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98c588b6d2
Allow generators to explicitly signal an error if the C structs contain unsupported or invalid fields. Signed-off-by: Michael Tretter <m.tretter@pengutronix.de> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
311 lines
5.7 KiB
C
311 lines
5.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019-2020 Pengutronix, Michael Tretter <kernel@pengutronix.de>
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*
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* Helper functions to generate a raw byte sequence payload from values.
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/v4l2-controls.h>
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#include <linux/device.h>
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#include <linux/export.h>
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#include <linux/log2.h>
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#include "nal-rbsp.h"
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void rbsp_init(struct rbsp *rbsp, void *addr, size_t size,
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struct nal_rbsp_ops *ops)
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{
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if (!rbsp)
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return;
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rbsp->data = addr;
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rbsp->size = size;
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rbsp->pos = 0;
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rbsp->ops = ops;
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rbsp->error = 0;
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}
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void rbsp_unsupported(struct rbsp *rbsp)
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{
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rbsp->error = -EINVAL;
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}
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static int rbsp_read_bits(struct rbsp *rbsp, int n, unsigned int *value);
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static int rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int value);
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/*
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* When reading or writing, the emulation_prevention_three_byte is detected
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* only when the 2 one bits need to be inserted. Therefore, we are not
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* actually adding the 0x3 byte, but the 2 one bits and the six 0 bits of the
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* next byte.
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*/
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#define EMULATION_PREVENTION_THREE_BYTE (0x3 << 6)
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static int add_emulation_prevention_three_byte(struct rbsp *rbsp)
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{
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rbsp->num_consecutive_zeros = 0;
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rbsp_write_bits(rbsp, 8, EMULATION_PREVENTION_THREE_BYTE);
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return 0;
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}
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static int discard_emulation_prevention_three_byte(struct rbsp *rbsp)
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{
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unsigned int tmp = 0;
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rbsp->num_consecutive_zeros = 0;
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rbsp_read_bits(rbsp, 8, &tmp);
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if (tmp != EMULATION_PREVENTION_THREE_BYTE)
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return -EINVAL;
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return 0;
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}
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static inline int rbsp_read_bit(struct rbsp *rbsp)
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{
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int shift;
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int ofs;
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int bit;
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int err;
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if (rbsp->num_consecutive_zeros == 22) {
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err = discard_emulation_prevention_three_byte(rbsp);
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if (err)
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return err;
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}
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shift = 7 - (rbsp->pos % 8);
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ofs = rbsp->pos / 8;
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if (ofs >= rbsp->size)
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return -EINVAL;
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bit = (rbsp->data[ofs] >> shift) & 1;
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rbsp->pos++;
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if (bit == 1 ||
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(rbsp->num_consecutive_zeros < 7 && (rbsp->pos % 8 == 0)))
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rbsp->num_consecutive_zeros = 0;
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else
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rbsp->num_consecutive_zeros++;
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return bit;
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}
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static inline int rbsp_write_bit(struct rbsp *rbsp, bool value)
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{
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int shift;
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int ofs;
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if (rbsp->num_consecutive_zeros == 22)
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add_emulation_prevention_three_byte(rbsp);
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shift = 7 - (rbsp->pos % 8);
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ofs = rbsp->pos / 8;
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if (ofs >= rbsp->size)
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return -EINVAL;
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rbsp->data[ofs] &= ~(1 << shift);
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rbsp->data[ofs] |= value << shift;
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rbsp->pos++;
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if (value ||
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(rbsp->num_consecutive_zeros < 7 && (rbsp->pos % 8 == 0))) {
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rbsp->num_consecutive_zeros = 0;
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} else {
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rbsp->num_consecutive_zeros++;
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}
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return 0;
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}
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static inline int rbsp_read_bits(struct rbsp *rbsp, int n, unsigned int *value)
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{
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int i;
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int bit;
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unsigned int tmp = 0;
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if (n > 8 * sizeof(*value))
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return -EINVAL;
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for (i = n; i > 0; i--) {
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bit = rbsp_read_bit(rbsp);
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if (bit < 0)
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return bit;
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tmp |= bit << (i - 1);
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}
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if (value)
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*value = tmp;
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return 0;
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}
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static int rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int value)
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{
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int ret;
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if (n > 8 * sizeof(value))
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return -EINVAL;
