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8202398: Optimize Arrays.deepHashCode

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Reviewed-by: psandoz
This commit is contained in:
Martin Buchholz 2018-05-02 11:21:27 -07:00
parent 526a2dbe28
commit 405f933513
1 changed files with 23 additions and 20 deletions
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43
src/java.base/share/classes/java/util/Arrays.java
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@ -4723,27 +4723,16 @@ public class Arrays {
int result = 1;
for (Object element : a) {
int elementHash = 0;
if (element instanceof Object[])
elementHash = deepHashCode((Object[]) element);
else if (element instanceof byte[])
elementHash = hashCode((byte[]) element);
else if (element instanceof short[])
elementHash = hashCode((short[]) element);
else if (element instanceof int[])
elementHash = hashCode((int[]) element);
else if (element instanceof long[])
elementHash = hashCode((long[]) element);
else if (element instanceof char[])
elementHash = hashCode((char[]) element);
else if (element instanceof float[])
elementHash = hashCode((float[]) element);
else if (element instanceof double[])
elementHash = hashCode((double[]) element);
else if (element instanceof boolean[])
elementHash = hashCode((boolean[]) element);
else if (element != null)
final int elementHash;
final Class<?> cl;
if (element == null)
elementHash = 0;
else if ((cl = element.getClass().getComponentType()) == null)
elementHash = element.hashCode();
else if (element instanceof Object[])
elementHash = deepHashCode((Object[]) element);
else
elementHash = primitiveArrayHashCode(element, cl);
result = 31 * result + elementHash;
}
@ -4751,6 +4740,20 @@ public class Arrays {
return result;
}
private static int primitiveArrayHashCode(Object a, Class<?> cl) {
return
(cl == byte.class) ? hashCode((byte[]) a) :
(cl == int.class) ? hashCode((int[]) a) :
(cl == long.class) ? hashCode((long[]) a) :
(cl == char.class) ? hashCode((char[]) a) :
(cl == short.class) ? hashCode((short[]) a) :
(cl == boolean.class) ? hashCode((boolean[]) a) :
(cl == double.class) ? hashCode((double[]) a) :
// If new primitive types are ever added, this method must be
// expanded or we will fail here with ClassCastException.
hashCode((float[]) a);
}
/**
* Returns {@code true} if the two specified arrays are <i>deeply
* equal</i> to one another. Unlike the {@link #equals(Object[],Object[])}