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beetle-psx-libretro/mednafen/tremor/vorbisfile.c
twinaphex ed76b0e040 Cleanups
2015-07-29 19:30:37 +02:00

1812 lines
56 KiB
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/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE. *
* *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
* THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2009 *
* BY THE Xiph.Org FOUNDATION http://www.xiph.org/ *
* *
********************************************************************
function: stdio-based convenience library for opening/seeking/decoding
last mod: $Id: vorbisfile.c,v 1.6 2003/03/30 23:40:56 xiphmont Exp $
********************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <math.h>
#include "ivorbiscodec.h"
#include "ivorbisfile.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 coarse 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 */
static long _get_data(OggVorbis_File *vf){
errno=0;
if(!(vf->callbacks.read_func))return(-1);
if(vf->datasource){
char *buffer=ogg_sync_buffer(&vf->oy,CHUNKSIZE);
long bytes=(vf->callbacks.read_func)(buffer,1,CHUNKSIZE,vf->datasource);
if(bytes>0)ogg_sync_wrote(&vf->oy,bytes);
if(bytes==0 && errno)return(-1);
return(bytes);
}else
return(0);
}
/* save a tiny smidge of verbosity to make the code more readable */
static int _seek_helper(OggVorbis_File *vf,ogg_int64_t offset){
if(vf->datasource){
if(!(vf->callbacks.seek_func)||
(vf->callbacks.seek_func)(vf->datasource, offset, SEEK_SET) == -1)
return OV_EREAD;
vf->offset=offset;
ogg_sync_reset(&vf->oy);
}else{
/* shouldn't happen unless someone writes a broken callback */
return OV_EFAULT;
}
return 0;
}
/* 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: <0) did not find a page (OV_FALSE, OV_EOF, OV_EREAD)
n) found a page at absolute offset n */
static ogg_int64_t _get_next_page(OggVorbis_File *vf,ogg_page *og,
ogg_int64_t boundary){
if(boundary>0)boundary+=vf->offset;
while(1){
long more;
if(boundary>0 && vf->offset>=boundary)return(OV_FALSE);
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(OV_FALSE);
{
long ret=_get_data(vf);
if(ret==0)return(OV_EOF);
if(ret<0)return(OV_EREAD);
}
}else{
/* got a page. Return the offset at the page beginning,
advance the internal offset past the page end */
ogg_int64_t 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. */
/* returns offset or OV_EREAD, OV_FAULT */
static ogg_int64_t _get_prev_page(OggVorbis_File *vf,ogg_page *og){
ogg_int64_t begin=vf->offset;
ogg_int64_t end=begin;
ogg_int64_t ret;
ogg_int64_t offset=-1;
while(offset==-1){
begin-=CHUNKSIZE;
if(begin<0)
begin=0;
ret=_seek_helper(vf,begin);
if(ret)return(ret);
while(vf->offset<end){
memset(og,0,sizeof(*og));
ret=_get_next_page(vf,og,end-vf->offset);
if(ret==OV_EREAD)return(OV_EREAD);
if(ret<0){
break;
}else{
offset=ret;
}
}
}
/* In a fully compliant, non-multiplexed stream, we'll still be
holding the last page. In multiplexed (or noncompliant streams),
we will probably have to re-read the last page we saw */
if(og->header_len==0){
ret=_seek_helper(vf,offset);
if(ret)return(ret);
ret=_get_next_page(vf,og,CHUNKSIZE);
if(ret<0)
/* this shouldn't be possible */
return(OV_EFAULT);
}
return(offset);
}
static void _add_serialno(ogg_page *og,ogg_uint32_t **serialno_list, int *n){
ogg_uint32_t s = ogg_page_serialno(og);
(*n)++;
if(*serialno_list){
*serialno_list = _ogg_realloc(*serialno_list, sizeof(**serialno_list)*(*n));
}else{
*serialno_list = _ogg_malloc(sizeof(**serialno_list));
}
(*serialno_list)[(*n)-1] = s;
}
/* returns nonzero if found */
static int _lookup_serialno(ogg_uint32_t s, ogg_uint32_t *serialno_list, int n){
if(serialno_list){
while(n--){
if(*serialno_list == s) return 1;
serialno_list++;
}
}
return 0;
}
static int _lookup_page_serialno(ogg_page *og, ogg_uint32_t *serialno_list, int n){
ogg_uint32_t s = ogg_page_serialno(og);
return _lookup_serialno(s,serialno_list,n);
}
/* performs the same search as _get_prev_page, but prefers pages of
the specified serial number. If a page of the specified serialno is
spotted during the seek-back-and-read-forward, it will return the
info of last page of the matching serial number instead of the very
last page. If no page of the specified serialno is seen, it will
return the info of last page and alter *serialno. */
static ogg_int64_t _get_prev_page_serial(OggVorbis_File *vf,
ogg_uint32_t *serial_list, int serial_n,
int *serialno, ogg_int64_t *granpos){
