[SPARK-8223] [SPARK-8224] [SQL] shift left and shift right

Jira:
https://issues.apache.org/jira/browse/SPARK-8223
https://issues.apache.org/jira/browse/SPARK-8224

~~I am aware of #7174 and will update this pr, if it's merged.~~ Done
I don't know if #7034 can simplify this, but we can have a look on it, if it gets merged

rxin In the Jira ticket the function as no second argument. I added a `numBits` argument that allows to specify the number of bits. I guess this improves the usability. I wanted to add `shiftleft(value)` as well, but the `selectExpr` dataframe tests crashes, if I have both. I order to do this, I added the following to the functions.scala `def shiftRight(e: Column): Column = ShiftRight(e.expr, lit(1).expr)`, but as I mentioned this doesn't pass tests like `df.selectExpr("shiftRight(a)", ...` (not enough arguments exception).

If we need the bitwise shift in order to be hive compatible, I suggest to add `shiftLeft` and something like `shiftLeftX`

Author: Tarek Auel <tarek.auel@googlemail.com>

Closes #7178 from tarekauel/8223 and squashes the following commits:

8023bb5 [Tarek Auel] [SPARK-8223][SPARK-8224] fixed test
f3f64e6 [Tarek Auel] [SPARK-8223][SPARK-8224] Integer -> Int
f628706 [Tarek Auel] [SPARK-8223][SPARK-8224] removed toString; updated function description
3b56f2a [Tarek Auel] Merge remote-tracking branch 'origin/master' into 8223
5189690 [Tarek Auel] [SPARK-8223][SPARK-8224] minor fix and style fix
9434a28 [Tarek Auel] Merge remote-tracking branch 'origin/master' into 8223
44ee324 [Tarek Auel] [SPARK-8223][SPARK-8224] docu fix
ac7fe9d [Tarek Auel] [SPARK-8223][SPARK-8224] right and left bit shift

2 files changed, 72 insertions, 0 deletions

diff --git a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
index e6f623bdf3..a5b6828685 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/functions.scala
@@ -1299,6 +1299,44 @@ object functions {
   def rint(columnName: String): Column = rint(Column(columnName))
 
   /**
+   * Shift the the given value numBits left. If the given value is a long value, this function
+   * will return a long value else it will return an integer value.
+   *
+   * @group math_funcs
+   * @since 1.5.0
+   */
+  def shiftLeft(e: Column, numBits: Int): Column = ShiftLeft(e.expr, lit(numBits).expr)
+
+  /**
+   * Shift the the given value numBits left. If the given value is a long value, this function
+   * will return a long value else it will return an integer value.
+   *
+   * @group math_funcs
+   * @since 1.5.0
+   */
+  def shiftLeft(columnName: String, numBits: Int): Column =
+    shiftLeft(Column(columnName), numBits)
+
+  /**
+   * Shift the the given value numBits right. If the given value is a long value, it will return
+   * a long value else it will return an integer value.
+   *
+   * @group math_funcs
+   * @since 1.5.0
+   */
+  def shiftRight(e: Column, numBits: Int): Column = ShiftRight(e.expr, lit(numBits).expr)
+
+  /**
+   * Shift the the given value numBits right. If the given value is a long value, it will return
+   * a long value else it will return an integer value.
+   *
+   * @group math_funcs
+   * @since 1.5.0
+   */
+  def shiftRight(columnName: String, numBits: Int): Column =
+    shiftRight(Column(columnName), numBits)
+
+  /**
    * Computes the signum of the given value.
    *
    * @group math_funcs
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala
index c03cde38d7..4c5696deaf 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/MathExpressionsSuite.scala
@@ -259,6 +259,40 @@ class MathExpressionsSuite extends QueryTest {
     testOneToOneNonNegativeMathFunction(log1p, math.log1p)
   }
 
+  test("shift left") {
+    val df = Seq[(Long, Integer, Short, Byte, Integer, Integer)]((21, 21, 21, 21, 21, null))
+      .toDF("a", "b", "c", "d", "e", "f")
+
+    checkAnswer(
+      df.select(
+        shiftLeft('a, 1), shiftLeft('b, 1), shiftLeft('c, 1), shiftLeft('d, 1),
+        shiftLeft('f, 1)),
+        Row(42.toLong, 42, 42.toShort, 42.toByte, null))
+
+    checkAnswer(
+      df.selectExpr(
+        "shiftLeft(a, 1)", "shiftLeft(b, 1)", "shiftLeft(b, 1)", "shiftLeft(d, 1)",
+        "shiftLeft(f, 1)"),
+      Row(42.toLong, 42, 42.toShort, 42.toByte, null))
+  }
+
+  test("shift right") {
+    val df = Seq[(Long, Integer, Short, Byte, Integer, Integer)]((42, 42, 42, 42, 42, null))
+      .toDF("a", "b", "c", "d", "e", "f")
+
+    checkAnswer(
+      df.select(
+        shiftRight('a, 1), shiftRight('b, 1), shiftRight('c, 1), shiftRight('d, 1),
+        shiftRight('f, 1)),
+      Row(21.toLong, 21, 21.toShort, 21.toByte, null))
+
+    checkAnswer(
+      df.selectExpr(
+        "shiftRight(a, 1)", "shiftRight(b, 1)", "shiftRight(c, 1)", "shiftRight(d, 1)",
+        "shiftRight(f, 1)"),
+      Row(21.toLong, 21, 21.toShort, 21.toByte, null))
+  }
+
   test("binary log") {
     val df = Seq[(Integer, Integer)]((123, null)).toDF("a", "b")
     checkAnswer(