# 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 Feather file format
# cython: profile=False
# distutils: language = c++
# cython: language_level=3
from cython.operator cimport dereference as deref
from pyarrow.includes.common cimport *
from pyarrow.includes.libarrow cimport *
from pyarrow.includes.libarrow_feather cimport *
from pyarrow.lib cimport (check_status, Table, _Weakrefable,
get_writer, get_reader, pyarrow_wrap_table)
from pyarrow.lib import tobytes
class FeatherError(Exception):
pass
def write_feather(Table table, object dest, compression=None,
compression_level=None, chunksize=None, version=2):
cdef shared_ptr[COutputStream] sink
get_writer(dest, &sink)
cdef CFeatherProperties properties
if version == 2:
properties.version = kFeatherV2Version
else:
properties.version = kFeatherV1Version
if compression == 'zstd':
properties.compression = CCompressionType_ZSTD
elif compression == 'lz4':
properties.compression = CCompressionType_LZ4_FRAME
else:
properties.compression = CCompressionType_UNCOMPRESSED
if chunksize is not None:
properties.chunksize = chunksize
if compression_level is not None:
properties.compression_level = compression_level
with nogil:
check_status(WriteFeather(deref(table.table), sink.get(),
properties))
cdef class FeatherReader(_Weakrefable):
cdef:
shared_ptr[CFeatherReader] reader
def __cinit__(self, source, c_bool use_memory_map, c_bool use_threads):
cdef:
shared_ptr[CRandomAccessFile] reader
CIpcReadOptions options = CIpcReadOptions.Defaults()
options.use_threads = use_threads
get_reader(source, use_memory_map, &reader)
with nogil:
self.reader = GetResultValue(CFeatherReader.Open(reader, options))
@property
def version(self):
return self.reader.get().version()
def read(self):
cdef shared_ptr[CTable] sp_table
with nogil:
check_status(self.reader.get()
.Read(&sp_table))
return pyarrow_wrap_table(sp_table)
def read_indices(self, indices):
cdef:
shared_ptr[CTable] sp_table
vector[int] c_indices
for index in indices:
c_indices.push_back(index)
with nogil:
check_status(self.reader.get()
.Read(c_indices, &sp_table))
return pyarrow_wrap_table(sp_table)
def read_names(self, names):
cdef:
shared_ptr[CTable] sp_table
vector[c_string] c_names
for name in names:
c_names.push_back(tobytes(name))
with nogil:
check_status(self.reader.get()
.Read(c_names, &sp_table))
return pyarrow_wrap_table(sp_table)
