ueshin commented on a change in pull request #24918: [SPARK-28077][SQL] Support
ANSI SQL OVERLAY function.
URL: https://github.com/apache/spark/pull/24918#discussion_r297459041
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
##########
@@ -454,6 +454,68 @@ case class StringReplace(srcExpr: Expression, searchExpr:
Expression, replaceExp
override def prettyName: String = "replace"
}
+object Overlay {
+
+ def calcuate(input: UTF8String, replace: UTF8String, pos: Integer, len:
Integer): UTF8String = {
+ val header = input.substringSQL(1, pos - 1)
+ var length = len
+ if (len < 0) {
+ length = replace.toString().length()
+ }
+ val tailer = input.substringSQL(pos + length, Int.MaxValue)
+ UTF8String.fromString(header.toString + replace.toString + tailer.toString)
+ }
+}
+
+// scalastyle:off line.size.limit
+@ExpressionDescription(
+ usage = "_FUNC_(input, replace, pos[, len]) - Replace `input` with `replace`
that starts at `pos` and is of length `len`.",
+ examples = """
+ Examples:
+ > SELECT _FUNC_('Spark SQL' PLACING '_' FROM 6);
+ Spark_SQL
+ > SELECT _FUNC_('Spark SQL' PLACING 'CORE' FROM 7);
+ Spark CORE
+ > SELECT _FUNC_('Spark SQL' PLACING 'ANSI ' FROM 7 FOR 0);
+ Spark ANSI SQL
+ > SELECT _FUNC_('Spark SQL' PLACING 'tructured' FROM 2 FOR 4);
+ Structured SQL
+ """)
+// scalastyle:on line.size.limit
+case class Overlay(input: Expression, replace: Expression, pos: Expression,
len: Expression)
+ extends QuaternaryExpression with ImplicitCastInputTypes with NullIntolerant
{
+
+ def this(str: Expression, replace: Expression, pos: Expression) = {
+ this(str, replace, pos, Literal.create(-1, IntegerType))
+ }
+
+ override def dataType: DataType = StringType
+
+ override def inputTypes: Seq[AbstractDataType] =
+ Seq(StringType, StringType, IntegerType, IntegerType)
+
+ override def children: Seq[Expression] = input :: replace :: pos :: len ::
Nil
+
+ override def nullSafeEval(inputEval: Any, replaceEval: Any, posEval: Any,
lenEval: Any): Any = {
+ val inputStr = inputEval.asInstanceOf[UTF8String]
+ val replaceStr = replaceEval.asInstanceOf[UTF8String]
+ val position = posEval.asInstanceOf[Int]
+ val length = lenEval.asInstanceOf[Int]
+ Overlay.calcuate(inputStr, replaceStr, position, length)
+ }
+
+ override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+ val result = ctx.addMutableState("UTF8String", "result")
Review comment:
I don't think we need to put this to mutable state?
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