/***************************************************************************
 *             __________               __   ___.
 *   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;
  }
}

/* Seek to file_loc (or close to it).  Return 1 on success (and
   modify samplesdone and currentblock), 0 if failed 

   Seeking uses the following array:

     the sample_byte_size array contains the length in bytes of
     each block ("sample" in Applespeak).

   So we just find the last block before (or at) the requested position.

   Each ALAC block seems to be independent of all the others.
 */

unsigned int alac_seek_raw (demux_res_t* demux_res, 
                        stream_t* stream,
                        unsigned int file_loc, 
                        uint32_t* samplesdone, int* currentblock)
{
  unsigned int i;
  unsigned int 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 the sample_byte_size array. */
  newpos=demux_res->mdat_offset;
  for (i=0;(i<demux_res->num_sample_byte_sizes) &&
           (newpos+demux_res->sample_byte_size[i]<=file_loc);i++) {
    newpos+=demux_res->sample_byte_size[i];
  }
  
  newblock=i;
  newsample=0;

  /* Get the sample offset of the block */
  for (i=0,j=0;(i<demux_res->num_time_to_samples) && (j<newblock);
       i++,j+=demux_res->time_to_sample[i].sample_count) {
    if (newblock-j < demux_res->time_to_sample[i].sample_count) {
        newsample+=(newblock-j)*demux_res->time_to_sample[i].sample_duration;
        break;
    } else {
        newsample+=(demux_res->time_to_sample[i].sample_duration
                   * demux_res->time_to_sample[i].sample_count);
    }
  }

  /* 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;
  }
}