1 /********************************************************************

     2  *                                                                  *

     3  * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *

     4  *                                                                  *

     5  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *

     6  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *

     7  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *

     8  *                                                                  *

     9  * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2003    *

    10  * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *

    11  *                                                                  *

    12  ********************************************************************

    13 

    14  function: stdio-based convenience library for opening/seeking/decoding

    15  last mod: $Id: vorbisfile.c,v 1.6 2003/03/30 23:40:56 xiphmont Exp $

    16 

    17  ********************************************************************/

    18 

    19 #include <stdlib.h>

    20 #include <stdio.h>

    21 #include <errno.h>

    22 #include <string.h>

    23 #include <math.h>

    24 

    25 #include "ivorbiscodec.h"

    26 #include "ivorbisfile.h"

    27 

    28 #include "misc.h"

    29 

    30 /* A 'chained bitstream' is a Vorbis bitstream that contains more than

    31    one logical bitstream arranged end to end (the only form of Ogg

    32    multiplexing allowed in a Vorbis bitstream; grouping [parallel

    33    multiplexing] is not allowed in Vorbis) */

    34 

    35 /* A Vorbis file can be played beginning to end (streamed) without

    36    worrying ahead of time about chaining (see decoder_example.c).  If

    37    we have the whole file, however, and want random access

    38    (seeking/scrubbing) or desire to know the total length/time of a

    39    file, we need to account for the possibility of chaining. */

    40 

    41 /* We can handle things a number of ways; we can determine the entire

    42    bitstream structure right off the bat, or find pieces on demand.

    43    This example determines and caches structure for the entire

    44    bitstream, but builds a virtual decoder on the fly when moving

    45    between links in the chain. */

    46 

    47 /* There are also different ways to implement seeking.  Enough

    48    information exists in an Ogg bitstream to seek to

    49    sample-granularity positions in the output.  Or, one can seek by

    50    picking some portion of the stream roughly in the desired area if

    51    we only want coarse navigation through the stream. */

    52 

    53 /*************************************************************************

    54  * Many, many internal helpers.  The intention is not to be confusing; 

    55  * rampant duplication and monolithic function implementation would be 

    56  * harder to understand anyway.  The high level functions are last.  Begin

    57  * grokking near the end of the file */

    58 

    59 

    60 /* read a little more data from the file/pipe into the ogg_sync framer */

    61 static long _get_data(OggVorbis_File *vf){

    62   errno=0;

    63   if(vf->datasource){

    64     unsigned char *buffer=ogg_sync_bufferin(vf->oy,CHUNKSIZE);

    65     long bytes=(vf->callbacks.read_func)(buffer,1,CHUNKSIZE,vf->datasource);

    66     if(bytes>0)ogg_sync_wrote(vf->oy,bytes);

    67     if(bytes==0 && errno)return(-1);

    68     return(bytes);

    69   }else

    70     return(0);

    71 }

    72 

    73 /* save a tiny smidge of verbosity to make the code more readable */

    74 static void _seek_helper(OggVorbis_File *vf,ogg_int64_t offset){

    75   if(vf->datasource){ 

    76     (vf->callbacks.seek_func)(vf->datasource, offset, SEEK_SET);

    77     vf->offset=offset;

    78     ogg_sync_reset(vf->oy);

    79   }else{

    80     /* shouldn't happen unless someone writes a broken callback */

    81     return;

    82   }

    83 }

    84 

    85 /* The read/seek functions track absolute position within the stream */

    86 

    87 /* from the head of the stream, get the next page.  boundary specifies

    88    if the function is allowed to fetch more data from the stream (and

    89    how much) or only use internally buffered data.

    90 

    91    boundary: -1) unbounded search

    92               0) read no additional data; use cached only

    93 	      n) search for a new page beginning for n bytes

    94 

    95    return:   <0) did not find a page (OV_FALSE, OV_EOF, OV_EREAD)

    96               n) found a page at absolute offset n 

    97 

    98               produces a refcounted page */

    99 

   100 static ogg_int64_t _get_next_page(OggVorbis_File *vf,ogg_page *og,

   101 				  ogg_int64_t boundary){

   102   if(boundary>0)boundary+=vf->offset;

   103   while(1){

   104     long more;

   105 

   106     if(boundary>0 && vf->offset>=boundary)return(OV_FALSE);

   107     more=ogg_sync_pageseek(vf->oy,og);

   108     

   109     if(more<0){

   110       /* skipped n bytes */

   111       vf->offset-=more;

   112     }else{

   113       if(more==0){

   114 	/* send more paramedics */

   115 	if(!boundary)return(OV_FALSE);

   116 	{

   117 	  long ret=_get_data(vf);

   118 	  if(ret==0)return(OV_EOF);

   119 	  if(ret<0)return(OV_EREAD);

   120 	}

   121       }else{

   122 	/* got a page.  Return the offset at the page beginning,

   123            advance the internal offset past the page end */

   124 	ogg_int64_t ret=vf->offset;

   125 	vf->offset+=more;

   126 	return(ret);

   127 	

   128       }

   129     }

   130   }

   131 }

   132 

   133 /* find the latest page beginning before the current stream cursor

   134    position. Much dirtier than the above as Ogg doesn't have any

   135    backward search linkage.  no 'readp' as it will certainly have to

   136    read. */

   137 /* returns offset or OV_EREAD, OV_FAULT and produces a refcounted page */

   138 

   139 static ogg_int64_t _get_prev_page(OggVorbis_File *vf,ogg_page *og){

   140   ogg_int64_t begin=vf->offset;

   141   ogg_int64_t end=begin;

   142   ogg_int64_t ret;

   143   ogg_int64_t offset=-1;

   144 

   145   while(offset==-1){

   146     begin-=CHUNKSIZE;