ogg_page og;
ogg_int64_t begin=vf->offset;
ogg_int64_t end=begin;
ogg_int64_t ret;
ogg_int64_t prefoffset=-1;
ogg_int64_t offset=-1;
ogg_int64_t ret_serialno=-1;
ogg_int64_t ret_gran=-1;
while(offset==-1){
begin-=CHUNKSIZE;
if(begin<0)
begin=0;
ret=_seek_helper(vf,begin);
if(ret)return(ret);
while(vf->offset<end){
ret=_get_next_page(vf,&og,end-vf->offset);
if(ret==OV_EREAD)return(OV_EREAD);
if(ret<0){
break;
}else{
ret_serialno=ogg_page_serialno(&og);
ret_gran=ogg_page_granulepos(&og);
offset=ret;
if((ogg_uint32_t)ret_serialno == *serialno){
prefoffset=ret;
*granpos=ret_gran;
}
if(!_lookup_serialno((ogg_uint32_t)ret_serialno,serial_list,serial_n)){
/* we fell off the end of the link, which means we seeked
back too far and shouldn't have been looking in that link
to begin with. If we found the preferred serial number,
forget that we saw it. */
prefoffset=-1;
}
}
}
}
/* we're not interested in the page... just the serialno and granpos. */
if(prefoffset>=0)return(prefoffset);
*serialno = ret_serialno;
*granpos = ret_gran;
return(offset);
}
/* 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,
ogg_uint32_t **serialno_list, int *serialno_n,
ogg_page *og_ptr){
ogg_page og;
ogg_packet op;
int i,ret;
int allbos=0;
if(!og_ptr){
ogg_int64_t llret=_get_next_page(vf,&og,CHUNKSIZE);
if(llret==OV_EREAD)return(OV_EREAD);
if(llret<0)return(OV_ENOTVORBIS);
og_ptr=&og;
}
vorbis_info_init(vi);
vorbis_comment_init(vc);
vf->ready_state=OPENED;
/* extract the serialnos of all BOS pages + the first set of vorbis
headers we see in the link */
while(ogg_page_bos(og_ptr)){
if(serialno_list){
if(_lookup_page_serialno(og_ptr,*serialno_list,*serialno_n)){
/* a dupe serialnumber in an initial header packet set == invalid stream */
if(*serialno_list)_ogg_free(*serialno_list);
*serialno_list=0;
*serialno_n=0;
ret=OV_EBADHEADER;
goto bail_header;
}
_add_serialno(og_ptr,serialno_list,serialno_n);
}
if(vf->ready_state<STREAMSET){
/* we don't have a vorbis stream in this link yet, so begin
prospective stream setup. We need a stream to get packets */
ogg_stream_reset_serialno(&vf->os,ogg_page_serialno(og_ptr));
ogg_stream_pagein(&vf->os,og_ptr);
if(ogg_stream_packetout(&vf->os,&op) > 0 &&
vorbis_synthesis_idheader(&op)){
/* vorbis header; continue setup */
vf->ready_state=STREAMSET;
if((ret=vorbis_synthesis_headerin(vi,vc,&op))){
ret=OV_EBADHEADER;
goto bail_header;
}
}
}
/* get next page */
{
ogg_int64_t llret=_get_next_page(vf,og_ptr,CHUNKSIZE);
if(llret==OV_EREAD){
ret=OV_EREAD;
goto bail_header;
}
if(llret<0){
ret=OV_ENOTVORBIS;
goto bail_header;
}
/* if this page also belongs to our vorbis stream, submit it and break */
if(vf->ready_state==STREAMSET &&
vf->os.serialno == ogg_page_serialno(og_ptr)){
ogg_stream_pagein(&vf->os,og_ptr);
break;
}
}
}
if(vf->ready_state!=STREAMSET){
ret = OV_ENOTVORBIS;
goto bail_header;
}
while(1){
i=0;
while(i<2){ /* get a page loop */
while(i<2){ /* get a packet loop */
int result=ogg_stream_packetout(&vf->os,&op);
if(result==0)break;
if(result==-1){
ret=OV_EBADHEADER;
goto bail_header;
}
if((ret=vorbis_synthesis_headerin(vi,vc,&op)))
goto bail_header;
i++;
}
while(i<2){
if(_get_next_page(vf,og_ptr,CHUNKSIZE)<0){
ret=OV_EBADHEADER;
goto bail_header;
}
/* if this page belongs to the correct stream, go parse it */
if(vf->os.serialno == ogg_page_serialno(og_ptr)){
ogg_stream_pagein(&vf->os,og_ptr);
break;
}
/* if we never see the final vorbis headers before the link
ends, abort */
if(ogg_page_bos(og_ptr)){
if(allbos){
ret = OV_EBADHEADER;
goto bail_header;
}else
allbos=1;
}
/* otherwise, keep looking */
}
}
return 0;
}
bail_header:
vorbis_info_clear(vi);
vorbis_comment_clear(vc);
vf->ready_state=OPENED;
return ret;
}
/* Starting from current cursor position, get initial PCM offset of
next page. Consumes the page in the process without decoding
audio, however this is only called during stream parsing upon
seekable open. */
static ogg_int64_t _initial_pcmoffset(OggVorbis_File *vf, vorbis_info *vi){
ogg_page og;
ogg_int64_t accumulated=0;
long lastblock=-1;
int result;
int serialno = vf->os.serialno;
while(1){
ogg_packet op;
if(_get_next_page(vf,&og,-1)<0)
break; /* should not be possible unless the file is truncated/mangled */
if(ogg_page_bos(&og)) break;
if(ogg_page_serialno(&og)!=serialno) continue;
/* count blocksizes of all frames in the page */
ogg_stream_pagein(&vf->os,&og);
while((result=ogg_stream_packetout(&vf->os,&op))){
