forked from len0rd/rockbox
		
	Slight code improvements to the MDCT functions. git-svn-id: svn://svn.rockbox.org/rockbox/trunk@6590 a1c6a512-1295-4272-9138-f99709370657
		
			
				
	
	
		
			351 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			351 lines
		
	
	
	
		
			9.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /********************************************************************
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|  *                                                                  *
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|  * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *
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|  *                                                                  *
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|  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
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|  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
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|  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
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|  *                                                                  *
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|  * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
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|  * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
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|  *                                                                  *
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|  ********************************************************************
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| 
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|  function: basic codebook pack/unpack/code/decode operations
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| 
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|  ********************************************************************/
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| 
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| #include "config-tremor.h"
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| #include <string.h>
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| #include <math.h>
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| #include "ogg.h"
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| #include "ivorbiscodec.h"
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| #include "codebook.h"
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| #include "misc.h"
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| #include "os.h"
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| 
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| /* unpacks a codebook from the packet buffer into the codebook struct,
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|    readies the codebook auxiliary structures for decode *************/
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| int vorbis_staticbook_unpack(oggpack_buffer *opb,static_codebook *s){
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|   long i,j;
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|   memset(s,0,sizeof(*s));
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| 
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|   /* make sure alignment is correct */
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|   if(oggpack_read(opb,24)!=0x564342)goto _eofout;
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| 
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|   /* first the basic parameters */
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|   s->dim=oggpack_read(opb,16);
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|   s->entries=oggpack_read(opb,24);
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|   if(s->entries==-1)goto _eofout;
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| 
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|   /* codeword ordering.... length ordered or unordered? */
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|   switch((int)oggpack_read(opb,1)){
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|   case 0:
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|     /* unordered */
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|     s->lengthlist=(long *)_ogg_malloc(sizeof(*s->lengthlist)*s->entries);
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| 
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|     /* allocated but unused entries? */
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|     if(oggpack_read(opb,1)){
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|       /* yes, unused entries */
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| 
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|       for(i=0;i<s->entries;i++){
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| 	if(oggpack_read(opb,1)){
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| 	  long num=oggpack_read(opb,5);
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| 	  if(num==-1)goto _eofout;
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| 	  s->lengthlist[i]=num+1;
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| 	}else
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| 	  s->lengthlist[i]=0;
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|       }
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|     }else{
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|       /* all entries used; no tagging */
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|       for(i=0;i<s->entries;i++){
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| 	long num=oggpack_read(opb,5);
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| 	if(num==-1)goto _eofout;
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| 	s->lengthlist[i]=num+1;
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|       }
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|     }
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|     
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|     break;
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|   case 1:
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|     /* ordered */
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|     {
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|       long length=oggpack_read(opb,5)+1;
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|       s->lengthlist=(long *)_ogg_malloc(sizeof(*s->lengthlist)*s->entries);
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| 
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|       for(i=0;i<s->entries;){
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| 	long num=oggpack_read(opb,_ilog(s->entries-i));
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| 	if(num==-1)goto _eofout;
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| 	for(j=0;j<num && i<s->entries;j++,i++)
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| 	  s->lengthlist[i]=length;
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| 	length++;
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|       }
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|     }
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|     break;
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|   default:
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|     /* EOF */
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|     return(-1);
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|   }
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|   
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|   /* Do we have a mapping to unpack? */
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|   switch((s->maptype=oggpack_read(opb,4))){
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|   case 0:
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|     /* no mapping */
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|     break;
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|   case 1: case 2:
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|     /* implicitly populated value mapping */
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|     /* explicitly populated value mapping */
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| 
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|     s->q_min=oggpack_read(opb,32);
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|     s->q_delta=oggpack_read(opb,32);
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|     s->q_quant=oggpack_read(opb,4)+1;
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|     s->q_sequencep=oggpack_read(opb,1);
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| 
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|     {
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|       int quantvals=0;
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|       switch(s->maptype){
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|       case 1:
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| 	quantvals=_book_maptype1_quantvals(s);
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| 	break;
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|       case 2:
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| 	quantvals=s->entries*s->dim;
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| 	break;
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|       }
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|       
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|       /* quantized values */