   147     if(begin<0)

   148       begin=0;

   149     _seek_helper(vf,begin);

   150     while(vf->offset<end){

   151       ret=_get_next_page(vf,og,end-vf->offset);

   152       if(ret==OV_EREAD)return(OV_EREAD);

   153       if(ret<0){

   154 	break;

   155       }else{

   156 	offset=ret;

   157       }

   158     }

   159   }

   160 

   161   /* we have the offset.  Actually snork and hold the page now */

   162   _seek_helper(vf,offset);

   163   ret=_get_next_page(vf,og,CHUNKSIZE);

   164   if(ret<0)

   165     /* this shouldn't be possible */

   166     return(OV_EFAULT);

   167 

   168   return(offset);

   169 }

   170 

   171 /* finds each bitstream link one at a time using a bisection search

   172    (has to begin by knowing the offset of the lb's initial page).

   173    Recurses for each link so it can alloc the link storage after

   174    finding them all, then unroll and fill the cache at the same time */

   175 static int _bisect_forward_serialno(OggVorbis_File *vf,

   176 				    ogg_int64_t begin,

   177 				    ogg_int64_t searched,

   178 				    ogg_int64_t end,

   179 				    ogg_uint32_t currentno,

   180 				    long m){

   181   ogg_int64_t endsearched=end;

   182   ogg_int64_t next=end;

   183   ogg_page og={0,0,0,0};

   184   ogg_int64_t ret;

   185   

   186   /* the below guards against garbage seperating the last and

   187      first pages of two links. */

   188   while(searched<endsearched){

   189     ogg_int64_t bisect;

   190     

   191     if(endsearched-searched<CHUNKSIZE){

   192       bisect=searched;

   193     }else{

   194       bisect=(searched+endsearched)/2;

   195     }

   196     

   197     _seek_helper(vf,bisect);

   198     ret=_get_next_page(vf,&og,-1);

   199     if(ret==OV_EREAD)return(OV_EREAD);

   200     if(ret<0 || ogg_page_serialno(&og)!=currentno){

   201       endsearched=bisect;

   202       if(ret>=0)next=ret;

   203     }else{

   204       searched=ret+og.header_len+og.body_len;

   205     }

   206     ogg_page_release(&og);

   207   }

   208 

   209   _seek_helper(vf,next);

   210   ret=_get_next_page(vf,&og,-1);

   211   if(ret==OV_EREAD)return(OV_EREAD);

   212   

   213   if(searched>=end || ret<0){

   214     ogg_page_release(&og);

   215     vf->links=m+1;

   216     vf->offsets=_ogg_malloc((vf->links+1)*sizeof(*vf->offsets));

   217     vf->serialnos=_ogg_malloc(vf->links*sizeof(*vf->serialnos));

   218     vf->offsets[m+1]=searched;

   219   }else{

   220     ret=_bisect_forward_serialno(vf,next,vf->offset,

   221 				 end,ogg_page_serialno(&og),m+1);

   222     ogg_page_release(&og);

   223     if(ret==OV_EREAD)return(OV_EREAD);

   224   }

   225   

   226   vf->offsets[m]=begin;

   227   vf->serialnos[m]=currentno;

   228   return(0);

   229 }

   230 

   231 /* uses the local ogg_stream storage in vf; this is important for

   232    non-streaming input sources */

   233 /* consumes the page that's passed in (if any) */

   234 

   235 static int _fetch_headers(OggVorbis_File *vf,

   236 			  vorbis_info *vi,

   237 			  vorbis_comment *vc,

   238 			  ogg_uint32_t *serialno,

   239 			  ogg_page *og_ptr){

   240   ogg_page og={0,0,0,0};

   241   ogg_packet op={0,0,0,0,0,0};

   242   int i,ret;

   243   

   244   if(!og_ptr){

   245     ogg_int64_t llret=_get_next_page(vf,&og,CHUNKSIZE);

   246     if(llret==OV_EREAD)return(OV_EREAD);

   247     if(llret<0)return OV_ENOTVORBIS;

   248     og_ptr=&og;

   249   }

   250 

   251   ogg_stream_reset_serialno(vf->os,ogg_page_serialno(og_ptr));

   252   if(serialno)*serialno=vf->os->serialno;

   253   vf->ready_state=STREAMSET;

   254   

   255   /* extract the initial header from the first page and verify that the

   256      Ogg bitstream is in fact Vorbis data */

   257   

   258   vorbis_info_init(vi);

   259   vorbis_comment_init(vc);

   260   

   261   i=0;

   262   while(i<3){

   263     ogg_stream_pagein(vf->os,og_ptr);

   264     while(i<3){

   265       int result=ogg_stream_packetout(vf->os,&op);

   266       if(result==0)break;

   267       if(result==-1){

   268 	ret=OV_EBADHEADER;

   269 	goto bail_header;

   270       }

   271       if((ret=vorbis_synthesis_headerin(vi,vc,&op))){

   272 	goto bail_header;

   273       }

   274       i++;

   275     }

   276     if(i<3)

   277       if(_get_next_page(vf,og_ptr,CHUNKSIZE)<0){

   278 	ret=OV_EBADHEADER;

   279 	goto bail_header;

   280       }

   281   }

   282 

   283   ogg_packet_release(&op);

   284   ogg_page_release(&og);

   285   return 0; 

   286 

   287  bail_header:

   288   ogg_packet_release(&op);

   289   ogg_page_release(&og);

   290   vorbis_info_clear(vi);

   291   vorbis_comment_clear(vc);

   292   vf->ready_state=OPENED;

   293 

   294   return ret;

