Wes McKinney created ARROW-56:
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Summary: Format: Specify LSB bit ordering in bit arrays
Key: ARROW-56
URL: https://issues.apache.org/jira/browse/ARROW-56
Project: Apache Arrow
Issue Type: New Feature
Components: Format
Reporter: Wes McKinney
In https://github.com/apache/arrow/blob/master/format/Layout.md, we describe
bitmaps for nulls (presumably same encoding for boolean data) and provide the C
code for accessing a bit:
{{bitmask[j / 8] & (1 << (j % 8))}}
Implicitly this is LSB bit-endianness
(https://en.wikipedia.org/wiki/Bit_numbering) -- see the discussion of
bitpacking in the Parquet format:
https://github.com/apache/parquet-format/blob/master/Encodings.md#run-length-encoding--bit-packing-hybrid-rle--3
If this is what we want, we should make this aspect of the format explicit.
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