beliefer 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_r296566625
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/stringExpressions.scala
##########
@@ -454,6 +454,70 @@ case class StringReplace(srcExpr: Expression, searchExpr:
Expression, replaceExp
override def prettyName: String = "replace"
}
+// 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(Integer.MAX_VALUE))
+ }
+
+ 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].toString
+ val position = posEval.asInstanceOf[Int]
+ var length = lenEval.asInstanceOf[Int]
+ if (length.equals(Int.MaxValue)) {
+ length = replaceStr.size
+ }
+ val headStr = inputStr.substringSQL(1, position - 1)
+ val tailStr = inputStr.substringSQL(position + length, Int.MaxValue)
+ UTF8String.fromString(headStr.toString + replaceStr + tailStr.toString)
+ }
+
+ override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
+ val isMax = ctx.freshName("isMax")
+ val length = ctx.freshName("length")
+ val integer = classOf[java.lang.Integer].getName
+ val head = ctx.freshName("head")
+ val tail = ctx.freshName("tail")
+ defineCodeGen(ctx, ev, (input, replace, pos, len) => {
+ s"""
+ boolean $isMax = $len.equals($integer.MAX_VALUE);
+ int $length = $len;
+ if ($isMax) {
+ $length = $replace.toString.size;
+ }
+ UTF8String $head = $input.substringSQL(1, $pos - 1);
+ UTF8String $tail = $input.substringSQL($pos + $length,
$integer.MAX_VALUE);
+ $head + $replace + $tail;
+ }
Review comment:
@ueshin Thanks for your review. I added some tests in
`StringExpressionsSuite`.
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