/********************************************************************
 *                                                                  *
 * 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: residue backend 0, 1 and 2 implementation

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

#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "ogg.h"
#include "ivorbiscodec.h"
#include "codec_internal.h"
#include "codebook.h"
#include "misc.h"
#include "os.h"

void res_clear_info(vorbis_info_residue *info){
  if(info){
    if(info->stagemasks)_ogg_free(info->stagemasks);
    if(info->stagebooks)_ogg_free(info->stagebooks);
    memset(info,0,sizeof(*info));
  }
}

static int ilog(unsigned int v){
  int ret=0;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

/* vorbis_info is for range checking */
int res_unpack(vorbis_info_residue *info,
		vorbis_info *vi,oggpack_buffer *opb){
  int j,k;
  codec_setup_info     *ci=(codec_setup_info *)vi->codec_setup;
  memset(info,0,sizeof(*info));

  info->type=oggpack_read(opb,16);
  if(info->type>2 || info->type<0)goto errout;
  info->begin=oggpack_read(opb,24);
  info->end=oggpack_read(opb,24);
  info->grouping=oggpack_read(opb,24)+1;
  info->partitions=oggpack_read(opb,6)+1;
  info->groupbook=oggpack_read(opb,8);
  if(info->groupbook>=ci->books)goto errout;

  info->stagemasks=_ogg_malloc(info->partitions*sizeof(*info->stagemasks));
  info->stagebooks=_ogg_malloc(info->partitions*8*sizeof(*info->stagebooks));

  for(j=0;j<info->partitions;j++){
    int cascade=oggpack_read(opb,3);
    if(oggpack_read(opb,1))
      cascade|=(oggpack_read(opb,5)<<3);
    info->stagemasks[j]=cascade;
  }

  for(j=0;j<info->partitions;j++){
    for(k=0;k<8;k++){
      if((info->stagemasks[j]>>k)&1){
	unsigned char book=oggpack_read(opb,8);
	if(book>=ci->books)goto errout;
	info->stagebooks[j*8+k]=book;
	if(k+1>info->stages)info->stages=k+1;
      }else
	info->stagebooks[j*8+k]=0xff;
    }
  }

  if(oggpack_eop(opb))goto errout;

  return 0;
 errout:
  res_clear_info(info);
  return 1;
}

int res_inverse(vorbis_dsp_state *vd,vorbis_info_residue *info,
		ogg_int32_t **in,int *nonzero,int ch){
  
  int i,j,k,s,used=0;
  codec_setup_info     *ci=(codec_setup_info *)vd->vi->codec_setup;
  codebook *phrasebook=ci->book_param+info->groupbook;
  int samples_per_partition=info->grouping;
  int partitions_per_word=phrasebook->dim;
  int pcmend=ci->blocksizes[vd->W];

  if(info->type<2){
    int max=pcmend>>1;
    int end=(info->end<max?info->end:max);
    int n=end-info->begin;
    
    if(n>0){
      int partvals=n/samples_per_partition;
      int partwords=(partvals+partitions_per_word-1)/partitions_per_word;
      
      for(i=0;i<ch;i++)
	if(nonzero[i])
	  in[used++]=in[i];
      ch=used;
      
      if(used){
	
	char **partword=(char **)alloca(ch*sizeof(*partword));
	for(j=0;j<ch;j++)
	  partword[j]=(char *)alloca(partwords*partitions_per_word*
				     sizeof(*partword[j]));
	
	for(s=0;s<info->stages;s++){
	  
	  for(i=0;i<partvals;){
	    if(s==0){
	      /* fetch the partition word for each channel */
	      
	      partword[0][i+partitions_per_word-1]=1;
	      for(k=partitions_per_word-2;k>=0;k--)
		partword[0][i+k]=partword[0][i+k+1]*info->partitions;
	      
	      for(j=1;j<ch;j++)
		for(k=partitions_per_word-1;k>=0;k--)
		  partword[j][i+k]=partword[j-1][i+k];
	      
	      for(j=0;j<ch;j++){
		int temp=vorbis_book_decode(phrasebook,&vd->opb);
		if(oggpack_eop(&vd->opb))goto eopbreak;
		
		/* this can be done quickly in assembly due to the quotient
		   always being at most six bits */
		for(k=0;k<partitions_per_word;k++){
		  ogg_uint32_t div=partword[j][i+k];
		  partword[j][i+k]=temp/div;
		  temp-=partword[j][i+k]*div;
		}
		
	      }
	    }
	    
	    /* now we decode residual values for the partitions */
	    for(k=0;k<partitions_per_word && i<partvals;k++,i++)
	      for(j=0;j<ch;j++){
		long offset=info->begin+i*samples_per_partition;
		if(info->stagemasks[partword[j][i]]&(1<<s)){
		  codebook *stagebook=ci->book_param+
		    info->stagebooks[(partword[j][i]<<3)+s];
		  if(info->type){
		    if(vorbis_book_decodev_add(stagebook,in[j]+offset,&vd->opb,
					       samples_per_partition,-8)==-1)
		      goto eopbreak;
		  }else{
		    if(vorbis_book_decodevs_add(stagebook,in[j]+offset,&vd->opb,
						samples_per_partition,-8)==-1)
		      goto eopbreak;
		  }
		}
	      }
	  }
	} 
      }
    }
  }else{
    int max=(pcmend*ch)>>1;
    int end=(info->end<max?info->end:max);
    int n=end-info->begin;
    
    if(n>0){
      int partvals=n/samples_per_partition;
      int partwords=(partvals+partitions_per_word-1)/partitions_per_word;
    
      char *partword=
	(char *)alloca(partwords*partitions_per_word*sizeof(*partword));
      int beginoff=info->begin/ch;
      
      for(i=0;i<ch;i++)if(nonzero[i])break;
      if(i==ch)return(0); /* no nonzero vectors */
      
      samples_per_partition/=ch;
      
      for(s=0;s<info->stages;s++){
	for(i=0;i<partvals;){
	  
	  if(s==0){
	    int temp;
	    partword[i+partitions_per_word-1]=1;
	    for(k=partitions_per_word-2;k>=0;k--)
	      partword[i+k]=partword[i+k+1]*info->partitions;
	    
	    /* fetch the partition word */
	    temp=vorbis_book_decode(phrasebook,&vd->opb);
	    if(temp==-1)goto eopbreak;
	    
	    /* this can be done quickly in assembly due to the quotient
	       always being at most six bits */
	    for(k=0;k<partitions_per_word;k++){
	      ogg_uint32_t div=partword[i+k];
	      partword[i+k]=temp/div;
	      temp-=partword[i+k]*div;
	    }
	  }
	  
	  /* now we decode residual values for the partitions */
	  for(k=0;k<partitions_per_word && i<partvals;k++,i++){
	    if(info->stagemasks[partword[i]]&(1<<s)){
	      codebook *stagebook=ci->book_param+
		info->stagebooks[(partword[i]<<3)+s];
	      if(vorbis_book_decodevv_add(stagebook,in,
					  i*samples_per_partition+beginoff,ch,
					  &vd->opb,
					  samples_per_partition,-8)==-1)
		goto eopbreak;
	    }
	  }
	}
      } 
    }
  }
 errout:
 eopbreak:
  
  return 0;
}