[jira] [Assigned] (ARROW-4018) [C++] RLE decoder may not big-endian compatible

[Kazuaki Ishizaki (Jira)]

     [ 
https://issues.apache.org/jira/browse/ARROW-4018?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Kazuaki Ishizaki reassigned ARROW-4018:
---------------------------------------

    Assignee: Kazuaki Ishizaki

> [C++] RLE decoder may not big-endian compatible
> -----------------------------------------------
>
>                 Key: ARROW-4018
>                 URL: https://issues.apache.org/jira/browse/ARROW-4018
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: C++
>    Affects Versions: 0.11.1
>            Reporter: Antoine Pitrou
>            Assignee: Kazuaki Ishizaki
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> This issue was found by Coverity. The {{RleDecoder::NextCounts}} method has 
> the following code to fetch the repeated literal in repeated runs:
> {code:c++}
>     bool result =
>         
> bit_reader_.GetAligned<T>(static_cast<int>(BitUtil::CeilDiv(bit_width_, 8)),
>                                   reinterpret_cast<T*>(&current_value_));
> {code}
> Coverity says this:
> bq. Pointer "&this->current_value_" points to an object whose effective type 
> is "unsigned long long" (64 bits, unsigned) but is dereferenced as a narrower 
> "unsigned int" (32 bits, unsigned). This may lead to unexpected results 
> depending on machine endianness.
> bq. 
> In addition, it's not obvious whether {{current_value_}} also needs 
> byte-swapping (presumably, at least in the Parquet file format, it's supposed 
> to be stored in little-endian format in the RLE bitstream).



--
This message was sent by Atlassian Jira
(v8.3.4#803005)