ardix/kernel/ringbuf.c
2020-11-24 23:46:33 +01:00

85 lines
2.7 KiB
C

/* SPDX-License-Identifier: BSD-3-Clause */
/* See the end of this file for copyright, licensing, and warranty information. */
/* Simple ring buffer implementation. */
#include <ardix/malloc.h>
#include <ardix/ringbuf.h>
#include <ardix/types.h>
#include <stddef.h>
struct ringbuf *ringbuf_create(size_t size)
{
struct ringbuf *buf = malloc(sizeof(*buf) + size);
if (buf == NULL)
return NULL;
buf->capacity = size;
buf->len = 0;
buf->rpos = 0;
buf->wpos = 0;
return buf;
}
inline void ringbuf_destroy(struct ringbuf *buf)
{
free(buf);
}
size_t ringbuf_read(void *dest, struct ringbuf *buf, size_t len)
{
uint8_t *tmp = dest;
while (len-- > 0 && buf->len > 0) {
*tmp++ = buf->data[buf->rpos++];
buf->len--;
/* wrap around */
if (buf->rpos == buf->capacity)
buf->rpos = 0;
}
return (size_t)tmp - (size_t)dest;
}
size_t ringbuf_write(struct ringbuf *buf, const void *src, size_t len)
{
const uint8_t *tmp = src;
while (len-- > 0 && buf->len < buf->capacity) {
buf->data[buf->wpos++] = *tmp++;
buf->len++;
/* wrap around */
if (buf->wpos == buf->capacity)
buf->wpos = 0;
}
return (size_t)tmp - (size_t)src;
}
/*
* Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
* 2. 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.
* 3. Neither the name of the copyright holder 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 HOLDER 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.
*/