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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.nio;
import dalvik.system.VMRuntime;
import java.io.FileDescriptor;
import java.io.IOException;
import java.nio.channels.FileChannel.MapMode;
import libcore.io.ErrnoException;
import libcore.io.Libcore;
import libcore.io.Memory;
import static libcore.io.OsConstants.*;
class MemoryBlock {
/**
* Handles calling munmap(2) on a memory-mapped region.
*/
private static class MemoryMappedBlock extends MemoryBlock {
private MemoryMappedBlock(long address, long byteCount) {
super(address, byteCount);
}
@Override public void free() {
if (address != 0) {
try {
Libcore.os.munmap(address, size);
} catch (ErrnoException errnoException) {
// The RI doesn't throw, presumably on the assumption that you can't get into
// a state where munmap(2) could return an error.
throw new AssertionError(errnoException);
}
address = 0;
}
}
@Override protected void finalize() throws Throwable {
free();
}
}
/**
* Non-movable heap blocks are byte arrays on the Java heap that the GC
* guarantees not to move. Used to implement DirectByteBuffer.
*
* Losing the strong reference to the array is sufficient
* to allow the GC to reclaim the storage. No finalizer needed.
*/
private static class NonMovableHeapBlock extends MemoryBlock {
private byte[] array;
private NonMovableHeapBlock(byte[] array, long address, long byteCount) {
super(address, byteCount);
this.array = array;
}
@Override public byte[] array() {
return array;
}
@Override public void free() {
array = null;
address = 0;
}
}
/**
* Represents a block of memory we don't own. (We don't take ownership of memory corresponding
* to direct buffers created by the JNI NewDirectByteBuffer function.)
*/
private static class UnmanagedBlock extends MemoryBlock {
private UnmanagedBlock(long address, long byteCount) {
super(address, byteCount);
}
}
protected long address;
protected final long size;
public static MemoryBlock mmap(FileDescriptor fd, long offset, long size, MapMode mapMode) throws IOException {
if (size == 0) {
// You can't mmap(2) a zero-length region, but Java allows it.
return new MemoryBlock(0, 0);
}
// Check just those errors mmap(2) won't detect.
if (offset < 0 || size < 0 || offset > Integer.MAX_VALUE || size > Integer.MAX_VALUE) {
throw new IllegalArgumentException("offset=" + offset + " size=" + size);
}
int prot;
int flags;
if (mapMode == MapMode.PRIVATE) {
prot = PROT_READ|PROT_WRITE;
flags = MAP_PRIVATE;
} else if (mapMode == MapMode.READ_ONLY) {
prot = PROT_READ;
flags = MAP_SHARED;
} else { // mapMode == MapMode.READ_WRITE
prot = PROT_READ|PROT_WRITE;
flags = MAP_SHARED;
}
try {
long address = Libcore.os.mmap(0L, size, prot, flags, fd, offset);
return new MemoryMappedBlock(address, size);
} catch (ErrnoException errnoException) {
throw errnoException.rethrowAsIOException();
}
}
public static MemoryBlock allocate(int byteCount) {
VMRuntime runtime = VMRuntime.getRuntime();
byte[] array = (byte[]) runtime.newNonMovableArray(byte.class, byteCount);
long address = runtime.addressOf(array);
return new NonMovableHeapBlock(array, address, byteCount);
}
public static MemoryBlock wrapFromJni(long address, long byteCount) {
return new UnmanagedBlock(address, byteCount);
}
private MemoryBlock(long address, long size) {
this.address = address;
this.size = size;
}
// Used to support array/arrayOffset/hasArray for direct buffers.
public byte[] array() {
return null;
}
public void free() {
}
public final void pokeByte(int offset, byte value) {
Memory.pokeByte(address + offset, value);
}
public final void pokeByteArray(int offset, byte[] src, int srcOffset, int byteCount) {
Memory.pokeByteArray(address + offset, src, srcOffset, byteCount);
}
public final void pokeCharArray(int offset, char[] src, int srcOffset, int charCount, boolean swap) {
Memory.pokeCharArray(address + offset, src, srcOffset, charCount, swap);
}
public final void pokeDoubleArray(int offset, double[] src, int srcOffset, int doubleCount, boolean swap) {
Memory.pokeDoubleArray(address + offset, src, srcOffset, doubleCount, swap);
}
public final void pokeFloatArray(int offset, float[] src, int srcOffset, int floatCount, boolean swap) {
Memory.pokeFloatArray(address + offset, src, srcOffset, floatCount, swap);
}
public final void pokeIntArray(int offset, int[] src, int srcOffset, int intCount, boolean swap) {
Memory.pokeIntArray(address + offset, src, srcOffset, intCount, swap);
}
public final void pokeLongArray(int offset, long[] src, int srcOffset, int longCount, boolean swap) {
Memory.pokeLongArray(address + offset, src, srcOffset, longCount, swap);
}
public final void pokeShortArray(int offset, short[] src, int srcOffset, int shortCount, boolean swap) {
Memory.pokeShortArray(address + offset, src, srcOffset, shortCount, swap);
}
public final byte peekByte(int offset) {
return Memory.peekByte(address + offset);
}
public final void peekByteArray(int offset, byte[] dst, int dstOffset, int byteCount) {
Memory.peekByteArray(address + offset, dst, dstOffset, byteCount);
}
public final void peekCharArray(int offset, char[] dst, int dstOffset, int charCount, boolean swap) {
Memory.peekCharArray(address + offset, dst, dstOffset, charCount, swap);
}
public final void peekDoubleArray(int offset, double[] dst, int dstOffset, int doubleCount, boolean swap) {
Memory.peekDoubleArray(address + offset, dst, dstOffset, doubleCount, swap);
}
public final void peekFloatArray(int offset, float[] dst, int dstOffset, int floatCount, boolean swap) {
Memory.peekFloatArray(address + offset, dst, dstOffset, floatCount, swap);
}
public final void peekIntArray(int offset, int[] dst, int dstOffset, int intCount, boolean swap) {
Memory.peekIntArray(address + offset, dst, dstOffset, intCount, swap);
}
public final void peekLongArray(int offset, long[] dst, int dstOffset, int longCount, boolean swap) {
Memory.peekLongArray(address + offset, dst, dstOffset, longCount, swap);
}
public final void peekShortArray(int offset, short[] dst, int dstOffset, int shortCount, boolean swap) {
Memory.peekShortArray(address + offset, dst, dstOffset, shortCount, swap);
}
public final void pokeShort(int offset, short value, ByteOrder order) {
Memory.pokeShort(address + offset, value, order.needsSwap);
}
public final short peekShort(int offset, ByteOrder order) {
return Memory.peekShort(address + offset, order.needsSwap);
}
public final void pokeInt(int offset, int value, ByteOrder order) {
Memory.pokeInt(address + offset, value, order.needsSwap);
}
public final int peekInt(int offset, ByteOrder order) {
return Memory.peekInt(address + offset, order.needsSwap);
}
public final void pokeLong(int offset, long value, ByteOrder order) {
Memory.pokeLong(address + offset, value, order.needsSwap);
}
public final long peekLong(int offset, ByteOrder order) {
return Memory.peekLong(address + offset, order.needsSwap);
}
public final long toLong() {
return address;
}
public final String toString() {
return getClass().getName() + "[" + address + "]";
}
public final long getSize() {
return size;
}
}
