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- /********************************************************************
- * *
- * THIS FILE IS PART OF THE Ogg Vorbis SOFTWARE CODEC SOURCE CODE. *
- * USE, DISTRIBUTION AND REPRODUCTION OF THIS SOURCE IS GOVERNED BY *
- * THE GNU PUBLIC LICENSE 2, WHICH IS INCLUDED WITH THIS SOURCE. *
- * PLEASE READ THESE TERMS DISTRIBUTING. *
- * *
- * THE OggSQUISH SOURCE CODE IS (C) COPYRIGHT 1994-2000 *
- * by Monty <monty@xiph.org> and The XIPHOPHORUS Company *
- * http://www.xiph.org/ *
- * *
- ********************************************************************
- function: stdio-based convenience library for opening/seeking/decoding
- last mod: $Id: vorbisfile.c,v 1.15.4.1 2000/04/06 15:59:37 xiphmont Exp $
- ********************************************************************/
- #include <stdlib.h>
- #include <stdio.h>
- #include <string.h>
- #include <math.h>
- #include "vorbis/codec.h"
- #include "vorbis/vorbisfile.h"
- #include "os.h"
- #include "misc.h"
- /* A 'chained bitstream' is a Vorbis bitstream that contains more than
- one logical bitstream arranged end to end (the only form of Ogg
- multiplexing allowed in a Vorbis bitstream; grouping [parallel
- multiplexing] is not allowed in Vorbis) */
- /* A Vorbis file can be played beginning to end (streamed) without
- worrying ahead of time about chaining (see decoder_example.c). If
- we have the whole file, however, and want random access
- (seeking/scrubbing) or desire to know the total length/time of a
- file, we need to account for the possibility of chaining. */
- /* We can handle things a number of ways; we can determine the entire
- bitstream structure right off the bat, or find pieces on demand.
- This example determines and caches structure for the entire
- bitstream, but builds a virtual decoder on the fly when moving
- between links in the chain. */
- /* There are also different ways to implement seeking. Enough
- information exists in an Ogg bitstream to seek to
- sample-granularity positions in the output. Or, one can seek by
- picking some portion of the stream roughly in the desired area if
- we only want course navigation through the stream. */
- /*************************************************************************
- * Many, many internal helpers. The intention is not to be confusing;
- * rampant duplication and monolithic function implementation would be
- * harder to understand anyway. The high level functions are last. Begin
- * grokking near the end of the file */
- /* read a little more data from the file/pipe into the ogg_sync framer */
- #define CHUNKSIZE 4096
- static long _get_data(OggVorbis_File *vf){
- char *buffer=ogg_sync_buffer(&vf->oy,4096);
- long bytes=fread(buffer,1,4096,vf->f);
- ogg_sync_wrote(&vf->oy,bytes);
- return(bytes);
- }
- /* save a tiny smidge of verbosity to make the code more readable */
- static void _seek_helper(OggVorbis_File *vf,long offset){
- fseek(vf->f,offset,SEEK_SET);
- vf->offset=offset;
- ogg_sync_reset(&vf->oy);
- }
- /* The read/seek functions track absolute position within the stream */
- /* from the head of the stream, get the next page. boundary specifies
- if the function is allowed to fetch more data from the stream (and
- how much) or only use internally buffered data.
- boundary: -1) unbounded search
- 0) read no additional data; use cached only
- n) search for a new page beginning for n bytes
- return: -1) did not find a page
- n) found a page at absolute offset n */
- static long _get_next_page(OggVorbis_File *vf,ogg_page *og,int boundary){
- if(boundary>0)boundary+=vf->offset;
- while(1){
- long more;
- if(boundary>0 && vf->offset>=boundary)return(-1);
- more=ogg_sync_pageseek(&vf->oy,og);
-
- if(more<0){
- /* skipped n bytes */
- vf->offset-=more;
- }else{
- if(more==0){
- /* send more paramedics */
- if(!boundary)return(-1);
- if(_get_data(vf)<=0)return(-1);
- }else{
- /* got a page. Return the offset at the page beginning,
- advance the internal offset past the page end */
- long ret=vf->offset;
- vf->offset+=more;
- return(ret);
-
- }
- }
- }
- }
- /* find the latest page beginning before the current stream cursor
- position. Much dirtier than the above as Ogg doesn't have any
- backward search linkage. no 'readp' as it will certainly have to
- read. */
- static long _get_prev_page(OggVorbis_File *vf,ogg_page *og){
- long begin=vf->offset;
- long ret;
- int offset=-1;
- while(offset==-1){
- begin-=CHUNKSIZE;
- _seek_helper(vf,begin);
- while(vf->offset<begin+CHUNKSIZE){
- ret=_get_next_page(vf,og,begin+CHUNKSIZE-vf->offset);
- if(ret==-1){
- break;
- }else{
- offset=ret;
- }
- }
- }
- /* we have the offset. Actually snork and hold the page now */
- _seek_helper(vf,offset);
- ret=_get_next_page(vf,og,CHUNKSIZE);
- if(ret==-1){
- /* this shouldn't be possible */
- fprintf(stderr,"Missed page fencepost at end of logical bitstream. "
- "Exiting.\n");
- exit(1);
- }
- return(offset);
- }
- /* finds each bitstream link one at a time using a bisection search
- (has to begin by knowing the offset of the lb's initial page).
- Recurses for each link so it can alloc the link storage after
- finding them all, then unroll and fill the cache at the same time */
- static void _bisect_forward_serialno(OggVorbis_File *vf,
- long begin,
- long searched,
- long end,
- long currentno,
- long m){
- long endsearched=end;
- long next=end;
- ogg_page og;
- long ret;
-
- /* the below guards against garbage seperating the last and
- first pages of two links. */
- while(searched<endsearched){
- long bisect;
-
- if(endsearched-searched<CHUNKSIZE){
- bisect=searched;
- }else{
- bisect=(searched+endsearched)/2;
- }
-
- _seek_helper(vf,bisect);
- ret=_get_next_page(vf,&og,-1);
- if(ret<0 || ogg_page_serialno(&og)!=currentno){
- endsearched=bisect;
- if(ret>=0)next=ret;
- }else{
- searched=ret+og.header_len+og.body_len;
- }
- }
- _seek_helper(vf,next);
- ret=_get_next_page(vf,&og,-1);
-
- if(searched>=end || ret==-1){
- vf->links=m+1;
- vf->offsets=malloc((m+2)*sizeof(long));
- vf->offsets[m+1]=searched;
- }else{
- _bisect_forward_serialno(vf,next,vf->offset,
- end,ogg_page_serialno(&og),m+1);
- }
-
- vf->offsets[m]=begin;
- }
- /* uses the local ogg_stream storage in vf; this is important for
- non-streaming input sources */
- static int _fetch_headers(OggVorbis_File *vf,vorbis_info *vi,vorbis_comment *vc,
- long *serialno){
- ogg_page og;
- ogg_packet op;
- int i,ret;
- ret=_get_next_page(vf,&og,CHUNKSIZE);
- if(ret==-1){
- fprintf(stderr,"Did not find initial header for bitstream.\n");
- return -1;
- }
-
- if(serialno)*serialno=ogg_page_serialno(&og);
- ogg_stream_init(&vf->os,ogg_page_serialno(&og));
-
- /* extract the initial header from the first page and verify that the
- Ogg bitstream is in fact Vorbis data */
-
- vorbis_info_init(vi);
- vorbis_comment_init(vc);
-
- i=0;
- while(i<3){
- ogg_stream_pagein(&vf->os,&og);
- while(i<3){
- int result=ogg_stream_packetout(&vf->os,&op);
- if(result==0)break;
- if(result==-1){
- fprintf(stderr,"Corrupt header in logical bitstream.\n");
- goto bail_header;
- }
- if(vorbis_synthesis_headerin(vi,vc,&op)){
- fprintf(stderr,"Illegal header in logical bitstream.\n");
- goto bail_header;
- }
- i++;
- }
- if(i<3)
- if(_get_next_page(vf,&og,1)<0){
- fprintf(stderr,"Missing header in logical bitstream.\n");
- goto bail_header;
- }
- }
- return 0;
- bail_header:
- vorbis_info_clear(vi);
- vorbis_comment_clear(vc);
- ogg_stream_clear(&vf->os);
- return -1;
- }
- /* last step of the OggVorbis_File initialization; get all the
- vorbis_info structs and PCM positions. Only called by the seekable
- initialization (local stream storage is hacked slightly; pay
- attention to how that's done) */
- static void _prefetch_all_headers(OggVorbis_File *vf,vorbis_info *first_i,
- vorbis_comment *first_c,
- long dataoffset){
- ogg_page og;
- int i,ret;
-
- vf->vi=calloc(vf->links,sizeof(vorbis_info));
- vf->vc=calloc(vf->links,sizeof(vorbis_info));
- vf->dataoffsets=malloc(vf->links*sizeof(long));
- vf->pcmlengths=malloc(vf->links*sizeof(int64_t));
- vf->serialnos=malloc(vf->links*sizeof(long));
-
- for(i=0;i<vf->links;i++){
- if(first_i && first_c && i==0){
- /* we already grabbed the initial header earlier. This just
- saves the waste of grabbing it again */
- memcpy(vf->vi+i,first_i,sizeof(vorbis_info));
- memcpy(vf->vc+i,first_c,sizeof(vorbis_comment));
- vf->dataoffsets[i]=dataoffset;
- }else{
- /* seek to the location of the initial header */
- _seek_helper(vf,vf->offsets[i]);
- if(_fetch_headers(vf,vf->vi+i,vf->vc+i,NULL)==-1){
- fprintf(stderr,"Error opening logical bitstream #%d.\n\n",i+1);
- vf->dataoffsets[i]=-1;
- }else{
- vf->dataoffsets[i]=vf->offset;
- ogg_stream_clear(&vf->os);
- }
- }
- /* get the serial number and PCM length of this link. To do this,
- get the last page of the stream */
- {
- long end=vf->offsets[i+1];
- _seek_helper(vf,end);
- while(1){
- ret=_get_prev_page(vf,&og);
- if(ret==-1){
- /* this should not be possible */
- fprintf(stderr,"Could not find last page of logical "
- "bitstream #%d\n\n",i);
- vorbis_info_clear(vf->vi+i);
- vorbis_comment_clear(vf->vc+i);
- break;
- }
- if(ogg_page_frameno(&og)!=-1){
- vf->serialnos[i]=ogg_page_serialno(&og);
- vf->pcmlengths[i]=ogg_page_frameno(&og);
- break;
- }
- }
- }
- }
- }
- static int _make_decode_ready(OggVorbis_File *vf){
- if(vf->decode_ready)exit(1);
- vorbis_synthesis_init(&vf->vd,vf->vi);
- vorbis_block_init(&vf->vd,&vf->vb);
- vf->decode_ready=1;
- return(0);
- }
- static int _open_seekable(OggVorbis_File *vf){
- vorbis_info initial_i;
- vorbis_comment initial_c;
- long serialno,end;
- int ret;
- long dataoffset;
- ogg_page og;
-
- /* is this even vorbis...? */
- ret=_fetch_headers(vf,&initial_i,&initial_c,&serialno);
- dataoffset=vf->offset;
- ogg_stream_clear(&vf->os);
- if(ret==-1)return(-1);
-
- /* we can seek, so set out learning all about this file */
- vf->seekable=1;
- fseek(vf->f,0,SEEK_END);
- vf->offset=vf->end=ftell(vf->f);
-
- /* We get the offset for the last page of the physical bitstream.
- Most OggVorbis files will contain a single logical bitstream */
- end=_get_prev_page(vf,&og);
- /* moer than one logical bitstream? */
- if(ogg_page_serialno(&og)!=serialno){
- /* Chained bitstream. Bisect-search each logical bitstream
- section. Do so based on serial number only */
- _bisect_forward_serialno(vf,0,0,end+1,serialno,0);
- }else{
- /* Only one logical bitstream */
- _bisect_forward_serialno(vf,0,end,end+1,serialno,0);
- }
- _prefetch_all_headers(vf,&initial_i,&initial_c,dataoffset);
- ov_raw_seek(vf,0);
- return(0);
- }
- static int _open_nonseekable(OggVorbis_File *vf){
- /* we cannot seek. Set up a 'single' (current) logical bitstream entry */
- vf->links=1;
- vf->vi=malloc(sizeof(vorbis_info));
- vf->vc=malloc(sizeof(vorbis_info));
- /* Try to fetch the headers, maintaining all the storage */
- if(_fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno)==-1)return(-1);
- _make_decode_ready(vf);
- return 0;
- }
- /* clear out the current logical bitstream decoder */
- static void _decode_clear(OggVorbis_File *vf){
- ogg_stream_clear(&vf->os);
- vorbis_dsp_clear(&vf->vd);
- vorbis_block_clear(&vf->vb);
- vf->pcm_offset=-1;
- vf->decode_ready=0;
- }
- /* fetch and process a packet. Handles the case where we're at a
- bitstream boundary and dumps the decoding machine. If the decoding
- machine is unloaded, it loads it. It also keeps pcm_offset up to
- date (seek and read both use this. seek uses a special hack with
- readp).