if(result>0){ /* ignore holes */
long thisblock=vorbis_packet_blocksize(vi,&op);
if(lastblock!=-1)
accumulated+=(lastblock+thisblock)>>2;
lastblock=thisblock;
}
}
if(ogg_page_granulepos(&og)!=-1){
/* pcm offset of last packet on the first audio page */
accumulated= ogg_page_granulepos(&og)-accumulated;
break;
}
}
/* less than zero? This is a stream with samples trimmed off
the beginning, a normal occurrence; set the offset to zero */
if(accumulated<0)accumulated=0;
return accumulated;
}
/* 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 int _bisect_forward_serialno(OggVorbis_File *vf,
ogg_int64_t begin,
ogg_int64_t searched,
ogg_int64_t end,
ogg_int64_t endgran,
int endserial,
ogg_uint32_t *currentno_list,
int currentnos,
long m){
ogg_int64_t pcmoffset;
ogg_int64_t dataoffset=searched;
ogg_int64_t endsearched=end;
ogg_int64_t next=end;
ogg_int64_t searchgran=-1;
ogg_page og;
ogg_int64_t ret,last;
int serialno = vf->os.serialno;
/* invariants:
we have the headers and serialnos for the link beginning at 'begin'
we have the offset and granpos of the last page in the file (potentially
not a page we care about)
*/
/* Is the last page in our list of current serialnumbers? */
if(_lookup_serialno(endserial,currentno_list,currentnos)){
/* last page is in the starting serialno list, so we've bisected
down to (or just started with) a single link. Now we need to
find the last vorbis page belonging to the first vorbis stream
for this link. */
while(endserial != serialno){
endserial = serialno;
vf->offset=_get_prev_page_serial(vf,currentno_list,currentnos,&endserial,&endgran);
}
vf->links=m+1;
if(vf->offsets)_ogg_free(vf->offsets);
if(vf->serialnos)_ogg_free(vf->serialnos);
if(vf->dataoffsets)_ogg_free(vf->dataoffsets);
vf->offsets=_ogg_malloc((vf->links+1)*sizeof(*vf->offsets));
vf->vi=_ogg_realloc(vf->vi,vf->links*sizeof(*vf->vi));
vf->vc=_ogg_realloc(vf->vc,vf->links*sizeof(*vf->vc));
vf->serialnos=_ogg_malloc(vf->links*sizeof(*vf->serialnos));
vf->dataoffsets=_ogg_malloc(vf->links*sizeof(*vf->dataoffsets));
vf->pcmlengths=_ogg_malloc(vf->links*2*sizeof(*vf->pcmlengths));
vf->offsets[m+1]=end;
vf->offsets[m]=begin;
vf->pcmlengths[m*2+1]=endgran;
}else{
ogg_uint32_t *next_serialno_list=NULL;
int next_serialnos=0;
vorbis_info vi;
vorbis_comment vc;
/* the below guards against garbage seperating the last and
first pages of two links. */
while(searched<endsearched){
ogg_int64_t bisect;
if(endsearched-searched<CHUNKSIZE){
bisect=searched;
}else{
bisect=(searched+endsearched)/2;
}
if(bisect != vf->offset){
ret=_seek_helper(vf,bisect);
if(ret)return(ret);
}
last=_get_next_page(vf,&og,-1);
if(last==OV_EREAD)return(OV_EREAD);
if(last<0 || !_lookup_page_serialno(&og,currentno_list,currentnos)){
endsearched=bisect;
if(last>=0)next=last;
}else{
searched=vf->offset;
}
}
/* Bisection point found */
/* for the time being, fetch end PCM offset the simple way */
{
int testserial = serialno+1;
vf->offset = next;
while(testserial != serialno){
testserial = serialno;
vf->offset=_get_prev_page_serial(vf,currentno_list,currentnos,&testserial,&searchgran);
}
}
if(vf->offset!=next){
ret=_seek_helper(vf,next);
if(ret)return(ret);
}
ret=_fetch_headers(vf,&vi,&vc,&next_serialno_list,&next_serialnos,NULL);
if(ret)return(ret);
serialno = vf->os.serialno;
dataoffset = vf->offset;
/* this will consume a page, however the next bistection always
starts with a raw seek */
pcmoffset = _initial_pcmoffset(vf,&vi);
ret=_bisect_forward_serialno(vf,next,vf->offset,end,endgran,endserial,
next_serialno_list,next_serialnos,m+1);
if(ret)return(ret);
if(next_serialno_list)_ogg_free(next_serialno_list);
vf->offsets[m+1]=next;
vf->serialnos[m+1]=serialno;
vf->dataoffsets[m+1]=dataoffset;
vf->vi[m+1]=vi;
vf->vc[m+1]=vc;
vf->pcmlengths[m*2+1]=searchgran;
vf->pcmlengths[m*2+2]=pcmoffset;
vf->pcmlengths[m*2+3]-=pcmoffset;
}
return(0);
}
static int _make_decode_ready(OggVorbis_File *vf){
if(vf->ready_state>STREAMSET)return 0;
if(vf->ready_state<STREAMSET)return OV_EFAULT;
if(vf->seekable){
if(vorbis_synthesis_init(&vf->vd,vf->vi+vf->current_link))
return OV_EBADLINK;
}else{
if(vorbis_synthesis_init(&vf->vd,vf->vi))
return OV_EBADLINK;
}
vorbis_block_init(&vf->vd,&vf->vb);
vf->ready_state=INITSET;
vf->bittrack=0;
vf->samptrack=0;
return 0;
}
static int _open_seekable2(OggVorbis_File *vf){
ogg_int64_t dataoffset=vf->dataoffsets[0],end,endgran=-1;
int endserial=vf->os.serialno;
int serialno=vf->os.serialno;
