[ARROW-13439] [C++] Unify BasicDecimal128 and BasicDecimal256 classes

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Won't Do
• Component/s: C++
• External issue URL: https://github.com/apache/arrow/issues/29106
• Assignee: yibocai#1
• Reporter: yibocai#1
• Created: 23/Jul/21 02:14
• Updated: 11/Jan/23 08:33
• Resolved: 27/Jul/21 07:52

Description

BasicDecimal128 uses two dedicated int64 (higher, lower) to store the value. It's possible to use std::array<uint64, 2> to store the value, just like BasicDecimal256 does, and to unify the two classes.
As decimal operations are quite expensive, guess this indirection won't cause performance loss.

Issue Links

• is related to: ARROW-13617 [C++] Make Decimal representations consistent