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

 *                                                                  *

 * THIS FILE IS PART OF THE OggVorbis SOFTWARE 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 SOURCE CODE IS (C) COPYRIGHT 1994-2015             *

 * by the Xiph.Org Foundation http://www.xiph.org/                  *

 *                                                                  *

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

 function: single-block PCM synthesis

 last mod: $Id: synthesis.c 19441 2015-01-21 01:17:41Z xiphmont $

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

#include <stdio.h>

#include <ogg/ogg.h>

#include "vorbis/codec.h"

#include "codec_internal.h"

#include "registry.h"

#include "misc.h"

#include "os.h"

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

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

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

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

  codec_setup_info     *ci= vi ? 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){

    /* this doesn;t get mapped through mode selection as it's used

       only for window selection */

    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;

  vb->eofflag=op->e_o_s;

  /* alloc pcm passback storage */

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

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

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

    vb->pcm[i]=_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,ci->map_param[ci->mode_param[mode]->

                                                   mapping]));

}

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

   Useful for sequential 'fast forward' */

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

  vorbis_dsp_state     *vd=vb->vd;

  private_state        *b=vd->backend_state;

  vorbis_info          *vi=vd->vi;

  codec_setup_info     *ci=vi->codec_setup;

  oggpack_buffer       *opb=&vb->opb;

  int                   mode;

  /* 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;

  vb->eofflag=op->e_o_s;

  /* no pcm */

  vb->pcmend=0;

  vb->pcm=NULL;

  return(0);

}

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

  codec_setup_info     *ci=vi->codec_setup;

  oggpack_buffer       opb;

  int                  mode;

  if(ci==NULL || ci->modes<=0){

    /* codec setup not properly intialized */

    return(OV_EFAULT);

  }

  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,ov_ilog(ci->modes-1));

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

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

}

int vorbis_synthesis_halfrate(vorbis_info *vi,int flag){

  /* set / clear half-sample-rate mode */

  codec_setup_info     *ci=vi->codec_setup;

  /* right now, our MDCT can't handle < 64 sample windows. */

  if(ci->blocksizes[0]<=64 && flag)return -1;

  ci->halfrate_flag=(flag?1:0);

  return 0;

}

int vorbis_synthesis_halfrate_p(vorbis_info *vi){

  codec_setup_info     *ci=vi->codec_setup;

  return ci->halfrate_flag;

}