# Copyright 2017 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. # ============================================================================== """Python wrappers for reader Datasets.""" import os from tensorflow.python import tf2 from tensorflow.python.data.ops import dataset_ops from tensorflow.python.data.ops import from_tensor_slices_op from tensorflow.python.data.ops import structured_function from tensorflow.python.data.util import convert from tensorflow.python.framework import dtypes from tensorflow.python.framework import ops from tensorflow.python.framework import tensor_shape from tensorflow.python.framework import tensor_spec from tensorflow.python.framework import type_spec from tensorflow.python.ops import array_ops from tensorflow.python.ops import gen_dataset_ops from tensorflow.python.ops import gen_experimental_dataset_ops as ged_ops from tensorflow.python.util import nest from tensorflow.python.util.tf_export import tf_export _DEFAULT_READER_BUFFER_SIZE_BYTES = 256 * 1024 # 256 KB def _normalise_fspath(path): """Convert pathlib-like objects to str (__fspath__ compatibility, PEP 519).""" return os.fspath(path) if isinstance(path, os.PathLike) else path def _create_or_validate_filenames_dataset(filenames, name=None): """Creates (or validates) a dataset of filenames. Args: filenames: Either a list or dataset of filenames. If it is a list, it is convert to a dataset. If it is a dataset, its type and shape is validated. name: (Optional.) A name for the tf.data operation. Returns: A dataset of filenames. """ if isinstance(filenames, dataset_ops.DatasetV2): element_type = dataset_ops.get_legacy_output_types(filenames) if element_type != dtypes.string: raise TypeError( "The `filenames` argument must contain `tf.string` elements. Got a " f"dataset of `{element_type!r}` elements.") element_shape = dataset_ops.get_legacy_output_shapes(filenames) if not element_shape.is_compatible_with(tensor_shape.TensorShape([])): raise TypeError( "The `filenames` argument must contain `tf.string` elements of shape " "[] (i.e. scalars). Got a dataset of element shape " f"{element_shape!r}.") else: filenames = nest.map_structure(_normalise_fspath, filenames) filenames = ops.convert_to_tensor(filenames, dtype_hint=dtypes.string) if filenames.dtype != dtypes.string: raise TypeError( "The `filenames` argument must contain `tf.string` elements. Got " f"`{filenames.dtype!r}` elements.") filenames = array_ops.reshape(filenames, [-1], name="flat_filenames") filenames = from_tensor_slices_op._TensorSliceDataset( # pylint: disable=protected-access filenames, is_files=True, name=name) return filenames def _create_dataset_reader(dataset_creator, filenames, num_parallel_reads=None, name=None): """Creates a dataset that reads the given files using the given reader. Args: dataset_creator: A function that takes in a single file name and returns a dataset. filenames: A `tf.data.Dataset` containing one or more filenames. num_parallel_reads: The number of parallel reads we should do. name: (Optional.) A name for the tf.data operation. Returns: A `Dataset` that reads data from `filenames`. """ def read_one_file(filename): filename = ops.convert_to_tensor(filename, dtypes.string, name="filename") return dataset_creator(filename) if num_parallel_reads is None: return filenames.flat_map(read_one_file, name=name) elif num_parallel_reads == dataset_ops.AUTOTUNE: return filenames.interleave( read_one_file, num_parallel_calls=num_parallel_reads, name=name) else: return ParallelInterleaveDataset( filenames, read_one_file, cycle_length=num_parallel_reads, block_length=1, sloppy=False, buffer_output_elements=None, prefetch_input_elements=None, name=name) def _get_type(value): """Returns the type of `value` if it is a TypeSpec.""" if isinstance(value, type_spec.TypeSpec): return value.value_type() else: return type(value) class _TextLineDataset(dataset_ops.DatasetSource): """A `Dataset` comprising records from one or more text files.""" def __init__(self, filenames, compression_type=None, buffer_size=None, name=None): """Creates a `TextLineDataset`. Args: filenames: A `tf.string` tensor containing one or more filenames. compression_type: (Optional.) A `tf.string` scalar evaluating to one of `""` (no compression), `"ZLIB"`, or `"GZIP"`. buffer_size: (Optional.) A `tf.int64` scalar denoting the number of bytes to buffer. A value of 0 results in the default buffering values chosen based on the compression type. name: (Optional.) A name for the tf.data operation. """ self._filenames = filenames self._compression_type = convert.optional_param_to_tensor( "compression_type", compression_type, argument_default="", argument_dtype=dtypes.string) self._buffer_size = convert.optional_param_to_tensor( "buffer_size", buffer_size, argument_default=_DEFAULT_READER_BUFFER_SIZE_BYTES) self._name = name variant_tensor = gen_dataset_ops.text_line_dataset( self._filenames, self._compression_type, self._buffer_size, metadata=self._metadata.SerializeToString()) super(_TextLineDataset, self).