[SPARK-17263][SQL] Add hexadecimal literal parsing

## What changes were proposed in this pull request?
This PR adds the ability to parse SQL (hexadecimal) binary literals (AKA bit strings). It follows the following syntax `X'[Hexadecimal Characters]+'`, for example: `X'01AB'` would create a binary the following binary array `0x01AB`.

If an uneven number of hexadecimal characters is passed, then the upper 4 bits of the initial byte are kept empty, and the lower 4 bits are filled using the first character. For example `X'1C7'` would create the following binary array `0x01C7`.

Binary data (Array[Byte]) does not have a proper `hashCode` and `equals` functions. This meant that comparing `Literal`s containing binary data was a pain. I have updated Literal.hashCode and Literal.equals to deal properly with binary data.

## How was this patch tested?
Added tests to the `ExpressionParserSuite`, `SQLQueryTestSuite` and `ExpressionSQLBuilderSuite`.

Author: Herman van Hovell <hvanhovell@databricks.com>

Closes #14832 from hvanhovell/SPARK-17263.

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/hive/src/test/scala/org/apache/spark/sql/catalyst/ExpressionSQLBuilderSuite.scala b/sql/hive/src/test/scala/org/apache/spark/sql/catalyst/ExpressionSQLBuilderSuite.scala
index 43a218b4d1..d2b2f38fa1 100644
--- a/sql/hive/src/test/scala/org/apache/spark/sql/catalyst/ExpressionSQLBuilderSuite.scala
+++ b/sql/hive/src/test/scala/org/apache/spark/sql/catalyst/ExpressionSQLBuilderSuite.scala
@@ -40,6 +40,7 @@ class ExpressionSQLBuilderSuite extends SQLBuilderTest {
     checkSQL(Literal(Double.NegativeInfinity), "CAST('-Infinity' AS DOUBLE)")
     checkSQL(Literal(Double.NaN), "CAST('NaN' AS DOUBLE)")
     checkSQL(Literal(BigDecimal("10.0000000").underlying), "10.0000000BD")
+    checkSQL(Literal(Array(0x01, 0xA3).map(_.toByte)), "X'01A3'")
     checkSQL(
       Literal(Timestamp.valueOf("2016-01-01 00:00:00")), "TIMESTAMP('2016-01-01 00:00:00.0')")
     // TODO tests for decimals