1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2019-2020 Pengutronix, Michael Tretter <kernel@pengutronix.de>
4 */
5
6#ifndef __NAL_RBSP_H__
7#define __NAL_RBSP_H__
8
9#include <linux/kernel.h>
10#include <linux/types.h>
11
12struct rbsp;
13
14struct nal_rbsp_ops {
15	int (*rbsp_bit)(struct rbsp *rbsp, int *val);
16	int (*rbsp_bits)(struct rbsp *rbsp, int n, unsigned int *val);
17	int (*rbsp_uev)(struct rbsp *rbsp, unsigned int *val);
18	int (*rbsp_sev)(struct rbsp *rbsp, int *val);
19};
20
21/**
22 * struct rbsp - State object for handling a raw byte sequence payload
23 * @data: pointer to the data of the rbsp
24 * @size: maximum size of the data of the rbsp
25 * @pos: current bit position inside the rbsp
26 * @num_consecutive_zeros: number of zeros before @pos
27 * @ops: per datatype functions for interacting with the rbsp
28 * @error: an error occurred while handling the rbsp
29 *
30 * This struct is passed around the various parsing functions and tracks the
31 * current position within the raw byte sequence payload.
32 *
33 * The @ops field allows to separate the operation, i.e., reading/writing a
34 * value from/to that rbsp, from the structure of the NAL unit. This allows to
35 * have a single function for iterating the NAL unit, while @ops has function
36 * pointers for handling each type in the rbsp.
37 */
38struct rbsp {
39	u8 *data;
40	size_t size;
41	unsigned int pos;
42	unsigned int num_consecutive_zeros;
43	struct nal_rbsp_ops *ops;
44	int error;
45};
46
47extern struct nal_rbsp_ops write;
48extern struct nal_rbsp_ops read;
49
50void rbsp_init(struct rbsp *rbsp, void *addr, size_t size,
51	       struct nal_rbsp_ops *ops);
52void rbsp_unsupported(struct rbsp *rbsp);
53
54void rbsp_bit(struct rbsp *rbsp, int *value);
55void rbsp_bits(struct rbsp *rbsp, int n, int *value);
56void rbsp_uev(struct rbsp *rbsp, unsigned int *value);
57void rbsp_sev(struct rbsp *rbsp, int *value);
58
59void rbsp_trailing_bits(struct rbsp *rbsp);
60
61#endif /* __NAL_RBSP_H__ */
62