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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 com.thinkaurelius.thrift.util.mem;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Field;
import java.nio.ByteBuffer;
import com.sun.jna.Pointer;
import sun.misc.Unsafe;
/**
* An off-heap region of memory that must be manually free'd when no longer needed.
*/
class Memory
{
private static final Unsafe unsafe;
static
{
try
{
Field field = sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
field.setAccessible(true);
unsafe = (sun.misc.Unsafe) field.get(null);
}
catch (Exception e)
{
throw new AssertionError(e);
}
}
protected long peer, size; // size could be changed by 'reallocate'
protected Memory(long size)
{
this(unsafe.allocateMemory(size), size);
}
protected Memory(long peer, long size)
{
this.peer = peer;
this.size = size;
}
public static Memory allocate(long bytes)
{
if (bytes < 0)
throw new IllegalArgumentException();
return new Memory(bytes);
}
public static Memory wrap(long peer, int limit)
{
return new Memory(peer, limit);
}
public void setByte(long offset, byte b)
{
checkPosition(offset);
setByteUnsafe(offset, b);
}
void setByteUnsafe(long offset, byte b)
{
unsafe.putByte(peer + offset, b);
}
public void setMemory(long offset, long bytes, byte b)
{
// check if the last element will fit into the memory
checkPosition(offset + bytes - 1);
unsafe.setMemory(peer + offset, bytes, b);
}
void copyMemory(long offset, long dstAddr, long bytes)
{
if (bytes > size - offset)
throw new IllegalArgumentException();
unsafe.copyMemory(peer + offset, dstAddr, bytes);
}
public void setLong(long offset, long l)
{
checkPosition(offset);
unsafe.putLong(peer + offset, l);
}
/**
* Transfers count bytes from buffer to Memory
*
* @param memoryOffset start offset in the memory
* @param buffer the data buffer
* @param bufferOffset start offset of the buffer
* @param count number of bytes to transfer
*/
public void setBytes(long memoryOffset, byte[] buffer, int bufferOffset, int count)
{
if (buffer == null)
throw new NullPointerException();
else if (bufferOffset < 0
|| count < 0
|| bufferOffset + count > buffer.length)
throw new IndexOutOfBoundsException();
else if (count == 0)
return;
checkPosition(memoryOffset);
long end = memoryOffset + count;
checkPosition(end - 1);
while (memoryOffset < end)
{
unsafe.putByte(peer + memoryOffset, buffer[bufferOffset]);
memoryOffset++;
bufferOffset++;
}
}
/**
* Transfers count bytes from buffer to Memory
*
* @param memoryOffset start offset in the memory
* @param buffer the data buffer
*/
public void setBytes(long memoryOffset, ByteBuffer buffer)
{
if (buffer == null)
throw new NullPointerException();
else if (buffer.remaining() == 0)
return;
int bufferOffset = buffer.position();
checkPosition(memoryOffset);
long end = memoryOffset + buffer.remaining();
checkPosition(end - 1);
while (memoryOffset < end)
{
unsafe.putByte(peer + memoryOffset, buffer.get(bufferOffset));
memoryOffset++;
bufferOffset++;
}
}
public byte getByte(long offset)
{
checkPosition(offset);
return getByteUnsafe(offset);
}
byte getByteUnsafe(long offset)
{
return unsafe.getByte(peer + offset);
}
public long getLong(long offset)
{
checkPosition(offset);
return unsafe.getLong(peer + offset);
}
/**
* Transfers count bytes from Memory starting at memoryOffset to buffer starting at bufferOffset
*
* @param memoryOffset start offset in the memory
* @param buffer the data buffer
* @param bufferOffset start offset of the buffer
* @param count number of bytes to transfer
*/
public void getBytes(long memoryOffset, byte[] buffer, int bufferOffset, int count)
{
if (buffer == null)
throw new NullPointerException();
else if (bufferOffset < 0 || count < 0 || count > buffer.length - bufferOffset)
throw new IndexOutOfBoundsException();
else if (count == 0)
return;
checkPosition(memoryOffset);
long end = memoryOffset + count;
checkPosition(end - 1);
while (memoryOffset < end)
{
buffer[bufferOffset++] = unsafe.getByte(peer + memoryOffset);
memoryOffset++;
}
}
private void checkPosition(long offset)
{
assert peer != 0 : "Memory was freed";
assert offset >= 0 && offset < size : "Illegal offset: " + offset + ", size: " + size;
}
public long getPeer()
{
return peer;
}
public Memory reallocate(int newSize)
{
peer = unsafe.reallocateMemory(peer, newSize);
size = newSize;
return this;
}
public void free()
{
assert peer != 0;
unsafe.freeMemory(peer);
peer = 0;
}
public long size()
{
return size;
}
@Override
public boolean equals(Object o)
{
if (this == o)
return true;
if (!(o instanceof Memory))
return false;
Memory b = (Memory) o;
if (peer == b.peer && size == b.size)
return true;
return false;
}
public String toString()
{
return new String(toBytes());
}
public String toString(String enc) throws UnsupportedEncodingException
{
return new String(toBytes(), enc);
}
public byte[] toBytes()
{
return toBytes((int) size);
}
public byte[] toBytes(int size)
{
assert size <= (int) this.size;
byte[] buf = new byte[size];
for (int i = 0; i < size; i++)
buf[i] = getByte(i);
return buf;
}
public ByteBuffer toByteBuffer()
{
ByteBuffer buffer = new Pointer(peer).getByteBuffer(0, size);
if (buffer != null)
return buffer;
buffer = ByteBuffer.allocate((int) size);
for (int i = 0; i < size; i++)
buffer.put(getByteUnsafe(i));
buffer.flip();
return buffer;
}
}