   295 }

   296 

   297 /* last step of the OggVorbis_File initialization; get all the

   298    vorbis_info structs and PCM positions.  Only called by the seekable

   299    initialization (local stream storage is hacked slightly; pay

   300    attention to how that's done) */

   301 

   302 /* this is void and does not propogate errors up because we want to be

   303    able to open and use damaged bitstreams as well as we can.  Just

   304    watch out for missing information for links in the OggVorbis_File

   305    struct */

   306 static void _prefetch_all_headers(OggVorbis_File *vf, ogg_int64_t dataoffset){

   307   ogg_page og={0,0,0,0};

   308   int i;

   309   ogg_int64_t ret;

   310   

   311   vf->vi=_ogg_realloc(vf->vi,vf->links*sizeof(*vf->vi));

   312   vf->vc=_ogg_realloc(vf->vc,vf->links*sizeof(*vf->vc));

   313   vf->dataoffsets=_ogg_malloc(vf->links*sizeof(*vf->dataoffsets));

   314   vf->pcmlengths=_ogg_malloc(vf->links*2*sizeof(*vf->pcmlengths));

   315   

   316   for(i=0;i<vf->links;i++){

   317     if(i==0){

   318       /* we already grabbed the initial header earlier.  Just set the offset */

   319       vf->dataoffsets[i]=dataoffset;

   320       _seek_helper(vf,dataoffset);

   321 

   322     }else{

   323 

   324       /* seek to the location of the initial header */

   325 

   326       _seek_helper(vf,vf->offsets[i]);

   327       if(_fetch_headers(vf,vf->vi+i,vf->vc+i,NULL,NULL)<0){

   328     	vf->dataoffsets[i]=-1;

   329       }else{

   330 	vf->dataoffsets[i]=vf->offset;

   331       }

   332     }

   333 

   334     /* fetch beginning PCM offset */

   335 

   336     if(vf->dataoffsets[i]!=-1){

   337       ogg_int64_t accumulated=0,pos;

   338       long        lastblock=-1;

   339       int         result;

   340 

   341       ogg_stream_reset_serialno(vf->os,vf->serialnos[i]);

   342 

   343       while(1){

   344 	ogg_packet op={0,0,0,0,0,0};

   345 

   346 	ret=_get_next_page(vf,&og,-1);

   347 	if(ret<0)

   348 	  /* this should not be possible unless the file is

   349              truncated/mangled */

   350 	  break;

   351        

   352 	if(ogg_page_serialno(&og)!=vf->serialnos[i])

   353 	  break;

   354 	

   355 	pos=ogg_page_granulepos(&og);

   356 

   357 	/* count blocksizes of all frames in the page */

   358 	ogg_stream_pagein(vf->os,&og);

   359 	while((result=ogg_stream_packetout(vf->os,&op))){

   360 	  if(result>0){ /* ignore holes */

   361 	    long thisblock=vorbis_packet_blocksize(vf->vi+i,&op);

   362 	    if(lastblock!=-1)

   363 	      accumulated+=(lastblock+thisblock)>>2;

   364 	    lastblock=thisblock;

   365 	  }

   366 	}

   367 	ogg_packet_release(&op);

   368 

   369 	if(pos!=-1){

   370 	  /* pcm offset of last packet on the first audio page */

   371 	  accumulated= pos-accumulated;

   372 	  break;

   373 	}

   374       }

   375 

   376       /* less than zero?  This is a stream with samples trimmed off

   377          the beginning, a normal occurrence; set the offset to zero */

   378       if(accumulated<0)accumulated=0;

   379 

   380       vf->pcmlengths[i*2]=accumulated;

   381     }

   382 

   383     /* get the PCM length of this link. To do this,

   384        get the last page of the stream */

   385     {

   386       ogg_int64_t end=vf->offsets[i+1];

   387       _seek_helper(vf,end);

   388 

   389       while(1){

   390 	ret=_get_prev_page(vf,&og);

   391 	if(ret<0){

   392 	  /* this should not be possible */

   393 	  vorbis_info_clear(vf->vi+i);

   394 	  vorbis_comment_clear(vf->vc+i);

   395 	  break;

   396 	}

   397 	if(ogg_page_granulepos(&og)!=-1){

   398 	  vf->pcmlengths[i*2+1]=ogg_page_granulepos(&og)-vf->pcmlengths[i*2];

   399 	  break;

   400 	}

   401 	vf->offset=ret;

   402       }

   403     }

   404   }

   405   ogg_page_release(&og);

   406 }

   407 

   408 static void _make_decode_ready(OggVorbis_File *vf){

   409   if(vf->ready_state!=STREAMSET)return;

   410   if(vf->seekable){

   411     vorbis_synthesis_init(&vf->vd,vf->vi+vf->current_link);

   412   }else{

   413     vorbis_synthesis_init(&vf->vd,vf->vi);

   414   }    

   415   vorbis_block_init(&vf->vd,&vf->vb);

   416   vf->ready_state=INITSET;

   417   vf->bittrack=0;

   418   vf->samptrack=0;

   419   return;

   420 }

   421 

   422 static int _open_seekable2(OggVorbis_File *vf){

   423   ogg_uint32_t serialno=vf->current_serialno;

   424   ogg_uint32_t tempserialno;

   425   ogg_int64_t dataoffset=vf->offset, end;

   426   ogg_page og={0,0,0,0};

   427 

   428   /* we're partially open and have a first link header state in

   429      storage in vf */

   430   /* we can seek, so set out learning all about this file */

   431   (vf->callbacks.seek_func)(vf->datasource,0,SEEK_END);

   432   vf->offset=vf->end=(vf->callbacks.tell_func)(vf->datasource);

   433   

   434   /* We get the offset for the last page of the physical bitstream.

