Tremor mainline succeptible to bug #340; corrected.

git-svn-id: https://svn.xiph.org/trunk/Tremor@13173 0101bb08-14d6-0310-b084-bc0e0c8e3800

1 files changed, 67 insertions, 70 deletions

diff --git a/sharedbook.c b/sharedbook.c
index b982c7a..8e07492 100644
--- a/sharedbook.c
+++ b/sharedbook.c
@@ -334,20 +334,17 @@ int vorbis_book_init_decode(codebook *c,const static_codebook *s){
   c->used_entries=n;
   c->dim=s->dim;
 
-  c->q_min=s->q_min;
-  c->q_delta=s->q_delta;
-
-  /* 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. */
-
-  {
+  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. */
+    
     /* 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);
@@ -372,67 +369,67 @@ int vorbis_book_init_decode(codebook *c,const static_codebook *s){
     for(i=0;i<n;i++)
       c->codelist[sortindex[i]]=codes[i];
     _ogg_free(codes);
-  }
-
-  
-  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;
+    
+    
+    
+    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;
+      }
     }
-  }
-
-  /* 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;
+    
+    /* 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;
+	  }
 	}
       }
     }
   }
-  
 
   return(0);
  err_out: