[01/18] media: allegro: extract RBSP handler from H.264 NAL generator

diff --git a/drivers/media/platform/allegro-dvt/Makefile b/drivers/media/platform/allegro-dvt/Makefile
index 8e306dcdc55c..10119e84a60f 100644
--- a/drivers/media/platform/allegro-dvt/Makefile
+++ b/drivers/media/platform/allegro-dvt/Makefile
@@ -1,5 +1,6 @@ 
 # SPDX-License-Identifier: GPL-2.0
 
-allegro-objs := allegro-core.o nal-h264.o allegro-mail.o
+allegro-objs := allegro-core.o allegro-mail.o
+allegro-objs += nal-rbsp.o nal-h264.o
 
 obj-$(CONFIG_VIDEO_ALLEGRO_DVT) += allegro.o
diff --git a/drivers/media/platform/allegro-dvt/nal-h264.c b/drivers/media/platform/allegro-dvt/nal-h264.c
index bd48b8883572..94dd9266d850 100644
--- a/drivers/media/platform/allegro-dvt/nal-h264.c
+++ b/drivers/media/platform/allegro-dvt/nal-h264.c
@@ -22,6 +22,7 @@ 
 #include <linux/log2.h>
 
 #include "nal-h264.h"
+#include "nal-rbsp.h"
 
 /*
  * See Rec. ITU-T H.264 (04/2017) Table 7-1 – NAL unit type codes, syntax
@@ -33,54 +34,6 @@  enum nal_unit_type {
 	FILLER_DATA = 12,
 };
 
-struct rbsp;
-
-struct nal_h264_ops {
-	int (*rbsp_bit)(struct rbsp *rbsp, int *val);
-	int (*rbsp_bits)(struct rbsp *rbsp, int n, unsigned int *val);
-	int (*rbsp_uev)(struct rbsp *rbsp, unsigned int *val);
-	int (*rbsp_sev)(struct rbsp *rbsp, int *val);
-};
-
-/**
- * struct rbsp - State object for handling a raw byte sequence payload
- * @data: pointer to the data of the rbsp
- * @size: maximum size of the data of the rbsp
- * @pos: current bit position inside the rbsp
- * @num_consecutive_zeros: number of zeros before @pos
- * @ops: per datatype functions for interacting with the rbsp
- * @error: an error occurred while handling the rbsp
- *
- * This struct is passed around the various parsing functions and tracks the
- * current position within the raw byte sequence payload.
- *
- * The @ops field allows to separate the operation, i.e., reading/writing a
- * value from/to that rbsp, from the structure of the NAL unit. This allows to
- * have a single function for iterating the NAL unit, while @ops has function
- * pointers for handling each type in the rbsp.
- */
-struct rbsp {
-	u8 *data;
-	size_t size;
-	unsigned int pos;
-	unsigned int num_consecutive_zeros;
-	struct nal_h264_ops *ops;
-	int error;
-};
-
-static void rbsp_init(struct rbsp *rbsp, void *addr, size_t size,
-		      struct nal_h264_ops *ops)
-{
-	if (!rbsp)
-		return;
-
-	rbsp->data = addr;
-	rbsp->size = size;
-	rbsp->pos = 0;
-	rbsp->ops = ops;
-	rbsp->error = 0;
-}
-
 /**
  * nal_h264_profile_from_v4l2() - Get profile_idc for v4l2 h264 profile
  * @profile: the profile as &enum v4l2_mpeg_video_h264_profile
@@ -155,281 +108,6 @@  int nal_h264_level_from_v4l2(enum v4l2_mpeg_video_h264_level level)
 	}
 }
 
