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# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed 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.
# ==============================================================================
"""For reading and writing TFRecords files."""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function
from tensorflow.python import pywrap_tensorflow
from tensorflow.python.framework import errors
from tensorflow.python.util import compat
from tensorflow.python.util.tf_export import tf_export
@tf_export("python_io.TFRecordCompressionType")
class TFRecordCompressionType(object):
"""The type of compression for the record."""
NONE = 0
ZLIB = 1
GZIP = 2
# NOTE(vrv): This will eventually be converted into a proto. to match
# the interface used by the C++ RecordWriter.
@tf_export("python_io.TFRecordOptions")
class TFRecordOptions(object):
"""Options used for manipulating TFRecord files."""
compression_type_map = {
TFRecordCompressionType.ZLIB: "ZLIB",
TFRecordCompressionType.GZIP: "GZIP",
TFRecordCompressionType.NONE: ""
}
def __init__(self, compression_type):
self.compression_type = compression_type
@classmethod
def get_compression_type_string(cls, options):
if not options:
return ""
return cls.compression_type_map[options.compression_type]
@tf_export("python_io.tf_record_iterator")
def tf_record_iterator(path, options=None):
"""An iterator that read the records from a TFRecords file.
Args:
path: The path to the TFRecords file.
options: (optional) A TFRecordOptions object.
Yields:
Strings.
Raises:
IOError: If `path` cannot be opened for reading.
"""
compression_type = TFRecordOptions.get_compression_type_string(options)
with errors.raise_exception_on_not_ok_status() as status:
reader = pywrap_tensorflow.PyRecordReader_New(
compat.as_bytes(path), 0, compat.as_bytes(compression_type), status)
if reader is None:
raise IOError("Could not open %s." % path)
while True:
try:
with errors.raise_exception_on_not_ok_status() as status:
reader.GetNext(status)
except errors.OutOfRangeError:
break
yield reader.record()
reader.Close()
@tf_export("python_io.TFRecordWriter")
class TFRecordWriter(object):
"""A class to write records to a TFRecords file.
This class implements `__enter__` and `__exit__`, and can be used
in `with` blocks like a normal file.
"""
# TODO(josh11b): Support appending?
def __init__(self, path, options=None):
"""Opens file `path` and creates a `TFRecordWriter` writing to it.
Args:
path: The path to the TFRecords file.
options: (optional) A TFRecordOptions object.
Raises:
IOError: If `path` cannot be opened for writing.
"""
compression_type = TFRecordOptions.get_compression_type_string(options)
with errors.raise_exception_on_not_ok_status() as status:
self._writer = pywrap_tensorflow.PyRecordWriter_New(
compat.as_bytes(path), compat.as_bytes(compression_type), status)
def __enter__(self):
"""Enter a `with` block."""
return self
def __exit__(self, unused_type, unused_value, unused_traceback):
"""Exit a `with` block, closing the file."""
self.close()
def write(self, record):
"""Write a string record to the file.
Args:
record: str
"""
self._writer.WriteRecord(record)
def flush(self):
"""Flush the file."""
with errors.raise_exception_on_not_ok_status() as status:
self._writer.Flush(status)
def close(self):
"""Close the file."""
with errors.raise_exception_on_not_ok_status() as status:
self._writer.Close(status)
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