[ARROW-13617] [C++] Make Decimal representations consistent

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/29258
• Assignee: Antoine Pitrou
• Reporter: David Li
• Created: 12/Aug/21 17:07
• Updated: 11/Jan/23 08:34
• Resolved: 13/Jan/22 10:59

Description

Right now Decimal128 is represented as two 64-bit integers (in native endian order) and Decimal256 is represented as a std::array (in native endian order). We could make these consistent (presumably there should be no performance impact). It may also make it easier to extract a common base class or other niceties.

Issue Links

• relates to: ARROW-10479 [C++][Decimal] Get rid of code duplication at Decimal
• relates to: ARROW-9404 [C++] Add support for Decimal16, Decimal32 and Decimal64
• relates to: ARROW-13439 [C++] Unify BasicDecimal128 and BasicDecimal256 classes
• links to: GitHub Pull Request #12134