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8223593: Refactor code for reallocating storage

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Reviewed-by: prappo, plevart, rriggs, smarks
This commit is contained in:
Ivan Gerasimov 2019-05-21 18:40:29 -07:00
parent 54d0b2a8d6
commit 218204b1a3
11 changed files with 129 additions and 247 deletions
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38
src/java.base/share/classes/java/util/AbstractCollection.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2019, 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
@ -25,6 +25,8 @@
package java.util;
import jdk.internal.util.ArraysSupport;
/**
* This class provides a skeletal implementation of the {@code Collection}
* interface, to minimize the effort required to implement this interface. <p>
@ -203,14 +205,6 @@ public abstract class AbstractCollection<E> implements Collection<E> {
return it.hasNext() ? finishToArray(r, it) : r;
}
/**
* The maximum size of array to allocate.
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* Reallocates the array being used within toArray when the iterator
* returned more elements than expected, and finishes filling it from
@ -223,29 +217,19 @@ public abstract class AbstractCollection<E> implements Collection<E> {
*/
@SuppressWarnings("unchecked")
private static <T> T[] finishToArray(T[] r, Iterator<?> it) {
int i = r.length;
int len = r.length;
int i = len;
while (it.hasNext()) {
int cap = r.length;
if (i == cap) {
int newCap = cap + (cap >> 1) + 1;
// overflow-conscious code
if (newCap - MAX_ARRAY_SIZE > 0)
newCap = hugeCapacity(cap + 1);
r = Arrays.copyOf(r, newCap);
if (i == len) {
len = ArraysSupport.newLength(len,
1, /* minimum growth */
(len >> 1) + 1 /* preferred growth */);
r = Arrays.copyOf(r, len);
}
r[i++] = (T)it.next();
}
// trim if overallocated
return (i == r.length) ? r : Arrays.copyOf(r, i);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError
("Required array size too large");
return (minCapacity > MAX_ARRAY_SIZE) ?
Integer.MAX_VALUE :
MAX_ARRAY_SIZE;
return (i == len) ? r : Arrays.copyOf(r, i);
}
// Modification Operations

55
src/java.base/share/classes/java/util/ArrayList.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2019, 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
@ -29,6 +29,7 @@ import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.function.UnaryOperator;
import jdk.internal.access.SharedSecrets;
import jdk.internal.util.ArraysSupport;
/**
* Resizable-array implementation of the {@code List} interface. Implements
@ -218,14 +219,6 @@ public class ArrayList<E> extends AbstractList<E>
}
}
/**
* The maximum size of array to allocate (unless necessary).
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* Increases the capacity to ensure that it can hold at least the
* number of elements specified by the minimum capacity argument.
@ -234,47 +227,21 @@ public class ArrayList<E> extends AbstractList<E>
* @throws OutOfMemoryError if minCapacity is less than zero
*/
private Object[] grow(int minCapacity) {
return elementData = Arrays.copyOf(elementData,
newCapacity(minCapacity));
int oldCapacity = elementData.length;
if (oldCapacity > 0 || elementData != DEFAULTCAPACITY_EMPTY_ELEMENTDATA) {
int newCapacity = ArraysSupport.newLength(oldCapacity,
minCapacity - oldCapacity, /* minimum growth */
oldCapacity >> 1 /* preferred growth */);
return elementData = Arrays.copyOf(elementData, newCapacity);
} else {
return elementData = new Object[Math.max(DEFAULT_CAPACITY, minCapacity)];
}
}
private Object[] grow() {
return grow(size + 1);
}
/**
* Returns a capacity at least as large as the given minimum capacity.
* Returns the current capacity increased by 50% if that suffices.
* Will not return a capacity greater than MAX_ARRAY_SIZE unless
* the given minimum capacity is greater than MAX_ARRAY_SIZE.
*
* @param minCapacity the desired minimum capacity
* @throws OutOfMemoryError if minCapacity is less than zero
*/
private int newCapacity(int minCapacity) {
// overflow-conscious code
int oldCapacity = elementData.length;
int newCapacity = oldCapacity + (oldCapacity >> 1);
if (newCapacity - minCapacity <= 0) {
if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA)
return Math.max(DEFAULT_CAPACITY, minCapacity);
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return minCapacity;
}
return (newCapacity - MAX_ARRAY_SIZE <= 0)
? newCapacity
: hugeCapacity(minCapacity);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return (minCapacity > MAX_ARRAY_SIZE)
? Integer.MAX_VALUE
: MAX_ARRAY_SIZE;
}
/**
* Returns the number of elements in this list.
*