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|       s->quantlist=(long *)_ogg_malloc(sizeof(*s->quantlist)*quantvals);
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|       for(i=0;i<quantvals;i++)
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| 	s->quantlist[i]=oggpack_read(opb,s->q_quant);
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|       
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|       if(quantvals&&s->quantlist[quantvals-1]==-1)goto _eofout;
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|     }
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|     break;
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|   default:
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|     goto _errout;
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|   }
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| 
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|   /* all set */
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|   return(0);
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|   
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|  _errout:
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|  _eofout:
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|   vorbis_staticbook_clear(s);
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|   return(-1); 
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| }
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| 
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| /* the 'eliminate the decode tree' optimization actually requires the
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|    codewords to be MSb first, not LSb.  This is an annoying inelegancy
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|    (and one of the first places where carefully thought out design
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|    turned out to be wrong; Vorbis II and future Ogg codecs should go
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|    to an MSb bitpacker), but not actually the huge hit it appears to
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|    be.  The first-stage decode table catches most words so that
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|    bitreverse is not in the main execution path. */
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| 
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| static inline ogg_uint32_t bitreverse(register ogg_uint32_t x){
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|   x=    ((x>>16)&0x0000ffff) | ((x<<16)&0xffff0000);
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|   x=    ((x>> 8)&0x00ff00ff) | ((x<< 8)&0xff00ff00);
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|   x=    ((x>> 4)&0x0f0f0f0f) | ((x<< 4)&0xf0f0f0f0);
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|   x=    ((x>> 2)&0x33333333) | ((x<< 2)&0xcccccccc);
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|   return((x>> 1)&0x55555555) | ((x<< 1)&0xaaaaaaaa);
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| }
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| 
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| static inline long decode_packed_entry_number(codebook *book, 
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| 					      oggpack_buffer *b){
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|   int  read=book->dec_maxlength;
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|   long lo,hi;
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|   long lok = oggpack_look(b,book->dec_firsttablen);
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|  
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|   if (lok >= 0) {
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|     long entry = book->dec_firsttable[lok];
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|     if(entry&0x80000000UL){
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|       lo=(entry>>15)&0x7fff;
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|       hi=book->used_entries-(entry&0x7fff);
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|     }else{
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|       oggpack_adv(b, book->dec_codelengths[entry-1]);
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|       return(entry-1);
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|     }
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|   }else{
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|     lo=0;
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|     hi=book->used_entries;
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|   }
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| 
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|   lok = oggpack_look(b, read);
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| 
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|   while(lok<0 && read>1)
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|     lok = oggpack_look(b, --read);
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|   if(lok<0)return -1;
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| 
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|   /* bisect search for the codeword in the ordered list */
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|   {
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|     ogg_uint32_t testword=bitreverse((ogg_uint32_t)lok);
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| 
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|     while(hi-lo>1){
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|       long p=(hi-lo)>>1;
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|       long test=book->codelist[lo+p]>testword;    
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|       lo+=p&(test-1);
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|       hi-=p&(-test);
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|     }
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| 
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|     if(book->dec_codelengths[lo]<=read){
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|       oggpack_adv(b, book->dec_codelengths[lo]);
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|       return(lo);
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|     }
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|   }
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|   
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|   oggpack_adv(b, read);
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|   return(-1);
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| }
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| 
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| /* Decode side is specced and easier, because we don't need to find
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|    matches using different criteria; we simply read and map.  There are
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|    two things we need to do 'depending':
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|    
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|    We may need to support interleave.  We don't really, but it's
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|    convenient to do it here rather than rebuild the vector later.
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| 
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|    Cascades may be additive or multiplicitive; this is not inherent in
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|    the codebook, but set in the code using the codebook.  Like
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|    interleaving, it's easiest to do it here.  
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|    addmul==0 -> declarative (set the value)
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|    addmul==1 -> additive
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|    addmul==2 -> multiplicitive */
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| 
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| /* returns the [original, not compacted] entry number or -1 on eof *********/
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| long vorbis_book_decode(codebook *book, oggpack_buffer *b){
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|   long packed_entry=decode_packed_entry_number(book,b);
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|   if(packed_entry>=0)
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|     return(book->dec_index[packed_entry]);
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|   
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|   /* if there's no dec_index, the codebook unpacking isn't collapsed */
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|   return(packed_entry);
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| }
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| 
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| /* returns 0 on OK or -1 on eof *************************************/
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| long vorbis_book_decodevs_add(codebook *book,ogg_int32_t *a,
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| 			      oggpack_buffer *b,int n,int point){
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|   int step=n/book->dim;
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|   long *entry = (long *)alloca(sizeof(*entry)*step);
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|   ogg_int32_t **t = (ogg_int32_t **)alloca(sizeof(*t)*step);
