+ 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;