def __init__(self, table_file):
        self.table_file = table_file
        
        # Read the pointer to the directory
        dirpos = table_file.read_ulong()
        # Seek to where the directory begins and read it
        table_file.seek(dirpos)
        typecode, self.dir = table_file.read_pickle()
        
        # Set the "read()" method of this object to the appropriate
        # read method of the underlying StructFile for the table's
        # data type.
        try:
            self.read = self.table_file._type_readers[typecode]
        except KeyError:
            raise Exception("Can't (yet) read an array table of type %r" % self.typecode)
        
        self.typecode = typecode
        self.itemsize = array(typecode).itemsize
dataset/ETHPy150Open tallstreet/Whoosh-AppEngine/src/whoosh/tables.py/ArrayReader.__init__/original