c031bf8611
This might become useful if we want to dynamically allocate an array that stores the entire queue.
96 lines
3.1 KiB
C
96 lines
3.1 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause */
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/* See the end of this file for copyright, licensing, and warranty information. */
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/* Simple ring buffer implementation. */
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#include <ardix/malloc.h>
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#include <ardix/ringbuf.h>
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#include <ardix/types.h>
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#include <stddef.h>
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struct ringbuf *ringbuf_create(size_t size)
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{
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struct ringbuf *buf = malloc(sizeof(*buf) + size);
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if (buf == NULL)
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return NULL;
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buf->size = size;
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buf->rpos = &buf->data[0];
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buf->wpos = &buf->data[0];
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return buf;
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}
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inline void ringbuf_destroy(struct ringbuf *buf)
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{
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free(buf);
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}
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size_t ringbuf_read(uint8_t *dest, struct ringbuf *buf, size_t len)
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{
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size_t n = 0;
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while (len-- > 0 && buf->rpos != buf->wpos) {
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*dest++ = *buf->rpos++;
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n++;
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/* wrap around */
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if ((ptrdiff_t)(buf->rpos) - (ptrdiff_t)(&buf->data[0]) >= (ptrdiff_t)(buf->size))
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buf->rpos = &buf->data[0];
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}
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return n;
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}
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size_t ringbuf_write(struct ringbuf *buf, const uint8_t *src, size_t len)
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{
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size_t n = 0;
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while (len-- > 0 && buf->wpos != buf->rpos) {
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*buf->wpos++ = *src++;
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n++;
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/* wrap around */
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if ((ptrdiff_t)(buf->wpos) - (ptrdiff_t)(&buf->data[0]) >= (ptrdiff_t)(buf->size))
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buf->wpos = &buf->data[0];
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}
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return n;
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}
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size_t ringbuf_size(struct ringbuf *buf)
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{
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ptrdiff_t size = (ptrdiff_t)(buf->wpos) - (ptrdiff_t)(buf->rpos);
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if (size < 0) {
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/* wpos has wrapped around already, but rpos has not */
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size = (ptrdiff_t)(buf->wpos) - (ptrdiff_t)(&buf->data[0]);
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size += (ptrdiff_t)(buf->size) - ((ptrdiff_t)(buf->rpos) - (ptrdiff_t)(&buf->data[0]));
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}
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return (size_t)size;
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}
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/*
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* Copyright (c) 2020 Felix Kopp <sandtler@sandtler.club>
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its contributors may be
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* used to endorse or promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
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* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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