#include "os.h"

/**** pack/unpack helpers ******************************************/

int _ilog(unsigned int v){

  int ret=0;

  while(v){

    ret++;

    v>>=1;

  }

  return(ret);

}

static ogg_uint32_t decpack(long entry,long used_entry,long quantvals,

			    codebook *b,oggpack_buffer *opb,int maptype){

  ogg_uint32_t ret=0;

  int j;

  switch(b->dec_type){

  case 0:

    return (ogg_uint32_t)entry;

  case 1:

    if(maptype==1){

      /* vals are already read into temporary colum vector here */

      for(j=0;j<b->dim;j++){

	ogg_uint32_t off=entry%quantvals;

	entry/=quantvals;

	ret|=((ogg_uint16_t *)(b->q_val))[off]<<(b->q_bits*j);

      }

    }else{

      for(j=0;j<b->dim;j++)

	ret|=oggpack_read(opb,b->q_bits)<<(b->q_bits*j);

    }

    return ret;

  case 2:

    for(j=0;j<b->dim;j++){

      ogg_uint32_t off=entry%quantvals;

      entry/=quantvals;

      ret|=off<<(b->q_pack*j);

    }

    return ret;

  case 3:

    return (ogg_uint32_t)used_entry;

  }

}

/* 32 bit float (not IEEE; nonnormalized mantissa +

   biased exponent) : neeeeeee eeemmmmm mmmmmmmm mmmmmmmm 

   Why not IEEE?  It's just not that important here. */

static ogg_int32_t _float32_unpack(long val,int *point){

  long   mant=val&0x1fffff;

  int    sign=val&0x80000000;

  *point=((val&0x7fe00000L)>>21)-788;

  if(mant){

    while(!(mant&0x40000000)){

      mant<<=1;

      *point-=1;

    }

    if(sign)mant= -mant;

  }else{

    *point=-9999;

  }

  return mant;

}

/* choose the smallest supported node size that fits our decode table.

   Legal bytewidths are 1/1 1/2 2/2 2/4 4/4 */

static int _determine_node_bytes(long used, int leafwidth){

  /* special case small books to size 4 to avoid multiple special

     cases in repack */

  if(used<2)

    return 4;

  if(leafwidth==3)leafwidth=4;

  if(_ilog(3*used-6)+1 <= leafwidth*4) 

    return leafwidth/2?leafwidth/2:1;

  return leafwidth;

}

/* convenience/clarity; leaves are specified as multiple of node word

   size (1 or 2) */

static int _determine_leaf_words(int nodeb, int leafwidth){

  if(leafwidth>nodeb)return 2;

  return 1;

}

/* given a list of word lengths, number of used entries, and byte

   width of a leaf, generate the decode table */

static int _make_words(char *l,long n,ogg_uint32_t *r,long quantvals,

		       codebook *b, oggpack_buffer *opb,int maptype){

  long i,j,count=0;

  long top=0;

  ogg_uint32_t marker[33];

  if(n<2){

    r[0]=0x80000000;

  }else{

    memset(marker,0,sizeof(marker));

    for(i=0;i<n;i++){

      long length=l[i];

      if(length){

	ogg_uint32_t entry=marker[length];

	long chase=0;

	if(count && !entry)return -1; /* overpopulated tree! */

	/* chase the tree as far as it's already populated, fill in past */

	for(j=0;j<length-1;j++){

	  int bit=(entry>>(length-j-1))&1;

	  if(chase>=top){ 

	    top++;

	    r[chase*2]=top;

	    r[chase*2+1]=0;

	  }else

	    if(!r[chase*2+bit])

	      r[chase*2+bit]=top;

	  chase=r[chase*2+bit];

	}

	{	

	  int bit=(entry>>(length-j-1))&1;

	  if(chase>=top){ 

	    top++;

	    r[chase*2+1]=0;

	  }

	  r[chase*2+bit]= decpack(i,count++,quantvals,b,opb,maptype) | 

	    0x80000000;

	}

	/* Look to see if the next shorter marker points to the node

	   above. if so, update it and repeat.  */

	for(j=length;j>0;j--){          

	  if(marker[j]&1){

	    marker[j]=marker[j-1]<<1;

	    break;

	  }

	  marker[j]++;

	}

	/* prune the tree; the implicit invariant says all the longer

	   markers were dangling from our just-taken node.  Dangle them

	   from our *new* node. */

	for(j=length+1;j<33;j++)

	  if((marker[j]>>1) == entry){

	    entry=marker[j];

	    marker[j]=marker[j-1]<<1;

	  }else

	    break;

      }

    }

  }

  return 0;

}

static int _make_decode_table(codebook *s,char *lengthlist,long quantvals,

			      oggpack_buffer *opb,int maptype){

  int i;

  ogg_uint32_t *work;

  if(s->dec_nodeb==4){

    s->dec_table=_ogg_malloc((s->used_entries*2+1)*sizeof(*work));

