vorbisfile has a flaw where a bad link is not initialized [proper
[platform/upstream/libvorbis.git] / lib / vorbisfile.c
index 846c4d4..24011d7 100644 (file)
@@ -11,7 +11,7 @@
  ********************************************************************
 
  function: stdio-based convenience library for opening/seeking/decoding
- last mod: $Id: vorbisfile.c,v 1.66 2003/03/02 21:32:00 xiphmont Exp $
+ last mod: $Id: vorbisfile.c,v 1.73 2003/09/02 04:39:26 xiphmont Exp $
 
  ********************************************************************/
 
@@ -387,16 +387,20 @@ static void _prefetch_all_headers(OggVorbis_File *vf, ogg_int64_t dataoffset){
   }
 }
 
-static void _make_decode_ready(OggVorbis_File *vf){
-  if(vf->ready_state!=STREAMSET)return;
+static int _make_decode_ready(OggVorbis_File *vf){
+  if(vf->ready_state!=STREAMSET)return OV_EFAULT;
   if(vf->seekable){
-    vorbis_synthesis_init(&vf->vd,vf->vi+vf->current_link);
+    if(vorbis_synthesis_init(&vf->vd,vf->vi+vf->current_link))
+      return OV_EBADLINK;
   }else{
-    vorbis_synthesis_init(&vf->vd,vf->vi);
+    if(vorbis_synthesis_init(&vf->vd,vf->vi))
+      return OV_EBADLINK;
   }    
   vorbis_block_init(&vf->vd,&vf->vb);
   vf->ready_state=INITSET;
-  return;
+  vf->bittrack=0.f;
+  vf->samptrack=0.f;
+  return 0;
 }
 
 static int _open_seekable2(OggVorbis_File *vf){
@@ -439,9 +443,6 @@ static void _decode_clear(OggVorbis_File *vf){
   vorbis_dsp_clear(&vf->vd);
   vorbis_block_clear(&vf->vb);
   vf->ready_state=OPENED;
-
-  vf->bittrack=0.f;
-  vf->samptrack=0.f;
 }
 
 /* fetch and process a packet.  Handles the case where we're at a
@@ -540,17 +541,22 @@ static int _fetch_and_process_packet(OggVorbis_File *vf,
     }
 
     if(vf->ready_state>=OPENED){
+      int ret;
       if(!readp)return(0);
-      if(_get_next_page(vf,&og,-1)<0)return(OV_EOF); /* eof. 
-                                                       leave unitialized */
-      /* bitrate tracking; add the header's bytes here, the body bytes
-        are done by packet above */
+      if((ret=_get_next_page(vf,&og,-1))<0){
+       return(OV_EOF); /* eof. 
+                          leave unitialized */
+      }
+
+       /* bitrate tracking; add the header's bytes here, the body bytes
+          are done by packet above */
       vf->bittrack+=og.header_len*8;
       
       /* has our decoding just traversed a bitstream boundary? */
       if(vf->ready_state==INITSET){
        if(vf->current_serialno!=ogg_page_serialno(&og)){
-         if(!spanp)return(OV_EOF);
+         if(!spanp)
+           return(OV_EOF);
 
          _decode_clear(vf);
          
@@ -607,7 +613,10 @@ static int _fetch_and_process_packet(OggVorbis_File *vf,
        }
       }
       
-      _make_decode_ready(vf);
+      {
+       int ret=_make_decode_ready(vf);
+       if(ret<0)return ret;
+      }
     }
     ogg_stream_pagein(&vf->os,&og);
   }
@@ -656,7 +665,7 @@ static int _ov_open1(void *f,OggVorbis_File *vf,char *initial,
   if((ret=_fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno,NULL))<0){
     vf->datasource=NULL;
     ov_clear(vf);
-  }else if(vf->ready_state < PARTOPEN)
+  }else 
     vf->ready_state=PARTOPEN;
   return(ret);
 }
@@ -731,7 +740,35 @@ int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){
 
   return ov_open_callbacks((void *)f, vf, initial, ibytes, callbacks);
 }
+/* cheap hack for game usage where downsampling is desirable; there's
+   no need for SRC as we can just do it cheaply in libvorbis. */
+int ov_halfrate(OggVorbis_File *vf,int flag){
+  int i;
+  if(vf->vi==NULL)return OV_EINVAL;
+  if(!vf->seekable)return OV_EINVAL;
+  if(vf->ready_state>=STREAMSET)
+    _decode_clear(vf); /* clear out stream state; later on libvorbis
+                          will be able to swap this on the fly, but
+                          for now dumping the decode machine is needed
+                          to reinit the MDCT lookups.  1.1 libvorbis
+                          is planned to be able to switch on the fly */
   
