1berry/openjdk
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

8266097: Better hashing support

Browse Source 
Reviewed-by: chegar, dfuchs, ahgross, smarks, rhalade
This commit is contained in:
Julia Boes 2021-05-25 10:19:55 +00:00 committed by Henry Jen
parent 3a7b663b6f
commit dd199ee063
2 changed files with 38 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

46
src/java.base/share/classes/java/util/HashMap.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -27,6 +27,7 @@ package java.util;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
@ -1504,23 +1505,28 @@ public class HashMap<K,V> extends AbstractMap<K,V>
* @throws IOException if an I/O error occurs
*/
@java.io.Serial
private void readObject(java.io.ObjectInputStream s)
private void readObject(ObjectInputStream s)
throws IOException, ClassNotFoundException {
// Read in the threshold (ignored), loadfactor, and any hidden stuff
s.defaultReadObject();
ObjectInputStream.GetField fields = s.readFields();
// Read loadFactor (ignore threshold)
float lf = fields.get("loadFactor", 0.75f);
if (lf <= 0 || Float.isNaN(lf))
throw new InvalidObjectException("Illegal load factor: " + lf);
lf = Math.min(Math.max(0.25f, lf), 4.0f);
HashMap.UnsafeHolder.putLoadFactor(this, lf);
reinitialize();
if (loadFactor <= 0 || Float.isNaN(loadFactor))
throw new InvalidObjectException("Illegal load factor: " +
loadFactor);
s.readInt(); // Read and ignore number of buckets
int mappings = s.readInt(); // Read number of mappings (size)
if (mappings < 0)
throw new InvalidObjectException("Illegal mappings count: " +
mappings);
else if (mappings > 0) { // (if zero, use defaults)
// Size the table using given load factor only if within
// range of 0.25...4.0
float lf = Math.min(Math.max(0.25f, loadFactor), 4.0f);
if (mappings < 0) {
throw new InvalidObjectException("Illegal mappings count: " + mappings);
} else if (mappings == 0) {
// use defaults
} else if (mappings > 0) {
float fc = (float)mappings / lf + 1.0f;
int cap = ((fc < DEFAULT_INITIAL_CAPACITY) ?
DEFAULT_INITIAL_CAPACITY :
@ -1549,6 +1555,18 @@ public class HashMap<K,V> extends AbstractMap<K,V>
}
}
// Support for resetting final field during deserializing
private static final class UnsafeHolder {
private UnsafeHolder() { throw new InternalError(); }
private static final jdk.internal.misc.Unsafe unsafe
= jdk.internal.misc.Unsafe.getUnsafe();
private static final long LF_OFFSET
= unsafe.objectFieldOffset(HashMap.class, "loadFactor");
static void putLoadFactor(HashMap<?, ?> map, float lf) {
unsafe.putFloat(map, LF_OFFSET, lf);
}
}
/* ------------------------------------------------------------ */
// iterators

11
src/java.base/share/classes/java/util/HashSet.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -297,8 +297,8 @@ public class HashSet<E>
@java.io.Serial
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
// Read in any hidden serialization magic
s.defaultReadObject();
// Consume and ignore stream fields (currently zero).
s.readFields();
// Read capacity and verify non-negative.
int capacity = s.readInt();
@ -313,12 +313,13 @@ public class HashSet<E>
throw new InvalidObjectException("Illegal load factor: " +
loadFactor);
}
// Clamp load factor to range of 0.25...4.0.
loadFactor = Math.min(Math.max(0.25f, loadFactor), 4.0f);
// Read size and verify non-negative.
int size = s.readInt();
if (size < 0) {
throw new InvalidObjectException("Illegal size: " +
size);
throw new InvalidObjectException("Illegal size: " + size);
}
// Set the capacity according to the size and load factor ensuring that