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while (n--) {
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ret = rbsp_write_bit(rbsp, (value >> n) & 1);
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if (ret)
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return ret;
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}
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return 0;
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}
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static int rbsp_read_uev(struct rbsp *rbsp, unsigned int *value)
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{
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int leading_zero_bits = 0;
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unsigned int tmp = 0;
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int ret;
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while ((ret = rbsp_read_bit(rbsp)) == 0)
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leading_zero_bits++;
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if (ret < 0)
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return ret;
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if (leading_zero_bits > 0) {
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ret = rbsp_read_bits(rbsp, leading_zero_bits, &tmp);
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if (ret)
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return ret;
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}
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if (value)
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*value = (1 << leading_zero_bits) - 1 + tmp;
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return 0;
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}
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static int rbsp_write_uev(struct rbsp *rbsp, unsigned int *value)
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{
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int ret;
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int leading_zero_bits;
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if (!value)
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return -EINVAL;
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leading_zero_bits = ilog2(*value + 1);
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ret = rbsp_write_bits(rbsp, leading_zero_bits, 0);
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if (ret)
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return ret;
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return rbsp_write_bits(rbsp, leading_zero_bits + 1, *value + 1);
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}
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static int rbsp_read_sev(struct rbsp *rbsp, int *value)
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{
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int ret;
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unsigned int tmp;
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ret = rbsp_read_uev(rbsp, &tmp);
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if (ret)
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return ret;
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if (value) {
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if (tmp & 1)
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*value = (tmp + 1) / 2;
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else
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*value = -(tmp / 2);
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}
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return 0;
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}
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static int rbsp_write_sev(struct rbsp *rbsp, int *value)
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{
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unsigned int tmp;
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if (!value)
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return -EINVAL;
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if (*value > 0)
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tmp = (2 * (*value)) | 1;
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else
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tmp = -2 * (*value);
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return rbsp_write_uev(rbsp, &tmp);
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}
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static int __rbsp_write_bit(struct rbsp *rbsp, int *value)
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{
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return rbsp_write_bit(rbsp, *value);
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}
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static int __rbsp_write_bits(struct rbsp *rbsp, int n, unsigned int *value)
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{
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return rbsp_write_bits(rbsp, n, *value);
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}
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struct nal_rbsp_ops write = {
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.rbsp_bit = __rbsp_write_bit,
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.rbsp_bits = __rbsp_write_bits,
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.rbsp_uev = rbsp_write_uev,
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.rbsp_sev = rbsp_write_sev,
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};
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static int __rbsp_read_bit(struct rbsp *rbsp, int *value)
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{
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int tmp = rbsp_read_bit(rbsp);
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if (tmp < 0)
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return tmp;
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*value = tmp;
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return 0;
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}
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struct nal_rbsp_ops read = {
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.rbsp_bit = __rbsp_read_bit,
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.rbsp_bits = rbsp_read_bits,
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.rbsp_uev = rbsp_read_uev,
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.rbsp_sev = rbsp_read_sev,
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};
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void rbsp_bit(struct rbsp *rbsp, int *value)
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{
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if (rbsp->error)
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return;
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rbsp->error = rbsp->ops->rbsp_bit(rbsp, value);
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}
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void rbsp_bits(struct rbsp *rbsp, int n, int *value)
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{
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if (rbsp->error)
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return;
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rbsp->error = rbsp->ops->rbsp_bits(rbsp, n, value);
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}
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void rbsp_uev(struct rbsp *rbsp, unsigned int *value)
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{
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if (rbsp->error)
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return;
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rbsp->error = rbsp->ops->rbsp_uev(rbsp, value);
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}
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void rbsp_sev(struct rbsp *rbsp, int *value)
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{
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if (rbsp->error)
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return;
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rbsp->error = rbsp->ops->rbsp_sev(rbsp, value);
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}
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void rbsp_trailing_bits(struct rbsp *rbsp)
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{
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unsigned int rbsp_stop_one_bit = 1;
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unsigned int rbsp_alignment_zero_bit = 0;
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rbsp_bit(rbsp, &rbsp_stop_one_bit);
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rbsp_bits(rbsp, round_up(rbsp->pos, 8) - rbsp->pos,
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&rbsp_alignment_zero_bit);
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}
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