[SPARK-57172][SQL] Simplify Crc32 codegen by extracting a static Java helper

sql/catalyst/src/main/java/org/apache/spark/sql/catalyst/expressions/ExpressionImplUtils.java

@@ -25,6 +25,7 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Locale;
+import java.util.zip.CRC32;
 import javax.crypto.Cipher;
 import javax.crypto.spec.GCMParameterSpec;
 import javax.crypto.spec.IvParameterSpec;
@@ -342,4 +343,15 @@ public static UTF8String quote(UTF8String str) {
     String sp = str.toString().replaceAll(qtChar, qtCharRep);
     return UTF8String.fromString(qtChar + sp + qtChar);
   }
+
+  /**
+   * Computes the CRC32 checksum of {@code bytes} for the {@code crc32} expression.
+   * Shared by the eval and codegen paths so the per-stage generated Java is a
+   * single call rather than an inline allocate / update / getValue sequence.
+   */
+  public static long crc32(byte[] bytes) {
+    CRC32 checksum = new CRC32();
+    checksum.update(bytes, 0, bytes.length);
+    return checksum.getValue();
+  }
 }

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/hash.scala

@@ -19,7 +19,6 @@ package org.apache.spark.sql.catalyst.expressions
 
 import java.math.{BigDecimal, RoundingMode}
 import java.util.concurrent.TimeUnit._
-import java.util.zip.CRC32
 
 import scala.annotation.tailrec
 
@@ -214,20 +213,13 @@ case class Crc32(child: Expression)
   override def contextIndependentFoldable: Boolean = child.contextIndependentFoldable
 
   protected override def nullSafeEval(input: Any): Any = {
-    val checksum = new CRC32
-    checksum.update(input.asInstanceOf[Array[Byte]], 0, input.asInstanceOf[Array[Byte]].length)
-    checksum.getValue
+    ExpressionImplUtils.crc32(input.asInstanceOf[Array[Byte]])
   }
 
   override def doGenCode(ctx: CodegenContext, ev: ExprCode): ExprCode = {
-    val CRC32 = "java.util.zip.CRC32"
-    val checksum = ctx.freshName("checksum")
+    val utils = classOf[ExpressionImplUtils].getName
     nullSafeCodeGen(ctx, ev, value => {
-      s"""
-        $CRC32 $checksum = new $CRC32();
-        $checksum.update($value, 0, $value.length);
-        ${ev.value} = $checksum.getValue();
-      """
+      s"${ev.value} = $utils.crc32($value);"
     })
   }