/* we're partially open and have a first link header state in
storage in vf */
/* fetch initial PCM offset */
ogg_int64_t pcmoffset = _initial_pcmoffset(vf,vf->vi);
/* we can seek, so set out learning all about this file */
if(vf->callbacks.seek_func && vf->callbacks.tell_func){
(vf->callbacks.seek_func)(vf->datasource,0,SEEK_END);
vf->offset=vf->end=(vf->callbacks.tell_func)(vf->datasource);
}else{
vf->offset=vf->end=-1;
}
/* If seek_func is implemented, tell_func must also be implemented */
if(vf->end==-1) return(OV_EINVAL);
/* Get the offset of the last page of the physical bitstream, or, if
we're lucky the last vorbis page of this link as most OggVorbis
files will contain a single logical bitstream */
end=_get_prev_page_serial(vf,vf->serialnos+2,vf->serialnos[1],&endserial,&endgran);
if(end<0)return(end);
/* now determine bitstream structure recursively */
if(_bisect_forward_serialno(vf,0,dataoffset,vf->offset,endgran,endserial,
vf->serialnos+2,vf->serialnos[1],0)<0)return(OV_EREAD);
vf->offsets[0]=0;
vf->serialnos[0]=serialno;
vf->dataoffsets[0]=dataoffset;
vf->pcmlengths[0]=pcmoffset;
vf->pcmlengths[1]-=pcmoffset;
return(ov_raw_seek(vf,dataoffset));
}
/* clear out the current logical bitstream decoder */
static void _decode_clear(OggVorbis_File *vf){
vorbis_dsp_clear(&vf->vd);
vorbis_block_clear(&vf->vb);
vf->ready_state=OPENED;
}
/* 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: <0) error, OV_HOLE (lost packet) or OV_EOF
0) need more data (only if readp==0)
1) got a packet
*/
static int _fetch_and_process_packet(OggVorbis_File *vf,
ogg_packet *op_in,
int readp,
int spanp){
ogg_page og;
/* handle one packet. Try to fetch it from current stream state */
/* extract packets from page */
while(1){
if(vf->ready_state==STREAMSET){
int ret=_make_decode_ready(vf);
if(ret<0)return ret;
}
/* process a packet if we can. If the machine isn't loaded,
neither is a page */
if(vf->ready_state==INITSET){
while(1) {
ogg_packet op;
ogg_packet *op_ptr=(op_in?op_in:&op);
int result=ogg_stream_packetout(&vf->os,op_ptr);
ogg_int64_t granulepos;
op_in=NULL;
if(result==-1)return(OV_HOLE); /* hole in the data. */
if(result>0){
/* got a packet. process it */
granulepos=op_ptr->granulepos;
if(!vorbis_synthesis(&vf->vb,op_ptr)){ /* lazy check for lazy
header handling. The
header packets aren't
audio, so if/when we
submit them,
vorbis_synthesis will
reject them */
/* suck in the synthesis data and track bitrate */
{
int oldsamples=vorbis_synthesis_pcmout(&vf->vd,NULL);
/* for proper use of libvorbis within libvorbisfile,
oldsamples will always be zero. */
if(oldsamples)return(OV_EFAULT);
vorbis_synthesis_blockin(&vf->vd,&vf->vb);
vf->samptrack+=vorbis_synthesis_pcmout(&vf->vd,NULL)-oldsamples;
vf->bittrack+=op_ptr->bytes*8;
}
/* update the pcm offset. */
if(granulepos!=-1 && !op_ptr->e_o_s){
int link=(vf->seekable?vf->current_link:0);
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*
As an aside, this trick is inaccurate if we begin
reading anew right at the last page; the end-of-stream
granulepos declares the last frame in the stream, and the
last packet of the last page may be a partial frame.
So, we need a previous granulepos from an in-sequence page
to have a reference point. Thus the !op_ptr->e_o_s clause
above */
if(vf->seekable && link>0)
granulepos-=vf->pcmlengths[link*2];
if(granulepos<0)granulepos=0; /* actually, this
shouldn't be possible
here unless the stream
is very broken */
samples=vorbis_synthesis_pcmout(&vf->vd,NULL);
granulepos-=samples;
for(i=0;i<link;i++)
granulepos+=vf->pcmlengths[i*2+1];
vf->pcm_offset=granulepos;
}
return(1);
}
}
else
break;
}
}
if(vf->ready_state>=OPENED){
ogg_int64_t ret;
while(1){
/* the loop is not strictly necessary, but there's no sense in
doing the extra checks of the larger loop for the common
case in a multiplexed bistream where the page is simply
part of a different logical bitstream; keep reading until
we get one with the correct serialno */
if(!readp)return(0);
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;
if(vf->ready_state==INITSET){
if(vf->current_serialno!=ogg_page_serialno(&og)){
/* two possibilities:
1) our decoding just traversed a bitstream boundary
2) another stream is multiplexed into this logical section */
if(ogg_page_bos(&og)){
/* boundary case */
if(!spanp)
return(OV_EOF);
_decode_clear(vf);
if(!vf->seekable){
vorbis_info_clear(vf->vi);
vorbis_comment_clear(vf->vc);
}
break;
}else
