+
+ /* track the frame number... This is for convenience, but also
+ making sure our last packet doesn't end with added padding. If
+ the last packet is partial, the number of samples we'll have to
+ return will be past the vb->granulepos.
+
+ This is not foolproof! It will be confused if we begin
+ decoding at the last page after a seek or hole. In that case,
+ we don't have a starting point to judge where the last frame
+ is. For this reason, vorbisfile will always try to make sure
+ it reads the last two marked pages in proper sequence */
+
+ if(b->sample_count==-1){
+ b->sample_count=0;
+ }else{
+ b->sample_count+=ci->blocksizes[v->lW]/4+ci->blocksizes[v->W]/4;
+ }
+
+ if(v->granulepos==-1){
+ if(vb->granulepos!=-1){ /* only set if we have a position to set to */
+
+ v->granulepos=vb->granulepos;
+
+ /* is this a short page? */
+ if(b->sample_count>v->granulepos){
+ /* corner case; if this is both the first and last audio page,
+ then spec says the end is cut, not beginning */
+ long extra=b->sample_count-vb->granulepos;
+
+ /* we use ogg_int64_t for granule positions because a
+ uint64 isn't universally available. Unfortunately,
+ that means granposes can be 'negative' and result in
+ extra being negative */
+ if(extra<0)
+ extra=0;
+
+ if(vb->eofflag){
+ /* trim the end */
+ /* no preceding granulepos; assume we started at zero (we'd
+ have to in a short single-page stream) */
+ /* granulepos could be -1 due to a seek, but that would result
+ in a long count, not short count */
+
+ /* Guard against corrupt/malicious frames that set EOP and
+ a backdated granpos; don't rewind more samples than we
+ actually have */
+ if(extra > (v->pcm_current - v->pcm_returned)<<hs)
+ extra = (v->pcm_current - v->pcm_returned)<<hs;
+
+ v->pcm_current-=extra>>hs;
+ }else{
+ /* trim the beginning */
+ v->pcm_returned+=extra>>hs;
+ if(v->pcm_returned>v->pcm_current)
+ v->pcm_returned=v->pcm_current;
+ }
+
+ }
+
+ }
+ }else{
+ v->granulepos+=ci->blocksizes[v->lW]/4+ci->blocksizes[v->W]/4;
+ if(vb->granulepos!=-1 && v->granulepos!=vb->granulepos){
+
+ if(v->granulepos>vb->granulepos){
+ long extra=v->granulepos-vb->granulepos;
+
+ if(extra)
+ if(vb->eofflag){
+ /* partial last frame. Strip the extra samples off */
+
+ /* Guard against corrupt/malicious frames that set EOP and
+ a backdated granpos; don't rewind more samples than we
+ actually have */
+ if(extra > (v->pcm_current - v->pcm_returned)<<hs)
+ extra = (v->pcm_current - v->pcm_returned)<<hs;
+
+ /* we use ogg_int64_t for granule positions because a
+ uint64 isn't universally available. Unfortunately,
+ that means granposes can be 'negative' and result in
+ extra being negative */
+ if(extra<0)
+ extra=0;
+
+ v->pcm_current-=extra>>hs;
+ } /* else {Shouldn't happen *unless* the bitstream is out of
+ spec. Either way, believe the bitstream } */
+ } /* else {Shouldn't happen *unless* the bitstream is out of
+ spec. Either way, believe the bitstream } */
+ v->granulepos=vb->granulepos;
+ }
+ }
+
+ /* Update, cleanup */
+
+ if(vb->eofflag)v->eofflag=1;
+ return(0);
+
+}
+
+/* pcm==NULL indicates we just want the pending samples, no more */
+int vorbis_synthesis_pcmout(vorbis_dsp_state *v,float ***pcm){
+ vorbis_info *vi=v->vi;
+
+ if(v->pcm_returned>-1 && v->pcm_returned<v->pcm_current){
+ if(pcm){
+ int i;
+ for(i=0;i<vi->channels;i++)
+ v->pcmret[i]=v->pcm[i]+v->pcm_returned;
+ *pcm=v->pcmret;
+ }
+ return(v->pcm_current-v->pcm_returned);
+ }
+ return(0);
+}
+
+int vorbis_synthesis_read(vorbis_dsp_state *v,int n){
+ if(n && v->pcm_returned+n>v->pcm_current)return(OV_EINVAL);
+ v->pcm_returned+=n;