[CALCITE-6805] Support hex function for Hive and Spark Library

[xuzifu666]

Currently Spark Hive hex and unhex function not introduce for calcite, need to support it.

jira: https://issues.apache.org/jira/browse/CALCITE-6805

[xuzifu666]

@rubenada Thanks for your review, all comments had addressed, PTAL

[rubenada]

Thanks @xuzifu666 . I left another minor comment, but overall lgtm.
One small detail: there's a typo on the Jira title, PR title and (most importantly) on the commit message (Libaray instead of Library), could you please fix that?

[xuzifu666]

Thanks @xuzifu666 . I left another minor comment, but overall lgtm. One small detail: there's a typo on the Jira title, PR title and (most importantly) on the commit message (Libaray instead of Library), could you please fix that?

Very Thanks for @rubenada review , had addressed comments and fix the title of pr and commit, PTAL~

[caicancai]

You need to add more tests

e.g.

scala> val df = spark.sql("select unhex(null)")
df: org.apache.spark.sql.DataFrame = [unhex(NULL): binary]

scala> df.show()
+-----------+
|unhex(NULL)|
+-----------+
|       null|
+-----------+


scala> val df = spark.sql("select unhex(0)")
df: org.apache.spark.sql.DataFrame = [unhex(0): binary]

scala> df.show()
+--------+
|unhex(0)|
+--------+
|    [00]|
+--------+


scala> val df = spark.sql("select unhex(-1)")
df: org.apache.spark.sql.DataFrame = [unhex(-1): binary]

scala> df.show()
+---------+
|unhex(-1)|
+---------+
|     null|
+---------+

[xuzifu666]

done

[caicancai]

Are you sure that unhex(0) is equal to null? I tested it in Spark and the result is [00]

[xuzifu666]

Yes, unhex maybe had some problem in hive and spark side, after discussion I remove the implement of unhex from this pr, this pr change to support hex only and issue also changed too.

[rubenada]

@xuzifu666 feel free to open a separate Jira ticket (related to this one) to cover the unhex implementation, even if you don't plan to work on it right away.

[xuzifu666]

@caicancai had addressed comments，PTAL

[caicancai]

I'm not sure if it's UTF-8, but I'd accept it if it's compatible with all tests

[xuzifu666]

Thanks, UTF-8 seems ok for all, I had consider other funciton such md5/base32.. function also use UTF8 and CI is OK.

[rubenada]

LGTM, @caicancai waiting for you approval too before finalize the merge.

[caicancai]

Need to add some tests

[xuzifu666]

Need to add some tests

Thanks for reminder, I had add more tests for it~ @caicancai

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[caicancai]

LGTM

[caicancai]

Just a small suggestion, you don't need to compress and submit every time, just compress and submit after the final approval.