-static int rbsp_read_bits(struct rbsp *rbsp, int n, unsigned int *value);
-static int rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int value);
-
-/*
- * When reading or writing, the emulation_prevention_three_byte is detected
- * only when the 2 one bits need to be inserted. Therefore, we are not
- * actually adding the 0x3 byte, but the 2 one bits and the six 0 bits of the
- * next byte.
- */
-#define EMULATION_PREVENTION_THREE_BYTE (0x3 << 6)
-
-static int add_emulation_prevention_three_byte(struct rbsp *rbsp)
-{
-	rbsp->num_consecutive_zeros = 0;
-	rbsp_write_bits(rbsp, 8, EMULATION_PREVENTION_THREE_BYTE);
-
-	return 0;
-}
-
-static int discard_emulation_prevention_three_byte(struct rbsp *rbsp)
-{
-	unsigned int tmp = 0;
-
-	rbsp->num_consecutive_zeros = 0;
-	rbsp_read_bits(rbsp, 8, &tmp);
-	if (tmp != EMULATION_PREVENTION_THREE_BYTE)
-		return -EINVAL;
-
-	return 0;
-}
-
-static inline int rbsp_read_bit(struct rbsp *rbsp)
-{
-	int shift;
-	int ofs;
-	int bit;
-	int err;
-
-	if (rbsp->num_consecutive_zeros == 22) {
-		err = discard_emulation_prevention_three_byte(rbsp);
-		if (err)
-			return err;
-	}
-
-	shift = 7 - (rbsp->pos % 8);
-	ofs = rbsp->pos / 8;
-	if (ofs >= rbsp->size)
-		return -EINVAL;
-
-	bit = (rbsp->data[ofs] >> shift) & 1;
-
-	rbsp->pos++;
-
-	if (bit == 1 ||
-	    (rbsp->num_consecutive_zeros < 7 && (rbsp->pos % 8 == 0)))
-		rbsp->num_consecutive_zeros = 0;
-	else
-		rbsp->num_consecutive_zeros++;
-
-	return bit;
-}
-
-static inline int rbsp_write_bit(struct rbsp *rbsp, bool value)
-{
-	int shift;
-	int ofs;
-
-	if (rbsp->num_consecutive_zeros == 22)
-		add_emulation_prevention_three_byte(rbsp);
-
-	shift = 7 - (rbsp->pos % 8);
-	ofs = rbsp->pos / 8;
-	if (ofs >= rbsp->size)
-		return -EINVAL;
-
-	rbsp->data[ofs] &= ~(1 << shift);
-	rbsp->data[ofs] |= value << shift;
-
-	rbsp->pos++;
-
-	if (value ||
-	    (rbsp->num_consecutive_zeros < 7 && (rbsp->pos % 8 == 0))) {
-		rbsp->num_consecutive_zeros = 0;
-	} else {
-		rbsp->num_consecutive_zeros++;
-	}
-
-	return 0;
-}
-
-static inline int rbsp_read_bits(struct rbsp *rbsp, int n, unsigned int *value)
-{
-	int i;
-	int bit;
-	unsigned int tmp = 0;
-
-	if (n > 8 * sizeof(*value))
-		return -EINVAL;
-
-	for (i = n; i > 0; i--) {
-		bit = rbsp_read_bit(rbsp);
-		if (bit < 0)
-			return bit;
-		tmp |= bit << (i - 1);
-	}
-
-	if (value)
-		*value = tmp;
-
-	return 0;
-}
-
-static int rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int value)
-{
-	int ret;
-
-	if (n > 8 * sizeof(value))
-		return -EINVAL;
-
-	while (n--) {
-		ret = rbsp_write_bit(rbsp, (value >> n) & 1);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-
-static int rbsp_read_uev(struct rbsp *rbsp, unsigned int *value)
-{
-	int leading_zero_bits = 0;
-	unsigned int tmp = 0;
-	int ret;
-
-	while ((ret = rbsp_read_bit(rbsp)) == 0)
-		leading_zero_bits++;
-	if (ret < 0)
-		return ret;
