/********************************************************************
 *                                                                  *
 * 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 1994-2002    *
 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: basic codebook pack/unpack/code/decode operations

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

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

/* unpacks a codebook from the packet buffer into the codebook struct,
   readies the codebook auxiliary structures for decode *************/
static_codebook *vorbis_staticbook_unpack(oggpack_buffer *opb){
  long i,j;
  static_codebook *s=_ogg_calloc(1,sizeof(*s));

  /* make sure alignment is correct */
  if(oggpack_read(opb,24)!=0x564342)goto _eofout;

  /* first the basic parameters */
  s->dim=oggpack_read(opb,16);
  s->entries=oggpack_read(opb,24);
  if(s->entries==-1)goto _eofout;

  if(ilog(s->dim)+ ilog(s->entries)>24)goto _eofout;

  /* codeword ordering.... length ordered or unordered? */
  switch((int)oggpack_read(opb,1)){
  case 0:{
    long unused;
    /* allocated but unused entries? */
    unused=oggpack_read(opb,1);
    if((s->entries*(unused?1:5)+7)>>3>opb->storage-oggpack_bytes(opb))
      goto _eofout;
    /* unordered */
    s->lengthlist=(long *)_ogg_malloc(sizeof(*s->lengthlist)*s->entries);

    /* allocated but unused entries? */
    if(unused){
      /* yes, unused entries */

      for(i=0;i<s->entries;i++){
	if(oggpack_read(opb,1)){
	  long num=oggpack_read(opb,5);
	  if(num==-1)goto _eofout;
	  s->lengthlist[i]=num+1;
	}else
	  s->lengthlist[i]=0;
      }
    }else{
      /* all entries used; no tagging */
      for(i=0;i<s->entries;i++){
	long num=oggpack_read(opb,5);
	if(num==-1)goto _eofout;
	s->lengthlist[i]=num+1;
      }
    }
    
    break;
  }
  case 1:
    /* ordered */
    {
      long length=oggpack_read(opb,5)+1;
      if(length==0)goto _eofout;
      s->lengthlist=(long *)_ogg_malloc(sizeof(*s->lengthlist)*s->entries);

      for(i=0;i<s->entries;){
	long num=oggpack_read(opb, ilog(s->entries-i));
	if(num==-1)goto _eofout;
	if(length>32 || num>s->entries-i ||
	   (num>0 && (num-1)>>(length>>1)>>((length+1)>>1))>0){
	  goto _errout;
	}
	for(j=0;j<num;j++,i++)
	  s->lengthlist[i]=length;
	length++;
      }
    }
    break;
  default:
    /* EOF */
    goto _eofout;
  }
  
  /* Do we have a mapping to unpack? */
  switch((s->maptype=oggpack_read(opb,4))){
  case 0:
    /* no mapping */
    break;
  case 1: case 2:
    /* implicitly populated value mapping */
    /* explicitly populated value mapping */

    s->q_min=oggpack_read(opb,32);
    s->q_delta=oggpack_read(opb,32);
    s->q_quant=oggpack_read(opb,4)+1;
    s->q_sequencep=oggpack_read(opb,1);
    if(s->q_sequencep==-1)goto _eofout;

    {
      int quantvals=0;
      switch(s->maptype){
      case 1:
	quantvals=(s->dim==0?0:_book_maptype1_quantvals(s));
	break;
      case 2:
	quantvals=s->entries*s->dim;
	break;
      }
      
      /* quantized values */
      if((quantvals*s->q_quant+7)>>3>opb->storage-oggpack_bytes(opb))
        goto _eofout;
      s->quantlist=(long *)_ogg_malloc(sizeof(*s->quantlist)*quantvals);
      for(i=0;i<quantvals;i++)
	s->quantlist[i]=oggpack_read(opb,s->q_quant);
      
      if(quantvals&&s->quantlist[quantvals-1]==-1)goto _eofout;
    }
    break;
  default:
    goto _errout;
  }

  /* all set */
  return(s);
  
 _errout:
 _eofout:
  vorbis_staticbook_destroy(s);
  return(NULL); 
}

STIN long decode_packed_entry_number(codebook *book, 
					      oggpack_buffer *b){
  int  read=book->dec_maxlength;
  long lo,hi;
  long lok = oggpack_look(b,book->dec_firsttablen);
 
  if (lok >= 0) {
    long entry = book->dec_firsttable[lok];
    if(entry&0x80000000UL){
      lo=(entry>>15)&0x7fff;
      hi=book->used_entries-(entry&0x7fff);
    }else{
      oggpack_adv(b, book->dec_codelengths[entry-1]);
      return(entry-1);
    }
  }else{
    lo=0;
    hi=book->used_entries;
  }

  lok = oggpack_look(b, read);

  while(lok<0 && read>1)
    lok = oggpack_look(b, --read);

  if(lok<0){
    oggpack_adv(b,1); /* force eop */
    return -1;
  }

  /* bisect search for the codeword in the ordered list */
  {
    ogg_uint32_t testword=bitreverse((ogg_uint32_t)lok);

    while(hi-lo>1){
      long p=(hi-lo)>>1;
      long test=book->codelist[lo+p]>testword;    
      lo+=p&(test-1);
      hi-=p&(-test);
    }

    if(book->dec_codelengths[lo]<=read){
      oggpack_adv(b, book->dec_codelengths[lo]);
      return(lo);
    }
  }
  
  oggpack_adv(b, read+1);
  return(-1);
}

/* Decode side is specced and easier, because we don't need to find
   matches using different criteria; we simply read and map.  There are
   two things we need to do 'depending':
   
   We may need to support interleave.  We don't really, but it's
   convenient to do it here rather than rebuild the vector later.

