RFR: 8310813: Simplify and modernize equals, hashCode, and compareTo for BigInteger [v2]

[Pavel Rappo]

On Wed, 5 Jul 2023 12:57:19 GMT, Pavel Rappo <prappo at openjdk.org> wrote:

> Unfortunately, we don't have mid-layer methods in between Arrays.hashCode and ArraysSupport.vectorizedHashCode like that of Arrays.mismatch and ArraysSupport.vectorizedMismatch. It's either all the null check but short-circuits or unconditional vectorization but the initial value. I wonder if we could consider `ArraysSupport.hashCode($type[] array, int fromIndex, int length, int initialValue)` overloads, which could be useful beyond BigInteger, as I've already seen in JDK. Contributors to ArraysSupport, @PaulSandoz, @ChrisHegarty, @cl4es, @stuart-marks; thoughts?

Here are a few more examples of code that could benefit from such a mid-layer API:
* https://github.com/openjdk/jdk/blob/0ef03f122866f010ebf50683097e9b92e41cdaad/src/java.base/share/classes/java/util/concurrent/CopyOnWriteArrayList.java#L1076-L1083
* https://github.com/openjdk/jdk/blob/0ef03f122866f010ebf50683097e9b92e41cdaad/src/java.base/share/classes/java/util/ArrayList.java#L669-L680
* https://github.com/openjdk/jdk/blob/0ef03f122866f010ebf50683097e9b92e41cdaad/src/java.base/share/classes/sun/security/pkcs10/PKCS10.java#L356-L362

While we are here, shouldn't this be called `unsignedHashCode` rather than `signedHashCode`?

https://github.com/openjdk/jdk/blob/0ef03f122866f010ebf50683097e9b92e41cdaad/src/java.base/share/classes/jdk/internal/util/ArraysSupport.java#L214-L220

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PR Comment: https://git.openjdk.org/jdk/pull/14630#issuecomment-1625253882