/*
 * Copyright (C) 2018 Intel Corporation. All rights reserved.
 *
 * 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 <asm/errno.h>
#include <string.h>
#include <stdbool.h>
#include "sbuf.h"

static inline bool sbuf_is_empty(shared_buf_t *sbuf)
{
	return (sbuf->head == sbuf->tail);
}

static inline uint32_t sbuf_next_ptr(uint32_t pos,
		uint32_t span, uint32_t scope)
{
	pos += span;
	pos = (pos >= scope) ? (pos - scope) : pos;
	return pos;
}

int sbuf_get(shared_buf_t *sbuf, uint8_t *data)
{
	const void *from;

	if ((sbuf == NULL) || (data == NULL))
		return -EINVAL;

	if (sbuf_is_empty(sbuf)) {
		/* no data available */
		return 0;
	}

	from = (void *)sbuf + SBUF_HEAD_SIZE + sbuf->head;

	memcpy(data, from, sbuf->ele_size);

	sbuf->head = sbuf_next_ptr(sbuf->head, sbuf->ele_size, sbuf->size);

	return sbuf->ele_size;
}

int sbuf_clear_buffered(shared_buf_t *sbuf)
{
	if (sbuf == NULL)
		return -EINVAL;

	sbuf->head = sbuf->tail;

	return 0;
}