PARQUET-1160: [C++] Implement BYTE_ARRAY-backed Decimal reads #495
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on disk. It does this by creating a TransferFunctor routine that transforms a ByteArrayType to an ::arrow::Decimal128Type. The routine does this by: 1. Creating an arrow::BinaryArray from the RecordReader's builder 2. Allocating a buffer for the arrow::Decimal128Array 3. Converting the big-endian bytes in each BinaryArray entry to two integers representing the high and low bits of each decimal value.
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@thaining Travis reports some code style issues you could probably get rid of by running |
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Fixed the indenting and column width changes in reader.cc suggested by 'make format' with clang-format 5.0.2. For arrow-reader-writer-test.cc, the program only suggested reordering of the using statements, which I had not touched. |
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@xhochy, a unit test conforming to the others for Spark was also included in the last batch of commits. |
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This PR needs to be moved to https://github.com/apache/arrow -- please let us know if you require assistance |
Looks like I do require assistance. The change squashes down to a clean commit, but I do not have write access to the repo. Can you advise me on next steps? Thanks. Ted |
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I rolled up your changes as this commit wesm/arrow@4f68fc3. You can open a PR starting from there |
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Thanks for the help. I was a little confused, and that gave me the push I needed. I've created PR apache/arrow#2646 |
This change enables support for DECIMALs backed by BYTE_ARRAYs
on disk. It does this by creating a TransferFunctor routine that
transforms a ByteArrayType to an ::arrow::Decimal128Type.
The routine does this by:
representing the high and low bits of each decimal value.