Github user ueshin commented on a diff in the pull request:
https://github.com/apache/spark/pull/1586#discussion_r15725455
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringOperations.scala
---
@@ -208,6 +211,96 @@ case class EndsWith(left: Expression, right:
Expression)
def compare(l: String, r: String) = l.endsWith(r)
}
+
+/**
+ * A function that returns the number of bytes in an expression
+ */
+case class Length(child: Expression) extends UnaryExpression {
+
+ type EvaluatedType = Any
+
+ override def dataType = IntegerType
+
+ override def foldable = child.foldable
+
+ override def nullable = child.nullable
+
+ override def toString = s"Length($child)"
+
+ override def eval(input: Row): EvaluatedType = {
+ val inputVal = child.eval(input)
+ if (inputVal == null) {
+ null
+ } else if (!inputVal.isInstanceOf[String]) {
+ inputVal.toString.length
+ } else {
+ OctetLenUtils.len(inputVal.asInstanceOf[String])
--- End diff --
We can just use `String#codePointCount`, which can do the same thing as
Hive's implementation.
`OctetLenUtils.len` implementation is not the same as Hive's one.
Hive uses `o.a.h.io.Text` as an argument of the method, which returns UTF-8
bytes by `getBytes()` but `java.lang.String#getBytes` returns
platform-dependent bytes.
The reason why Hive checks one by one here is not to decode string from
UTF-8 bytes.
Doing encode/decode is heavy, so we should do it as less as possible.
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