/********************************************************************

 *                                                                  *

 * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *

 *                                                                  *

 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *

 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *

 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *

 *                                                                  *

 * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2003    *

 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *

 *                                                                  *

 ********************************************************************

 function: single-block PCM synthesis

 last mod: $Id: synthesis.c,v 1.4 2003/03/29 03:07:21 xiphmont Exp $

 ********************************************************************/

#include <stdio.h>

#include <ogg/ogg.h>

#include "ivorbiscodec.h"

#include "codec_internal.h"

#include "registry.h"

#include "misc.h"

#include "block.h"

static int _vorbis_synthesis1(vorbis_block *vb,ogg_packet *op,int decodep){

  vorbis_dsp_state     *vd= vb ? vb->vd : 0;

  private_state        *b= vd ? (private_state *)vd->backend_state: 0;

  vorbis_info          *vi= vd ? vd->vi : 0;

  codec_setup_info     *ci= vi ? (codec_setup_info *)vi->codec_setup : 0;

  oggpack_buffer       *opb=vb ? &vb->opb : 0;

  int                   type,mode,i;

  if (!vd || !b || !vi || !ci || !opb) {

    return OV_EBADPACKET;

  }

  /* first things first.  Make sure decode is ready */

  _vorbis_block_ripcord(vb);

  oggpack_readinit(opb,op->packet,op->bytes);

  /* Check the packet type */

  if(oggpack_read(opb,1)!=0){

    /* Oops.  This is not an audio data packet */

    return(OV_ENOTAUDIO);

  }

  /* read our mode and pre/post windowsize */

  mode=oggpack_read(opb,b->modebits);

  if(mode==-1)return(OV_EBADPACKET);

  vb->mode=mode;

  if(!ci->mode_param[mode]){

    return(OV_EBADPACKET);

  }

  vb->W=ci->mode_param[mode]->blockflag;

  if(vb->W){

    vb->lW=oggpack_read(opb,1);

    vb->nW=oggpack_read(opb,1);

    if(vb->nW==-1)   return(OV_EBADPACKET);

  }else{

    vb->lW=0;

    vb->nW=0;

  }

  /* more setup */

  vb->granulepos=op->granulepos;

  vb->sequence=op->packetno; /* first block is third packet */

  vb->eofflag=op->e_o_s;

  if(decodep){

    /* alloc pcm passback storage */

    vb->pcmend=ci->blocksizes[vb->W];

    vb->pcm=(ogg_int32_t **)_vorbis_block_alloc(vb,sizeof(*vb->pcm)*vi->channels);

    for(i=0;i<vi->channels;i++)

      vb->pcm[i]=(ogg_int32_t *)_vorbis_block_alloc(vb,vb->pcmend*sizeof(*vb->pcm[i]));

    /* unpack_header enforces range checking */

    type=ci->map_type[ci->mode_param[mode]->mapping];

    return(_mapping_P[type]->inverse(vb,b->mode[mode]));

  }else{

    /* no pcm */

    vb->pcmend=0;

    vb->pcm=NULL;

    return(0);

  }

}

int vorbis_synthesis(vorbis_block *vb,ogg_packet *op){

  return _vorbis_synthesis1(vb,op,1);

}

/* used to track pcm position without actually performing decode.

   Useful for sequential 'fast forward' */

int vorbis_synthesis_trackonly(vorbis_block *vb,ogg_packet *op){

  return _vorbis_synthesis1(vb,op,0);

}

long vorbis_packet_blocksize(vorbis_info *vi,ogg_packet *op){

  codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;

  oggpack_buffer       opb;

  int                  mode;

  oggpack_readinit(&opb,op->packet,op->bytes);

  /* Check the packet type */

  if(oggpack_read(&opb,1)!=0){

    /* Oops.  This is not an audio data packet */

    return(OV_ENOTAUDIO);

  }

  {

    int modebits=0;

    int v=ci->modes;

    while(v>1){

      modebits++;

      v>>=1;

    }

    /* read our mode and pre/post windowsize */

    mode=oggpack_read(&opb,modebits);

  }

  if(mode==-1 || !ci->mode_param[mode])return(OV_EBADPACKET);

  return(ci->blocksizes[ci->mode_param[mode]->blockflag]);

}