[CH] Support function base64/unbase64 (#6077)

[CH] Support function base64/unbase64

Co-authored-by: liuneng1994 <[email protected]>

backends-clickhouse/src/test/scala/org/apache/gluten/execution/GlutenClickhouseStringFunctionsSuite.scala

@@ -97,4 +97,44 @@ class GlutenClickhouseStringFunctionsSuite extends GlutenClickHouseWholeStageTra
     }
   }
 
+  test("base64") {
+    val tableName = "base64_table"
+    withTable(tableName) {
+      sql(s"create table $tableName(data String) using parquet")
+      sql(s"""
+             |insert into $tableName values
+             |  ("hello")
+          """.stripMargin)
+
+      val sql_str =
+        s"""
+           |select
+           |    base64(data)
+           |  from $tableName
+      """.stripMargin
+
+      runQueryAndCompare(sql_str) { _ => }
+    }
+  }
+
+  test("unbase64") {
+    val tableName = "unbase64_table"
+    withTable(tableName) {
+      sql(s"create table $tableName(data String) using parquet")
+      sql(s"""
+             |insert into $tableName values
+             |  ("U3BhcmsgU1FM")
+          """.stripMargin)
+
+      val sql_str =
+        s"""
+           |select
+           |    unbase64(data)
+           |  from $tableName
+      """.stripMargin
+
+      runQueryAndCompare(sql_str) { _ => }
+    }
+  }
+
 }

gluten-core/src/main/scala/org/apache/gluten/expression/ExpressionMappings.scala

@@ -101,6 +101,8 @@ object ExpressionMappings {
     Sig[Encode](ENCODE),
     Sig[Uuid](UUID),
     Sig[BitLength](BIT_LENGTH),
+    Sig[UnBase64](UNBASE64),
+    Sig[Base64](BASE64),
 
     // URL functions
     Sig[ParseUrl](PARSE_URL),

shims/common/src/main/scala/org/apache/gluten/expression/ExpressionNames.scala

@@ -127,6 +127,8 @@ object ExpressionNames {
   final val ENCODE = "encode"
   final val UUID = "uuid"
   final val BIT_LENGTH = "bit_length"
+  final val UNBASE64 = "unbase64"
+  final val BASE64 = "base64"
 
   // URL functions
   final val PARSE_URL = "parse_url"