DiskLoc ExtentManager::getPrevRecord( const DiskLoc& loc ) const {
DiskLoc prev = getPrevRecordInExtent( loc );
if ( !prev.isNull() )
return prev;
// now traverse extents
Extent *e = extentFor(loc);
while ( 1 ) {
if ( e->xprev.isNull() )
return DiskLoc(); // end of collection
e = e->xprev.ext();
if ( !e->firstRecord.isNull() )
break;
// entire extent could be empty, keep looking
}
return e->firstRecord;
}
DiskLoc ExtentManager::getNextRecord( const DiskLoc& loc ) {
DiskLoc next = getNextRecordInExtent( loc );
if ( !next.isNull() )
return next;
// now traverse extents
Extent *e = extentFor(loc);
while ( 1 ) {
if ( e->xnext.isNull() )
return DiskLoc(); // end of collection
e = e->xnext.ext();
if ( !e->firstRecord.isNull() )
break;
// entire extent could be empty, keep looking
}
return e->firstRecord;
}
