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

[Antoine Pitrou (JIRA)]

Antoine Pitrou created ARROW-4018:
-------------------------------------

             Summary: [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


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
(v7.6.3#76005)