- return: -1) hole in the data (lost packet)
- 0) need more date (only if readp==0)/eof
- 1) got a packet
- */
- static int _process_packet(OggVorbis_File *vf,int readp){
- ogg_page og;
- /* handle one packet. Try to fetch it from current stream state */
- /* extract packets from page */
- while(1){
-
- /* process a packet if we can. If the machine isn't loaded,
- neither is a page */
- if(vf->decode_ready){
- ogg_packet op;
- int result=ogg_stream_packetout(&vf->os,&op);
- int64_t frameno;
-
- if(result==-1)return(-1); /* hole in the data. alert the toplevel */
- if(result>0){
- /* got a packet. process it */
- frameno=op.frameno;
- if(!vorbis_synthesis(&vf->vb,&op)){ /* lazy check for lazy
- header handling. The
- header packets aren't
- audio, so if/when we
- submit them,
- vorbis_synthesis will
- reject them */
- vorbis_synthesis_blockin(&vf->vd,&vf->vb);
-
- /* update the pcm offset. */
- if(frameno!=-1){
- int link=(vf->seekable?vf->current_link:0);
- double **dummy;
- int i,samples;
-
- /* this packet has a pcm_offset on it (the last packet
- completed on a page carries the offset) After processing
- (above), we know the pcm position of the *last* sample
- ready to be returned. Find the offset of the *first* */
-
- samples=vorbis_synthesis_pcmout(&vf->vd,&dummy);
-
- frameno-=samples;
- for(i=0;i<link;i++)
- frameno+=vf->pcmlengths[i];
- vf->pcm_offset=frameno;
- }
- return(1);
- }
- }
- }
- if(!readp)return(0);
- if(_get_next_page(vf,&og,-1)<0)return(0); /* eof. leave unitialized */
- /* has our decoding just traversed a bitstream boundary? */
- if(vf->decode_ready){
- if(vf->current_serialno!=ogg_page_serialno(&og)){
- _decode_clear(vf);
- }
- }
- /* Do we need to load a new machine before submitting the page? */
- /* This is different in the seekable and non-seekable cases.
- In the seekable case, we already have all the header
- information loaded and cached; we just initialize the machine
- with it and continue on our merry way.
- In the non-seekable (streaming) case, we'll only be at a
- boundary if we just left the previous logical bitstream and
- we're now nominally at the header of the next bitstream
- */
- if(!vf->decode_ready){
- int link;
- if(vf->seekable){
- vf->current_serialno=ogg_page_serialno(&og);
-
- /* match the serialno to bitstream section. We use this rather than
- offset positions to avoid problems near logical bitstream
- boundaries */
- for(link=0;link<vf->links;link++)
- if(vf->serialnos[link]==vf->current_serialno)break;
- if(link==vf->links)return(-1); /* sign of a bogus stream. error out,
- leave machine uninitialized */
-
- vf->current_link=link;
- ogg_stream_init(&vf->os,vf->current_serialno);
- ogg_stream_reset(&vf->os);
- }else{
- /* we're streaming */
- /* fetch the three header packets, build the info struct */
-
- _fetch_headers(vf,vf->vi,vf->vc,&vf->current_serialno);
- vf->current_link++;
- link=0;
- }
-
- _make_decode_ready(vf);
- }
- ogg_stream_pagein(&vf->os,&og);
- }
- }
- /**********************************************************************
- * The helpers are over; it's all toplevel interface from here on out */
-
- /* clear out the OggVorbis_File struct */
- int ov_clear(OggVorbis_File *vf){
- if(vf){
- vorbis_block_clear(&vf->vb);
- vorbis_dsp_clear(&vf->vd);
- ogg_stream_clear(&vf->os);
-
- if(vf->vi && vf->links){
- int i;
- for(i=0;i<vf->links;i++){
- vorbis_info_clear(vf->vi+i);
- vorbis_comment_clear(vf->vc+i);
- }
- free(vf->vi);
- free(vf->vc);
- }
- if(vf->dataoffsets)free(vf->dataoffsets);
- if(vf->pcmlengths)free(vf->pcmlengths);
- if(vf->serialnos)free(vf->serialnos);
- if(vf->offsets)free(vf->offsets);
- ogg_sync_clear(&vf->oy);
- if(vf->f)fclose(vf->f);
- memset(vf,0,sizeof(OggVorbis_File));
- }
- #ifdef DEBUG_LEAKS
- _VDBG_dump();
- #endif
- return(0);
- }
- /* inspects the OggVorbis file and finds/documents all the logical
- bitstreams contained in it. Tries to be tolerant of logical
- bitstream sections that are truncated/woogie.