    /* +1 (rather than -2) is to accommodate 0 and 1 sized books,

       which are specialcased to nodeb==4 */

    if(_make_words(lengthlist,s->entries,

		   s->dec_table,quantvals,s,opb,maptype))return 1;

    return 0;

  }

  work=alloca((s->used_entries*2-2)*sizeof(*work));

  if(_make_words(lengthlist,s->entries,work,quantvals,s,opb,maptype))return 1;

  s->dec_table=_ogg_malloc((s->used_entries*(s->dec_leafw+1)-2)*

			   s->dec_nodeb);

  if(s->dec_leafw==1){

    switch(s->dec_nodeb){

    case 1:

      for(i=0;i<s->used_entries*2-2;i++)

	  ((unsigned char *)s->dec_table)[i]=

	    ((work[i] & 0x80000000UL) >> 24) | work[i];

      break;

    case 2:

      for(i=0;i<s->used_entries*2-2;i++)

	  ((ogg_uint16_t *)s->dec_table)[i]=

	    ((work[i] & 0x80000000UL) >> 16) | work[i];

      break; 

    }

  }else{

    /* more complex; we have to do a two-pass repack that updates the

       node indexing. */

    long top=s->used_entries*3-2;

    if(s->dec_nodeb==1){

      unsigned char *out=(unsigned char *)s->dec_table;

      for(i=s->used_entries*2-4;i>=0;i-=2){

	if(work[i]&0x80000000UL){

	  if(work[i+1]&0x80000000UL){

	    top-=4;

	    out[top]=(work[i]>>8 & 0x7f)|0x80;

	    out[top+1]=(work[i+1]>>8 & 0x7f)|0x80;

	    out[top+2]=work[i] & 0xff;

	    out[top+3]=work[i+1] & 0xff;

	  }else{

	    top-=3;

	    out[top]=(work[i]>>8 & 0x7f)|0x80;

	    out[top+1]=work[work[i+1]*2];

	    out[top+2]=work[i] & 0xff;

	  }

	}else{

	  if(work[i+1]&0x80000000UL){

	    top-=3;

	    out[top]=work[work[i]*2];

	    out[top+1]=(work[i+1]>>8 & 0x7f)|0x80;

	    out[top+2]=work[i+1] & 0xff;

	  }else{

	    top-=2;

	    out[top]=work[work[i]*2];

	    out[top+1]=work[work[i+1]*2];

	  }

	}

	work[i]=top;

      }

    }else{

      ogg_uint16_t *out=(ogg_uint16_t *)s->dec_table;

      for(i=s->used_entries*2-4;i>=0;i-=2){

	if(work[i]&0x80000000UL){

	  if(work[i+1]&0x80000000UL){

	    top-=4;

	    out[top]=(work[i]>>16 & 0x7fff)|0x8000;

	    out[top+1]=(work[i+1]>>16 & 0x7fff)|0x8000;

	    out[top+2]=work[i] & 0xffff;

	    out[top+3]=work[i+1] & 0xffff;

	  }else{

	    top-=3;

	    out[top]=(work[i]>>16 & 0x7fff)|0x8000;

	    out[top+1]=work[work[i+1]*2];

	    out[top+2]=work[i] & 0xffff;

	  }

	}else{

	  if(work[i+1]&0x80000000UL){

	    top-=3;

	    out[top]=work[work[i]*2];

	    out[top+1]=(work[i+1]>>16 & 0x7fff)|0x8000;

	    out[top+2]=work[i+1] & 0xffff;

	  }else{

	    top-=2;

	    out[top]=work[work[i]*2];

	    out[top+1]=work[work[i+1]*2];

	  }

	}

	work[i]=top;

      }

    }

  }

  return 0;

}

/* most of the time, entries%dimensions == 0, but we need to be

   well defined.  We define that the possible vales at each

   scalar is values == entries/dim.  If entries%dim != 0, we'll

   have 'too few' values (values*dim<entries), which means that

   we'll have 'left over' entries; left over entries use zeroed

   values (and are wasted).  So don't generate codebooks like

   that */

/* there might be a straightforward one-line way to do the below

   that's portable and totally safe against roundoff, but I haven't

   thought of it.  Therefore, we opt on the side of caution */

long _book_maptype1_quantvals(codebook *b){

  /* get us a starting hint, we'll polish it below */

  int bits=_ilog(b->entries);

  int vals=b->entries>>((bits-1)*(b->dim-1)/b->dim);

  while(1){

    long acc=1;

    long acc1=1;

    int i;

    for(i=0;i<b->dim;i++){

      acc*=vals;

      acc1*=vals+1;

    }

    if(acc<=b->entries && acc1>b->entries){

      return(vals);

