/*

 * Copyright (c) 2013-2017, 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.

 */

#include "pt_event_queue.h"

#include <string.h>

static inline uint8_t pt_evq_inc(uint8_t idx)

{

	idx += 1;

	idx %= evq_max;

	return idx;

}

static struct pt_event *pt_event_init(struct pt_event *event)

{

	if (event)

		memset(event, 0, sizeof(*event));

	return event;

}

void pt_evq_init(struct pt_event_queue *evq)

{

	if (!evq)

		return;

	memset(evq, 0, sizeof(*evq));

}

struct pt_event *pt_evq_standalone(struct pt_event_queue *evq)

{

	if (!evq)

		return NULL;

	return pt_event_init(&evq->standalone);

}

struct pt_event *pt_evq_enqueue(struct pt_event_queue *evq,

				enum pt_event_binding evb)

{

	uint8_t begin, end, gap, idx;

	if (!evq)

		return NULL;

	if (evb_max <= evb)

		return NULL;

	begin = evq->begin[evb];

	idx = evq->end[evb];

	if (evq_max <= begin)

		return NULL;

	if (evq_max <= idx)

		return NULL;

	end = pt_evq_inc(idx);

	gap = pt_evq_inc(end);

	/* Leave a gap so we don't overwrite the last dequeued event. */

	if (begin == gap)

		return NULL;

	evq->end[evb] = end;

	return pt_event_init(&evq->queue[evb][idx]);

}

struct pt_event *pt_evq_dequeue(struct pt_event_queue *evq,

				enum pt_event_binding evb)

{

	uint8_t begin, end;

	if (!evq)

		return NULL;

	if (evb_max <= evb)

		return NULL;

	begin = evq->begin[evb];

	end = evq->end[evb];

	if (evq_max <= begin)

		return NULL;

	if (evq_max <= end)

		return NULL;

	if (begin == end)

		return NULL;

	evq->begin[evb] = pt_evq_inc(begin);

	return &evq->queue[evb][begin];

}

int pt_evq_clear(struct pt_event_queue *evq, enum pt_event_binding evb)

{

	if (!evq)

		return -pte_internal;

	if (evb_max <= evb)

		return -pte_internal;

	evq->begin[evb] = 0;

	evq->end[evb] = 0;

	return 0;

}

int pt_evq_empty(const struct pt_event_queue *evq, enum pt_event_binding evb)

{

	uint8_t begin, end;

	if (!evq)

		return -pte_internal;

	if (evb_max <= evb)

		return -pte_internal;

	begin = evq->begin[evb];

	end = evq->end[evb];

	if (evq_max <= begin)

		return -pte_internal;

	if (evq_max <= end)

		return -pte_internal;

	return begin == end;

}

int pt_evq_pending(const struct pt_event_queue *evq, enum pt_event_binding evb)

{

	int errcode;

	errcode = pt_evq_empty(evq, evb);

	if (errcode < 0)

		return errcode;

	return !errcode;

}

struct pt_event *pt_evq_find(struct pt_event_queue *evq,

			     enum pt_event_binding evb,

			     enum pt_event_type evt)

{

	uint8_t begin, end;

	if (!evq)

		return NULL;

	if (evb_max <= evb)

		return NULL;

	begin = evq->begin[evb];

	end = evq->end[evb];

	if (evq_max <= begin)

		return NULL;

	if (evq_max <= end)

		return NULL;

	for (; begin != end; begin = pt_evq_inc(begin)) {

		struct pt_event *ev;

		ev = &evq->queue[evb][begin];

		if (ev->type == evt)

			return ev;

	}

	return NULL;

}