continue; /* possibility #2 */
}
}
break;
}
}
/* 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->ready_state!=INITSET){
int link;
if(vf->ready_state<STREAMSET){
if(vf->seekable){
ogg_uint32_t 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]==serialno)break;
if(link==vf->links) continue; /* not the desired Vorbis
bitstream section; keep
trying */
vf->current_serialno=serialno;
vf->current_link=link;
ogg_stream_reset_serialno(&vf->os,vf->current_serialno);
vf->ready_state=STREAMSET;
}else{
/* we're streaming */
/* fetch the three header packets, build the info struct */
int ret=_fetch_headers(vf,vf->vi,vf->vc,NULL,NULL,&og);
if(ret)return(ret);
vf->current_serialno=vf->os.serialno;
vf->current_link++;
link=0;
}
}
}
/* the buffered page is the data we want, and we're ready for it;
add it to the stream state */
ogg_stream_pagein(&vf->os,&og);
}
}
/* if, eg, 64 bit stdio is configured by default, this will build with
fseek64 */
static int _fseek64_wrap(FILE *f,ogg_int64_t off,int whence){
if(f==NULL)return(-1);
return fseek(f,off,whence);
}
static int _ov_open1(void *f,OggVorbis_File *vf,const char *initial,
long ibytes, ov_callbacks callbacks){
int offsettest=((f && callbacks.seek_func)?callbacks.seek_func(f,0,SEEK_CUR):-1);
ogg_uint32_t *serialno_list=NULL;
int serialno_list_size=0;
int ret;
memset(vf,0,sizeof(*vf));
vf->datasource=f;
vf->callbacks = callbacks;
/* 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 (especially 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(offsettest!=-1)vf->seekable=1;
/* No seeking yet; Set up a 'single' (current) logical bitstream
entry for partial open */
vf->links=1;
vf->vi=_ogg_calloc(vf->links,sizeof(*vf->vi));
vf->vc=_ogg_calloc(vf->links,sizeof(*vf->vc));
ogg_stream_init(&vf->os,-1); /* fill in the serialno later */
/* Fetch all BOS pages, store the vorbis header and all seen serial
numbers, load subsequent vorbis setup headers */
if((ret=_fetch_headers(vf,vf->vi,vf->vc,&serialno_list,&serialno_list_size,NULL))<0){
vf->datasource=NULL;
ov_clear(vf);
}else{
/* serial number list for first link needs to be held somewhere
for second stage of seekable stream open; this saves having to
seek/reread first link's serialnumber data then. */
vf->serialnos=_ogg_calloc(serialno_list_size+2,sizeof(*vf->serialnos));
vf->serialnos[0]=vf->current_serialno=vf->os.serialno;
vf->serialnos[1]=serialno_list_size;
memcpy(vf->serialnos+2,serialno_list,serialno_list_size*sizeof(*vf->serialnos));
vf->offsets=_ogg_calloc(1,sizeof(*vf->offsets));
vf->dataoffsets=_ogg_calloc(1,sizeof(*vf->dataoffsets));
vf->offsets[0]=0;
vf->dataoffsets[0]=vf->offset;
vf->ready_state=PARTOPEN;
}
if(serialno_list)_ogg_free(serialno_list);
return(ret);
}
static int _ov_open2(OggVorbis_File *vf){
if(vf->ready_state != PARTOPEN) return OV_EINVAL;
vf->ready_state=OPENED;
if(vf->seekable){
int ret=_open_seekable2(vf);
if(ret){
vf->datasource=NULL;
ov_clear(vf);
}
return(ret);
}else
vf->ready_state=STREAMSET;
return 0;
}
/* 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);
}
_ogg_free(vf->vi);
_ogg_free(vf->vc);
}
if(vf->dataoffsets)_ogg_free(vf->dataoffsets);
if(vf->pcmlengths)_ogg_free(vf->pcmlengths);
if(vf->serialnos)_ogg_free(vf->serialnos);
if(vf->offsets)_ogg_free(vf->offsets);
ogg_sync_clear(&vf->oy);
if(vf->datasource && vf->callbacks.close_func)
(vf->callbacks.close_func)(vf->datasource);
memset(vf,0,sizeof(*vf));
}
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_callbacks(void *f,OggVorbis_File *vf,
const char *initial,long ibytes,ov_callbacks callbacks){
int ret=_ov_open1(f,vf,initial,ibytes,callbacks);
if(ret)return ret;
return _ov_open2(vf);
}
int ov_open(FILE *f,OggVorbis_File *vf,const char *initial,long ibytes){
ov_callbacks callbacks = {
(size_t (*)(void *, size_t, size_t, void *)) fread,
(int (*)(void *, ogg_int64_t, int)) _fseek64_wrap,
(int (*)(void *)) fclose,
(long (*)(void *)) ftell
};
return ov_open_callbacks((void *)f, vf, initial, ibytes, callbacks);
}
/* 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(vf->ready_state<OPENED)return(OV_EINVAL);
if(i>=vf->links)return(OV_EINVAL);
if(!vf->seekable && i!=0)return(ov_bitrate(vf,0));
if(i<0){
ogg_int64_t bits=0;
int i;
for(i=0;i<vf->links;i++)
bits+=(vf->offsets[i+1]-vf->dataoffsets[i])*8;
/* This once read: return(rint(bits/ov_time_total(vf,-1)));
* gcc 3.x on x86 miscompiled this at optimisation level 2 and above,
* so this is slightly transformed to make it work.
