circuitpython/py/ringbuf.h

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Paul Sokolovsky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef MICROPY_INCLUDED_PY_RINGBUF_H
#define MICROPY_INCLUDED_PY_RINGBUF_H
#include <stddef.h>
#include <stdint.h>
typedef struct _ringbuf_t {
uint8_t *buf;
uint16_t size;
uint16_t iget;
uint16_t iput;
} ringbuf_t;
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// Static initialization:
// byte buf_array[N];
// ringbuf_t buf = {buf_array, sizeof(buf_array)};
// Dynamic initialization. This needs to become findable as a root pointer!
#define ringbuf_alloc(r, sz) \
{ \
(r)->buf = m_new(uint8_t, sz); \
(r)->size = sz; \
(r)->iget = (r)->iput = 0; \
}
static inline int ringbuf_get(ringbuf_t *r) {
if (r->iget == r->iput) {
return -1;
}
uint8_t v = r->buf[r->iget++];
if (r->iget >= r->size) {
r->iget = 0;
}
return v;
}
static inline int ringbuf_put(ringbuf_t *r, uint8_t v) {
uint32_t iput_new = r->iput + 1;
if (iput_new >= r->size) {
iput_new = 0;
}
if (iput_new == r->iget) {
return -1;
}
r->buf[r->iput] = v;
r->iput = iput_new;
return 0;
}
static inline size_t ringbuf_free(ringbuf_t *r) {
return (r->size + r->iget - r->iput - 1) % r->size;
}
static inline size_t ringbuf_avail(ringbuf_t *r) {
return (r->size + r->iput - r->iget) % r->size;
}
// Note: big-endian. No-op if not enough room available for both bytes.
int ringbuf_get16(ringbuf_t *r);
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int ringbuf_peek16(ringbuf_t *r);
int ringbuf_put16(ringbuf_t *r, uint16_t v);
#endif // MICROPY_INCLUDED_PY_RINGBUF_H