__init__(variant_tensor) @property def element_spec(self): return tensor_spec.TensorSpec([], dtypes.string) @tf_export("data.TextLineDataset", v1=[]) class TextLineDatasetV2(dataset_ops.DatasetSource): r"""Creates a `Dataset` comprising lines from one or more text files. The `tf.data.TextLineDataset` loads text from text files and creates a dataset where each line of the files becomes an element of the dataset. For example, suppose we have 2 files "text_lines0.txt" and "text_lines1.txt" with the following lines: >>> with open('/tmp/text_lines0.txt', 'w') as f: ... f.write('the cow\n') ... f.write('jumped over\n') ... f.write('the moon\n') >>> with open('/tmp/text_lines1.txt', 'w') as f: ... f.write('jack and jill\n') ... f.write('went up\n') ... f.write('the hill\n') We can construct a TextLineDataset from them as follows: >>> dataset = tf.data.TextLineDataset(['/tmp/text_lines0.txt', ... '/tmp/text_lines1.txt']) The elements of the dataset are expected to be: >>> for element in dataset.as_numpy_iterator(): ... print(element) b'the cow' b'jumped over' b'the moon' b'jack and jill' b'went up' b'the hill' """ def __init__(self, filenames, compression_type=None, buffer_size=None, num_parallel_reads=None, name=None): r"""Creates a `TextLineDataset`. The elements of the dataset will be the lines of the input files, using the newline character '\n' to denote line splits. The newline characters will be stripped off of each element. Args: filenames: A `tf.data.Dataset` whose elements are `tf.string` scalars, a `tf.string` tensor, or a value that can be converted to a `tf.string` tensor (such as a list of Python strings). compression_type: (Optional.) A `tf.string` scalar evaluating to one of `""` (no compression), `"ZLIB"`, or `"GZIP"`. buffer_size: (Optional.) A `tf.int64` scalar denoting the number of bytes to buffer. A value of 0 results in the default buffering values chosen based on the compression type. num_parallel_reads: (Optional.) A `tf.int64` scalar representing the number of files to read in parallel. If greater than one, the records of files read in parallel are outputted in an interleaved order. If your input pipeline is I/O bottlenecked, consider setting this parameter to a value greater than one to parallelize the I/O. If `None`, files will be read sequentially. name: (Optional.) A name for the tf.data operation. """ filenames = _create_or_validate_filenames_dataset(filenames, name=name) self._filenames = filenames self._compression_type = compression_type self._buffer_size = buffer_size def creator_fn(filename): return _TextLineDataset( filename, compression_type, buffer_size, name=name) self._impl = _create_dataset_reader( creator_fn, filenames, num_parallel_reads, name=name) variant_tensor = self._impl._variant_tensor # pylint: disable=protected-access super(TextLineDatasetV2, self).__init__(variant_tensor) @property def element_spec(self): return tensor_spec.TensorSpec([], dtypes.string) @tf_export(v1=["data.TextLineDataset"]) class TextLineDatasetV1(dataset_ops.DatasetV1Adapter): """A `Dataset` comprising lines from one or more text files.""" def __init__(self, filenames, compression_type=None, buffer_size=None, num_parallel_reads=None, name=None): wrapped = TextLineDatasetV2(filenames, compression_type, buffer_size, num_parallel_reads, name) super(TextLineDatasetV1, self).__init__(wrapped) __init__.__doc__ = TextLineDatasetV2.__init__.__doc__ @property def _filenames(self): return self._dataset._filenames # pylint: disable=protected-access @_filenames.setter def _filenames(self, value): self._dataset._filenames = value # pylint: disable=protected-access class _TFRecordDataset(dataset_ops.DatasetSource): """A `Dataset` comprising records from one or more TFRecord files.""" def __init__(self, filenames, compression_type=None, buffer_size=None, name=None): """Creates a `TFRecordDataset`. Args: filenames: A `tf.string` tensor containing one or more filenames. compression_type: (Optional.) A `tf.string` scalar evaluating to one of `""` (no compression), `"ZLIB"`, or `"GZIP"`. buffer_size: (Optional.) A `tf.int64` scalar representing the number of bytes in the read buffer. 