com.sun.marlin.OffHeapArray Maven / Gradle / Ivy
/*
* Copyright (c) 2007, 2018, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package com.sun.marlin;
import static com.sun.marlin.MarlinConst.LOG_UNSAFE_MALLOC;
import java.lang.reflect.Field;
import java.security.AccessController;
import java.security.PrivilegedAction;
import sun.misc.Unsafe;
/**
*
*/
final class OffHeapArray {
// unsafe reference
static final Unsafe UNSAFE;
// size of int / float
static final int SIZE_INT;
static {
UNSAFE = AccessController.doPrivileged(new PrivilegedAction() {
@Override
public Unsafe run() {
Unsafe ref = null;
try {
final Field field = Unsafe.class.getDeclaredField("theUnsafe");
field.setAccessible(true);
ref = (Unsafe) field.get(null);
} catch (Exception e) {
throw new InternalError("Unable to get sun.misc.Unsafe instance", e);
}
return ref;
}
});
SIZE_INT = Unsafe.ARRAY_INT_INDEX_SCALE;
}
/* members */
long address;
long length;
int used;
OffHeapArray(final Object parent, final long len) {
// note: may throw OOME:
this.address = UNSAFE.allocateMemory(len);
this.length = len;
this.used = 0;
if (LOG_UNSAFE_MALLOC) {
MarlinUtils.logInfo(System.currentTimeMillis()
+ ": OffHeapArray.allocateMemory = "
+ len + " to addr = " + this.address);
}
// Register a cleaning function to ensure freeing off-heap memory:
MarlinUtils.getCleaner().register(parent, () -> this.free());
}
/*
* As realloc may change the address, updating address is MANDATORY
* @param len new array length
* @throws OutOfMemoryError if the allocation is refused by the system
*/
void resize(final long len) {
// note: may throw OOME:
this.address = UNSAFE.reallocateMemory(address, len);
this.length = len;
if (LOG_UNSAFE_MALLOC) {
MarlinUtils.logInfo(System.currentTimeMillis()
+ ": OffHeapArray.reallocateMemory = "
+ len + " to addr = " + this.address);
}
}
void free() {
UNSAFE.freeMemory(this.address);
if (LOG_UNSAFE_MALLOC) {
MarlinUtils.logInfo(System.currentTimeMillis()
+ ": OffHeapArray.freeMemory = "
+ this.length
+ " at addr = " + this.address);
}
this.address = 0L;
}
void fill(final byte val) {
UNSAFE.setMemory(this.address, this.length, val);
}
}