LINKED(elt, link)); \
+		(elt)->link.next = (void *)(-1); \
+		LOCK(&(queue).taillock); \
+		(queue).tail->link.next = elt; \
+		(queue).tail = elt; \
+		UNLOCK(&(queue).taillock); \
+		(elt)->link.linked = ISC_TRUE; \
+	} while (0)
+
+#define ISC_QUEUE_POP(queue, link, ret) \
+	do { \
+		LOCK(&(queue).headlock); \
+		ret = (queue).head->link.next; \
+		if (ret == (void *)(-1)) { \
+			UNLOCK(&(queue).headlock); \
+			ret = NULL; \
+		} else { \
+			(queue).head->link.next = ret->link.next; \
+			if (ret->link.next == (void *)(-1)) { \
+				LOCK(&(queue).taillock); \
+				(queue).tail = (queue).head; \
+				UNLOCK(&(queue).taillock); \
+			} \
+			UNLOCK(&(queue).headlock); \
+			ret->link.next = (void *)(-1); \
+			ret->link.linked = ISC_FALSE; \
+		} \
+	} while (0)
+
+#endif /* ISC_QUEUE_H */