-
-	if (leading_zero_bits > 0) {
-		ret = rbsp_read_bits(rbsp, leading_zero_bits, &tmp);
-		if (ret)
-			return ret;
-	}
-
-	if (value)
-		*value = (1 << leading_zero_bits) - 1 + tmp;
-
-	return 0;
-}
-
-static int rbsp_write_uev(struct rbsp *rbsp, unsigned int *value)
-{
-	int ret;
-	int leading_zero_bits;
-
-	if (!value)
-		return -EINVAL;
-
-	leading_zero_bits = ilog2(*value + 1);
-
-	ret = rbsp_write_bits(rbsp, leading_zero_bits, 0);
-	if (ret)
-		return ret;
-
-	return rbsp_write_bits(rbsp, leading_zero_bits + 1, *value + 1);
-}
-
-static int rbsp_read_sev(struct rbsp *rbsp, int *value)
-{
-	int ret;
-	unsigned int tmp;
-
-	ret = rbsp_read_uev(rbsp, &tmp);
-	if (ret)
-		return ret;
-
-	if (value) {
-		if (tmp & 1)
-			*value = (tmp + 1) / 2;
-		else
-			*value = -(tmp / 2);
-	}
-
-	return 0;
-}
-
-static int rbsp_write_sev(struct rbsp *rbsp, int *value)
-{
-	unsigned int tmp;
-
-	if (!value)
-		return -EINVAL;
-
-	if (*value > 0)
-		tmp = (2 * (*value)) | 1;
-	else
-		tmp = -2 * (*value);
-
-	return rbsp_write_uev(rbsp, &tmp);
-}
-
-static int __rbsp_write_bit(struct rbsp *rbsp, int *value)
-{
-	return rbsp_write_bit(rbsp, *value);
-}
-
-static int __rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int *value)
-{
-	return rbsp_write_bits(rbsp, n, *value);
-}
-
-static struct nal_h264_ops write = {
-	.rbsp_bit = __rbsp_write_bit,
-	.rbsp_bits = __rbsp_write_bits,
-	.rbsp_uev = rbsp_write_uev,
-	.rbsp_sev = rbsp_write_sev,
-};
-
-static int __rbsp_read_bit(struct rbsp *rbsp, int *value)
-{
-	int tmp = rbsp_read_bit(rbsp);
-
-	if (tmp < 0)
-		return tmp;
-	*value = tmp;
-
-	return 0;
-}
-
-static struct nal_h264_ops read = {
-	.rbsp_bit = __rbsp_read_bit,
-	.rbsp_bits = rbsp_read_bits,
-	.rbsp_uev = rbsp_read_uev,
-	.rbsp_sev = rbsp_read_sev,
-};
-
-static inline void rbsp_bit(struct rbsp *rbsp, int *value)
-{
-	if (rbsp->error)
-		return;
-	rbsp->error = rbsp->ops->rbsp_bit(rbsp, value);
-}
-
-static inline void rbsp_bits(struct rbsp *rbsp, int n, int *value)
-{
-	if (rbsp->error)
-		return;
-	rbsp->error = rbsp->ops->rbsp_bits(rbsp, n, value);
-}
-
-static inline void rbsp_uev(struct rbsp *rbsp, unsigned int *value)
-{
-	if (rbsp->error)
-		return;
-	rbsp->error = rbsp->ops->rbsp_uev(rbsp, value);
-}
-
-static inline void rbsp_sev(struct rbsp *rbsp, int *value)
-{
-	if (rbsp->error)
-		return;
-	rbsp->error = rbsp->ops->rbsp_sev(rbsp, value);
-}
-
-static void nal_h264_rbsp_trailing_bits(struct rbsp *rbsp)
-{
-	unsigned int rbsp_stop_one_bit = 1;
-	unsigned int rbsp_alignment_zero_bit = 0;
-
-	rbsp_bit(rbsp, &rbsp_stop_one_bit);
-	rbsp_bits(rbsp, round_up(rbsp->pos, 8) - rbsp->pos,
-		  &rbsp_alignment_zero_bit);
-}
-
 static void nal_h264_write_start_code_prefix(struct rbsp *rbsp)
 {
 	u8 *p = rbsp->data + DIV_ROUND_UP(rbsp->pos, 8);
@@ -767,7 +445,7 @@  ssize_t nal_h264_write_sps(const struct device *dev,
 
