def get_slice(self,column,start,end):
stream = StreamingTupleWithCallback(self._get_item_callback,
self._get_length_callback)
stream.set_meta('data',PeriodicLog.get_slice(self,column,start,end,1))
return stream
def _setup_data_stream(self,log,callback,start,end,extended,meta=None):
if meta is None:
meta = {}
stream = StreamingTupleWithCallback(callback,self._get_stream_length)
stream.set_meta('begin',start)
stream.set_meta('end',end)
stream.set_meta('log', log)
stream.set_meta('extended', extended)
positive = {'index':0}
negative = {'index':-1}
positive['seek'] = start
log.seek(end)
line = _readline_backwards(log)
negative['seek'] = log.tell()
positive['last'] = None
negative['last'] = None
stream.set_meta('positive',positive)
stream.set_meta('negative',negative)
stream.get_meta().update(meta)
try:
callback(-1,stream)
callback(0,stream)
except IndexError:
pass
return stream