[MATH-1271] Unsigned operations

• Type: New Feature
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 4.0
• Fix Version/s: 4.0
• Labels: features
• External issue URL: https://github.com/apache/commons-math/pull/13
• Assignee: Unassigned
• Reporter: Qualtagh
• Created: 10/Sep/15 08:11
• Updated: 11/Sep/15 19:23
• Resolved: 11/Sep/15 19:23

Description

Add unsigned operations to ArithmeticUtils: divideUnsigned and remainderUnsigned. They exist in java.lang.Integer and java.lang.Long since Java 8. The inner implementation is based on leveraging to long (for ints) and to BigInteger (for longs). Comments in code suggest using tricks described in "Hacker's Delight" to stay with smaller type (int and long respectively). Those tricks were implemented in this pull request: https://github.com/apache/commons-math/pull/13

I don't know if using an algorithm from "Hacker's Delight" is compatible with Apache license. The code is faster than standard Java 8 implementation: 2 times for int and 8 times for long (verified with simple small tests).