sharedbook.c 12.7 KB
Newer Older
Monty's avatar
 
Monty committed
1 2 3 4
/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *
 *                                                                  *
Monty's avatar
 
Monty committed
5 6 7 8
 * 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.       *
 *                                                                  *
Monty's avatar
 
Monty committed
9 10 11 12 13 14 15 16 17 18 19 20
 * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
 * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: basic shared codebook operations

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

#include <stdlib.h>
#include <math.h>
#include <string.h>
21
#include <ogg/ogg.h>
Monty's avatar
 
Monty committed
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123
#include "misc.h"
#include "ivorbiscodec.h"
#include "codebook.h"

/**** pack/unpack helpers ******************************************/
int _ilog(unsigned int v){
  int ret=0;
  while(v){
    ret++;
    v>>=1;
  }
  return(ret);
}

/* 32 bit float (not IEEE; nonnormalized mantissa +
   biased exponent) : neeeeeee eeemmmmm mmmmmmmm mmmmmmmm 
   Why not IEEE?  It's just not that important here. */

#define VQ_FEXP 10
#define VQ_FMAN 21
#define VQ_FEXP_BIAS 768 /* bias toward values smaller than 1. */

static ogg_int32_t _float32_unpack(long val,int *point){
  long   mant=val&0x1fffff;
  int    sign=val&0x80000000;
  long   exp =(val&0x7fe00000L)>>VQ_FMAN;

  exp-=(VQ_FMAN-1)+VQ_FEXP_BIAS;

  if(mant){
    while(!(mant&0x40000000)){
      mant<<=1;
      exp-=1;
    }

    if(sign)mant= -mant;
  }else{
    sign=0;
    exp=-9999;
  }

  *point=exp;
  return mant;
}

/* given a list of word lengths, generate a list of codewords.  Works
   for length ordered or unordered, always assigns the lowest valued
   codewords first.  Extended to handle unused entries (length 0) */
ogg_uint32_t *_make_words(long *l,long n,long sparsecount){
  long i,j,count=0;
  ogg_uint32_t marker[33];
  ogg_uint32_t *r=(ogg_uint32_t *)_ogg_malloc((sparsecount?sparsecount:n)*sizeof(*r));
  memset(marker,0,sizeof(marker));

  for(i=0;i<n;i++){
    long length=l[i];
    if(length>0){
      ogg_uint32_t entry=marker[length];
      
      /* when we claim a node for an entry, we also claim the nodes
	 below it (pruning off the imagined tree that may have dangled
	 from it) as well as blocking the use of any nodes directly
	 above for leaves */
      
      /* update ourself */
      if(length<32 && (entry>>length)){
	/* error condition; the lengths must specify an overpopulated tree */
	_ogg_free(r);
	return(NULL);
      }
      r[count++]=entry;
    
      /* 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){
	    /* have to jump branches */
	    if(j==1)
	      marker[1]++;
	    else
	      marker[j]=marker[j-1]<<1;
	    break; /* invariant says next upper marker would already
		      have been moved if it was on the same path */
	  }
	  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;
    }else
      if(sparsecount==0)count++;
  }
124 125 126 127 128 129 130 131 132 133 134 135 136 137

  /* sanity check the huffman tree; an underpopulated tree must be
     rejected. The only exception is the one-node pseudo-nil tree,
     which appears to be underpopulated because the tree doesn't
     really exist; there's only one possible 'codeword' or zero bits,
     but the above tree-gen code doesn't mark that. */
  if(sparsecount != 1){
    for(i=1;i<33;i++)
      if(marker[i] & (0xffffffffUL>>(32-i))){
       _ogg_free(r);
       return(NULL);
      }
  }

Monty's avatar
 
Monty committed
138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225
  /* bitreverse the words because our bitwise packer/unpacker is LSb
     endian */
  for(i=0,count=0;i<n;i++){
    ogg_uint32_t temp=0;
    for(j=0;j<l[i];j++){
      temp<<=1;
      temp|=(r[count]>>j)&1;
    }

    if(sparsecount){
      if(l[i])
	r[count++]=temp;
    }else
      r[count++]=temp;
  }

  return(r);
}

/* 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(const static_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++;
      }
    }
  }
}

/* different than what _book_unquantize does for mainline:
   we repack the book in a fixed point format that shares the same
   binary point.  Upon first use, we can shift point if needed */

/* we need to deal with two map types: in map type 1, the values are
   generated algorithmically (each column of the vector counts through
   the values in the quant vector). in map type 2, all the values came
   in in an explicit list.  Both value lists must be unpacked */

ogg_int32_t *_book_unquantize(const static_codebook *b,int n,int *sparsemap,
			      int *maxpoint){
  long j,k,count=0;
  if(b->maptype==1 || b->maptype==2){
    int quantvals;
    int minpoint,delpoint;
    ogg_int32_t mindel=_float32_unpack(b->q_min,&minpoint);
    ogg_int32_t delta=_float32_unpack(b->q_delta,&delpoint);
    ogg_int32_t *r=(ogg_int32_t *)_ogg_calloc(n*b->dim,sizeof(*r));
    int *rp=(int *)_ogg_calloc(n*b->dim,sizeof(*rp));

