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https://issues.apache.org/jira/browse/ARROW-229?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Uwe L. Korn updated ARROW-229:
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Description: In some situations, you want to cast the data in a
PrimitiveArray to a different (but similar) data type, e.g. from {{uint32_t}}
to {{int32_t}} or {{uint32_t}} to {{uint8_t}}. This can either be done by
reinterpreting the data or needs to involve a copy if the size of the
underlying type changes. There is already an implementation for this in
{{parquet-cpp}} that could be pulled out into Arrow:
https://github.com/apache/parquet-cpp/blob/9a0407e684c0a6299d0e6ab98c11c1162915c0ee/src/parquet/arrow/writer.cc#L71
(was: Depending on the type conversion, this is either just a
reinterpret_cast on the data pointer or involves a data copy.)
> C++: Add Helper to cast primitive arrays
> ----------------------------------------
>
> Key: ARROW-229
> URL: https://issues.apache.org/jira/browse/ARROW-229
> Project: Apache Arrow
> Issue Type: New Feature
> Components: C++
> Reporter: Uwe L. Korn
> Labels: newbie
>
> In some situations, you want to cast the data in a PrimitiveArray to a
> different (but similar) data type, e.g. from {{uint32_t}} to {{int32_t}} or
> {{uint32_t}} to {{uint8_t}}. This can either be done by reinterpreting the
> data or needs to involve a copy if the size of the underlying type changes.
> There is already an implementation for this in {{parquet-cpp}} that could be
> pulled out into Arrow:
> https://github.com/apache/parquet-cpp/blob/9a0407e684c0a6299d0e6ab98c11c1162915c0ee/src/parquet/arrow/writer.cc#L71
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