- return: -1) error
- 0) OK
- */
- int ov_open(FILE *f,OggVorbis_File *vf,char *initial,long ibytes){
- long offset=fseek(f,0,SEEK_CUR);
- int ret;
- memset(vf,0,sizeof(OggVorbis_File));
- vf->f=f;
- /* init the framing state */
- ogg_sync_init(&vf->oy);
- /* perhaps some data was previously read into a buffer for testing
- against other stream types. Allow initialization from this
- previously read data (as we may be reading from a non-seekable
- stream) */
- if(initial){
- char *buffer=ogg_sync_buffer(&vf->oy,ibytes);
- memcpy(buffer,initial,ibytes);
- ogg_sync_wrote(&vf->oy,ibytes);
- }
- /* can we seek? Stevens suggests the seek test was portable */
- if(offset!=-1){
- ret=_open_seekable(vf);
- }else{
- ret=_open_nonseekable(vf);
- }
- if(ret){
- vf->f=NULL;
- ov_clear(vf);
- }
- return(ret);
- }
- /* How many logical bitstreams in this physical bitstream? */
- long ov_streams(OggVorbis_File *vf){
- return vf->links;
- }
- /* Is the FILE * associated with vf seekable? */
- long ov_seekable(OggVorbis_File *vf){
- return vf->seekable;
- }
- /* returns the bitrate for a given logical bitstream or the entire
- physical bitstream. If the file is open for random access, it will
- find the *actual* average bitrate. If the file is streaming, it
- returns the nominal bitrate (if set) else the average of the
- upper/lower bounds (if set) else -1 (unset).
- If you want the actual bitrate field settings, get them from the
- vorbis_info structs */
- long ov_bitrate(OggVorbis_File *vf,int i){
- if(i>=vf->links)return(-1);
- if(!vf->seekable && i!=0)return(ov_bitrate(vf,0));
- if(i<0){
- int64_t bits=0;
- int i;
- for(i=0;i<vf->links;i++)
- bits+=(vf->offsets[i+1]-vf->dataoffsets[i])*8;
- return(rint(bits/ov_time_total(vf,-1)));
- }else{
- if(vf->seekable){
- /* return the actual bitrate */
- return(rint((vf->offsets[i+1]-vf->dataoffsets[i])*8/ov_time_total(vf,i)));
- }else{
- /* return nominal if set */
- if(vf->vi[i].bitrate_nominal>0){
- return vf->vi[i].bitrate_nominal;
- }else{
- if(vf->vi[i].bitrate_upper>0){
- if(vf->vi[i].bitrate_lower>0){
- return (vf->vi[i].bitrate_upper+vf->vi[i].bitrate_lower)/2;
- }else{
- return vf->vi[i].bitrate_upper;
- }
- }
- return(-1);
- }
- }
- }
- }
- /* Guess */
- long ov_serialnumber(OggVorbis_File *vf,int i){
- if(i>=vf->links)return(-1);
- if(!vf->seekable && i>=0)return(ov_serialnumber(vf,-1));
- if(i<0){
- return(vf->current_serialno);
- }else{
- return(vf->serialnos[i]);
- }
- }
- /* returns: total raw (compressed) length of content if i==-1
- raw (compressed) length of that logical bitstream for i==0 to n
- -1 if the stream is not seekable (we can't know the length)
- */
- long ov_raw_total(OggVorbis_File *vf,int i){
- if(!vf->seekable || i>=vf->links)return(-1);
- if(i<0){
- long acc=0;
- int i;
- for(i=0;i<vf->links;i++)
- acc+=ov_raw_total(vf,i);
- return(acc);
- }else{
- return(vf->offsets[i+1]-vf->offsets[i]);
- }
- }
- /* returns: total PCM length (samples) of content if i==-1
- PCM length (samples) of that logical bitstream for i==0 to n
- -1 if the stream is not seekable (we can't know the length)
- */
- int64_t ov_pcm_total(OggVorbis_File *vf,int i){
- if(!vf->seekable || i>=vf->links)return(-1);
- if(i<0){
- int64_t acc=0;
- int i;
- for(i=0;i<vf->links;i++)
- acc+=ov_pcm_total(vf,i);
- return(acc);
- }else{
- return(vf->pcmlengths[i]);
- }
- }
- /* returns: total seconds of content if i==-1