 	nal_h264_rbsp_sps(&rbsp, sps);
 
-	nal_h264_rbsp_trailing_bits(&rbsp);
+	rbsp_trailing_bits(&rbsp);
 
 	if (rbsp.error)
 		return rbsp.error;
@@ -814,7 +492,7 @@  ssize_t nal_h264_read_sps(const struct device *dev,
 
 	nal_h264_rbsp_sps(&rbsp, sps);
 
-	nal_h264_rbsp_trailing_bits(&rbsp);
+	rbsp_trailing_bits(&rbsp);
 
 	if (rbsp.error)
 		return rbsp.error;
@@ -859,7 +537,7 @@  ssize_t nal_h264_write_pps(const struct device *dev,
 
 	nal_h264_rbsp_pps(&rbsp, pps);
 
-	nal_h264_rbsp_trailing_bits(&rbsp);
+	rbsp_trailing_bits(&rbsp);
 
 	if (rbsp.error)
 		return rbsp.error;
@@ -896,7 +574,7 @@  ssize_t nal_h264_read_pps(const struct device *dev,
 
 	nal_h264_rbsp_pps(&rbsp, pps);
 
-	nal_h264_rbsp_trailing_bits(&rbsp);
+	rbsp_trailing_bits(&rbsp);
 
 	if (rbsp.error)
 		return rbsp.error;
@@ -942,7 +620,7 @@  ssize_t nal_h264_write_filler(const struct device *dev, void *dest, size_t n)
 
 	nal_h264_write_filler_data(&rbsp);
 
-	nal_h264_rbsp_trailing_bits(&rbsp);
+	rbsp_trailing_bits(&rbsp);
 
 	return DIV_ROUND_UP(rbsp.pos, 8);
 }
@@ -991,7 +669,7 @@  ssize_t nal_h264_read_filler(const struct device *dev, void *src, size_t n)
 		return -EINVAL;
 
 	nal_h264_read_filler_data(&rbsp);
-	nal_h264_rbsp_trailing_bits(&rbsp);
+	rbsp_trailing_bits(&rbsp);
 
