[foreign-memaccess+abi] RFR: 8290880: Add static MemorySegment::mismatch method

[Paul Sandoz]

On Fri, 22 Jul 2022 12:52:40 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> As discussed in [1], it would be useful if the `MemorySegment` class provided a static mismatch method, similarly to what we have provided for `copy`.
> 
> This patch adds that method, and rewrites the existing instance `mismatch` method to be based on that new static method.
> It then adds new tests to cover the new static method.
> 
> [1] - https://mail.openjdk.org/pipermail/panama-dev/2022-June/017099.html

src/java.base/share/classes/java/lang/foreign/MemorySegment.java line 2015:

> 2013:      * @see MemorySegment#mismatch(MemorySegment)
> 2014:      */
> 2015:     static long mismatch(MemorySegment srcSegment, long srcOffset, MemorySegment dstSegment, long dstOffset, long bytes) {

Should we make the signature the same as that for Arrays.mismatch e.g.:

    public static int mismatch(byte[] a, int aFromIndex, int aToIndex,
                               byte[] b, int bFromIndex, int bToIndex) {

?
It's tempting to make both mismatch methods static.

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PR: https://git.openjdk.org/panama-foreign/pull/691