+  for(i=0;i<vf->links;i++){
+    if(vorbis_synthesis_halfrate(vf->vi+i,flag)){
+      ov_halfrate(vf,0);
+      return OV_EINVAL;
+    }
+  }
+  return 0;
+}
+
+int ov_halfrate_p(OggVorbis_File *vf){
+  if(vf->vi==NULL)return OV_EINVAL;
+  return vorbis_synthesis_halfrate_p(vf->vi);
+}
+
 /* Only partially open the vorbis file; test for Vorbisness, and load
    the headers for the first chain.  Do not seek (although test for
    seekability).  Use ov_test_open to finish opening the file, else
@@ -915,10 +952,15 @@ int ov_raw_seek(OggVorbis_File *vf,ogg_int64_t pos){
 
   if(pos<0 || pos>vf->end)return(OV_EINVAL);
 
-  /* clear out decoding machine state */
+  /* don't yet clear out decoding machine (if it's initialized), in
+     the case we're in the same link.  Restart the decode lapping, and
+     let _fetch_and_process_packet deal with a potential bitstream
+     boundary */
   vf->pcm_offset=-1;
-  _decode_clear(vf);
-  
+  ogg_stream_reset_serialno(&vf->os,
+                           vf->current_serialno); /* must set serialno */
+  vorbis_synthesis_restart(&vf->vd);
+    
   _seek_helper(vf,pos);
 
   /* we need to make sure the pcm_offset is set, but we don't want to
@@ -944,34 +986,45 @@ int ov_raw_seek(OggVorbis_File *vf,ogg_int64_t pos){
     int thisblock;
     int eosflag;
 
-    ogg_stream_init(&work_os,-1); /* get the memory ready */
+    ogg_stream_init(&work_os,vf->current_serialno); /* get the memory ready */
+    ogg_stream_reset(&work_os); /* eliminate the spurious OV_HOLE
+                                   return from not necessarily
+                                   starting from the beginning */
 
     while(1){
-      if(vf->ready_state==STREAMSET){
+      if(vf->ready_state>=STREAMSET){
        /* snarf/scan a packet if we can */
        int result=ogg_stream_packetout(&work_os,&op);
       
        if(result>0){
 
-         if(vf->vi[vf->current_link].codec_setup)
+         if(vf->vi[vf->current_link].codec_setup){
            thisblock=vorbis_packet_blocksize(vf->vi+vf->current_link,&op);
-         if(eosflag)
+           if(thisblock<0){
+             ogg_stream_packetout(&vf->os,NULL);
+             thisblock=0;
+           }else{
+             
+             if(eosflag)
+             ogg_stream_packetout(&vf->os,NULL);
+             else
+               if(lastblock)accblock+=(lastblock+thisblock)>>2;
+           }       
+
+           if(op.granulepos!=-1){
+             int i,link=vf->current_link;
+             ogg_int64_t granulepos=op.granulepos-vf->pcmlengths[link*2];
+             if(granulepos<0)granulepos=0;
+             
+             for(i=0;i<link;i++)
+               granulepos+=vf->pcmlengths[i*2+1];
+             vf->pcm_offset=granulepos-accblock;
+             break;
+           }
+           lastblock=thisblock;
+           continue;
+         }else
            ogg_stream_packetout(&vf->os,NULL);
-         else
-           if(lastblock)accblock+=(lastblock+thisblock)>>2;
-
-         if(op.granulepos!=-1){
-           int i,link=vf->current_link;
-           ogg_int64_t granulepos=op.granulepos-vf->pcmlengths[link*2];
-           if(granulepos<0)granulepos=0;
-           
-           for(i=0;i<link;i++)
-             granulepos+=vf->pcmlengths[i*2+1];
-           vf->pcm_offset=granulepos-accblock;
-           break;
-         }
-         lastblock=thisblock;
-         continue;
        }
       }
       
