# Licensed to the Apache Software Foundation (ASF) under one
# or more contributor license agreements. See the NOTICE file
# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
# ---------------------------------------------------------------------
# Implement legacy Feather file format
class FeatherError(Exception):
pass
cdef class FeatherWriter:
cdef:
unique_ptr[CFeatherWriter] writer
cdef public:
int64_t num_rows
def __cinit__(self):
self.num_rows = -1
def open(self, object dest):
cdef shared_ptr[OutputStream] sink
get_writer(dest, &sink)
with nogil:
check_status(CFeatherWriter.Open(sink, &self.writer))
def close(self):
if self.num_rows < 0:
self.num_rows = 0
self.writer.get().SetNumRows(self.num_rows)
with nogil:
check_status(self.writer.get().Finalize())
def write_array(self, object name, object col, object mask=None):
cdef Array arr
if self.num_rows >= 0:
if len(col) != self.num_rows:
raise ValueError('prior column had a different number of rows')
else:
self.num_rows = len(col)
if isinstance(col, Array):
arr = col
else:
arr = Array.from_pandas(col, mask=mask)
cdef c_string c_name = tobytes(name)
with nogil:
check_status(
self.writer.get().Append(c_name, deref(arr.sp_array)))
cdef class FeatherReader:
cdef:
unique_ptr[CFeatherReader] reader
def __cinit__(self):
pass
def open(self, source):
cdef shared_ptr[RandomAccessFile] reader
get_reader(source, &reader)
with nogil:
check_status(CFeatherReader.Open(reader, &self.reader))
property num_rows:
def __get__(self):
return self.reader.get().num_rows()
property num_columns:
def __get__(self):
return self.reader.get().num_columns()
def get_column_name(self, int i):
cdef c_string name = self.reader.get().GetColumnName(i)
return frombytes(name)
def get_column(self, int i):
if i < 0 or i >= self.num_columns:
raise IndexError(i)
cdef shared_ptr[CColumn] sp_column
with nogil:
check_status(self.reader.get()
.GetColumn(i, &sp_column))
cdef Column col = Column()
col.init(sp_column)
return col