    *maxpoint=minpoint;

    /* maptype 1 and 2 both use a quantized value vector, but
       different sizes */
    switch(b->maptype){
    case 1:
      /* 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 */
      quantvals=_book_maptype1_quantvals(b);
      for(j=0;j<b->entries;j++){
	if((sparsemap && b->lengthlist[j]) || !sparsemap){
	  ogg_int32_t last=0;
	  int lastpoint=0;
	  int indexdiv=1;
	  for(k=0;k<b->dim;k++){
	    int index= (j/indexdiv)%quantvals;
226
	    int point=0;
Monty's avatar
 
Monty committed
227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259
	    int val=VFLOAT_MULTI(delta,delpoint,
				 abs(b->quantlist[index]),&point);

	    val=VFLOAT_ADD(mindel,minpoint,val,point,&point);
	    val=VFLOAT_ADD(last,lastpoint,val,point,&point);
	    
	    if(b->q_sequencep){
	      last=val;	  
	      lastpoint=point;
	    }
	    
	    if(sparsemap){
	      r[sparsemap[count]*b->dim+k]=val;
	      rp[sparsemap[count]*b->dim+k]=point;
	    }else{
	      r[count*b->dim+k]=val;
	      rp[count*b->dim+k]=point;
	    }
	    if(*maxpoint<point)*maxpoint=point;
	    indexdiv*=quantvals;
	  }
	  count++;
	}

      }
      break;
    case 2:
      for(j=0;j<b->entries;j++){
	if((sparsemap && b->lengthlist[j]) || !sparsemap){
	  ogg_int32_t last=0;
	  int         lastpoint=0;

	  for(k=0;k<b->dim;k++){
260
	    int point=0;
Monty's avatar
 
Monty committed
261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296
	    int val=VFLOAT_MULTI(delta,delpoint,
				 abs(b->quantlist[j*b->dim+k]),&point);

	    val=VFLOAT_ADD(mindel,minpoint,val,point,&point);
	    val=VFLOAT_ADD(last,lastpoint,val,point,&point);
	    
	    if(b->q_sequencep){
	      last=val;	  
	      lastpoint=point;
	    }

	    if(sparsemap){
	      r[sparsemap[count]*b->dim+k]=val;
	      rp[sparsemap[count]*b->dim+k]=point;
	    }else{
	      r[count*b->dim+k]=val;
	      rp[count*b->dim+k]=point;
	    }
	    if(*maxpoint<point)*maxpoint=point;
	  }
	  count++;
	}
      }
      break;
    }

    for(j=0;j<n*b->dim;j++)
      if(rp[j]<*maxpoint)
	r[j]>>=*maxpoint-rp[j];
	    
    _ogg_free(rp);
    return(r);
  }
  return(NULL);
}

297
void vorbis_staticbook_destroy(static_codebook *b){
Monty's avatar
 
Monty committed
298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325
  if(b->quantlist)_ogg_free(b->quantlist);
  if(b->lengthlist)_ogg_free(b->lengthlist);
  memset(b,0,sizeof(*b));
  _ogg_free(b);
}

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->valuelist)_ogg_free(b->valuelist);
  if(b->codelist)_ogg_free(b->codelist);

  if(b->dec_index)_ogg_free(b->dec_index);
  if(b->dec_codelengths)_ogg_free(b->dec_codelengths);
  if(b->dec_firsttable)_ogg_free(b->dec_firsttable);

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

static ogg_uint32_t bitreverse(ogg_uint32_t x){
  x=    ((x>>16)&0x0000ffffUL) | ((x<<16)&0xffff0000UL);
  x=    ((x>> 8)&0x00ff00ffUL) | ((x<< 8)&0xff00ff00UL);
  x=    ((x>> 4)&0x0f0f0f0fUL) | ((x<< 4)&0xf0f0f0f0UL);
  x=    ((x>> 2)&0x33333333UL) | ((x<< 2)&0xccccccccUL);
  return((x>> 1)&0x55555555UL) | ((x<< 1)&0xaaaaaaaaUL);
}

static int sort32a(const void *a,const void *b){
Monty's avatar
 
Monty committed
326 327
  return (**(ogg_uint32_t **)a>**(ogg_uint32_t **)b)-
    (**(ogg_uint32_t **)a<**(ogg_uint32_t **)b);
Monty's avatar
 
Monty committed
328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344
}

/* decode codebook arrangement is more heavily optimized than encode */
int vorbis_book_init_decode(codebook *c,const static_codebook *s){
  int i,j,n=0,tabn;
  int *sortindex;
  memset(c,0,sizeof(*c));
  
  /* count actually used entries */
  for(i=0;i<s->entries;i++)
    if(s->lengthlist[i]>0)
      n++;

  c->entries=s->entries;
  c->used_entries=n;
  c->dim=s->dim;

345 346 347 348 349 350 351 352 353 354 355
  if(n>0){
    /* two different remappings go on here.  
       
