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diff --git a/libipt/internal/include/pt_event_queue.h b/libipt/internal/include/pt_event_queue.h
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+++ b/libipt/internal/include/pt_event_queue.h
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+/*
+ * Copyright (c) 2013-2019, Intel Corporation
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *  * Neither the name of Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef PT_EVENT_QUEUE_H
+#define PT_EVENT_QUEUE_H
+
+#include "intel-pt.h"
+
+#include <stdint.h>
+
+
+/* Events are grouped by the packet the event binds to. */
+enum pt_event_binding {
+	evb_psbend,
+	evb_tip,
+	evb_fup,
+
+	evb_max
+};
+
+enum {
+	/* The maximal number of pending events - should be a power of two. */
+	evq_max = 8
+};
+
+/* A queue of events. */
+struct pt_event_queue {
+	/* A collection of event queues, one per binding. */
+	struct pt_event queue[evb_max][evq_max];
+
+	/* The begin and end indices for the above event queues. */
+	uint8_t begin[evb_max];
+	uint8_t end[evb_max];
+
+	/* A standalone event to be published immediately. */
+	struct pt_event standalone;
+};
+
+
+/* Initialize (or reset) an event queue. */
+extern void pt_evq_init(struct pt_event_queue *);
+
+/* Get a standalone event.
+ *
+ * Returns a pointer to the standalone event on success.
+ * Returns NULL if @evq is NULL.
+ */
+extern struct pt_event *pt_evq_standalone(struct pt_event_queue *evq);
+
+/* Enqueue an event.
+ *
+ * Adds a new event to @evq for binding @evb.
+ *
+ * Returns a pointer to the new event on success.
+ * Returns NULL if @evq is NULL or @evb is invalid.
+ * Returns NULL if @evq is full.
+ */
+extern struct pt_event *pt_evq_enqueue(struct pt_event_queue *evq,
+				       enum pt_event_binding evb);
+
+
+/* Dequeue an event.
+ *
+ * Removes the first event for binding @evb from @evq.
+ *
+ * Returns a pointer to the dequeued event on success.
+ * Returns NULL if @evq is NULL or @evb is invalid.
+ * Returns NULL if @evq is empty.
+ */
+extern struct pt_event *pt_evq_dequeue(struct pt_event_queue *evq,
+				       enum pt_event_binding evb);
+
+/* Clear a queue and discard events.
+ *
+ * Removes all events for binding @evb from @evq.
+ *
+ * Returns zero on success, a negative error code otherwise.
+ * Returns -pte_internal if @evq is NULL or @evb is invalid.
+ */
+extern int pt_evq_clear(struct pt_event_queue *evq,
+			enum pt_event_binding evb);
+
+/* Check for emptiness.
+ *
+ * Check if @evq for binding @evb is empty.
+ *
+ * Returns a positive number if @evq is empty.
+ * Returns zero if @evq is not empty.
+ * Returns -pte_internal if @evq is NULL or @evb is invalid.
+ */
+extern int pt_evq_empty(const struct pt_event_queue *evq,
+			enum pt_event_binding evb);
+
+/* Check for non-emptiness.
+ *
+ * Check if @evq for binding @evb contains pending events.
+ *
+ * Returns a positive number if @evq is not empty.
+ * Returns zero if @evq is empty.
+ * Returns -pte_internal if @evq is NULL or @evb is invalid.
+ */
+extern int pt_evq_pending(const struct pt_event_queue *evq,
+			  enum pt_event_binding evb);
+
+/* Find an event by type.
+ *
+ * Searches @evq for binding @evb for an event of type @evt.
+ *
+ * Returns a pointer to the first matching event on success.
+ * Returns NULL if there is no such event.
+ * Returns NULL if @evq is NULL.
+ * Returns NULL if @evb or @evt is invalid.
+ */
+extern struct pt_event *pt_evq_find(struct pt_event_queue *evq,
+				    enum pt_event_binding evb,
+				    enum pt_event_type evt);
+
+#endif /* PT_EVENT_QUEUE_H */