   435      Most OggVorbis files will contain a single logical bitstream */

   436   end=_get_prev_page(vf,&og);

   437   if(end<0)return(end);

   438 

   439   /* more than one logical bitstream? */

   440   tempserialno=ogg_page_serialno(&og);

   441   ogg_page_release(&og);

   442 

   443   if(tempserialno!=serialno){

   444 

   445     /* Chained bitstream. Bisect-search each logical bitstream

   446        section.  Do so based on serial number only */

   447     if(_bisect_forward_serialno(vf,0,0,end+1,serialno,0)<0)return(OV_EREAD);

   448 

   449   }else{

   450 

   451     /* Only one logical bitstream */

   452     if(_bisect_forward_serialno(vf,0,end,end+1,serialno,0))return(OV_EREAD);

   453 

   454   }

   455 

   456   /* the initial header memory is referenced by vf after; don't free it */

   457   _prefetch_all_headers(vf,dataoffset);

   458   return(ov_raw_seek(vf,0));

   459 }

   460 

   461 /* clear out the current logical bitstream decoder */ 

   462 static void _decode_clear(OggVorbis_File *vf){

   463   vorbis_dsp_clear(&vf->vd);

   464   vorbis_block_clear(&vf->vb);

   465   vf->ready_state=OPENED;

   466 }

   467 

   468 /* fetch and process a packet.  Handles the case where we're at a

   469    bitstream boundary and dumps the decoding machine.  If the decoding

   470    machine is unloaded, it loads it.  It also keeps pcm_offset up to

   471    date (seek and read both use this.  seek uses a special hack with

   472    readp). 

   473 

   474    return: <0) error, OV_HOLE (lost packet) or OV_EOF

   475             0) need more data (only if readp==0)

   476 	    1) got a packet 

   477 */

   478 

   479 static int _fetch_and_process_packet(OggVorbis_File *vf,

   480 				     int readp,

   481 				     int spanp){

   482   ogg_page og={0,0,0,0};

   483   ogg_packet op={0,0,0,0,0,0};

   484   int ret=0;

   485 

   486   /* handle one packet.  Try to fetch it from current stream state */

   487   /* extract packets from page */

   488   while(1){

   489     

   490     /* process a packet if we can.  If the machine isn't loaded,

   491        neither is a page */

   492     if(vf->ready_state==INITSET){

   493       while(1) {

   494 	int result=ogg_stream_packetout(vf->os,&op);

   495 	ogg_int64_t granulepos;

   496 

   497 	if(result<0){

   498 	  ret=OV_HOLE; /* hole in the data. */

   499 	  goto cleanup;

   500 	}

   501 	if(result>0){

   502 	  /* got a packet.  process it */

   503 	  granulepos=op.granulepos;

   504 	  if(!vorbis_synthesis(&vf->vb,&op,1)){ /* lazy check for lazy

   505 						      header handling.  The

   506 						      header packets aren't

   507 						      audio, so if/when we

   508 						      submit them,

   509 						      vorbis_synthesis will

   510 						      reject them */

   511 

   512 	    /* suck in the synthesis data and track bitrate */

   513 	    {

   514 	      int oldsamples=vorbis_synthesis_pcmout(&vf->vd,NULL);

   515 	      /* for proper use of libvorbis within libvorbisfile,

   516                  oldsamples will always be zero. */

   517 	      if(oldsamples){

   518 		ret=OV_EFAULT;

   519 		goto cleanup;

   520 	      }

   521 

   522 	      vorbis_synthesis_blockin(&vf->vd,&vf->vb);

   523 	      vf->samptrack+=vorbis_synthesis_pcmout(&vf->vd,NULL)-oldsamples;

   524 	      vf->bittrack+=op.bytes*8;

   525 	    }

   526 	  

   527 	    /* update the pcm offset. */

   528 	    if(granulepos!=-1 && !op.e_o_s){

   529 	      int link=(vf->seekable?vf->current_link:0);

   530 	      int i,samples;

   531 	    

   532 	      /* this packet has a pcm_offset on it (the last packet

   533 	         completed on a page carries the offset) After processing

   534 	         (above), we know the pcm position of the *last* sample

   535 	         ready to be returned. Find the offset of the *first*

   536 

   537 	         As an aside, this trick is inaccurate if we begin

   538 	         reading anew right at the last page; the end-of-stream

   539 	         granulepos declares the last frame in the stream, and the

   540 	         last packet of the last page may be a partial frame.

   541 	         So, we need a previous granulepos from an in-sequence page

   542 	         to have a reference point.  Thus the !op.e_o_s clause

   543 	         above */

   544 

   545 	      if(vf->seekable && link>0)

   546 		granulepos-=vf->pcmlengths[link*2];

   547 	      if(granulepos<0)granulepos=0; /* actually, this

   548 					       shouldn't be possible

   549 					       here unless the stream

   550 					       is very broken */

   551 

   552 	      samples=vorbis_synthesis_pcmout(&vf->vd,NULL);

   553 	    

   554 	      granulepos-=samples;

   555 	      for(i=0;i<link;i++)

   556 	        granulepos+=vf->pcmlengths[i*2+1];

   557 	      vf->pcm_offset=granulepos;

   558 	    }

   559 	    ret=1;

   560 	    goto cleanup;

   561 	  }

   562 	}

   563 	else 

   564 	  break;

   565       }

   566     }

   567 

   568     if(vf->ready_state>=OPENED){

   569       int ret;

   570       if(!readp){

   571 	ret=0;

   572 	goto cleanup;

   573       }

   574       if((ret=_get_next_page(vf,&og,-1))<0){

   575 	ret=OV_EOF; /* eof. leave unitialized */

   576 	goto cleanup;

   577       }

   578 

   579 	/* bitrate tracking; add the header's bytes here, the body bytes

   580 	   are done by packet above */

   581       vf->bittrack+=og.header_len*8;

   582       

   583       /* has our decoding just traversed a bitstream boundary? */

   584       if(vf->ready_state==INITSET){

   585 	if(vf->current_serialno!=ogg_page_serialno(&og)){

   586 	  if(!spanp){

   587 	    ret=OV_EOF;

   588 	    goto cleanup;

   589 	  }

   590 

   591 	  _decode_clear(vf);

   592 	  

   593 	  if(!vf->seekable){

   594 	    vorbis_info_clear(vf->vi);

   595 	    vorbis_comment_clear(vf->vc);

   596 	  }

   597 	}

   598       }

   599     }

   600 

   601     /* Do we need to load a new machine before submitting the page? */

   602     /* This is different in the seekable and non-seekable cases.  

