1/*
2 * This file is part of the MicroPython project, http://micropython.org/
3 *
4 * The MIT License (MIT)
5 *
6 * Copyright (c) 2016 Paul Sokolovsky
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
24 * THE SOFTWARE.
25 */
26#ifndef MICROPY_INCLUDED_PY_RINGBUF_H
27#define MICROPY_INCLUDED_PY_RINGBUF_H
28
29#include <stddef.h>
30#include <stdint.h>
31
32#ifdef _MSC_VER
33#include "py/mpconfig.h" // For inline.
34#endif
35
36typedef struct _ringbuf_t {
37 uint8_t *buf;
38 uint16_t size;
39 uint16_t iget;
40 uint16_t iput;
41} ringbuf_t;
42
43// Static initialization:
44// byte buf_array[N];
45// ringbuf_t buf = {buf_array, sizeof(buf_array)};
46
47// Dynamic initialization. This needs to become findable as a root pointer!
48#define ringbuf_alloc(r, sz) \
49 { \
50 (r)->buf = m_new(uint8_t, sz); \
51 (r)->size = sz; \
52 (r)->iget = (r)->iput = 0; \
53 }
54
55static inline int ringbuf_get(ringbuf_t *r) {
56 if (r->iget == r->iput) {
57 return -1;
58 }
59 uint8_t v = r->buf[r->iget++];
60 if (r->iget >= r->size) {
61 r->iget = 0;
62 }
63 return v;
64}
65
66static inline int ringbuf_peek(ringbuf_t *r) {
67 if (r->iget == r->iput) {
68 return -1;
69 }
70 return r->buf[r->iget];
71}
72
73static inline int ringbuf_put(ringbuf_t *r, uint8_t v) {
74 uint32_t iput_new = r->iput + 1;
75 if (iput_new >= r->size) {
76 iput_new = 0;
77 }
78 if (iput_new == r->iget) {
79 return -1;
80 }
81 r->buf[r->iput] = v;
82 r->iput = iput_new;
83 return 0;
84}
85
86static inline size_t ringbuf_free(ringbuf_t *r) {
87 return (r->size + r->iget - r->iput - 1) % r->size;
88}
89
90static inline size_t ringbuf_avail(ringbuf_t *r) {
91 return (r->size + r->iput - r->iget) % r->size;
92}
93
94// Note: big-endian. No-op if not enough room available for both bytes.
95int ringbuf_get16(ringbuf_t *r);
96int ringbuf_peek16(ringbuf_t *r);
97int ringbuf_put16(ringbuf_t *r, uint16_t v);
98
99#endif // MICROPY_INCLUDED_PY_RINGBUF_H
100