@@ -987,11 +1040,11 @@ int ov_raw_seek(OggVorbis_File *vf,ogg_int64_t pos){
       }
       
       /* has our decoding just traversed a bitstream boundary? */
-      if(vf->ready_state==STREAMSET)
+      if(vf->ready_state>=STREAMSET)
        if(vf->current_serialno!=ogg_page_serialno(&og)){
-       _decode_clear(vf); /* clear out stream state */
-       ogg_stream_clear(&work_os);
-      }
+         _decode_clear(vf); /* clear out stream state */
+         ogg_stream_clear(&work_os);
+       }
 
       if(vf->ready_state<STREAMSET){
        int link;
@@ -1017,6 +1070,8 @@ int ov_raw_seek(OggVorbis_File *vf,ogg_int64_t pos){
   }
 
   ogg_stream_clear(&work_os);
+  vf->bittrack=0.f;
+  vf->samptrack=0.f;
   return(0);
 
  seek_error:
@@ -1127,17 +1182,26 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
     {
       ogg_page og;
       ogg_packet op;
-      /* clear out decoding machine state */
-      _decode_clear(vf);  
+      
       /* seek */
       _seek_helper(vf,best);
+      vf->pcm_offset=-1;
       
       if(_get_next_page(vf,&og,-1)<0)return(OV_EOF); /* shouldn't happen */
-      vf->current_serialno=ogg_page_serialno(&og);
-      vf->current_link=link;
       
+      if(link!=vf->current_link){
+       /* Different link; dump entire decode machine */
+       _decode_clear(vf);  
+       
+       vf->current_link=link;
+       vf->current_serialno=ogg_page_serialno(&og);
+       vf->ready_state=STREAMSET;
+       
+      }else{
+       vorbis_synthesis_restart(&vf->vd);
+      }
+
       ogg_stream_reset_serialno(&vf->os,vf->current_serialno);
-      vf->ready_state=STREAMSET;
       ogg_stream_pagein(&vf->os,&og);
 
       /* pull out all but last packet; the one with granulepos */
@@ -1148,10 +1212,9 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
              preceeding page. Keep fetching previous pages until we
              get one with a granulepos or without the 'continued' flag
              set.  Then just use raw_seek for simplicity. */
-
-         _decode_clear(vf);  
+         
          _seek_helper(vf,best);
-
+         
          while(1){
            result=_get_prev_page(vf,&og);
            if(result<0) goto seek_error;
@@ -1163,9 +1226,9 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
          }
        }
        if(result<0){
-      result = OV_EBADPACKET; 
-      goto seek_error;
-    }
+         result = OV_EBADPACKET; 
+         goto seek_error;
+       }
        if(op.granulepos!=-1){
          vf->pcm_offset=op.granulepos-vf->pcmlengths[vf->current_link*2];
          if(vf->pcm_offset<0)vf->pcm_offset=0;
@@ -1182,6 +1245,8 @@ int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
     result=OV_EFAULT;
     goto seek_error;
   }
+  vf->bittrack=0.f;
+  vf->samptrack=0.f;
   return(0);
   
  seek_error:
@@ -1198,7 +1263,7 @@ int ov_pcm_seek(OggVorbis_File *vf,ogg_int64_t pos){
   int thisblock,lastblock=0;
   int ret=ov_pcm_seek_page(vf,pos);
   if(ret<0)return(ret);
-  _make_decode_ready(vf);
+  if((ret=_make_decode_ready(vf)))return ret;
 
   /* discard leading packets we don't need for the lapping of the
      position we want; don't decode them */
@@ -1210,7 +1275,10 @@ int ov_pcm_seek(OggVorbis_File *vf,ogg_int64_t pos){
     int ret=ogg_stream_packetpeek(&vf->os,&op);
     if(ret>0){
       thisblock=vorbis_packet_blocksize(vf->vi+vf->current_link,&op);
-      if(thisblock<0)thisblock=0; /* non audio packet */
+      if(thisblock<0){
+       ogg_stream_packetout(&vf->os,NULL);
+       continue; /* non audio packet */
+      }
       if(lastblock)vf->pcm_offset+=(lastblock+thisblock)>>2;
       
       if(vf->pcm_offset+((thisblock+
@@ -1255,7 +1323,8 @@ int ov_pcm_seek(OggVorbis_File *vf,ogg_int64_t pos){
        
        ogg_stream_reset_serialno(&vf->os,vf->current_serialno); 
        vf->ready_state=STREAMSET;      
-       _make_decode_ready(vf);
+       ret=_make_decode_ready(vf);
+       if(ret)return ret;
        lastblock=0;
       }
 