    }else{

      if(acc>b->entries){

        vals--;

      }else{

        vals++;

      }

    }

  }

}

void vorbis_book_clear(codebook *b){

  /* static book is not cleared; we're likely called on the lookup and

     the static codebook belongs to the info struct */

  if(b->q_val)_ogg_free(b->q_val);

  if(b->dec_table)_ogg_free(b->dec_table);

  memset(b,0,sizeof(*b));

}

int vorbis_book_unpack(oggpack_buffer *opb,codebook *s){

  char         *lengthlist=NULL;

  int           quantvals=0;

  long          i,j,k;

  int           maptype;

    lengthlist=(char *)alloca(sizeof(*lengthlist)*s->entries);

	  lengthlist[i]=num+1;

	  s->used_entries++;

	  if(num+1>s->dec_maxlength)s->dec_maxlength=num+1;

	  lengthlist[i]=0;

      s->used_entries=s->entries;

	lengthlist[i]=num+1;

	if(num+1>s->dec_maxlength)s->dec_maxlength=num+1;

      s->used_entries=s->entries;

      lengthlist=(char *)alloca(sizeof(*lengthlist)*s->entries);

	  lengthlist[i]=length;

	s->dec_maxlength=length;

  if((maptype=oggpack_read(opb,4))>0){

    s->q_min=_float32_unpack(oggpack_read(opb,32),&s->q_minp);

    s->q_del=_float32_unpack(oggpack_read(opb,32),&s->q_delp);

    s->q_bits=oggpack_read(opb,4)+1;

    s->q_seq=oggpack_read(opb,1);

    s->q_del>>=s->q_bits;

    s->q_delp+=s->q_bits;

  }

  switch(maptype){

    /* no mapping; decode type 0 */

    /* how many bytes for the indexing? */

    /* this is the correct boundary here; we lose one bit to

       node/leaf mark */

    s->dec_nodeb=_determine_node_bytes(s->used_entries,_ilog(s->entries)/8+1); 

    s->dec_leafw=_determine_leaf_words(s->dec_nodeb,_ilog(s->entries)/8+1); 

    s->dec_type=0;

    if(_make_decode_table(s,lengthlist,quantvals,opb,maptype)) goto _errout;

  case 1:

    /* mapping type 1; implicit values by lattice  position */

    quantvals=_book_maptype1_quantvals(s);

    /* dec_type choices here are 1,2; 3 doesn't make sense */

      /* packed values */

      long total1=(s->q_bits*s->dim+8)/8; /* remember flag bit */

      /* vector of column offsets; remember flag bit */

      long total2=(_ilog(quantvals-1)*s->dim+8)/8+(s->q_bits+7)/8;

      if(total1<=4 && total1<=total2){

	/* use dec_type 1: vector of packed values */

	/* need quantized values before  */

	s->q_val=alloca(sizeof(ogg_uint16_t)*quantvals);

	for(i=0;i<quantvals;i++)

	  ((ogg_uint16_t *)s->q_val)[i]=oggpack_read(opb,s->q_bits);

	if(oggpack_eop(opb)){

	  s->q_val=0; /* cleanup must not free alloca memory */

	  goto _eofout;

	}

	s->dec_type=1;

	s->dec_nodeb=_determine_node_bytes(s->used_entries,

					   (s->q_bits*s->dim+8)/8); 

	s->dec_leafw=_determine_leaf_words(s->dec_nodeb,

					   (s->q_bits*s->dim+8)/8); 

	if(_make_decode_table(s,lengthlist,quantvals,opb,maptype)){

	  s->q_val=0; /* cleanup must not free alloca memory */

	  goto _errout;

	}

	s->q_val=0; /* about to go out of scope; _make_decode_table

                       was using it */

      }else{

	/* use dec_type 2: packed vector of column offsets */

	/* need quantized values before */

	if(s->q_bits<=8){

	  s->q_val=_ogg_malloc(quantvals);

	  for(i=0;i<quantvals;i++)

	    ((unsigned char *)s->q_val)[i]=oggpack_read(opb,s->q_bits);

	}else{

	  s->q_val=_ogg_malloc(quantvals*2);

	  for(i=0;i<quantvals;i++)

	    ((ogg_uint16_t *)s->q_val)[i]=oggpack_read(opb,s->q_bits);

	}

	if(oggpack_eop(opb))goto _eofout;

	s->q_pack=_ilog(quantvals-1); 

	s->dec_type=2;

	s->dec_nodeb=_determine_node_bytes(s->used_entries,

					   (_ilog(quantvals-1)*s->dim+8)/8); 

	s->dec_leafw=_determine_leaf_words(s->dec_nodeb,

					   (_ilog(quantvals-1)*s->dim+8)/8); 

	if(_make_decode_table(s,lengthlist,quantvals,opb,maptype))goto _errout;