- seconds in that logical bitstream for i==0 to n
- -1 if the stream is not seekable (we can't know the length)
- */
- double ov_time_total(OggVorbis_File *vf,int i){
- if(!vf->seekable || i>=vf->links)return(-1);
- if(i<0){
- double acc=0;
- int i;
- for(i=0;i<vf->links;i++)
- acc+=ov_time_total(vf,i);
- return(acc);
- }else{
- return((float)(vf->pcmlengths[i])/vf->vi[i].rate);
- }
- }
- /* seek to an offset relative to the *compressed* data. This also
- immediately sucks in and decodes pages to update the PCM cursor. It
- will cross a logical bitstream boundary, but only if it can't get
- any packets out of the tail of the bitstream we seek to (so no
- surprises).
- returns zero on success, nonzero on failure */
- int ov_raw_seek(OggVorbis_File *vf,long pos){
- if(!vf->seekable)return(-1); /* don't dump machine if we can't seek */
- if(pos<0 || pos>vf->offsets[vf->links])goto seek_error;
- /* clear out decoding machine state */
- _decode_clear(vf);
- /* seek */
- _seek_helper(vf,pos);
- /* we need to make sure the pcm_offset is set. We use the
- _fetch_packet helper to process one packet with readp set, then
- call it until it returns '0' with readp not set (the last packet
- from a page has the 'frameno' field set, and that's how the
- helper updates the offset */
- switch(_process_packet(vf,1)){
- case 0:
- /* oh, eof. There are no packets remaining. Set the pcm offset to
- the end of file */
- vf->pcm_offset=ov_pcm_total(vf,-1);
- return(0);
- case -1:
- /* error! missing data or invalid bitstream structure */
- goto seek_error;
- default:
- /* all OK */
- break;
- }
- while(1){
- switch(_process_packet(vf,0)){
- case 0:
- /* the offset is set. If it's a bogus bitstream with no offset
- information, it's not but that's not our fault. We still run
- gracefully, we're just missing the offset */
- return(0);
- case -1:
- /* error! missing data or invalid bitstream structure */
- goto seek_error;
- default:
- /* continue processing packets */
- break;
- }
- }
-
- seek_error:
- /* dump the machine so we're in a known state */
- _decode_clear(vf);
- return -1;
- }
- /* seek to a sample offset relative to the decompressed pcm stream
- returns zero on success, nonzero on failure */
- int ov_pcm_seek(OggVorbis_File *vf,int64_t pos){
- int link=-1;
- int64_t total=ov_pcm_total(vf,-1);
- if(!vf->seekable)return(-1); /* don't dump machine if we can't seek */
- if(pos<0 || pos>total)goto seek_error;
- /* which bitstream section does this pcm offset occur in? */
- for(link=vf->links-1;link>=0;link--){
- total-=vf->pcmlengths[link];
- if(pos>=total)break;
- }
- /* search within the logical bitstream for the page with the highest
- pcm_pos preceeding (or equal to) pos. There is a danger here;
- missing pages or incorrect frame number information in the
- bitstream could make our task impossible. Account for that (it
- would be an error condition) */
- {
- int64_t target=pos-total;
- long end=vf->offsets[link+1];
- long begin=vf->offsets[link];
- long best=begin;
- ogg_page og;
- while(begin<end){
- long bisect;
- long ret;
-
- if(end-begin<CHUNKSIZE){
- bisect=begin;
- }else{
- bisect=(end+begin)/2;
- }
-
- _seek_helper(vf,bisect);
- ret=_get_next_page(vf,&og,end-bisect);
-
- if(ret==-1){
- end=bisect;
- }else{
- int64_t frameno=ogg_page_frameno(&og);
- if(frameno<target){
- best=ret; /* raw offset of packet with frameno */
