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/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright (C)2012 Xiph.Org Foundation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* \file opus_common.c Common functions of the opus decoder and audio format
* handler.
*/
#include "para.h"
#include "error.h"
#include "opus_common.h"
#include "portable_io.h"
struct packet {
const char *data;
int maxlen;
int pos;
};
static int read_chars(struct packet *p, unsigned char *str, int nb_chars)
{
int i;
if (p->pos > p->maxlen - nb_chars)
return 0;
for (i = 0; i < nb_chars; i++)
str[i] = p->data[p->pos++];
return 1;
}
static int read_uint32(struct packet *p, uint32_t *val)
{
if (p->pos > p->maxlen - 4)
return 0;
*val = read_u32(p->data + p->pos);
p->pos += 4;
return 1;
}
static int read_uint16(struct packet *p, uint16_t *val)
{
if (p->pos > p->maxlen - 2)
return 0;
*val = read_u16(p->data + p->pos);
p->pos += 2;
return 1;
}
/**
* Get metadata of an opus stream.
*
* This is called from both the audio format handler (which passes ogg packet
* 0) and from the decoder.
*
* \param packet Start of the packet.
* \param len Number of bytes.
* \param h Result.
*
* \return Standard.
*/
int opus_parse_header(const char *packet, int len, struct opus_header *h)
{
int i;
char str[9];
struct packet p;
unsigned char ch, channel_mapping;
p.data = packet;
p.maxlen = len;
p.pos = 0;
str[8] = 0;
if (len < 19)
return -E_OPUS_HEADER;
read_chars(&p, (unsigned char*)str, 8);
if (memcmp(str, "OpusHead", 8) != 0)
return -E_OPUS_HEADER;
if (!read_chars(&p, &ch, 1))
return -E_OPUS_HEADER;
h->version = ch;
if ((h->version & 240) != 0) /* Only major version 0 supported. */
return -E_OPUS_HEADER;
if (!read_chars(&p, &ch, 1))
return -E_OPUS_HEADER;
h->channels = ch;
if (h->channels == 0)
return -E_OPUS_HEADER;
if (!read_uint16(&p, &h->preskip))
return -E_OPUS_HEADER;
if (!read_uint32(&p, &h->input_sample_rate))
return -E_OPUS_HEADER;
if (!read_uint16(&p, &h->gain))
return -E_OPUS_HEADER;
if (!read_chars(&p, &ch, 1))
return -E_OPUS_HEADER;
channel_mapping = ch;
if (channel_mapping != 0) {
if (!read_chars(&p, &ch, 1))
return -E_OPUS_HEADER;
if (ch < 1)
return -E_OPUS_HEADER;
h->nb_streams = ch;
if (!read_chars(&p, &ch, 1))
return -E_OPUS_HEADER;
if (ch > h->nb_streams || (ch + h->nb_streams) > 255)
return -E_OPUS_HEADER;
h->nb_coupled = ch;
/* Multi-stream support */
for (i = 0; i < h->channels; i++) {
if (!read_chars(&p, &h->stream_map[i], 1))
return -E_OPUS_HEADER;
if (h->stream_map[i] > (h->nb_streams + h->nb_coupled)
&& h->stream_map[i] != 255)
return -E_OPUS_HEADER;
}
} else {
if (h->channels > 2)
return -E_OPUS_HEADER;
h->nb_streams = 1;
h->nb_coupled = h->channels > 1;
h->stream_map[0] = 0;
h->stream_map[1] = 1;
}
/*
* For version 0/1 we know there won't be any more data so reject any
* that have data past the end.
*/
if ((h->version == 0 || h->version == 1) && p.pos != len)
return -E_OPUS_HEADER;
return 1;
}
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