#1933 remove use of sun.misc.Unsafe

[robfrank]

What does this PR do?

removes the use sun.mis.Unsafe

Motivation

Unsafe will be removed

Related issues

#1933

Checklist

• I have run the build using mvn clean package command
• My unit tests cover both failure and success scenarios

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ -6.17%	✅ ∅

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (7800b87)	69934	44795	64.05%
Head commit (bc5db5a)	15755 (-54179)	9120 (-35675)	57.89% (-6.17%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#1934)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[lvca]

It looks good to me!

[watford-ep]

If you're using MemorySegments, I think this code could be simplified (and likely doesn't need the Arena given these are heap allocated JVM arrays):

// assumes left and right are non-null and length is non-zero
if (left.length < length || right.length < length) return false;

MemorySegment leftSegment = MemorySegment.ofArray(left).asSlice(0, length);
MemorySegment rightSegment = MemorySegment.ofArray(right).asSlice(0, length);

// mismatch is optimized and should be faster than a for loop
return leftSegment.mismatch(rightSegment) == -1;

Compare needs to take into account the possibility that left or right is a prefix of the other, but would use the same general flow:

// assumes left and right are non-null
MemorySegment leftSegment = MemorySegment.ofArray(left);
MemorySegment rightSegment = MemorySegment.ofArray(right);

long index = leftSegment.mismatch(rightSegment);
if (index == -1) {
    return Integer.compare(left.length, right.length);
}

// index is either the byte offset which differs or the length of the shorter array
if (index >= left.length || index >= right.length) {
    return Integer.compare(left.length, right.length);
}

return Integer.compare(Byte.toUnsignedInt(left[(int)index]), Byte.toUnsignedInt(right[(int)index]));

[robfrank]

Wow, thank you!