- begin=vf->offset; /* raw offset of next packet */
- }else{
- end=bisect;
- }
- }
- }
- /* found our page. seek to it (call raw_seek). */
-
- if(ov_raw_seek(vf,best))goto seek_error;
- }
- /* verify result */
- if(vf->pcm_offset>=pos)goto seek_error;
- if(pos>ov_pcm_total(vf,-1))goto seek_error;
- /* discard samples until we reach the desired position. Crossing a
- logical bitstream boundary with abandon is OK. */
- while(vf->pcm_offset<pos){
- double **pcm;
- long target=pos-vf->pcm_offset;
- long samples=vorbis_synthesis_pcmout(&vf->vd,&pcm);
- if(samples>target)samples=target;
- vorbis_synthesis_read(&vf->vd,samples);
- vf->pcm_offset+=samples;
-
- if(samples<target)
- if(_process_packet(vf,1)==0)
- vf->pcm_offset=ov_pcm_total(vf,-1); /* eof */
- }
- return 0;
-
- seek_error:
- /* dump machine so we're in a known state */
- _decode_clear(vf);
- return -1;
- }
- /* seek to a playback time relative to the decompressed pcm stream
- returns zero on success, nonzero on failure */
- int ov_time_seek(OggVorbis_File *vf,double seconds){
- /* translate time to PCM position and call ov_pcm_seek */
- int link=-1;
- int64_t pcm_total=ov_pcm_total(vf,-1);
- double time_total=ov_time_total(vf,-1);
- if(!vf->seekable)return(-1); /* don't dump machine if we can't seek */
- if(seconds<0 || seconds>time_total)goto seek_error;
-
- /* which bitstream section does this time offset occur in? */
- for(link=vf->links-1;link>=0;link--){
- pcm_total-=vf->pcmlengths[link];
- time_total-=ov_time_total(vf,link);
- if(seconds>=time_total)break;
- }
- /* enough information to convert time offset to pcm offset */
- {
- int64_t target=pcm_total+(seconds-time_total)*vf->vi[link].rate;
- return(ov_pcm_seek(vf,target));
- }
- seek_error:
- /* dump machine so we're in a known state */
- _decode_clear(vf);
- return -1;
- }
- /* tell the current stream offset cursor. Note that seek followed by
- tell will likely not give the set offset due to caching */
- long ov_raw_tell(OggVorbis_File *vf){
- return(vf->offset);
- }
- /* return PCM offset (sample) of next PCM sample to be read */
- int64_t ov_pcm_tell(OggVorbis_File *vf){
- return(vf->pcm_offset);
- }
- /* return time offset (seconds) of next PCM sample to be read */
- double ov_time_tell(OggVorbis_File *vf){
- /* translate time to PCM position and call ov_pcm_seek */
- int link=-1;
- int64_t pcm_total=0;
- double time_total=0.;
-
- if(vf->seekable){
- pcm_total=ov_pcm_total(vf,-1);
- time_total=ov_time_total(vf,-1);
-
- /* which bitstream section does this time offset occur in? */
- for(link=vf->links-1;link>=0;link--){
- pcm_total-=vf->pcmlengths[link];
- time_total-=ov_time_total(vf,link);
- if(vf->pcm_offset>pcm_total)break;
- }
- }
- return((double)time_total+(double)(vf->pcm_offset-pcm_total)/vf->vi[link].rate);
- }
- /* link: -1) return the vorbis_info struct for the bitstream section
- currently being decoded
- 0-n) to request information for a specific bitstream section
-
- In the case of a non-seekable bitstream, any call returns the
- current bitstream. NULL in the case that the machine is not
- initialized */
- vorbis_info *ov_info(OggVorbis_File *vf,int link){
- if(vf->seekable){
- if(link<0)
- if(vf->decode_ready)
- return vf->vi+vf->current_link;
- else
- return NULL;
- else
- if(link>=vf->links)
- return NULL;
- else
- return vf->vi+link;
- }else{
- if(vf->decode_ready)