   Cascades may be additive or multiplicitive; this is not inherent in
   the codebook, but set in the code using the codebook.  Like
   interleaving, it's easiest to do it here.  
   addmul==0 -> declarative (set the value)
   addmul==1 -> additive
   addmul==2 -> multiplicitive */

/* returns the [original, not compacted] entry number or -1 on eof *********/
long vorbis_book_decode(codebook *book, oggpack_buffer *b){
  if(book->used_entries>0){
    long packed_entry=decode_packed_entry_number(book,b);
    if(packed_entry>=0)
      return(book->dec_index[packed_entry]);
  }

  /* if there's no dec_index, the codebook unpacking isn't collapsed */
  return(-1);
}

/* returns 0 on OK or -1 on eof *************************************/
/* decode vector / dim granularity gaurding is done in the upper layer */
long vorbis_book_decodevs_add(codebook *book,ogg_int32_t *a,
			      oggpack_buffer *b,int n,int point){
  if(book->used_entries>0){  
    int step=n/book->dim;
    long *entry = (long *)alloca(sizeof(*entry)*step);
    ogg_int32_t **t = (ogg_int32_t **)alloca(sizeof(*t)*step);
    int i,j,o;
    int shift=point-book->binarypoint;
    
    if(shift>=0){
      for (i = 0; i < step; i++) {
	entry[i]=decode_packed_entry_number(book,b);
	if(entry[i]==-1)return(-1);
	t[i] = book->valuelist+entry[i]*book->dim;
      }
      for(i=0,o=0;i<book->dim;i++,o+=step)
	for (j=0;j<step;j++)
	  a[o+j]+=t[j][i]>>shift;
    }else{
      for (i = 0; i < step; i++) {
	entry[i]=decode_packed_entry_number(book,b);
	if(entry[i]==-1)return(-1);
	t[i] = book->valuelist+entry[i]*book->dim;
      }
      for(i=0,o=0;i<book->dim;i++,o+=step)
	for (j=0;j<step;j++)
	  a[o+j]+=t[j][i]<<-shift;
    }
  }
  return(0);
}

/* decode vector / dim granularity gaurding is done in the upper layer */
long vorbis_book_decodev_add(codebook *book,ogg_int32_t *a,
			     oggpack_buffer *b,int n,int point){
  if(book->used_entries>0){
    int i,j,entry;
    ogg_int32_t *t;
    int shift=point-book->binarypoint;
    
    if(shift>=0){
      for(i=0;i<n;){
	entry = decode_packed_entry_number(book,b);
	if(entry==-1)return(-1);
	t     = book->valuelist+entry*book->dim;
	for (j=0;j<book->dim;)
	  a[i++]+=t[j++]>>shift;
      }
    }else{
      for(i=0;i<n;){
	entry = decode_packed_entry_number(book,b);
	if(entry==-1)return(-1);
	t     = book->valuelist+entry*book->dim;
	for (j=0;j<book->dim;)
	  a[i++]+=t[j++]<<-shift;
      }
    }
  }
  return(0);
}

/* unlike the others, we guard against n not being an integer number
   of <dim> internally rather than in the upper layer (called only by
   floor0) */
long vorbis_book_decodev_set(codebook *book,ogg_int32_t *a,
			     oggpack_buffer *b,int n,int point){
  if(book->used_entries>0){
    int i,j,entry;
    ogg_int32_t *t;
    int shift=point-book->binarypoint;
    
    if(shift>=0){
      
      for(i=0;i<n;){
	entry = decode_packed_entry_number(book,b);
	if(entry==-1)return(-1);
	t     = book->valuelist+entry*book->dim;
	for (j=0;i<n && j<book->dim;){
	  a[i++]=t[j++]>>shift;
	}
      }
    }else{
      
      for(i=0;i<n;){
	entry = decode_packed_entry_number(book,b);
	if(entry==-1)return(-1);
	t     = book->valuelist+entry*book->dim;
	for (j=0;i<n && j<book->dim;){
	  a[i++]=t[j++]<<-shift;
	}
      }
    }
  }else{

    int i,j;
    for(i=0;i<n;){
      a[i++]=0;
    }
  }
  return(0);
}

/* decode vector / dim granularity gaurding is done in the upper layer */
long vorbis_book_decodevv_add(codebook *book,ogg_int32_t **a,\
			      long offset,int ch,
			      oggpack_buffer *b,int n,int point){
  if(book->used_entries>0){
    long i,j,entry;
    int chptr=0;
    int shift=point-book->binarypoint;
    
    if(shift>=0){
      
      for(i=offset;i<offset+n;){
	entry = decode_packed_entry_number(book,b);
	if(entry==-1)return(-1);
	{
	  const ogg_int32_t *t = book->valuelist+entry*book->dim;
	  for (j=0;j<book->dim;j++){
	    a[chptr++][i]+=t[j]>>shift;
	    if(chptr==ch){
	      chptr=0;
	      i++;
	    }
	  }
	}
      }
    }else{
      
      for(i=offset;i<offset+n;){
	entry = decode_packed_entry_number(book,b);
	if(entry==-1)return(-1);
	{
	  const ogg_int32_t *t = book->valuelist+entry*book->dim;
	  for (j=0;j<book->dim;j++){
	    a[chptr++][i]+=t[j]<<-shift;
	    if(chptr==ch){
	      chptr=0;
	      i++;
	    }
	  }
	}
      }
    }
  }
  return(0);
}
