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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 Dave Chapman
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <codecs.h>
#include <inttypes.h>
#include "m4a.h"
/* Implementation of the stream.h functions used by libalac */
#define _Swap32(v) do { \
v = (((v) & 0x000000FF) << 0x18) | \
(((v) & 0x0000FF00) << 0x08) | \
(((v) & 0x00FF0000) >> 0x08) | \
(((v) & 0xFF000000) >> 0x18); } while(0)
#define _Swap16(v) do { \
v = (((v) & 0x00FF) << 0x08) | \
(((v) & 0xFF00) >> 0x08); } while (0)
/* A normal read without any byte-swapping */
void stream_read(stream_t *stream, size_t size, void *buf)
{
stream->ci->read_filebuf(buf,size);
if (stream->ci->curpos >= stream->ci->filesize) { stream->eof=1; }
}
int32_t stream_read_int32(stream_t *stream)
{
int32_t v;
stream_read(stream, 4, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap32(v);
#endif
return v;
}
int32_t stream_tell(stream_t *stream)
{
return stream->ci->curpos;
}
uint32_t stream_read_uint32(stream_t *stream)
{
uint32_t v;
stream_read(stream, 4, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap32(v);
#endif
return v;
}
int16_t stream_read_int16(stream_t *stream)
{
int16_t v;
stream_read(stream, 2, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap16(v);
#endif
return v;
}
uint16_t stream_read_uint16(stream_t *stream)
{
uint16_t v;
stream_read(stream, 2, &v);
#ifdef ROCKBOX_LITTLE_ENDIAN
_Swap16(v);
#endif
return v;
}
int8_t stream_read_int8(stream_t *stream)
{
int8_t v;
stream_read(stream, 1, &v);
return v;
}
uint8_t stream_read_uint8(stream_t *stream)
{
uint8_t v;
stream_read(stream, 1, &v);
return v;
}
void stream_skip(stream_t *stream, size_t skip)
{
(void)stream;
#if 1
char buf;
while (skip > 0) {
stream->ci->read_filebuf(&buf,1);
skip--;
}
#endif
//stream->ci->advance_buffer(skip);
}
int stream_eof(stream_t *stream)
{
return stream->eof;
}
void stream_create(stream_t *stream,struct codec_api* ci)
{
stream->ci=ci;
stream->eof=0;
}
/* This function was part of the original alac decoder implementation */
int get_sample_info(demux_res_t *demux_res, uint32_t samplenum,
uint32_t *sample_duration,
uint32_t *sample_byte_size)
{
unsigned int duration_index_accum = 0;
unsigned int duration_cur_index = 0;
if (samplenum >= demux_res->num_sample_byte_sizes) {
return 0;
}
if (!demux_res->num_time_to_samples) {
return 0;
}
while ((demux_res->time_to_sample[duration_cur_index].sample_count
+ duration_index_accum) <= samplenum) {
duration_index_accum +=
demux_res->time_to_sample[duration_cur_index].sample_count;
duration_cur_index++;
if (duration_cur_index >= demux_res->num_time_to_samples) {
return 0;
}
}
*sample_duration =
demux_res->time_to_sample[duration_cur_index].sample_duration;
*sample_byte_size = demux_res->sample_byte_size[samplenum];
return 1;
}
/* Seek to sample_loc (or close to it). Return 1 on success (and
modify samplesdone and currentblock), 0 if failed
Seeking uses the following two arrays:
1) the sample_byte_size array contains the length in bytes of
each block ("sample" in Applespeak).
2) the time_to_sample array contains the duration (in samples) of
each block of data.
So we just find the block number we are going to seek to (using
time_to_sample) and then find the offset in the file (using
sample_byte_size).
Each ALAC block seems to be independent of all the others.
*/
unsigned int alac_seek (demux_res_t* demux_res,
stream_t* stream,
unsigned int sample_loc,
uint32_t* samplesdone, int* currentblock)
{
int flag;
unsigned int i,j;
unsigned int newblock;
unsigned int newsample;
unsigned int newpos;
/* First check we have the appropriate metadata - we should always
have it. */
if ((demux_res->num_time_to_samples==0) ||
(demux_res->num_sample_byte_sizes==0)) { return 0; }
/* Find the destination block from time_to_sample array */
i=0;
newblock=0;
newsample=0;
flag=0;
while ((i<demux_res->num_time_to_samples) && (flag==0) &&
(newsample < sample_loc)) {
j=(sample_loc-newsample) /
demux_res->time_to_sample[i].sample_duration;
if (j <= demux_res->time_to_sample[i].sample_count) {
newblock+=j;
newsample+=j*demux_res->time_to_sample[i].sample_duration;
flag=1;
} else {
newsample+=(demux_res->time_to_sample[i].sample_duration
* demux_res->time_to_sample[i].sample_count);
newblock+=demux_res->time_to_sample[i].sample_count;
i++;
}
}
/* We know the new block, now calculate the file position */
newpos=demux_res->mdat_offset;
for (i=0;i<newblock;i++) {
newpos+=demux_res->sample_byte_size[i];
}
/* We know the new file position, so let's try to seek to it */
if (stream->ci->seek_buffer(newpos)) {
*samplesdone=newsample;
*currentblock=newblock;
return 1;
} else {
return 0;
}
}
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