0 means no buffering. name: (Optional.) A name for the tf.data operation. """ self._filenames = filenames self._compression_type = convert.optional_param_to_tensor( "compression_type", compression_type, argument_default="", argument_dtype=dtypes.string) self._buffer_size = convert.optional_param_to_tensor( "buffer_size", buffer_size, argument_default=_DEFAULT_READER_BUFFER_SIZE_BYTES) self._name = name variant_tensor = gen_dataset_ops.tf_record_dataset( self._filenames, self._compression_type, self._buffer_size, metadata=self._metadata.SerializeToString()) super(_TFRecordDataset, self).__init__(variant_tensor) @property def element_spec(self): return tensor_spec.TensorSpec([], dtypes.string) class ParallelInterleaveDataset(dataset_ops.UnaryDataset): """A `Dataset` that maps a function over its input and flattens the result.""" def __init__(self, input_dataset, map_func, cycle_length, block_length, sloppy, buffer_output_elements, prefetch_input_elements, name=None): """See `tf.data.experimental.parallel_interleave()` for details.""" self._input_dataset = input_dataset self._map_func = structured_function.StructuredFunctionWrapper( map_func, self._transformation_name(), dataset=input_dataset) if not isinstance(self._map_func.output_structure, dataset_ops.DatasetSpec): raise TypeError( "The `map_func` argument must return a `Dataset` object. Got " f"{_get_type(self._map_func.output_structure)!r}.") self._element_spec = self._map_func.output_structure._element_spec # pylint: disable=protected-access self._cycle_length = ops.convert_to_tensor( cycle_length, dtype=dtypes.int64, name="cycle_length") self._block_length = ops.convert_to_tensor( block_length, dtype=dtypes.int64, name="block_length") self._buffer_output_elements = convert.optional_param_to_tensor( "buffer_output_elements", buffer_output_elements, argument_default=2 * block_length) self._prefetch_input_elements = convert.optional_param_to_tensor( "prefetch_input_elements", prefetch_input_elements, argument_default=2 * cycle_length) if sloppy is None: self._deterministic = "default" elif sloppy: self._deterministic = "false" else: self._deterministic = "true" self._name = name variant_tensor = ged_ops.legacy_parallel_interleave_dataset_v2( self._input_dataset._variant_tensor, # pylint: disable=protected-access self._map_func.function.captured_inputs, self._cycle_length, self._block_length, self._buffer_output_elements, self._prefetch_input_elements, f=self._map_func.function, deterministic=self._deterministic, **self._common_args) super(ParallelInterleaveDataset, self).__init__(input_dataset, variant_tensor) def _functions(self): return [self._map_func] @property def element_spec(self): return self._element_spec def _transformation_name(self): return "tf.data.experimental.parallel_interleave()" @tf_export("data.TFRecordDataset", v1=[]) class TFRecordDatasetV2(dataset_ops.DatasetV2): """A `Dataset` comprising records from one or more TFRecord files. This dataset loads TFRecords from the files as bytes, exactly as they were written.`TFRecordDataset` does not do any parsing or decoding on its own. Parsing and decoding can be done by applying `Dataset.map` transformations after the `TFRecordDataset`. A minimal example is given below: >>> import tempfile >>> example_path = os.path.join(tempfile.gettempdir(), "example.tfrecords") >>> np.random.seed(0) >>> # Write the records to a file. ... with tf.io.TFRecordWriter(example_path) as file_writer: ... for _ in range(4): ... x, y = np.random.random(), np.random.random() ... ... record_bytes = tf.train.Example(features=tf.train.Features(feature={ ... "x": tf.train.Feature(float_list=tf.train.FloatList(value=[x])), ... "y": tf.train.Feature(float_list=tf.train.FloatList(value=[y])), ... })).SerializeToString() ... file_writer.write(record_bytes) >>> # Read the data back out. >>> def decode_fn(record_bytes): ... return tf.io.parse_single_example( ... # Data ... record_bytes, ... ... # Schema ... {"x": tf.io.FixedLenFeature([], dtype=tf.float32), ... "y": tf.io.FixedLenFeature([], dtype=tf.float32)} ... ) >>> for batch in tf.data.TFRecordDataset([example_path]).map(decode_fn): ... print("x = {x:.4f}, y = {y:.4f}".format(**batch)) x = 0.5488, y = 0.7152 x = 0.6028, y = 0.5449 x = 0.4237, y = 0.6459 x = 0.4376, y = 0.8918 """ def __init__(self, filenames, compression_type=None, buffer_size=None, num_parallel_reads=None, name=None): """Creates a `TFRecordDataset` to read one or more TFRecord files. Each element of the dataset will contain a single TFRecord. Args: filenames: A `tf.string` tensor or `tf.data.Dataset` containing one or more filenames. compression_type: (Optional.) A `tf.string` scalar evaluating to one of `""` (no compression), `"ZLIB"`, or `"GZIP"`. buffer_size: (Optional.) A `tf.int64` scalar representing the number of bytes in the read buffer. If your input pipeline is I/O bottlenecked, consider setting this parameter to a value 1-100 MBs. If `None`, a sensible default for both local and remote file systems is used. num_parallel_reads: (Optional.) A `tf.int64` scalar representing the number of files to read in parallel. If greater than one, the records of files read in parallel are outputted in an interleaved order. If your input pipeline is I/O bottlenecked, consider setting this parameter to a value greater than one to parallelize the I/O. If `None`, files will be read sequentially. name: (Optional.) A name for the tf.data operation. Raises: TypeError: If any argument does not have the expected type. ValueError: If any argument does not have the expected shape. """ filenames = _create_or_validate_filenames_dataset(filenames, name=name) self._filenames = filenames self._compression_type = compression_type self._buffer_size = buffer_size self._num_parallel_reads = num_parallel_reads def creator_fn(filename): return _TFRecordDataset( filename, compression_type, buffer_size, name=name) self._impl = _create_dataset_reader( creator_fn, filenames, num_parallel_reads, name=name) variant_tensor = self._impl._variant_tensor # pylint: disable=protected-access super(TFRecordDatasetV2, self).__init__(variant_tensor) def _inputs(self): return self._impl._inputs() # pylint: disable=protected-access @property def element_spec(self): return tensor_spec.TensorSpec([], dtypes.string) @tf_export(v1=["data.TFRecordDataset"]) class TFRecordDatasetV1(dataset_ops.DatasetV1Adapter): """A `Dataset` comprising records from one or more TFRecord files.""" def __init__(self, filenames, compression_type=None, buffer_size=None, num_parallel_reads=None, name=None): wrapped = TFRecordDatasetV2( filenames, compression_type, buffer_size, num_parallel_reads, name=name) super(TFRecordDatasetV1, self).__init__(wrapped) __init__.__doc__ = TFRecordDatasetV2.__init__.__doc__ @property def _filenames(self): return self._dataset._filenames # pylint: disable=protected-access @_filenames.setter def _filenames(self, value): self._dataset._filenames = value # pylint: disable=protected-access class _FixedLengthRecordDataset(dataset_ops.DatasetSource): """A `Dataset` of fixed-length records from one or more binary files.""" def __init__(self, filenames, record_bytes, header_bytes=None, footer_bytes=None, buffer_size=None, compression_type=None, name=None): """Creates a `FixedLengthRecordDataset`. Args: filenames: A `tf.string` tensor containing one or more filenames. record_bytes: A `tf.int64` scalar representing the number of bytes in each record. header_bytes: (Optional.) A `tf.int64` scalar representing the number of bytes to skip at the start of a file. footer_bytes: (Optional.) A `tf.int64` scalar representing the number of bytes to ignore at the end of a file. buffer_size: (Optional.) A `tf.int64` scalar representing the number of bytes to buffer when reading. compression_type: (Optional.) A `tf.string` scalar evaluating to one of `""` (no compression), `"ZLIB"`, or `"GZIP"`. name: (Optional.) A name for the tf.data operation. """ self._filenames = filenames self._record_bytes = ops.convert_to_tensor( record_bytes, dtype=dtypes.int64, name="record_bytes") self._header_bytes = convert.optional_param_to_tensor( "header_bytes", header_bytes) self._footer_bytes = convert.optional_param_to_tensor( "footer_bytes", footer_bytes) self._buffer_size = convert.optional_param_to_tensor( "buffer_size", buffer_size, _DEFAULT_READER_BUFFER_SIZE_BYTES) self._compression_type = convert.optional_param_to_tensor( "compression_type", compression_type, argument_default="", argument_dtype=dtypes.string) self._name = name variant_tensor = gen_dataset_ops.fixed_length_record_dataset_v2( self._filenames, self._header_bytes, self._record_bytes, self._footer_bytes, self._buffer_size, self._compression_type, metadata=self._metadata.SerializeToString()) super(_FixedLengthRecordDataset, self).