You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
242 lines
7.5 KiB
242 lines
7.5 KiB
/*****************************************************************************
|
|
* xiph.h: Xiph helpers
|
|
*****************************************************************************
|
|
* Copyright (C) 2010 Laurent Aimar
|
|
*
|
|
* Authors: Laurent Aimar <fenrir _AT_ videolan _DOT_ org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU Lesser General Public License as published by
|
|
* the Free Software Foundation; either version 2.1 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public License
|
|
* along with this program; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
|
|
*****************************************************************************/
|
|
|
|
#include <assert.h>
|
|
#include <limits.h>
|
|
#define XIPH_MAX_HEADER_COUNT (256)
|
|
|
|
/* Temp ffmpeg vorbis format */
|
|
static inline bool xiph_IsLavcFormat(const void *extra, unsigned i_extra,
|
|
vlc_fourcc_t i_codec)
|
|
{
|
|
switch(i_codec)
|
|
{
|
|
case VLC_CODEC_VORBIS:
|
|
return i_extra >= 6 && GetWBE(extra) == 30;
|
|
case VLC_CODEC_THEORA:
|
|
return i_extra >= 6 && GetWBE(extra) == 42;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
static inline unsigned xiph_CountLavcHeaders(const void *p_extra, unsigned i_extra)
|
|
{
|
|
const uint8_t *p = (const uint8_t*) p_extra;
|
|
const uint8_t *p_end = &p[i_extra];
|
|
/* Check headers count */
|
|
for (int i=0; i<3; i++)
|
|
{
|
|
if(p_end - p < 2)
|
|
return 0;
|
|
uint16_t i_size = GetWBE(p);
|
|
if(&p[2U + i_size] > p_end)
|
|
return 0;
|
|
p += 2 + i_size;
|
|
}
|
|
return 3;
|
|
}
|
|
|
|
static inline unsigned xiph_CountHeaders(const void *p_extra, unsigned i_extra)
|
|
{
|
|
const uint8_t *p = (const uint8_t*) p_extra;
|
|
if (!i_extra)
|
|
return 0;
|
|
/* First byte is headers count */
|
|
if(1U + *p > i_extra)
|
|
return 0;
|
|
return *p + 1;
|
|
}
|
|
|
|
static inline unsigned xiph_CountUnknownHeaders(const void *p_extra, unsigned i_extra,
|
|
vlc_fourcc_t i_codec)
|
|
{
|
|
if (xiph_IsLavcFormat(p_extra, i_extra, i_codec))
|
|
return xiph_CountLavcHeaders(p_extra, i_extra);
|
|
else
|
|
return xiph_CountHeaders(p_extra, i_extra);
|
|
}
|
|
|
|
static inline int xiph_SplitLavcHeaders(unsigned packet_size[],
|
|
const void *packet[], unsigned *packet_count,
|
|
unsigned i_extra, const void *p_extra)
|
|
{
|
|
const uint8_t *current = (const uint8_t *)p_extra;
|
|
const uint8_t *end = ¤t[i_extra];
|
|
if (i_extra < 2)
|
|
return VLC_EGENERIC;
|
|
/* Parse the packet count and their sizes */
|
|
const unsigned count = xiph_CountLavcHeaders(current, i_extra);
|
|
if(count == 0)
|
|
return VLC_EGENERIC;
|
|
if (packet_count)
|
|
*packet_count = count;
|
|
/* count is trusted here (xiph_CountHeaders) */
|
|
for (unsigned i=0; i < count; i++)
|
|
{
|
|
/* each payload is prefixed by word size */
|
|
packet_size[i] = GetWBE(current);
|
|
if(¤t[2U + packet_size[i]] > end)
|
|
return VLC_EGENERIC;
|
|
packet[i] = current + 2;
|
|
current += packet_size[i] + 2;
|
|
}
|
|
return VLC_SUCCESS;
|
|
}
|
|
|
|
static inline int xiph_SplitHeaders(unsigned packet_size[],
|
|
const void *packet[], unsigned *packet_count,
|
|
unsigned i_extra, const void *p_extra)
|
|
{
|
|
const uint8_t *current = (const uint8_t *)p_extra;
|
|
const uint8_t *end = ¤t[i_extra];
|
|
if (i_extra < 1)
|
|
return VLC_EGENERIC;
|
|
|
|
/* Parse the packet count and their sizes */
|
|
const unsigned count = xiph_CountHeaders(current, i_extra);
|
|
if(count == 0)
|
|
return VLC_EGENERIC;
|
|
|
|
if (packet_count)
|
|
*packet_count = count;
|
|
|
|
/* - 1 byte (N-1) packets
|
|
* - N-1 variable length payload sizes
|
|
* - N-1 payloads
|
|
* - Nth packet (remaining) */
|
|
|
|
/* skip count byte header */
|
|
++current;
|
|
/* read sizes for N-1 packets */
|
|
unsigned total_payload_minus_last = 0;
|
|
for (unsigned i = 0; i < count - 1; i++)
|
|
{
|
|
packet_size[i] = 0;
|
|
for (;;) {
|
|
if (current >= end)
|
|
return VLC_EGENERIC;
|
|
packet_size[i] += *current;
|
|
if (*current++ != 255)
|
|
break;
|
|
}
|
|
if(UINT_MAX - total_payload_minus_last < packet_size[i])
|
|
return VLC_EGENERIC;
|
|
total_payload_minus_last += packet_size[i];
|
|
}
|
|
if(current + total_payload_minus_last > end)
|
|
return VLC_EGENERIC;
|
|
/* set pointers for N-1 packets */
|
|
for (unsigned i = 0; i < count - 1; i++)
|
|
{
|
|
packet[i] = current;
|
|
current += packet_size[i];
|
|
}
|
|
/* Last packet is remaining size */
|
|
packet_size[count - 1] = end - current;
|
|
packet[count - 1] = current;
|
|
|
|
return VLC_SUCCESS;
|
|
}
|
|
|
|
static inline int xiph_PackHeaders(int *extra_size, void **extra,
|
|
unsigned packet_size[],
|
|
const void *const packet[],
|
|
unsigned packet_count)
|
|
{
|
|
if (packet_count <= 0 || packet_count > XIPH_MAX_HEADER_COUNT)
|
|
return VLC_EGENERIC;
|
|
|
|
/* Compute the size needed for the whole extra data */
|
|
unsigned payload_size = 0;
|
|
unsigned header_size = 1;
|
|
for (unsigned i = 0; i < packet_count; i++) {
|
|
payload_size += packet_size[i];
|
|
if (i < packet_count - 1)
|
|
header_size += 1 + packet_size[i] / 255;
|
|
}
|
|
|
|
/* */
|
|
*extra_size = header_size + payload_size;
|
|
*extra = malloc(*extra_size);
|
|
if (*extra == NULL)
|
|
return VLC_ENOMEM;
|
|
|
|
/* Write the header */
|
|
uint8_t *current = (uint8_t*)*extra;
|
|
*current++ = packet_count - 1;
|
|
for (unsigned i = 0; i < packet_count - 1; i++) {
|
|
unsigned t = packet_size[i];
|
|
for (;;) {
|
|
if (t >= 255) {
|
|
*current++ = 255;
|
|
t -= 255;
|
|
} else {
|
|
*current++ = t;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Copy the payloads */
|
|
for (unsigned i = 0; i < packet_count; i++) {
|
|
if (packet_size[i] > 0) {
|
|
memcpy(current, packet[i], packet_size[i]);
|
|
current += packet_size[i];
|
|
}
|
|
}
|
|
assert(current == (uint8_t*)*extra + *extra_size);
|
|
return VLC_SUCCESS;
|
|
}
|
|
|
|
static inline int xiph_AppendHeaders(int *extra_size, void **extra,
|
|
unsigned size, const void *data)
|
|
{
|
|
unsigned packet_size[XIPH_MAX_HEADER_COUNT];
|
|
const void *packet[XIPH_MAX_HEADER_COUNT];
|
|
unsigned count;
|
|
|
|
if (*extra_size > 0 && *extra) {
|
|
if (xiph_SplitHeaders(packet_size, packet, &count, *extra_size, *extra))
|
|
return VLC_EGENERIC;
|
|
} else {
|
|
count = 0;
|
|
}
|
|
if (count >= XIPH_MAX_HEADER_COUNT)
|
|
return VLC_EGENERIC;
|
|
|
|
void *old = *extra;
|
|
|
|
packet_size[count] = size;
|
|
packet[count] = (void*)data;
|
|
if (xiph_PackHeaders(extra_size, extra, packet_size,
|
|
packet, count + 1)) {
|
|
*extra_size = 0;
|
|
*extra = NULL;
|
|
}
|
|
|
|
free(old);
|
|
|
|
if (*extra_size <= 0)
|
|
return VLC_EGENERIC;
|
|
return VLC_SUCCESS;
|
|
}
|
|
|