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https://issues.apache.org/jira/browse/FLINK-3140?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15062006#comment-15062006
]
ASF GitHub Bot commented on FLINK-3140:
---------------------------------------
Github user tillrohrmann commented on a diff in the pull request:
https://github.com/apache/flink/pull/1465#discussion_r47902384
--- Diff:
flink-staging/flink-table/src/main/scala/org/apache/flink/api/table/typeinfo/NullMaskUtils.scala
---
@@ -0,0 +1,92 @@
+/*
+ * 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.flink.api.table.typeinfo
+
+import org.apache.flink.api.table.Row
+import org.apache.flink.core.memory.{DataInputView, DataOutputView}
+
+object NullMaskUtils {
+
+ def writeNullMask(len: Int, value: Row, target: DataOutputView): Unit = {
+ var b = 0x00
+ var bytePos = 0
+
+ var fieldPos = 0
+ while (fieldPos < len) {
+ b = 0x00
+ // set bits in byte
+ bytePos = 0
+ while (bytePos < 8 && fieldPos < len) {
+ b = b << 1
+ // set bit if field is null
+ if(value.productElement(fieldPos) == null) {
+ b |= 0x01
+ }
+ bytePos += 1
+ fieldPos += 1
+ }
+ // shift bits if last byte is not completely filled
+ while (bytePos < 8) {
+ b = b << 1
+ bytePos += 1
+ }
+ // write byte
+ target.writeByte(b)
+ }
--- End diff --
I think the same can be expressed a bit more sacalesque
```
value.productIterator.grouped(8).foreach{
group =>
val byte = group.foldLeft(0){
(byteResult, element) =>
(byteResult << 1) | (if (element == null) 0x01 else 0x00)
}
val finalResult = byte << (8 - group.length)
target.writeByte(finalResult)
}
```
> NULL value data layout in Row Serializer/Comparator
> ---------------------------------------------------
>
> Key: FLINK-3140
> URL: https://issues.apache.org/jira/browse/FLINK-3140
> Project: Flink
> Issue Type: Sub-task
> Components: Table API
> Reporter: Chengxiang Li
> Assignee: Timo Walther
>
> To store/materialize NULL value in Row objects, we should need new Row
> Serializer/Comparator which is aware of NULL value fields.
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