On Thu, 13 Jul 2023 14:50:55 GMT, Roger Riggs <rri...@openjdk.org> wrote:
>> Please review this PR to use modern APIs and language features to simplify
>> equals for BitSet.
>>
>> I couldn't see how to refactor hashCode using Arrays utility methods in a
>> way that preserves its specification. So, aside from refactoring its doc
>> comment and annotating it with `@Overrides`, I left it intact.
>
> LGTM
@RogerRiggs, @Martin-Buchholz, are you okay with a few redundant range checks?
`Arrays.equals(a, aFromIndex, aToIndex, b, bFromIndex, bToIndex)` performs two
range checks, which aren't needed here. However, `Arrays.equals` is readable; a
less readable but leaner alternative would be `ArraysSupport.mismatch(a,
aFromIndex, b, bFromIndex, length)`. Here's a diff from this PR's version, to
consider:
diff --git a/src/java.base/share/classes/java/util/BitSet.java
b/src/java.base/share/classes/java/util/BitSet.java
index 7189dc49228..fea9693d7ed 100644
--- a/src/java.base/share/classes/java/util/BitSet.java
+++ b/src/java.base/share/classes/java/util/BitSet.java
@@ -33,6 +33,8 @@ import java.util.function.IntConsumer;
import java.util.stream.IntStream;
import java.util.stream.StreamSupport;
+import jdk.internal.util.ArraysSupport;
+
/**
* This class implements a vector of bits that grows as needed. Each
* component of the bit set has a {@code boolean} value. The
@@ -1076,8 +1078,11 @@ public class BitSet implements Cloneable,
java.io.Serializable {
checkInvariants();
set.checkInvariants();
+ if (wordsInUse != set.wordsInUse)
+ return false;
+
// Check words in use by both BitSets
- return Arrays.equals(words, 0, wordsInUse, set.words, 0,
set.wordsInUse);
+ return ArraysSupport.mismatch(words, 0, set.words, 0, wordsInUse) ==
-1;
}
/**
-------------
PR Comment: https://git.openjdk.org/jdk/pull/14868#issuecomment-1642734404