   603 

   604        In the seekable case, we already have all the header

   605        information loaded and cached; we just initialize the machine

   606        with it and continue on our merry way.

   607 

   608        In the non-seekable (streaming) case, we'll only be at a

   609        boundary if we just left the previous logical bitstream and

   610        we're now nominally at the header of the next bitstream

   611     */

   612 

   613     if(vf->ready_state!=INITSET){ 

   614       int link;

   615 

   616       if(vf->ready_state<STREAMSET){

   617 	if(vf->seekable){

   618 	  vf->current_serialno=ogg_page_serialno(&og);

   619 	  

   620 	  /* match the serialno to bitstream section.  We use this rather than

   621 	     offset positions to avoid problems near logical bitstream

   622 	     boundaries */

   623 	  for(link=0;link<vf->links;link++)

   624 	    if(vf->serialnos[link]==vf->current_serialno)break;

   625 	  if(link==vf->links){

   626 	    ret=OV_EBADLINK; /* sign of a bogus stream.  error out,

   627 				leave machine uninitialized */

   628 	    goto cleanup;

   629 	  }

   630 	  

   631 	  vf->current_link=link;

   632 	  

   633 	  ogg_stream_reset_serialno(vf->os,vf->current_serialno);

   634 	  vf->ready_state=STREAMSET;

   635 	  

   636 	}else{

   637 	  /* we're streaming */

   638 	  /* fetch the three header packets, build the info struct */

   639 	  

   640 	  int ret=_fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno,&og);

   641 	  if(ret) goto cleanup;

   642 	  vf->current_link++;

   643 	  link=0;

   644 	}

   645       }

   646       

   647       _make_decode_ready(vf);

   648     }

   649     ogg_stream_pagein(vf->os,&og);

   650   }

   651  cleanup:

   652   ogg_packet_release(&op);

   653   ogg_page_release(&og);

   654   return ret;

   655 }

   656 

   657 /* if, eg, 64 bit stdio is configured by default, this will build with

   658    fseek64 */

   659 static int _fseek64_wrap(FILE *f,ogg_int64_t off,int whence){

   660   if(f==NULL)return(-1);

   661   return fseek(f,off,whence);

   662 }

   663 

   664 static int _ov_open1(void *f,OggVorbis_File *vf,char *initial,

   665 		     long ibytes, ov_callbacks callbacks){

   666   int offsettest=(f?callbacks.seek_func(f,0,SEEK_CUR):-1);

   667   int ret;

   668 

   669   memset(vf,0,sizeof(*vf));

   670   vf->datasource=f;

   671   vf->callbacks = callbacks;

   672 

   673   /* init the framing state */

   674   vf->oy=ogg_sync_create();

   675 

   676   /* perhaps some data was previously read into a buffer for testing

   677      against other stream types.  Allow initialization from this

   678      previously read data (as we may be reading from a non-seekable

   679      stream) */

   680   if(initial){

   681     unsigned char *buffer=ogg_sync_bufferin(vf->oy,ibytes);

   682     memcpy(buffer,initial,ibytes);

   683     ogg_sync_wrote(vf->oy,ibytes);

   684   }

   685 

   686   /* can we seek? Stevens suggests the seek test was portable */

   687   if(offsettest!=-1)vf->seekable=1;

   688 

   689   /* No seeking yet; Set up a 'single' (current) logical bitstream

   690      entry for partial open */

   691   vf->links=1;

   692   vf->vi=_ogg_calloc(vf->links,sizeof(*vf->vi));

   693   vf->vc=_ogg_calloc(vf->links,sizeof(*vf->vc));

   694   vf->os=ogg_stream_create(-1); /* fill in the serialno later */

   695 

   696   /* Try to fetch the headers, maintaining all the storage */

   697   if((ret=_fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno,NULL))<0){

   698     vf->datasource=NULL;

   699     ov_clear(vf);

   700   }else if(vf->ready_state < PARTOPEN)

   701     vf->ready_state=PARTOPEN;

   702   return(ret);

   703 }

   704 

   705 static int _ov_open2(OggVorbis_File *vf){

   706   if(vf->ready_state < OPENED)

   707     vf->ready_state=OPENED;

   708   if(vf->seekable){

   709     int ret=_open_seekable2(vf);

   710     if(ret){

   711       vf->datasource=NULL;

   712       ov_clear(vf);

   713     }

   714     return(ret);

   715   }

   716   return 0;

   717 }

   718 

   719 

   720 /* clear out the OggVorbis_File struct */

   721 int ov_clear(OggVorbis_File *vf){

   722   if(vf){

   723     vorbis_block_clear(&vf->vb);

   724     vorbis_dsp_clear(&vf->vd);

   725     ogg_stream_destroy(vf->os);

   726     

   727     if(vf->vi && vf->links){

   728       int i;

   729       for(i=0;i<vf->links;i++){

   730 	vorbis_info_clear(vf->vi+i);

   731 	vorbis_comment_clear(vf->vc+i);

   732       }

   733       _ogg_free(vf->vi);