@@ -1263,6 +1332,8 @@ int ov_pcm_seek(OggVorbis_File *vf,ogg_int64_t pos){
     }
   }
 
+  vf->bittrack=0.f;
+  vf->samptrack=0.f;
   /* discard samples until we reach the desired position. Crossing a
      logical bitstream boundary with abandon is OK. */
   while(vf->pcm_offset<pos){
@@ -1469,8 +1540,10 @@ long ov_read(OggVorbis_File *vf,char *buffer,int length,
     /* suck in another packet */
     {
       int ret=_fetch_and_process_packet(vf,NULL,1,1);
-      if(ret==OV_EOF)return(0);
-      if(ret<=0)return(ret);
+      if(ret==OV_EOF)
+       return(0);
+      if(ret<=0)
+       return(ret);
     }
 
   }
@@ -1624,105 +1697,95 @@ long ov_read_float(OggVorbis_File *vf,float ***pcm_channels,int length,
 }
 
 extern float *vorbis_window(vorbis_dsp_state *v,int W);
+extern void _analysis_output_always(char *base,int i,float *v,int n,int bark,int dB,
+                            ogg_int64_t off);
 
-static void _vorbis_splice(float *d,float *s,
-                         vorbis_dsp_state *v,int W){
-  
-  vorbis_info *vi=v->vi;
-  int n=vorbis_info_blocksize(vi,0)/2;
-  float *w=vorbis_window(v,W);
-  int i;
+static void _ov_splice(float **pcm,float **lappcm,
+                      int n1, int n2,
+                      int ch1, int ch2,
+                      float *w1, float *w2){
+  int i,j;
+  float *w=w1;
+  int n=n1;
 
-  for(i=0;i<n;i++){
-    float wd=w[i]*w[i];
-    float ws=1.-wd;
-    d[i]=d[i]*wd + s[i]*ws;
+  if(n1>n2){
+    n=n2;
+    w=w2;
   }
-}
-       
 
-       
-/* this sets up crosslapping of a sample by using trailing data from
-   sample 1 and lapping it into the windowing buffer of the second */
-
-int ov_crosslap(OggVorbis_File *vf1, OggVorbis_File *vf2){
-  vorbis_info *vi1,*vi2;
-  vorbis_dsp_state *vd1=&vf1->vd;
-  vorbis_dsp_state *vd2=&vf2->vd;
-  float **lappcm;
-  float **pcm;
-  vorbis_dsp_state *winstate;
-  int lapsize,lapcount=0,i,j;
-
-  /* first enforce some level of sanity... */
-  /* we need to know that sample rate & channels match.  To do that,
-     we need to verify the streams are actually initialized; the call
-     is not just to be used for end-to-beginning lapping */
+  /* splice */
+  for(j=0;j<ch1 && j<ch2;j++){
+    float *s=lappcm[j];
+    float *d=pcm[j];
 
-  if(vf1->ready_state<OPENED)return(OV_EINVAL);
-  if(vf2->ready_state<OPENED)return(OV_EINVAL);
+    for(i=0;i<n;i++){
+      float wd=w[i]*w[i];
+      float ws=1.-wd;
+      d[i]=d[i]*wd + s[i]*ws;
+    }
+  }
+  /* window from zero */
+  for(;j<ch2;j++){
+    float *d=pcm[j];
+    for(i=0;i<n;i++){
+      float wd=w[i]*w[i];
+      d[i]=d[i]*wd;
+    }
+  }
 