*/
return(bits*1000/ov_time_total(vf,-1));
}else{
if(vf->seekable){
/* return the actual bitrate */
return((vf->offsets[i+1]-vf->dataoffsets[i])*8000/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(OV_FALSE);
}
}
}
}
/* returns the actual bitrate since last call. returns -1 if no
additional data to offer since last call (or at beginning of stream),
EINVAL if stream is only partially open
*/
long ov_bitrate_instant(OggVorbis_File *vf){
int link=(vf->seekable?vf->current_link:0);
long ret;
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(vf->samptrack==0)return(OV_FALSE);
ret=vf->bittrack/vf->samptrack*vf->vi[link].rate;
vf->bittrack=0;
vf->samptrack=0;
return(ret);
}
/* Guess */
long ov_serialnumber(OggVorbis_File *vf,int i){
if(i>=vf->links)return(ov_serialnumber(vf,vf->links-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
OV_EINVAL if the stream is not seekable (we can't know the length)
or if stream is only partially open
*/
ogg_int64_t ov_raw_total(OggVorbis_File *vf,int i){
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable || i>=vf->links)return(OV_EINVAL);
if(i<0){
ogg_int64_t 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
OV_EINVAL if the stream is not seekable (we can't know the
length) or only partially open
*/
ogg_int64_t ov_pcm_total(OggVorbis_File *vf,int i){
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable || i>=vf->links)return(OV_EINVAL);
if(i<0){
ogg_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*2+1]);
}
}
/* returns: total milliseconds of content if i==-1
milliseconds in that logical bitstream for i==0 to n
OV_EINVAL if the stream is not seekable (we can't know the
length) or only partially open
*/
ogg_int64_t ov_time_total(OggVorbis_File *vf,int i){
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable || i>=vf->links)return(OV_EINVAL);
if(i<0){
ogg_int64_t acc=0;
int i;
for(i=0;i<vf->links;i++)
acc+=ov_time_total(vf,i);
return(acc);
}else{
return(((ogg_int64_t)vf->pcmlengths[i*2+1])*1000/vf->vi[i].rate);
}
}
/* seek to an offset relative to the *compressed* data. This also
scans packets 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,ogg_int64_t pos){
ogg_stream_state work_os;
int ret;
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable)
return(OV_ENOSEEK); /* don't dump machine if we can't seek */
if(pos<0 || pos>vf->end)return(OV_EINVAL);
/* is the seek position outside our current link [if any]? */
if(vf->ready_state>=STREAMSET){
if(pos<vf->offsets[vf->current_link] || pos>=vf->offsets[vf->current_link+1])
_decode_clear(vf); /* clear out stream 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;
ogg_stream_reset_serialno(&vf->os,
vf->current_serialno); /* must set serialno */
vorbis_synthesis_restart(&vf->vd);
ret=_seek_helper(vf,pos);
if(ret)goto seek_error;
/* we need to make sure the pcm_offset is set, but we don't want to
advance the raw cursor past good packets just to get to the first
with a granulepos. That's not equivalent behavior to beginning
decoding as immediately after the seek position as possible.
So, a hack. We use two stream states; a local scratch state and
the shared vf->os stream state. We use the local state to
scan, and the shared state as a buffer for later decode.
Unfortuantely, on the last page we still advance to last packet
because the granulepos on the last page is not necessarily on a
packet boundary, and we need to make sure the granpos is
correct.
*/
{
ogg_page og;
ogg_packet op;
int lastblock=0;
int accblock=0;
int thisblock=0;
int lastflag=0;
int firstflag=0;
ogg_int64_t pagepos=-1;
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){
/* 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){
thisblock=vorbis_packet_blocksize(vf->vi+vf->current_link,&op);
if(thisblock<0){
ogg_stream_packetout(&vf->os,NULL);
thisblock=0;
}else{
/* We can't get a guaranteed correct pcm position out of the
last page in a stream because it might have a 'short'
granpos, which can only be detected in the presence of a
preceding page. However, if the last page is also the first
page, the granpos rules of a first page take precedence. Not
only that, but for first==last, the EOS page must be treated
as if its a normal first page for the stream to open/play. */
if(lastflag && !firstflag)
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;
if(vf->pcm_offset<0)vf->pcm_offset=0;
break;
}
lastblock=thisblock;
continue;
}else
ogg_stream_packetout(&vf->os,NULL);
}
}
if(!lastblock){
pagepos=_get_next_page(vf,&og,-1);
if(pagepos<0){
vf->pcm_offset=ov_pcm_total(vf,-1);
break;
}
}else{
/* huh? Bogus stream with packets but no granulepos */
vf->pcm_offset=-1;
break;
}
/* has our decoding just traversed a bitstream boundary? */
if(vf->ready_state>=STREAMSET){
if(vf->current_serialno!=ogg_page_serialno(&og)){
/* two possibilities:
1) our decoding just traversed a bitstream boundary
2) another stream is multiplexed into this logical section? */
if(ogg_page_bos(&og)){
/* we traversed */
_decode_clear(vf); /* clear out stream state */
ogg_stream_clear(&work_os);
} /* else, do nothing; next loop will scoop another page */
}
}
if(vf->ready_state<STREAMSET){
int link;
ogg_uint32_t serialno = ogg_page_serialno(&og);
for(link=0;link<vf->links;link++)
if(vf->serialnos[link]==serialno)break;
if(link==vf->links) continue; /* not the desired Vorbis
bitstream section; keep
trying */
vf->current_link=link;
vf->current_serialno=serialno;
ogg_stream_reset_serialno(&vf->os,serialno);
ogg_stream_reset_serialno(&work_os,serialno);
vf->ready_state=STREAMSET;
firstflag=(pagepos<=vf->dataoffsets[link]);
}
ogg_stream_pagein(&vf->os,&og);
ogg_stream_pagein(&work_os,&og);
lastflag=ogg_page_eos(&og);
}
}
ogg_stream_clear(&work_os);
vf->bittrack=0;
vf->samptrack=0;
return(0);
seek_error:
/* dump the machine so we're in a known state */
vf->pcm_offset=-1;
ogg_stream_clear(&work_os);
_decode_clear(vf);
return OV_EBADLINK;
}
/* rescales the number x from the range of [0,from] to [0,to]
x is in the range [0,from]
from, to are in the range [1, 1<<62-1] */
ogg_int64_t rescale64(ogg_int64_t x, ogg_int64_t from, ogg_int64_t to){
ogg_int64_t frac=0;
ogg_int64_t ret=0;
int i;
if(x >= from) return to;
if(x <= 0) return 0;
for(i=0;i<64;i++){
if(x>=from){
frac|=1;
x-=from;
}
x<<=1;
frac<<=1;
}
for(i=0;i<64;i++){
if(frac & 1){
ret+=to;
}
frac>>=1;
ret>>=1;
}
return ret;
}
/* Page granularity seek (faster than sample granularity because we
don't do the last bit of decode to find a specific sample).