29
src/java.base/share/classes/java/util/PriorityQueue.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2019, 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
@ -28,6 +28,7 @@ package java.util;
import java.util.function.Consumer;
import java.util.function.Predicate;
import jdk.internal.access.SharedSecrets;
import jdk.internal.util.ArraysSupport;
/**
* An unbounded priority {@linkplain Queue queue} based on a priority heap.
@ -281,14 +282,6 @@ public class PriorityQueue<E> extends AbstractQueue<E>
heapify();
}
/**
* The maximum size of array to allocate.
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* Increases the capacity of the array.
*
@ -297,23 +290,13 @@ public class PriorityQueue<E> extends AbstractQueue<E>
private void grow(int minCapacity) {
int oldCapacity = queue.length;
// Double size if small; else grow by 50%
int newCapacity = oldCapacity + ((oldCapacity < 64) ?
(oldCapacity + 2) :
(oldCapacity >> 1));
// overflow-conscious code
if (newCapacity - MAX_ARRAY_SIZE > 0)
newCapacity = hugeCapacity(minCapacity);
int newCapacity = ArraysSupport.newLength(oldCapacity,
minCapacity - oldCapacity, /* minimum growth */
oldCapacity < 64 ? oldCapacity + 2 : oldCapacity >> 1
/* preferred growth */);
queue = Arrays.copyOf(queue, newCapacity);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return (minCapacity > MAX_ARRAY_SIZE) ?
Integer.MAX_VALUE :
MAX_ARRAY_SIZE;
}
/**
* Inserts the specified element into this priority queue.
*

51
src/java.base/share/classes/java/util/Vector.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1994, 2018, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1994, 2019, 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
@ -32,6 +32,8 @@ import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.function.UnaryOperator;
import jdk.internal.util.ArraysSupport;
/**
* The {@code Vector} class implements a growable array of
* objects. Like an array, it contains components that can be
@ -241,14 +243,6 @@ public class Vector<E>
}
}
/**
* The maximum size of array to allocate (unless necessary).
* Some VMs reserve some header words in an array.
* Attempts to allocate larger arrays may result in
* OutOfMemoryError: Requested array size exceeds VM limit
*/
private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
/**
* Increases the capacity to ensure that it can hold at least the
* number of elements specified by the minimum capacity argument.
@ -257,45 +251,18 @@ public class Vector<E>
* @throws OutOfMemoryError if minCapacity is less than zero
*/
private Object[] grow(int minCapacity) {
return elementData = Arrays.copyOf(elementData,
newCapacity(minCapacity));
int oldCapacity = elementData.length;
int newCapacity = ArraysSupport.newLength(oldCapacity,
minCapacity - oldCapacity, /* minimum growth */
capacityIncrement > 0 ? capacityIncrement : oldCapacity
/* preferred growth */);
return elementData = Arrays.copyOf(elementData, newCapacity);
}
private Object[] grow() {
return grow(elementCount + 1);
}
/**
* Returns a capacity at least as large as the given minimum capacity.
* Will not return a capacity greater than MAX_ARRAY_SIZE unless
* the given minimum capacity is greater than MAX_ARRAY_SIZE.
*
* @param minCapacity the desired minimum capacity
* @throws OutOfMemoryError if minCapacity is less than zero
*/
private int newCapacity(int minCapacity) {
// overflow-conscious code
int oldCapacity = elementData.length;
int newCapacity = oldCapacity + ((capacityIncrement > 0) ?
capacityIncrement : oldCapacity);
if (newCapacity - minCapacity <= 0) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return minCapacity;
}
return (newCapacity - MAX_ARRAY_SIZE <= 0)
? newCapacity
: hugeCapacity(minCapacity);
}
private static int hugeCapacity(int minCapacity) {
if (minCapacity < 0) // overflow
throw new OutOfMemoryError();
return (minCapacity > MAX_ARRAY_SIZE) ?
Integer.MAX_VALUE :
MAX_ARRAY_SIZE;
}
/**
* Sets the size of this vector. If the new size is greater than the
* current size, new {@code null} items are added to the end of

15
src/java.base/share/classes/java/util/regex/Pattern.java
View file

@ -43,6 +43,7 @@ import java.util.function.Predicate;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
import jdk.internal.util.ArraysSupport;
/**
* A compiled representation of a regular expression.
@ -2315,13 +2316,15 @@ loop: for(int x=0, offset=0; x<nCodePoints; x++, offset+=len) {
}
}
private void append(int ch, int len) {
if (len >= buffer.length) {
int[] tmp = new int[len+len];
System.arraycopy(buffer, 0, tmp, 0, len);
buffer = tmp;
private void append(int ch, int index) {
int len = buffer.length;
if (index - len >= 0) {
len = ArraysSupport.newLength(len,
1 + index - len, /* minimum growth */
len /* preferred growth */);
buffer = Arrays.copyOf(buffer, len);
}
buffer[len] = ch;
buffer[index] = ch;
}
/**