/
TFRecordWriter.scala
65 lines (57 loc) · 2.22 KB
/
TFRecordWriter.scala
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
/* Copyright 2017-18, Emmanouil Antonios Platanios. 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.
*/
package org.platanios.tensorflow.api.io
import java.io.BufferedOutputStream
import java.nio.file.{Files, Path, StandardOpenOption}
import org.platanios.tensorflow.api.utilities.{CRC32C, Coding}
import org.tensorflow.example.Example
/** Helper used to write `Example` protocol buffers to TensorFlow record files.
*
* @param filePath TensorFlow record file path.
*
* @author Emmanouil Antonios Platanios
*/
class TFRecordWriter(val filePath: Path) {
protected var fileStream: BufferedOutputStream = {
new BufferedOutputStream(Files.newOutputStream(
filePath, StandardOpenOption.CREATE_NEW, StandardOpenOption.APPEND))
}
/** Appends `example` to the TensorFlow records file. */
def write(example: Example): Unit = {
val recordBytes = example.toByteArray
// Format of a single record:
// uint64 length
// uint32 masked crc of length
// byte data[length]
// uint32 masked crc of data
val encLength = Coding.encodeFixedInt64(recordBytes.length)
val encLengthMaskedCrc = Coding.encodeFixedInt32(CRC32C.mask(CRC32C.value(encLength)))
val encDataMaskedCrc = Coding.encodeFixedInt32(CRC32C.mask(CRC32C.value(recordBytes)))
fileStream.write(encLength ++ encLengthMaskedCrc ++ recordBytes ++ encDataMaskedCrc)
}
/** Pushes outstanding examples to disk. */
def flush(): Unit = {
fileStream.flush()
}
/** Calls `flush()` and then closes the current TensorFlow records file. */
def close(): Unit = {
fileStream.close()
}
}
object TFRecordWriter {
def apply(filePath: Path): TFRecordWriter = {
new TFRecordWriter(filePath)
}
}