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|   int i,j,o;
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|   int shift=point-book->binarypoint;
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| 
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|   if(shift>=0){
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|     for (i = 0; i < step; i++) {
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|       entry[i]=decode_packed_entry_number(book,b);
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|       if(entry[i]==-1)return(-1);
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|       t[i] = book->valuelist+entry[i]*book->dim;
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|     }
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|     for(i=0,o=0;i<book->dim;i++,o+=step)
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|       for (j=0;j<step;j++)
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| 	a[o+j]+=t[j][i]>>shift;
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|   }else{
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|     for (i = 0; i < step; i++) {
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|       entry[i]=decode_packed_entry_number(book,b);
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|       if(entry[i]==-1)return(-1);
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|       t[i] = book->valuelist+entry[i]*book->dim;
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|     }
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|     for(i=0,o=0;i<book->dim;i++,o+=step)
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|       for (j=0;j<step;j++)
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| 	a[o+j]+=t[j][i]<<-shift;
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|   }
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|   return(0);
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| }
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| 
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| long vorbis_book_decodev_add(codebook *book,ogg_int32_t *a,
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| 			     oggpack_buffer *b,int n,int point){
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|   int i,j,entry;
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|   ogg_int32_t *t;
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|   int shift=point-book->binarypoint;
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|   
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|   if(shift>=0){
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|     for(i=0;i<n;){
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|       entry = decode_packed_entry_number(book,b);
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|       if(entry==-1)return(-1);
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|       t     = book->valuelist+entry*book->dim;
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|       for (j=0;j<book->dim;)
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| 	a[i++]+=t[j++]>>shift;
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|     }
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|   }else{
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|     shift = -shift;
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|     for(i=0;i<n;){
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|       entry = decode_packed_entry_number(book,b);
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|       if(entry==-1)return(-1);
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|       t     = book->valuelist+entry*book->dim;
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|       for (j=0;j<book->dim;)
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| 	a[i++]+=t[j++]<<shift;
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|     }
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|   }
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|   return(0);
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| }
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| 
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| long vorbis_book_decodev_set(codebook *book,ogg_int32_t *a,
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| 			     oggpack_buffer *b,int n,int point){
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|   int i,j,entry;
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|   ogg_int32_t *t;
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|   int shift=point-book->binarypoint;
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|   
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|   if(shift>=0){
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| 
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|     for(i=0;i<n;){
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|       entry = decode_packed_entry_number(book,b);
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|       if(entry==-1)return(-1);
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|       t     = book->valuelist+entry*book->dim;
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|       for (j=0;j<book->dim;){
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| 	a[i++]=t[j++]>>shift;
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|       }
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|     }
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|   }else{
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|     shift = -shift;
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|     for(i=0;i<n;){
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|       entry = decode_packed_entry_number(book,b);
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|       if(entry==-1)return(-1);
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|       t     = book->valuelist+entry*book->dim;
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|       for (j=0;j<book->dim;){
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| 	a[i++]=t[j++]<<shift;
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|       }
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|     }
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|   }
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|   return(0);
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| }
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| 
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| long vorbis_book_decodevv_add(codebook *book,ogg_int32_t **a,
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| 			      long offset,int ch,
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| 			      oggpack_buffer *b,int n,int point){
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|   long i,j,entry;
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|   int chptr=0;
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|   int shift=point-book->binarypoint;
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|   
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|   if(shift>=0){
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|     
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|     for(i=offset;i<offset+n;){
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|       entry = decode_packed_entry_number(book,b);
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|       if(entry==-1)return(-1);
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|       {
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| 	const ogg_int32_t *t = book->valuelist+entry*book->dim;
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| 	for (j=0;j<book->dim;j++){
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| 	  a[chptr++][i]+=t[j]>>shift;
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| 	  if(chptr==ch){
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| 	    chptr=0;
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| 	    i++;
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| 	  }
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| 	}
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|       }
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|     }
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|   }else{
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|     shift = -shift;
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|     for(i=offset;i<offset+n;){
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|       entry = decode_packed_entry_number(book,b);
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|       if(entry==-1)return(-1);
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|       {
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| 	const ogg_int32_t *t = book->valuelist+entry*book->dim;
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| 	for (j=0;j<book->dim;j++){
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| 	  a[chptr++][i]+=t[j]<<shift;
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| 	  if(chptr==ch){
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| 	    chptr=0;
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| 	    i++;
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| 	  }
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| 	}
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|       }
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|     }
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|   }
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|   return(0);
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| }
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