in src/main/scala/org/apache/spark/sql/datasketches/kll/expressions/KllDoublesSketchExpressions.scala [121:133]
override protected def nullSafeCodeGen(ctx: CodegenContext, ev: ExprCode, f: String => String): ExprCode = {
val sketchEval = child.genCode(ctx)
val sketch = ctx.freshName("sketch")
val code =
s"""
|${sketchEval.code}
|final org.apache.datasketches.kll.KllDoublesSketch $sketch = org.apache.spark.sql.datasketches.kll.types.KllDoublesSketchType.wrap(${sketchEval.value});
|final double ${ev.value} = $sketch.getMaxItem();
|final boolean ${ev.isNull} = ${sketchEval.isNull};
""".stripMargin
ev.copy(code = CodeBlock(Seq(code), Seq.empty))
}