Github user mateiz commented on a diff in the pull request:
https://github.com/apache/spark/pull/1658#discussion_r16207161
--- Diff:
core/src/main/scala/org/apache/spark/input/FixedLengthBinaryInputFormat.scala
---
@@ -0,0 +1,95 @@
+/*
+ * 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.
+ */
+
+package org.apache.spark.input
+
+import org.apache.hadoop.fs.Path
+import org.apache.hadoop.io.{BytesWritable, LongWritable}
+import org.apache.hadoop.mapreduce.lib.input.FileInputFormat
+import org.apache.hadoop.mapreduce.{InputSplit, JobContext, RecordReader,
TaskAttemptContext}
+
+/**
+ * Custom Input Format for reading and splitting flat binary files that
contain records,
+ * each of which are a fixed size in bytes. The fixed record size is
specified through
+ * a parameter recordLength in the Hadoop configuration.
+ */
+
+object FixedLengthBinaryInputFormat {
+
+ /**
+ * This function retrieves the recordLength by checking the
configuration parameter
+ *
+ */
+ def getRecordLength(context: JobContext): Int = {
+
+ // retrieve record length from configuration
+ context.getConfiguration.get("recordLength").toInt
+ }
+
+}
+
+class FixedLengthBinaryInputFormat extends FileInputFormat[LongWritable,
BytesWritable] {
+
+
+ /**
+ * Override of isSplitable to ensure initial computation of the record
length
+ */
+ override def isSplitable(context: JobContext, filename: Path): Boolean =
{
+
+ if (recordLength == -1) {
+ recordLength = FixedLengthBinaryInputFormat.getRecordLength(context)
+ }
+ if (recordLength <= 0) {
+ println("record length is less than 0, file cannot be split")
+ false
+ } else {
+ true
+ }
+
+ }
+
+ /**
+ * This input format overrides computeSplitSize() to make sure that each
split
+ * only contains full records. Each InputSplit passed to
FixedLengthBinaryRecordReader
+ * will start at the first byte of a record, and the last byte will the
last byte of a record.
+ */
+ override def computeSplitSize(blockSize: Long, minSize: Long, maxSize:
Long): Long = {
+
+ val defaultSize = super.computeSplitSize(blockSize, minSize, maxSize)
+
+ // If the default size is less than the length of a record, make it
equal to it
+ // Otherwise, make sure the split size is as close to possible as the
default size,
+ // but still contains a complete set of records, with the first record
+ // starting at the first byte in the split and the last record ending
with the last byte
+
+ defaultSize match {
+ case x if x < recordLength => recordLength.toLong
+ case _ => (Math.floor(defaultSize / recordLength) *
recordLength).toLong
+ }
--- End diff --
Probably clearer to write this as
```
if (defaultSize < recordLength) {
recordLenght.toLong
} else {
(Math.floor(defaultSize / recordLength) * recordLength).toLong
}
```
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