   734       _ogg_free(vf->vc);

   735     }

   736     if(vf->dataoffsets)_ogg_free(vf->dataoffsets);

   737     if(vf->pcmlengths)_ogg_free(vf->pcmlengths);

   738     if(vf->serialnos)_ogg_free(vf->serialnos);

   739     if(vf->offsets)_ogg_free(vf->offsets);

   740     ogg_sync_destroy(vf->oy);

   741 

   742     if(vf->datasource)(vf->callbacks.close_func)(vf->datasource);

   743     memset(vf,0,sizeof(*vf));

   744   }

   745 #ifdef DEBUG_LEAKS

   746   _VDBG_dump();

   747 #endif

   748   return(0);

   749 }

   750 

   751 /* inspects the OggVorbis file and finds/documents all the logical

   752    bitstreams contained in it.  Tries to be tolerant of logical

   753    bitstream sections that are truncated/woogie. 

   754 

   755    return: -1) error

   756             0) OK

   757 */

   758 

   759 int ov_open_callbacks(void *f,OggVorbis_File *vf,char *initial,long ibytes,

   760     ov_callbacks callbacks){

   761   int ret=_ov_open1(f,vf,initial,ibytes,callbacks);

   762   if(ret)return ret;

   763   return _ov_open2(vf);

   764 }

   765 

   766 int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){

   767   ov_callbacks callbacks = {

   768     (size_t (*)(void *, size_t, size_t, void *))  fread,

   769     (int (*)(void *, ogg_int64_t, int))              _fseek64_wrap,

   770     (int (*)(void *))                             fclose,

   771     (long (*)(void *))                            ftell

   772   };

   773 

   774   return ov_open_callbacks((void *)f, vf, initial, ibytes, callbacks);

   775 }

   776   

   777 /* Only partially open the vorbis file; test for Vorbisness, and load

   778    the headers for the first chain.  Do not seek (although test for

   779    seekability).  Use ov_test_open to finish opening the file, else

   780    ov_clear to close/free it. Same return codes as open. */

   781 

   782 int ov_test_callbacks(void *f,OggVorbis_File *vf,char *initial,long ibytes,

   783     ov_callbacks callbacks)

   784 {

   785   return _ov_open1(f,vf,initial,ibytes,callbacks);

   786 }

   787 

   788 int ov_test(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){

   789   ov_callbacks callbacks = {

   790     (size_t (*)(void *, size_t, size_t, void *))  fread,

   791     (int (*)(void *, ogg_int64_t, int))              _fseek64_wrap,

   792     (int (*)(void *))                             fclose,

   793     (long (*)(void *))                            ftell

   794   };

   795 

   796   return ov_test_callbacks((void *)f, vf, initial, ibytes, callbacks);

   797 }

   798   

   799 int ov_test_open(OggVorbis_File *vf){

   800   if(vf->ready_state!=PARTOPEN)return(OV_EINVAL);

   801   return _ov_open2(vf);

   802 }

   803 

   804 /* How many logical bitstreams in this physical bitstream? */

   805 long ov_streams(OggVorbis_File *vf){

   806   return vf->links;

   807 }

   808 

   809 /* Is the FILE * associated with vf seekable? */

   810 long ov_seekable(OggVorbis_File *vf){

   811   return vf->seekable;

   812 }

   813 

   814 /* returns the bitrate for a given logical bitstream or the entire

   815    physical bitstream.  If the file is open for random access, it will

   816    find the *actual* average bitrate.  If the file is streaming, it

   817    returns the nominal bitrate (if set) else the average of the

   818    upper/lower bounds (if set) else -1 (unset).

   819 

   820    If you want the actual bitrate field settings, get them from the

   821    vorbis_info structs */

   822 

   823 long ov_bitrate(OggVorbis_File *vf,int i){

   824   if(vf->ready_state<OPENED)return(OV_EINVAL);

   825   if(i>=vf->links)return(OV_EINVAL);

   826   if(!vf->seekable && i!=0)return(ov_bitrate(vf,0));

   827   if(i<0){

   828     ogg_int64_t bits=0;

   829     int i;

   830     for(i=0;i<vf->links;i++)

   831       bits+=(vf->offsets[i+1]-vf->dataoffsets[i])*8;

   832     /* This once read: return(rint(bits/ov_time_total(vf,-1)));

   833      * gcc 3.x on x86 miscompiled this at optimisation level 2 and above,

   834      * so this is slightly transformed to make it work.

   835      */

   836     return(bits*1000/ov_time_total(vf,-1));

   837   }else{

   838     if(vf->seekable){

   839       /* return the actual bitrate */

   840       return((vf->offsets[i+1]-vf->dataoffsets[i])*8000/ov_time_total(vf,i));

   841     }else{

   842       /* return nominal if set */

   843       if(vf->vi[i].bitrate_nominal>0){

   844 	return vf->vi[i].bitrate_nominal;

   845       }else{

   846 	if(vf->vi[i].bitrate_upper>0){

   847 	  if(vf->vi[i].bitrate_lower>0){

   848 	    return (vf->vi[i].bitrate_upper+vf->vi[i].bitrate_lower)/2;

   849 	  }else{

   850 	    return vf->vi[i].bitrate_upper;

   851 	  }

   852 	}

   853 	return(OV_FALSE);

   854       }

   855     }

   856   }

   857 }

   858 

   859 /* returns the actual bitrate since last call.  returns -1 if no

   860    additional data to offer since last call (or at beginning of stream),

   861    EINVAL if stream is only partially open 

   862 */

   863 long ov_bitrate_instant(OggVorbis_File *vf){

   864   int link=(vf->seekable?vf->current_link:0);

   865   long ret;

   866   if(vf->ready_state<OPENED)return(OV_EINVAL);