-  /* make sure vf1 is INITSET */
+}
+               
+/* make sure vf is INITSET */
+static int _ov_initset(OggVorbis_File *vf){
   while(1){
-    if(vf1->ready_state==INITSET)break;
+    if(vf->ready_state==INITSET)break;
     /* suck in another packet */
     {
-      int ret=_fetch_and_process_packet(vf1,NULL,1,0);
-      if(ret<0)return(ret);
+      int ret=_fetch_and_process_packet(vf,NULL,1,0);
+      if(ret<0 && ret!=OV_HOLE)return(ret);
     }
   }
+  return 0;
+}
 
-  /* make sure vf2 is INITSET and that we have a primed buffer; if
-     we're crosslapping at a stream section boundary, this also makes
-     sure we're sanity checking against the right stream information */
-
+/* make sure vf is INITSET and that we have a primed buffer; if
+   we're crosslapping at a stream section boundary, this also makes
+   sure we're sanity checking against the right stream information */
+static int _ov_initprime(OggVorbis_File *vf){
+  vorbis_dsp_state *vd=&vf->vd;
   while(1){
-    if(vf2->ready_state==INITSET)
-      if(vorbis_synthesis_pcmout(vd2,NULL))break;
-
+    if(vf->ready_state==INITSET)
+      if(vorbis_synthesis_pcmout(vd,NULL))break;
+    
     /* suck in another packet */
     {
-      int ret=_fetch_and_process_packet(vf2,NULL,1,0);
-      if(ret<0)return(ret);
+      int ret=_fetch_and_process_packet(vf,NULL,1,0);
+      if(ret<0 && ret!=OV_HOLE)return(ret);
     }
-  }
-
-  /* sanity-check settings */
-  vi1=ov_info(vf1,-1);
-  vi2=ov_info(vf2,-1);
-  if(vi1->channels != vi2->channels ||
-     vi1->rate     != vi2->rate) return OV_EINVAL;
-  
-  /* begin by grabbing enough data for lapping from vf1; this may be
-     in the form of unreturned, already-decoded pcm, remaining PCM we
-     will need to decode, or synthetic postextrapolation from last
-     packets. */
-
-  lappcm=alloca(sizeof(*lappcm)*vi1->channels);
-  lapsize=vorbis_info_blocksize(vi1,0);
-  if(vorbis_info_blocksize(vi2,0)<lapsize){
-    lapsize=vorbis_info_blocksize(vi2,0)/2;
-    winstate=vd2;
-  }else{
-    lapsize/=2;
-    winstate=vd1;
-  }
+  }  
+  return 0;
+}
 
-  for(i=0;i<vi1->channels;i++)
-    lappcm[i]=alloca(sizeof(**lappcm)*lapsize);
+/* grab enough data for lapping from vf; this may be in the form of
+   unreturned, already-decoded pcm, remaining PCM we will need to
+   decode, or synthetic postextrapolation from last packets. */
+static void _ov_getlap(OggVorbis_File *vf,vorbis_info *vi,vorbis_dsp_state *vd,
+                      float **lappcm,int lapsize){
+  int lapcount=0,i;
+  float **pcm;
 