Seek to the last [granule marked] page preceding the specified pos
location, such that decoding past the returned point will quickly
arrive at the requested position. */
int ov_pcm_seek_page(OggVorbis_File *vf,ogg_int64_t pos){
int link=-1;
ogg_int64_t result=0;
ogg_int64_t total=ov_pcm_total(vf,-1);
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable)return(OV_ENOSEEK);
if(pos<0 || pos>total)return(OV_EINVAL);
/* which bitstream section does this pcm offset occur in? */
for(link=vf->links-1;link>=0;link--){
total-=vf->pcmlengths[link*2+1];
if(pos>=total)break;
}
/* search within the logical bitstream for the page with the highest
pcm_pos preceding (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) */
/* new search algorithm by HB (Nicholas Vinen) */
{
ogg_int64_t end=vf->offsets[link+1];
ogg_int64_t begin=vf->offsets[link];
ogg_int64_t begintime = vf->pcmlengths[link*2];
ogg_int64_t endtime = vf->pcmlengths[link*2+1]+begintime;
ogg_int64_t target=pos-total+begintime;
ogg_int64_t best=begin;
ogg_page og;
while(begin<end){
ogg_int64_t bisect;
if(end-begin<CHUNKSIZE){
bisect=begin;
}else{
/* take a (pretty decent) guess. */
bisect=begin + rescale64(target-begintime,
endtime-begintime,
end-begin) - CHUNKSIZE;
if(bisect<begin+CHUNKSIZE)
bisect=begin;
}
if(bisect!=vf->offset){
result=_seek_helper(vf,bisect);
if(result) goto seek_error;
}
while(begin<end){
result=_get_next_page(vf,&og,end-vf->offset);
if(result==OV_EREAD) goto seek_error;
if(result<0){
if(bisect<=begin+1)
end=begin; /* found it */
else{
if(bisect==0) goto seek_error;
bisect-=CHUNKSIZE;
if(bisect<=begin)bisect=begin+1;
result=_seek_helper(vf,bisect);
if(result) goto seek_error;
}
}else{
ogg_int64_t granulepos;
if(ogg_page_serialno(&og)!=vf->serialnos[link])
continue;
granulepos=ogg_page_granulepos(&og);
if(granulepos==-1)continue;
if(granulepos<target){
best=result; /* raw offset of packet with granulepos */
begin=vf->offset; /* raw offset of next page */
begintime=granulepos;
if(target-begintime>44100)break;
bisect=begin; /* *not* begin + 1 */
}else{
if(bisect<=begin+1)
end=begin; /* found it */
else{
if(end==vf->offset){ /* we're pretty close - we'd be stuck in */
end=result;
bisect-=CHUNKSIZE; /* an endless loop otherwise. */
if(bisect<=begin)bisect=begin+1;
result=_seek_helper(vf,bisect);
if(result) goto seek_error;
}else{
end=bisect;
endtime=granulepos;
break;
}
}
}
}
}
}
/* found our page. seek to it, update pcm offset. Easier case than
raw_seek, don't keep packets preceding granulepos. */
{
ogg_page og;
ogg_packet op;
/* seek */
result=_seek_helper(vf,best);
vf->pcm_offset=-1;
if(result) goto seek_error;
result=_get_next_page(vf,&og,-1);
if(result<0) goto seek_error;
if(link!=vf->current_link){
/* Different link; dump entire decode machine */
_decode_clear(vf);
vf->current_link=link;
vf->current_serialno=vf->serialnos[link];
vf->ready_state=STREAMSET;
}else{
vorbis_synthesis_restart(&vf->vd);
}
ogg_stream_reset_serialno(&vf->os,vf->current_serialno);
ogg_stream_pagein(&vf->os,&og);
/* pull out all but last packet; the one with granulepos */
while(1){
result=ogg_stream_packetpeek(&vf->os,&op);
if(result==0){
/* !!! the packet finishing this page originated on a
preceding 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. */
result=_seek_helper(vf,best);
if(result<0) goto seek_error;
while(1){
result=_get_prev_page(vf,&og);
if(result<0) goto seek_error;
if(ogg_page_serialno(&og)==vf->current_serialno &&
(ogg_page_granulepos(&og)>-1 ||
!ogg_page_continued(&og))){
return ov_raw_seek(vf,result);
}
vf->offset=result;
}
}
if(result<0){
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;
vf->pcm_offset+=total;
break;
}else
result=ogg_stream_packetout(&vf->os,NULL);
}
}
}
/* verify result */
if(vf->pcm_offset>pos || pos>ov_pcm_total(vf,-1)){
result=OV_EFAULT;
goto seek_error;
}
vf->bittrack=0;
vf->samptrack=0;
return(0);
seek_error:
/* dump machine so we're in a known state */
vf->pcm_offset=-1;
_decode_clear(vf);
return (int)result;
}
/* 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,ogg_int64_t pos){
int thisblock,lastblock=0;
int ret=ov_pcm_seek_page(vf,pos);
if(ret<0)return(ret);
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 */
while(1){
ogg_packet op;
ogg_page og;
int ret=ogg_stream_packetpeek(&vf->os,&op);
if(ret>0){
thisblock=vorbis_packet_blocksize(vf->vi+vf->current_link,&op);
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+
vorbis_info_blocksize(vf->vi,1))>>2)>=pos)break;
/* remove the packet from packet queue and track its granulepos */
ogg_stream_packetout(&vf->os,NULL);
vorbis_synthesis_trackonly(&vf->vb,&op); /* set up a vb with
only tracking, no
pcm_decode */
vorbis_synthesis_blockin(&vf->vd,&vf->vb);
/* end of logical stream case is hard, especially with exact
