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/*****************************************************************************
* xiph.h: Xiph helpers
*****************************************************************************
* Copyright (C) 2010 Laurent Aimar
* $Id: 7d244286bef989d294e82881836c4d4535cd1d42 $
*
* 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>
#define XIPH_MAX_HEADER_COUNT (256)
/* Temp ffmpeg vorbis format */
static inline bool xiph_IsOldFormat( const void *extra, unsigned int i_extra )
{
if ( i_extra >= 6 && GetWBE( extra ) == 30 )
return true;
else
return false;
}
static inline unsigned int xiph_CountHeaders( const void *extra, unsigned int i_extra )
{
const uint8_t *p_extra = (uint8_t*) extra;
if ( !i_extra ) return 0;
if ( xiph_IsOldFormat( extra, i_extra ) )
{
/* Check headers count */
unsigned int overall_len = 6;
for ( int i=0; i<3; i++ )
{
uint16_t i_size = GetWBE( extra );
p_extra += 2 + i_size;
if ( overall_len > i_extra - i_size )
return 0;
overall_len += i_size;
}
return 3;
}
else
{
return *p_extra + 1;
}
}
static inline int xiph_SplitHeaders(unsigned packet_size[], void * packet[], unsigned *packet_count,
unsigned extra_size, const void *extra)
{
const uint8_t *current = (const uint8_t *)extra;
const uint8_t *end = ¤t[extra_size];
if (extra_size < 1)
return VLC_EGENERIC;
/* Parse the packet count and their sizes */
const unsigned count = xiph_CountHeaders( current++, extra_size );
if (packet_count)
*packet_count = count;
if ( xiph_IsOldFormat( extra, extra_size ) )
{
uint8_t *p_extra = (uint8_t*) extra;
unsigned int overall_len = count << 1;
for ( unsigned int i=0; i < count; i++ ) {
packet_size[i] = GetWBE( p_extra );
packet[i] = p_extra + 2;
p_extra += packet_size[i] + 2;
if (overall_len > extra_size - packet_size[i])
return VLC_EGENERIC;
overall_len += packet_size[i];
}
}
else
{
int size = 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;
}
size += packet_size[i];
}
if (end - current < size)
return VLC_EGENERIC;
packet_size[count - 1] = end - current - size;
for (unsigned i = 0; i < count; i++)
if (packet_size[i] > 0) {
packet[i] = (void *) current;
current += packet_size[i];
}
}
return VLC_SUCCESS;
}
static inline int xiph_PackHeaders(int *extra_size, void **extra,
unsigned packet_size[], const void *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];
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,
(const void **)packet, count + 1)) {
*extra_size = 0;
*extra = NULL;
}
free(old);
if (*extra_size <= 0)
return VLC_EGENERIC;
return VLC_SUCCESS;
}
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