   /* try first to decode the lapping data */
   while(lapcount<lapsize){
-    int samples=vorbis_synthesis_pcmout(vd1,&pcm);
+    int samples=vorbis_synthesis_pcmout(vd,&pcm);
     if(samples){
       if(samples>lapsize-lapcount)samples=lapsize-lapcount;
-      for(i=0;i<vi1->channels;i++)
+      for(i=0;i<vi->channels;i++)
        memcpy(lappcm[i]+lapcount,pcm[i],sizeof(**pcm)*samples);
       lapcount+=samples;
-      vorbis_synthesis_read(vd1,samples);
+      vorbis_synthesis_read(vd,samples);
     }else{
     /* suck in another packet */
-      int ret=_fetch_and_process_packet(vf1,NULL,1,0); /* do *not* span */
+      int ret=_fetch_and_process_packet(vf,NULL,1,0); /* do *not* span */
       if(ret==OV_EOF)break;
     }
   }
@@ -1730,30 +1793,186 @@ int ov_crosslap(OggVorbis_File *vf1, OggVorbis_File *vf2){
     /* failed to get lapping data from normal decode; pry it from the
        postextrapolation buffering, or the second half of the MDCT
        from the last packet */
-    int samples=vorbis_synthesis_lapout(&vf1->vd,&pcm);
-    if(samples>lapsize-lapcount)samples=lapsize-lapcount;
-    for(i=0;i<vi1->channels;i++)
-      memcpy(lappcm[i]+lapcount,pcm[i],sizeof(**pcm)*samples);
-    lapcount+=samples;
-
-    if(lapcount<lapsize)return OV_EFAULT;
+    int samples=vorbis_synthesis_lapout(&vf->vd,&pcm);
+    if(samples==0){
+      for(i=0;i<vi->channels;i++)
+       memset(lappcm[i]+lapcount,0,sizeof(**pcm)*lapsize-lapcount);
+      lapcount=lapsize;
+    }else{
+      if(samples>lapsize-lapcount)samples=lapsize-lapcount;
+      for(i=0;i<vi->channels;i++)
+       memcpy(lappcm[i]+lapcount,pcm[i],sizeof(**pcm)*samples);
+      lapcount+=samples;
+    }
   }
+}
+
+/* this sets up crosslapping of a sample by using trailing data from
+   sample 1 and lapping it into the windowing buffer of sample 2 */
+int ov_crosslap(OggVorbis_File *vf1, OggVorbis_File *vf2){
+  vorbis_info *vi1,*vi2;
+  float **lappcm;
+  float **pcm;
+  float *w1,*w2;
+  int n1,n2,i,ret,hs1,hs2;
+
+  if(vf1==vf2)return(0); /* degenerate case */
+  if(vf1->ready_state<OPENED)return(OV_EINVAL);
+  if(vf2->ready_state<OPENED)return(OV_EINVAL);
+
+  /* the relevant overlap buffers must be pre-checked and pre-primed
+     before looking at settings in the event that priming would cross
+     a bitstream boundary.  So, do it now */
+
+  ret=_ov_initset(vf1);
+  if(ret)return(ret);
+  ret=_ov_initprime(vf2);
+  if(ret)return(ret);
+
+  vi1=ov_info(vf1,-1);
+  vi2=ov_info(vf2,-1);
+  hs1=ov_halfrate_p(vf1);
+  hs2=ov_halfrate_p(vf2);
+
+  lappcm=alloca(sizeof(*lappcm)*vi1->channels);
+  n1=vorbis_info_blocksize(vi1,0)>>(1+hs1);
+  n2=vorbis_info_blocksize(vi2,0)>>(1+hs2);
+  w1=vorbis_window(&vf1->vd,0);
+  w2=vorbis_window(&vf2->vd,0);
+
+  for(i=0;i<vi1->channels;i++)
+    lappcm[i]=alloca(sizeof(**lappcm)*n1);
+
+  _ov_getlap(vf1,vi1,&vf1->vd,lappcm,n1);
 
   /* have a lapping buffer from vf1; now to splice it into the lapping
      buffer of vf2 */
+  /* consolidate and expose the buffer. */
+  vorbis_synthesis_lapout(&vf2->vd,&pcm);
+  _analysis_output_always("pcmL",0,pcm[0],n1*2,0,0,0);
+  _analysis_output_always("pcmR",0,pcm[1],n1*2,0,0,0);
+
+  /* splice */
+  _ov_splice(pcm,lappcm,n1,n2,vi1->channels,vi2->channels,w1,w2);
+  
+  /* done */
+  return(0);
+}
+
+static int _ov_64_seek_lap(OggVorbis_File *vf,ogg_int64_t pos,
+                          int (*localseek)(OggVorbis_File *,ogg_int64_t)){
+  vorbis_info *vi;
+  float **lappcm;
+  float **pcm;
+  float *w1,*w2;
+  int n1,n2,ch1,ch2,hs;
+  int i,ret;
+
+  if(vf->ready_state<OPENED)return(OV_EINVAL);
+  ret=_ov_initset(vf);
+  if(ret)return(ret);
+  vi=ov_info(vf,-1);
+  hs=ov_halfrate_p(vf);
+  
+  ch1=vi->channels;
+  n1=vorbis_info_blocksize(vi,0)>>(1+hs);
+  w1=vorbis_window(&vf->vd,0);  /* window arrays from libvorbis are
+                                  persistent; even if the decode state
+                                  from this link gets dumped, this
+                                  window array continues to exist */
+
+  lappcm=alloca(sizeof(*lappcm)*ch1);
+  for(i=0;i<ch1;i++)
+    lappcm[i]=alloca(sizeof(**lappcm)*n1);
+  _ov_getlap(vf,vi,&vf->vd,lappcm,n1);
+
+  /* have lapping data; seek and prime the buffer */
+  ret=localseek(vf,pos);
+  if(ret)return ret;
+  ret=_ov_initprime(vf);
+  if(ret)return(ret);
+
+ /* Guard against cross-link changes; they're perfectly legal */
+  vi=ov_info(vf,-1);
+  ch2=vi->channels;
+  n2=vorbis_info_blocksize(vi,0)>>(1+hs);
+  w2=vorbis_window(&vf->vd,0);
 