length positioning. */
if(op.granulepos>-1){
int i;
/* always believe the stream markers */
vf->pcm_offset=op.granulepos-vf->pcmlengths[vf->current_link*2];
if(vf->pcm_offset<0)vf->pcm_offset=0;
for(i=0;i<vf->current_link;i++)
vf->pcm_offset+=vf->pcmlengths[i*2+1];
}
lastblock=thisblock;
}else{
if(ret<0 && ret!=OV_HOLE)break;
/* suck in a new page */
if(_get_next_page(vf,&og,-1)<0)break;
if(ogg_page_bos(&og))_decode_clear(vf);
if(vf->ready_state<STREAMSET){
ogg_uint32_t serialno=ogg_page_serialno(&og);
int link;
for(link=0;link<vf->links;link++)
if(vf->serialnos[link]==serialno)break;
if(link==vf->links) continue;
vf->current_link=link;
vf->ready_state=STREAMSET;
vf->current_serialno=ogg_page_serialno(&og);
ogg_stream_reset_serialno(&vf->os,serialno);
ret=_make_decode_ready(vf);
if(ret)return ret;
lastblock=0;
}
ogg_stream_pagein(&vf->os,&og);
}
}
vf->bittrack=0;
vf->samptrack=0;
/* discard samples until we reach the desired position. Crossing a
logical bitstream boundary with abandon is OK. */
while(vf->pcm_offset<pos){
ogg_int64_t target=pos-vf->pcm_offset;
long samples=vorbis_synthesis_pcmout(&vf->vd,NULL);
if(samples>target)samples=target;
vorbis_synthesis_read(&vf->vd,samples);
vf->pcm_offset+=samples;
if(samples<target)
if(_fetch_and_process_packet(vf,NULL,1,1)<=0)
vf->pcm_offset=ov_pcm_total(vf,-1); /* eof */
}
return 0;
}
/* 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,ogg_int64_t milliseconds){
/* translate time to PCM position and call ov_pcm_seek */
int link=-1;
ogg_int64_t pcm_total=0;
ogg_int64_t time_total=0;
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable)return(OV_ENOSEEK);
if(milliseconds<0)return(OV_EINVAL);
/* which bitstream section does this time offset occur in? */
for(link=0;link<vf->links;link++){
ogg_int64_t addsec = ov_time_total(vf,link);
if(milliseconds<time_total+addsec)break;
time_total+=addsec;
pcm_total+=vf->pcmlengths[link*2+1];
}
if(link==vf->links)return(OV_EINVAL);
/* enough information to convert time offset to pcm offset */
{
ogg_int64_t target=pcm_total+(milliseconds-time_total)*vf->vi[link].rate/1000;
return(ov_pcm_seek(vf,target));
}
}
/* page-granularity version of ov_time_seek
returns zero on success, nonzero on failure */
int ov_time_seek_page(OggVorbis_File *vf,ogg_int64_t milliseconds){
/* translate time to PCM position and call ov_pcm_seek */
int link=-1;
ogg_int64_t pcm_total=0;
ogg_int64_t time_total=0;
if(vf->ready_state<OPENED)return(OV_EINVAL);
if(!vf->seekable)return(OV_ENOSEEK);
if(milliseconds<0)return(OV_EINVAL);
/* which bitstream section does this time offset occur in? */
for(link=0;link<vf->links;link++){
ogg_int64_t addsec = ov_time_total(vf,link);
if(milliseconds<time_total+addsec)break;
time_total+=addsec;
pcm_total+=vf->pcmlengths[link*2+1];
}
if(link==vf->links)return(OV_EINVAL);
/* enough information to convert time offset to pcm offset */
{
ogg_int64_t target=pcm_total+(milliseconds-time_total)*vf->vi[link].rate/1000;
return(ov_pcm_seek_page(vf,target));
}
}
/* tell the current stream offset cursor. Note that seek followed by
tell will likely not give the set offset due to caching */
ogg_int64_t ov_raw_tell(OggVorbis_File *vf){
if(vf->ready_state<OPENED)return(OV_EINVAL);
return(vf->offset);
}
/* return PCM offset (sample) of next PCM sample to be read */
ogg_int64_t ov_pcm_tell(OggVorbis_File *vf){
if(vf->ready_state<OPENED)return(OV_EINVAL);
return(vf->pcm_offset);
}
/* 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->ready_state>=STREAMSET)
return vf->vi+vf->current_link;
else
return vf->vi;
else
if(link>=vf->links)
return NULL;
else
return vf->vi+link;
}else{
return vf->vi;
}
}
/* 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
bytes_req) the byte length requested to be placed into buffer
return values: <0) error/hole in data (OV_HOLE), partial open (OV_EINVAL)
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 bytes_req,int *bitstream)
{
int i,j;
ogg_int32_t **pcm;
long samples;
if(vf->ready_state<OPENED)return(OV_EINVAL);
while(1)
{
if(vf->ready_state==INITSET)
{
samples=vorbis_synthesis_pcmout(&vf->vd,&pcm);
if(samples)
break;
}
/* 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(samples>0)
{
/* yay! proceed to pack data into the byte buffer */
long channels=ov_info(vf,-1)->channels;
if(samples>(bytes_req/(2*channels)))
samples=bytes_req/(2*channels);
for(i=0;i<channels;i++)
{ /* It's faster in this order */
ogg_int32_t *src=pcm[i];
short *dest=((short *)buffer)+i;
for(j=0;j<samples;j++)
{
*dest=CLIP_TO_15(src[j]>>9);
dest+=channels;
}
}
vorbis_synthesis_read(&vf->vd,samples);
vf->pcm_offset+=samples;
if(bitstream)
*bitstream=vf->current_link;
return(samples * 2 * channels);
}
return(samples);
}
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