   867   if(vf->samptrack==0)return(OV_FALSE);

   868   ret=vf->bittrack/vf->samptrack*vf->vi[link].rate;

   869   vf->bittrack=0;

   870   vf->samptrack=0;

   871   return(ret);

   872 }

   873 

   874 /* Guess */

   875 long ov_serialnumber(OggVorbis_File *vf,int i){

   876   if(i>=vf->links)return(ov_serialnumber(vf,vf->links-1));

   877   if(!vf->seekable && i>=0)return(ov_serialnumber(vf,-1));

   878   if(i<0){

   879     return(vf->current_serialno);

   880   }else{

   881     return(vf->serialnos[i]);

   882   }

   883 }

   884 

   885 /* returns: total raw (compressed) length of content if i==-1

   886             raw (compressed) length of that logical bitstream for i==0 to n

   887 	    OV_EINVAL if the stream is not seekable (we can't know the length)

   888 	    or if stream is only partially open

   889 */

   890 ogg_int64_t ov_raw_total(OggVorbis_File *vf,int i){

   891   if(vf->ready_state<OPENED)return(OV_EINVAL);

   892   if(!vf->seekable || i>=vf->links)return(OV_EINVAL);

   893   if(i<0){

   894     ogg_int64_t acc=0;

   895     int i;

   896     for(i=0;i<vf->links;i++)

   897       acc+=ov_raw_total(vf,i);

   898     return(acc);

   899   }else{

   900     return(vf->offsets[i+1]-vf->offsets[i]);

   901   }

   902 }

   903 

   904 /* returns: total PCM length (samples) of content if i==-1 PCM length

   905 	    (samples) of that logical bitstream for i==0 to n

   906 	    OV_EINVAL if the stream is not seekable (we can't know the

   907 	    length) or only partially open 

   908 */

   909 ogg_int64_t ov_pcm_total(OggVorbis_File *vf,int i){

   910   if(vf->ready_state<OPENED)return(OV_EINVAL);

   911   if(!vf->seekable || i>=vf->links)return(OV_EINVAL);

   912   if(i<0){

   913     ogg_int64_t acc=0;

   914     int i;

   915     for(i=0;i<vf->links;i++)

   916       acc+=ov_pcm_total(vf,i);

   917     return(acc);

   918   }else{

   919     return(vf->pcmlengths[i*2+1]);

   920   }

   921 }

   922 

   923 /* returns: total milliseconds of content if i==-1

   924             milliseconds in that logical bitstream for i==0 to n

   925 	    OV_EINVAL if the stream is not seekable (we can't know the

   926 	    length) or only partially open 

   927 */

   928 ogg_int64_t ov_time_total(OggVorbis_File *vf,int i){

   929   if(vf->ready_state<OPENED)return(OV_EINVAL);

   930   if(!vf->seekable || i>=vf->links)return(OV_EINVAL);

   931   if(i<0){

   932     ogg_int64_t acc=0;

   933     int i;

   934     for(i=0;i<vf->links;i++)

   935       acc+=ov_time_total(vf,i);

   936     return(acc);

   937   }else{

   938     return(((ogg_int64_t)vf->pcmlengths[i*2+1])*1000/vf->vi[i].rate);

   939   }

   940 }

   941 

   942 /* seek to an offset relative to the *compressed* data. This also

   943    scans packets to update the PCM cursor. It will cross a logical

   944    bitstream boundary, but only if it can't get any packets out of the

   945    tail of the bitstream we seek to (so no surprises).

   946 

   947    returns zero on success, nonzero on failure */

   948 

   949 int ov_raw_seek(OggVorbis_File *vf,ogg_int64_t pos){

   950   ogg_stream_state *work_os=NULL;

   951   ogg_page og={0,0,0,0};

   952   ogg_packet op={0,0,0,0,0,0};

   953   

   954   if(vf->ready_state<OPENED)return(OV_EINVAL);

   955   if(!vf->seekable)

   956     return(OV_ENOSEEK); /* don't dump machine if we can't seek */

   957 

   958   if(pos<0 || pos>vf->end)return(OV_EINVAL);

   959 

   960   /* don't yet clear out decoding machine (if it's initialized), in

   961      the case we're in the same link.  Restart the decode lapping, and

   962      let _fetch_and_process_packet deal with a potential bitstream

   963      boundary */

   964   vf->pcm_offset=-1;

   965   ogg_stream_reset_serialno(vf->os,

   966 			    vf->current_serialno); /* must set serialno */

   967   vorbis_synthesis_restart(&vf->vd);

   968     

   969   _seek_helper(vf,pos);

   970 

   971   /* we need to make sure the pcm_offset is set, but we don't want to

   972      advance the raw cursor past good packets just to get to the first

   973      with a granulepos.  That's not equivalent behavior to beginning

   974      decoding as immediately after the seek position as possible.

   975 

   976      So, a hack.  We use two stream states; a local scratch state and

   977      the shared vf->os stream state.  We use the local state to

   978      scan, and the shared state as a buffer for later decode. 

   979 

   980      Unfortuantely, on the last page we still advance to last packet

   981      because the granulepos on the last page is not necessarily on a

   982      packet boundary, and we need to make sure the granpos is

   983      correct. 