- return vf->vi;
- else
- return NULL;
- }
- }
- /* grr, strong typing, grr, no templates/inheritence, grr */
- vorbis_comment *ov_comment(OggVorbis_File *vf,int link){
- if(vf->seekable){
- if(link<0)
- if(vf->decode_ready)
- return vf->vc+vf->current_link;
- else
- return NULL;
- else
- if(link>=vf->links)
- return NULL;
- else
- return vf->vc+link;
- }else{
- if(vf->decode_ready)
- return vf->vc;
- else
- return NULL;
- }
- }
- /* up to this point, everything could more or less hide the multiple
- logical bitstream nature of chaining from the toplevel application
- if the toplevel application didn't particularly care. However, at
- the point that we actually read audio back, the multiple-section
- nature must surface: Multiple bitstream sections do not necessarily
- have to have the same number of channels or sampling rate.
- ov_read returns the sequential logical bitstream number currently
- being decoded along with the PCM data in order that the toplevel
- application can take action on channel/sample rate changes. This
- number will be incremented even for streamed (non-seekable) streams
- (for seekable streams, it represents the actual logical bitstream
- index within the physical bitstream. Note that the accessor
- functions above are aware of this dichotomy).
- input values: buffer) a buffer to hold packed PCM data for return
- length) the byte length requested to be placed into buffer
- bigendianp) should the data be packed LSB first (0) or
- MSB first (1)
- word) word size for output. currently 1 (byte) or
- 2 (16 bit short)
- return values: -1) error/hole in data
- 0) EOF
- n) number of bytes of PCM actually returned. The
- below works on a packet-by-packet basis, so the
- return length is not related to the 'length' passed
- in, just guaranteed to fit.
- *section) set to the logical bitstream number */
- long ov_read(OggVorbis_File *vf,char *buffer,int length,
- int bigendianp,int word,int sgned,int *bitstream){
- int i,j;
- while(1){
- if(vf->decode_ready){
- double **pcm;
- long samples=vorbis_synthesis_pcmout(&vf->vd,&pcm);
- if(samples){
- /* yay! proceed to pack data into the byte buffer */
- long channels=ov_info(vf,-1)->channels;
- long bytespersample=word * channels;
- if(samples>length/bytespersample)samples=length/bytespersample;
-
- /* a tight loop to pack each size */
- {
- if(word==1){
- int off=(sgned?0:128);
- for(j=0;j<samples;j++)
- for(i=0;i<channels;i++){
- int val=rint(pcm[i][j]*128.);
- if(val>127)val=127;
- if(val<-128)val=-128;
- *buffer++=val+off;
- }
- }else{
- int off=(sgned?0:32768);
- if(bigendianp){
- for(j=0;j<samples;j++)
- for(i=0;i<channels;i++){
- int val=rint(pcm[i][j]*32768.);
- if(val>32767)val=32767;
- if(val<-32768)val=-32768;
- val+=off;
- *buffer++=(val>>8);
- *buffer++=(val&0xff);
- }
- }else{
- for(j=0;j<samples;j++)
- for(i=0;i<channels;i++){
- int val=rint(pcm[i][j]*32768.);
- if(val>32767)val=32767;
- if(val<-32768)val=-32768;
- val+=off;
- *buffer++=(val&0xff);
- *buffer++=(val>>8);
- }
- }
- }
- }
-
- vorbis_synthesis_read(&vf->vd,samples);
- vf->pcm_offset+=samples;
- if(bitstream)*bitstream=vf->current_link;
- return(samples*bytespersample);
- }
- }
- /* suck in another packet */
- switch(_process_packet(vf,1)){
- case 0:
- return(0);
- case -1:
- return -1;
- default:
- break;
- }
- }
- }
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