__init__(variant_tensor) @property def element_spec(self): return tensor_spec.TensorSpec([], dtypes.string) @tf_export("data.FixedLengthRecordDataset", v1=[]) class FixedLengthRecordDatasetV2(dataset_ops.DatasetSource): """A `Dataset` of fixed-length records from one or more binary files. The `tf.data.FixedLengthRecordDataset` reads fixed length records from binary files and creates a dataset where each record becomes an element of the dataset. The binary files can have a fixed length header and a fixed length footer, which will both be skipped. For example, suppose we have 2 files "fixed_length0.bin" and "fixed_length1.bin" with the following content: >>> with open('/tmp/fixed_length0.bin', 'wb') as f: ... f.write(b'HEADER012345FOOTER') >>> with open('/tmp/fixed_length1.bin', 'wb') as f: ... f.write(b'HEADER6789abFOOTER') We can construct a `FixedLengthRecordDataset` from them as follows: >>> dataset1 = tf.data.FixedLengthRecordDataset( ... filenames=['/tmp/fixed_length0.bin', '/tmp/fixed_length1.bin'], ... record_bytes=2, header_bytes=6, footer_bytes=6) The elements of the dataset are: >>> for element in dataset1.as_numpy_iterator(): ... print(element) b'01' b'23' b'45' b'67' b'89' b'ab' """ def __init__(self, filenames, record_bytes, header_bytes=None, footer_bytes=None, buffer_size=None, compression_type=None, num_parallel_reads=None, name=None): """Creates a `FixedLengthRecordDataset`. Args: filenames: A `tf.string` tensor or `tf.data.Dataset` containing one or more filenames. record_bytes: A `tf.int64` scalar representing the number of bytes in each record. header_bytes: (Optional.) A `tf.int64` scalar representing the number of bytes to skip at the start of a file. footer_bytes: (Optional.) A `tf.int64` scalar representing the number of bytes to ignore at the end of a file. buffer_size: (Optional.) A `tf.int64` scalar representing the number of bytes to buffer when reading. compression_type: (Optional.) A `tf.string` scalar evaluating to one of `""` (no compression), `"ZLIB"`, or `"GZIP"`. num_parallel_reads: (Optional.) A `tf.int64` scalar representing the number of files to read in parallel. If greater than one, the records of files read in parallel are outputted in an interleaved order. If your input pipeline is I/O bottlenecked, consider setting this parameter to a value greater than one to parallelize the I/O. If `None`, files will be read sequentially. name: (Optional.) A name for the tf.data operation. """ filenames = _create_or_validate_filenames_dataset(filenames, name=name) self._filenames = filenames self._record_bytes = record_bytes self._header_bytes = header_bytes self._footer_bytes = footer_bytes self._buffer_size = buffer_size self._compression_type = compression_type def creator_fn(filename): return _FixedLengthRecordDataset( filename, record_bytes, header_bytes, footer_bytes, buffer_size, compression_type, name=name) self._impl = _create_dataset_reader( creator_fn, filenames, num_parallel_reads, name=name) variant_tensor = self._impl._variant_tensor # pylint: disable=protected-access super(FixedLengthRecordDatasetV2, self).__init__(variant_tensor) @property def element_spec(self): return tensor_spec.TensorSpec([], dtypes.string) @tf_export(v1=["data.FixedLengthRecordDataset"]) class FixedLengthRecordDatasetV1(dataset_ops.DatasetV1Adapter): """A `Dataset` of fixed-length records from one or more binary files.""" def __init__(self, filenames, record_bytes, header_bytes=None, footer_bytes=None, buffer_size=None, compression_type=None, num_parallel_reads=None, name=None): wrapped = FixedLengthRecordDatasetV2( filenames, record_bytes, header_bytes, footer_bytes, buffer_size, compression_type, num_parallel_reads, name=name) super(FixedLengthRecordDatasetV1, self).__init__(wrapped) __init__.__doc__ = FixedLengthRecordDatasetV2.__init__.__doc__ @property def _filenames(self): return self._dataset._filenames # pylint: disable=protected-access @_filenames.setter def _filenames(self, value): self._dataset._filenames = value # pylint: disable=protected-access if tf2.enabled(): FixedLengthRecordDataset = FixedLengthRecordDatasetV2 TFRecordDataset = TFRecordDatasetV2 TextLineDataset = TextLineDatasetV2 else: FixedLengthRecordDataset = FixedLengthRecordDatasetV1 TFRecordDataset = TFRecordDatasetV1 TextLineDataset = TextLineDatasetV1