   984   */

   985 

   986   {

   987     int lastblock=0;

   988     int accblock=0;

   989     int thisblock;

   990     int eosflag=0;

   991 

   992     work_os=ogg_stream_create(vf->current_serialno); /* get the memory ready */

   993     while(1){

   994       if(vf->ready_state>=STREAMSET){

   995 	/* snarf/scan a packet if we can */

   996 	int result=ogg_stream_packetout(work_os,&op);

   997       

   998 	if(result>0){

   999 

  1000 	  if(vf->vi[vf->current_link].codec_setup){

  1001 	    thisblock=vorbis_packet_blocksize(vf->vi+vf->current_link,&op);

  1002 	    if(thisblock<0){

  1003 	      ogg_stream_packetout(vf->os,NULL);

  1004 	      thisblock=0;

  1005 	    }else{

  1006 	      

  1007 	      if(eosflag)

  1008 		ogg_stream_packetout(vf->os,NULL);

  1009 	      else

  1010 		if(lastblock)accblock+=(lastblock+thisblock)>>2;

  1011 	    }	    

  1012 

  1013 	    if(op.granulepos!=-1){

  1014 	      int i,link=vf->current_link;

  1015 	      ogg_int64_t granulepos=op.granulepos-vf->pcmlengths[link*2];

  1016 	      if(granulepos<0)granulepos=0;

  1017 	      

  1018 	      for(i=0;i<link;i++)

  1019 		granulepos+=vf->pcmlengths[i*2+1];

  1020 	      vf->pcm_offset=granulepos-accblock;

  1021 	      break;

  1022 	    }

  1023 	    lastblock=thisblock;

  1024 	    continue;

  1025 	  }else

  1026 	    ogg_stream_packetout(vf->os,NULL);

  1027 	}

  1028       }

  1029       

  1030       if(!lastblock){

  1031 	if(_get_next_page(vf,&og,-1)<0){

  1032 	  vf->pcm_offset=ov_pcm_total(vf,-1);

  1033 	  break;

  1034 	}

  1035       }else{

  1036 	/* huh?  Bogus stream with packets but no granulepos */

  1037 	vf->pcm_offset=-1;

  1038 	break;

  1039       }

  1040       

  1041       /* has our decoding just traversed a bitstream boundary? */

  1042       if(vf->ready_state>=STREAMSET)

  1043 	if(vf->current_serialno!=ogg_page_serialno(&og)){

  1044 	  _decode_clear(vf); /* clear out stream state */

  1045 	  ogg_stream_destroy(work_os);

  1046 	}

  1047 

  1048       if(vf->ready_state<STREAMSET){

  1049 	int link;

  1050 	

  1051 	vf->current_serialno=ogg_page_serialno(&og);

  1052 	for(link=0;link<vf->links;link++)

  1053 	  if(vf->serialnos[link]==vf->current_serialno)break;

  1054 	if(link==vf->links)

  1055 	  goto seek_error; /* sign of a bogus stream.  error out,

  1056 			      leave machine uninitialized */

  1057  

  1058 	vf->current_link=link;

  1059 	

  1060 	ogg_stream_reset_serialno(vf->os,vf->current_serialno);

  1061 	ogg_stream_reset_serialno(work_os,vf->current_serialno); 

  1062 	vf->ready_state=STREAMSET;

  1063 	

  1064       }

  1065     

  1066       {

  1067 	ogg_page dup;

  1068 	ogg_page_dup(&dup,&og);

  1069 	eosflag=ogg_page_eos(&og);

  1070 	ogg_stream_pagein(vf->os,&og);

  1071 	ogg_stream_pagein(work_os,&dup);

  1072       }

  1073     }

  1074   }

  1075 

  1076   ogg_packet_release(&op);

  1077   ogg_page_release(&og);

  1078   ogg_stream_destroy(work_os);

  1079   vf->bittrack=0;

  1080   vf->samptrack=0;

  1081   return(0);

  1082 

  1083  seek_error:

  1084   ogg_packet_release(&op);

  1085   ogg_page_release(&og);

  1086 

  1087   /* dump the machine so we're in a known state */

  1088   vf->pcm_offset=-1;

  1089   ogg_stream_destroy(work_os);

  1090   _decode_clear(vf);

  1091   return OV_EBADLINK;

  1092 }

  1093 

  1094 /* Page granularity seek (faster than sample granularity because we

  1095    don't do the last bit of decode to find a specific sample).

  1096 

  1097    Seek to the last [granule marked] page preceeding the specified pos

  1098    location, such that decoding past the returned point will quickly

  1099    arrive at the requested position. */

  1100 int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){

  1101   int link=-1;

  1102   ogg_int64_t result=0;

  1103   ogg_int64_t total=ov_pcm_total(vf,-1);

  1104   ogg_page og={0,0,0,0};

  1105   ogg_packet op={0,0,0,0,0,0};

  1106 

  1107   if(vf->ready_state<OPENED)return(OV_EINVAL);

  1108   if(!vf->seekable)return(OV_ENOSEEK);

  1109   if(pos<0 || pos>total)return(OV_EINVAL);

  1110  

  1111   /* which bitstream section does this pcm offset occur in? */

  1112   for(link=vf->links-1;link>=0;link--){

  1113     total-=vf->pcmlengths[link*2+1];

  1114     if(pos>=total)break;

  1115   }

  1116 

  1117   /* search within the logical bitstream for the page with the highest

  1118      pcm_pos preceeding (or equal to) pos.  There is a danger here;

  1119      missing pages or incorrect frame number information in the

  1120      bitstream could make our task impossible.  Account for that (it

  1121      would be an error condition) */

  1122 

  1123   /* new search algorithm by HB (Nicholas Vinen) */

  1124   {

  1125     ogg_int64_t end=vf->offsets[link+1];

  1126     ogg_int64_t begin=vf->offsets[link];

  1127     ogg_int64_t begintime = vf->pcmlengths[link*2];

  1128     ogg_int64_t endtime = vf->pcmlengths[link*2+1]+begintime;

  1129     ogg_int64_t target=pos-total+begintime;

  1130     ogg_int64_t best=begin;

  1131     

  1132     while(begin<end){

  1133       ogg_int64_t bisect;

  1134