 	if (rbsp.error)
 		return rbsp.error;
diff --git a/drivers/media/platform/allegro-dvt/nal-rbsp.c b/drivers/media/platform/allegro-dvt/nal-rbsp.c
new file mode 100644
index 000000000000..935ba23844f2
--- /dev/null
+++ b/drivers/media/platform/allegro-dvt/nal-rbsp.c
@@ -0,0 +1,305 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019-2020 Pengutronix, Michael Tretter <kernel@pengutronix.de>
+ *
+ * Helper functions to generate a raw byte sequence payload from values.
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/v4l2-controls.h>
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/log2.h>
+
+#include "nal-rbsp.h"
+
+void rbsp_init(struct rbsp *rbsp, void *addr, size_t size,
+	       struct nal_rbsp_ops *ops)
+{
+	if (!rbsp)
+		return;
+
+	rbsp->data = addr;
+	rbsp->size = size;
+	rbsp->pos = 0;
+	rbsp->ops = ops;
+	rbsp->error = 0;
+}
+
+static int rbsp_read_bits(struct rbsp *rbsp, int n, unsigned int *value);
+static int rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int value);
+
+/*
+ * When reading or writing, the emulation_prevention_three_byte is detected
+ * only when the 2 one bits need to be inserted. Therefore, we are not
+ * actually adding the 0x3 byte, but the 2 one bits and the six 0 bits of the
+ * next byte.
+ */
+#define EMULATION_PREVENTION_THREE_BYTE (0x3 << 6)
+
+static int add_emulation_prevention_three_byte(struct rbsp *rbsp)
+{
+	rbsp->num_consecutive_zeros = 0;
+	rbsp_write_bits(rbsp, 8, EMULATION_PREVENTION_THREE_BYTE);
+
+	return 0;
+}
+
+static int discard_emulation_prevention_three_byte(struct rbsp *rbsp)
+{
+	unsigned int tmp = 0;
+
+	rbsp->num_consecutive_zeros = 0;
+	rbsp_read_bits(rbsp, 8, &tmp);
+	if (tmp != EMULATION_PREVENTION_THREE_BYTE)
+		return -EINVAL;
+
+	return 0;
+}
+
+static inline int rbsp_read_bit(struct rbsp *rbsp)
+{
+	int shift;
+	int ofs;
+	int bit;
+	int err;
+
+	if (rbsp->num_consecutive_zeros == 22) {
+		err = discard_emulation_prevention_three_byte(rbsp);
+		if (err)
+			return err;
+	}
+
+	shift = 7 - (rbsp->pos % 8);
+	ofs = rbsp->pos / 8;
+	if (ofs >= rbsp->size)
+		return -EINVAL;
+
+	bit = (rbsp->data[ofs] >> shift) & 1;
+
+	rbsp->pos++;
+
+	if (bit == 1 ||
+	    (rbsp->num_consecutive_zeros < 7 && (rbsp->pos % 8 == 0)))
+		rbsp->num_consecutive_zeros = 0;
+	else
+		rbsp->num_consecutive_zeros++;
+
+	return bit;
+}
+
+static inline int rbsp_write_bit(struct rbsp *rbsp, bool value)
+{
+	int shift;
+	int ofs;
+
+	if (rbsp->num_consecutive_zeros == 22)
+		add_emulation_prevention_three_byte(rbsp);
+
+	shift = 7 - (rbsp->pos % 8);
+	ofs = rbsp->pos / 8;
+	if (ofs >= rbsp->size)
+		return -EINVAL;
+
+	rbsp->data[ofs] &= ~(1 << shift);
+	rbsp->data[ofs] |= value << shift;
+
+	rbsp->pos++;
+
+	if (value ||
+	    (rbsp->num_consecutive_zeros < 7 && (rbsp->pos % 8 == 0))) {
+		rbsp->num_consecutive_zeros = 0;
+	} else {
+		rbsp->num_consecutive_zeros++;
+	}
+
+	return 0;
+}
+
+static inline int rbsp_read_bits(struct rbsp *rbsp, int n, unsigned int *value)
+{
+	int i;
+	int bit;
+	unsigned int tmp = 0;
+
+	if (n > 8 * sizeof(*value))
+		return -EINVAL;
+
+	for (i = n; i > 0; i--) {
+		bit = rbsp_read_bit(rbsp);
+		if (bit < 0)
+			return bit;
+		tmp |= bit << (i - 1);
+	}
+
+	if (value)
+		*value = tmp;
+
+	return 0;
+}
+
+static int rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int value)
+{
+	int ret;
+
+	if (n > 8 * sizeof(value))
+		return -EINVAL;
+
+	while (n--) {
+		ret = rbsp_write_bit(rbsp, (value >> n) & 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int rbsp_read_uev(struct rbsp *rbsp, unsigned int *value)
+{
+	int leading_zero_bits = 0;
+	unsigned int tmp = 0;
+	int ret;
+
+	while ((ret = rbsp_read_bit(rbsp)) == 0)
+		leading_zero_bits++;
+	if (ret < 0)
+		return ret;
+
+	if (leading_zero_bits > 0) {
+		ret = rbsp_read_bits(rbsp, leading_zero_bits, &tmp);
+		if (ret)
+			return ret;
+	}
+
+	if (value)
+		*value = (1 << leading_zero_bits) - 1 + tmp;
+
+	return 0;
+}
+
+static int rbsp_write_uev(struct rbsp *rbsp, unsigned int *value)
+{
+	int ret;
+	int leading_zero_bits;
+
+	if (!value)
+		return -EINVAL;
+
+	leading_zero_bits = ilog2(*value + 1);
+
+	ret = rbsp_write_bits(rbsp, leading_zero_bits, 0);
+	if (ret)
+		return ret;
+