       First, we collapse the likely sparse codebook down only to
       actually represented values/words.  This collapsing needs to be
       indexed as map-valueless books are used to encode original entry
       positions as integers.
       
       Second, we reorder all vectors, including the entry index above,
       by sorted bitreversed codeword to allow treeless decode. */
    
Monty's avatar
 
Monty committed
356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379
    /* perform sort */
    ogg_uint32_t *codes=_make_words(s->lengthlist,s->entries,c->used_entries);
    ogg_uint32_t **codep=(ogg_uint32_t **)alloca(sizeof(*codep)*n);
    
    if(codes==NULL)goto err_out;

    for(i=0;i<n;i++){
      codes[i]=bitreverse(codes[i]);
      codep[i]=codes+i;
    }

    qsort(codep,n,sizeof(*codep),sort32a);

    sortindex=(int *)alloca(n*sizeof(*sortindex));
    c->codelist=(ogg_uint32_t *)_ogg_malloc(n*sizeof(*c->codelist));
    /* the index is a reverse index */
    for(i=0;i<n;i++){
      int position=codep[i]-codes;
      sortindex[position]=i;
    }

    for(i=0;i<n;i++)
      c->codelist[sortindex[i]]=codes[i];
    _ogg_free(codes);
380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410
    
    
    
    c->valuelist=_book_unquantize(s,n,sortindex,&c->binarypoint);
    c->dec_index=(int *)_ogg_malloc(n*sizeof(*c->dec_index));
    
    for(n=0,i=0;i<s->entries;i++)
      if(s->lengthlist[i]>0)
	c->dec_index[sortindex[n++]]=i;
    
    c->dec_codelengths=(char *)_ogg_malloc(n*sizeof(*c->dec_codelengths));
    for(n=0,i=0;i<s->entries;i++)
      if(s->lengthlist[i]>0)
	c->dec_codelengths[sortindex[n++]]=s->lengthlist[i];
    
    c->dec_firsttablen=_ilog(c->used_entries)-4; /* this is magic */
    if(c->dec_firsttablen<5)c->dec_firsttablen=5;
    if(c->dec_firsttablen>8)c->dec_firsttablen=8;
    
    tabn=1<<c->dec_firsttablen;
    c->dec_firsttable=(ogg_uint32_t *)_ogg_calloc(tabn,sizeof(*c->dec_firsttable));
    c->dec_maxlength=0;
    
    for(i=0;i<n;i++){
      if(c->dec_maxlength<c->dec_codelengths[i])
	c->dec_maxlength=c->dec_codelengths[i];
      if(c->dec_codelengths[i]<=c->dec_firsttablen){
	ogg_uint32_t orig=bitreverse(c->codelist[i]);
	for(j=0;j<(1<<(c->dec_firsttablen-c->dec_codelengths[i]));j++)
	  c->dec_firsttable[orig|(j<<c->dec_codelengths[i])]=i+1;
      }
Monty's avatar
 
Monty committed
411
    }
412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436
    
    /* now fill in 'unused' entries in the firsttable with hi/lo search
       hints for the non-direct-hits */
    {
      ogg_uint32_t mask=0xfffffffeUL<<(31-c->dec_firsttablen);
      long lo=0,hi=0;
      
      for(i=0;i<tabn;i++){
	ogg_uint32_t word=i<<(32-c->dec_firsttablen);
	if(c->dec_firsttable[bitreverse(word)]==0){
	  while((lo+1)<n && c->codelist[lo+1]<=word)lo++;
	  while(    hi<n && word>=(c->codelist[hi]&mask))hi++;
	  
	  /* we only actually have 15 bits per hint to play with here.
	     In order to overflow gracefully (nothing breaks, efficiency
	     just drops), encode as the difference from the extremes. */
	  {
	    unsigned long loval=lo;
	    unsigned long hival=n-hi;
	    
	    if(loval>0x7fff)loval=0x7fff;
	    if(hival>0x7fff)hival=0x7fff;
	    c->dec_firsttable[bitreverse(word)]=
	      0x80000000UL | (loval<<15) | hival;
	  }
Monty's avatar
 
Monty committed
437 438 439 440 441 442 443 444 445 446 447
	}
      }
    }
  }

  return(0);
 err_out:
  vorbis_book_clear(c);
  return(-1);
}