   /* consolidate and expose the buffer. */
-  if(vorbis_synthesis_lapout(vd2,&pcm)<lapsize)return OV_EFAULT;
+  vorbis_synthesis_lapout(&vf->vd,&pcm);
 
   /* splice */
-  for(j=0;j<vi1->channels;j++){
-    float *s=lappcm[j];
-    float *d=pcm[j];
-    _vorbis_splice(d,s,winstate,0);
-  }
+  _ov_splice(pcm,lappcm,n1,n2,ch1,ch2,w1,w2);
+
+  /* done */
+  return(0);
+}
+
+int ov_raw_seek_lap(OggVorbis_File *vf,ogg_int64_t pos){
+  return _ov_64_seek_lap(vf,pos,ov_raw_seek);
+}
+
+int ov_pcm_seek_lap(OggVorbis_File *vf,ogg_int64_t pos){
+  return _ov_64_seek_lap(vf,pos,ov_pcm_seek);
+}
+
+int ov_pcm_seek_page_lap(OggVorbis_File *vf,ogg_int64_t pos){
+  return _ov_64_seek_lap(vf,pos,ov_pcm_seek_page);
+}
+
+static int _ov_d_seek_lap(OggVorbis_File *vf,double pos,
+                          int (*localseek)(OggVorbis_File *,double)){
+  vorbis_info *vi;
+  float **lappcm;
+  float **pcm;
+  float *w1,*w2;
+  int n1,n2,ch1,ch2,hs;
+  int i,ret;
+
+  if(vf->ready_state<OPENED)return(OV_EINVAL);
+  ret=_ov_initset(vf);
+  if(ret)return(ret);
+  vi=ov_info(vf,-1);
+  hs=ov_halfrate_p(vf);
+
+  ch1=vi->channels;
+  n1=vorbis_info_blocksize(vi,0)>>(1+hs);
+  w1=vorbis_window(&vf->vd,0);  /* window arrays from libvorbis are
+                                  persistent; even if the decode state
+                                  from this link gets dumped, this
+                                  window array continues to exist */
+
+  lappcm=alloca(sizeof(*lappcm)*ch1);
+  for(i=0;i<ch1;i++)
+    lappcm[i]=alloca(sizeof(**lappcm)*n1);
+  _ov_getlap(vf,vi,&vf->vd,lappcm,n1);
+
+  /* have lapping data; seek and prime the buffer */
+  ret=localseek(vf,pos);
+  if(ret)return ret;
+  ret=_ov_initprime(vf);
+  if(ret)return(ret);
+
+ /* Guard against cross-link changes; they're perfectly legal */
+  vi=ov_info(vf,-1);
+  ch2=vi->channels;
+  n2=vorbis_info_blocksize(vi,0)>>(1+hs);
+  w2=vorbis_window(&vf->vd,0);
+
+  /* consolidate and expose the buffer. */
+  vorbis_synthesis_lapout(&vf->vd,&pcm);
+
+  /* splice */
+  _ov_splice(pcm,lappcm,n1,n2,ch1,ch2,w1,w2);
 
   /* done */
   return(0);
 }
 
+int ov_time_seek_lap(OggVorbis_File *vf,double pos){
+  return _ov_d_seek_lap(vf,pos,ov_time_seek);
+}
 
+int ov_time_seek_page_lap(OggVorbis_File *vf,double pos){
+  return _ov_d_seek_lap(vf,pos,ov_time_seek_page);
+}