+	return rbsp_write_bits(rbsp, leading_zero_bits + 1, *value + 1);
+}
+
+static int rbsp_read_sev(struct rbsp *rbsp, int *value)
+{
+	int ret;
+	unsigned int tmp;
+
+	ret = rbsp_read_uev(rbsp, &tmp);
+	if (ret)
+		return ret;
+
+	if (value) {
+		if (tmp & 1)
+			*value = (tmp + 1) / 2;
+		else
+			*value = -(tmp / 2);
+	}
+
+	return 0;
+}
+
+static int rbsp_write_sev(struct rbsp *rbsp, int *value)
+{
+	unsigned int tmp;
+
+	if (!value)
+		return -EINVAL;
+
+	if (*value > 0)
+		tmp = (2 * (*value)) | 1;
+	else
+		tmp = -2 * (*value);
+
+	return rbsp_write_uev(rbsp, &tmp);
+}
+
+static int __rbsp_write_bit(struct rbsp *rbsp, int *value)
+{
+	return rbsp_write_bit(rbsp, *value);
+}
+
+static int __rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int *value)
+{
+	return rbsp_write_bits(rbsp, n, *value);
+}
+
+struct nal_rbsp_ops write = {
+	.rbsp_bit = __rbsp_write_bit,
+	.rbsp_bits = __rbsp_write_bits,
+	.rbsp_uev = rbsp_write_uev,
+	.rbsp_sev = rbsp_write_sev,
+};
+
+static int __rbsp_read_bit(struct rbsp *rbsp, int *value)
+{
+	int tmp = rbsp_read_bit(rbsp);
+
+	if (tmp < 0)
+		return tmp;
+	*value = tmp;
+
+	return 0;
+}
+
+struct nal_rbsp_ops read = {
+	.rbsp_bit = __rbsp_read_bit,
+	.rbsp_bits = rbsp_read_bits,
+	.rbsp_uev = rbsp_read_uev,
+	.rbsp_sev = rbsp_read_sev,
+};
+
+void rbsp_bit(struct rbsp *rbsp, int *value)
+{
+	if (rbsp->error)
+		return;
+	rbsp->error = rbsp->ops->rbsp_bit(rbsp, value);
+}
+
+void rbsp_bits(struct rbsp *rbsp, int n, int *value)
+{
+	if (rbsp->error)
+		return;
+	rbsp->error = rbsp->ops->rbsp_bits(rbsp, n, value);
+}
+
+void rbsp_uev(struct rbsp *rbsp, unsigned int *value)
+{
+	if (rbsp->error)
+		return;
+	rbsp->error = rbsp->ops->rbsp_uev(rbsp, value);
+}
+
+void rbsp_sev(struct rbsp *rbsp, int *value)
+{
+	if (rbsp->error)
+		return;
+	rbsp->error = rbsp->ops->rbsp_sev(rbsp, value);
+}
+
+void rbsp_trailing_bits(struct rbsp *rbsp)
+{
+	unsigned int rbsp_stop_one_bit = 1;
+	unsigned int rbsp_alignment_zero_bit = 0;
+
+	rbsp_bit(rbsp, &rbsp_stop_one_bit);
+	rbsp_bits(rbsp, round_up(rbsp->pos, 8) - rbsp->pos,
+		  &rbsp_alignment_zero_bit);
+}
diff --git a/drivers/media/platform/allegro-dvt/nal-rbsp.h b/drivers/media/platform/allegro-dvt/nal-rbsp.h
new file mode 100644
index 000000000000..90cc1a4f716d
--- /dev/null
+++ b/drivers/media/platform/allegro-dvt/nal-rbsp.h
@@ -0,0 +1,60 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2019-2020 Pengutronix, Michael Tretter <kernel@pengutronix.de>
+ */
+
+#ifndef __NAL_RBSP_H__
+#define __NAL_RBSP_H__
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+struct rbsp;
+
+struct nal_rbsp_ops {
+	int (*rbsp_bit)(struct rbsp *rbsp, int *val);
+	int (*rbsp_bits)(struct rbsp *rbsp, int n, unsigned int *val);
+	int (*rbsp_uev)(struct rbsp *rbsp, unsigned int *val);
+	int (*rbsp_sev)(struct rbsp *rbsp, int *val);
+};
+
+/**
+ * struct rbsp - State object for handling a raw byte sequence payload
+ * @data: pointer to the data of the rbsp
+ * @size: maximum size of the data of the rbsp
+ * @pos: current bit position inside the rbsp
+ * @num_consecutive_zeros: number of zeros before @pos
+ * @ops: per datatype functions for interacting with the rbsp
+ * @error: an error occurred while handling the rbsp
+ *
+ * This struct is passed around the various parsing functions and tracks the
+ * current position within the raw byte sequence payload.
+ *
+ * The @ops field allows to separate the operation, i.e., reading/writing a
+ * value from/to that rbsp, from the structure of the NAL unit. This allows to
+ * have a single function for iterating the NAL unit, while @ops has function
+ * pointers for handling each type in the rbsp.
+ */
+struct rbsp {
+	u8 *data;
+	size_t size;
+	unsigned int pos;
+	unsigned int num_consecutive_zeros;
+	struct nal_rbsp_ops *ops;
+	int error;
+};
+
+extern struct nal_rbsp_ops write;
+extern struct nal_rbsp_ops read;
+
+void rbsp_init(struct rbsp *rbsp, void *addr, size_t size,
+	       struct nal_rbsp_ops *ops);
+
+void rbsp_bit(struct rbsp *rbsp, int *value);
+void rbsp_bits(struct rbsp *rbsp, int n, int *value);
+void rbsp_uev(struct rbsp *rbsp, unsigned int *value);
+void rbsp_sev(struct rbsp *rbsp, int *value);
+
+void rbsp_trailing_bits(struct rbsp *rbsp);
+
+#endif /* __NAL_RBSP_H__ */