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	/*
	* Copyright (c) 2000, 2002, 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	/*
	*/

	package sun.nio.ch; // Formerly in sun.misc

	import java.nio.ByteOrder;
	import jdk.internal.misc.Unsafe;


	// ## In the fullness of time, this class will be eliminated

	/**
	* Proxies for objects that reside in native memory.
	*/

	class NativeObject { // package-private

	protected static final Unsafe unsafe = Unsafe.getUnsafe();

	// Native allocation address;
	// may be smaller than the base address due to page-size rounding
	//
	protected long allocationAddress;

	// Native base address
	//
	private final long address;

	/**
	* Creates a new native object that is based at the given native address.
	*/
	NativeObject(long address) {
	this.allocationAddress = address;
	this.address = address;
	}

	/**
	* Creates a new native object allocated at the given native address but
	* whose base is at the additional offset.
	*/
	NativeObject(long address, long offset) {
	this.allocationAddress = address;
	this.address = address + offset;
	}

	// Invoked only by AllocatedNativeObject
	//
	protected NativeObject(int size, boolean pageAligned) {
	if (!pageAligned) {
	this.allocationAddress = unsafe.allocateMemory(size);
	this.address = this.allocationAddress;
	} else {
	int ps = pageSize();
	long a = unsafe.allocateMemory(size + ps);
	this.allocationAddress = a;
	this.address = a + ps - (a & (ps - 1));
	}
	}

	/**
	* Returns the native base address of this native object.
	*
	* @return The native base address
	*/
	long address() {
	return address;
	}

	long allocationAddress() {
	return allocationAddress;
	}

	/**
	* Creates a new native object starting at the given offset from the base
	* of this native object.
	*
	* @param offset
	* The offset from the base of this native object that is to be
	* the base of the new native object
	*
	* @return The newly created native object
	*/
	NativeObject subObject(int offset) {
	return new NativeObject(offset + address);
	}

	/**
	* Reads an address from this native object at the given offset and
	* constructs a native object using that address.
	*
	* @param offset
	* The offset of the address to be read. Note that the size of an
	* address is implementation-dependent.
	*
	* @return The native object created using the address read from the
	* given offset
	*/
	NativeObject getObject(int offset) {
	long newAddress = 0L;
	switch (addressSize()) {
	case 8:
	newAddress = unsafe.getLong(offset + address);
	break;
	case 4:
	newAddress = unsafe.getInt(offset + address) & 0x00000000FFFFFFFF;
	break;
	default:
	throw new InternalError("Address size not supported");
	}

	return new NativeObject(newAddress);
	}

	/**
	* Writes the base address of the given native object at the given offset
	* of this native object.
	*
	* @param offset
	* The offset at which the address is to be written. Note that the
	* size of an address is implementation-dependent.
	*
	* @param ob
	* The native object whose address is to be written
	*/
	void putObject(int offset, NativeObject ob) {
	switch (addressSize()) {
	case 8:
	putLong(offset, ob.address);
	break;
	case 4:
	putInt(offset, (int)(ob.address & 0x00000000FFFFFFFF));
	break;
	default:
	throw new InternalError("Address size not supported");
	}
	}


	/* -- Value accessors: No range checking! -- */

	/**
	* Reads a byte starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the byte
	*
	* @return The byte value read
	*/
	final byte getByte(int offset) {
	return unsafe.getByte(offset + address);
	}

	/**
	* Writes a byte at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the byte
	*
	* @param value
	* The byte value to be written
	*/
	final void putByte(int offset, byte value) {
	unsafe.putByte(offset + address, value);
	}

	/**
	* Reads a short starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the short
	*
	* @return The short value read
	*/
	final short getShort(int offset) {
	return unsafe.getShort(offset + address);
	}

	/**
	* Writes a short at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the short
	*
	* @param value
	* The short value to be written
	*/
	final void putShort(int offset, short value) {
	unsafe.putShort(offset + address, value);
	}

	/**
	* Reads a char starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the char
	*
	* @return The char value read
	*/
	final char getChar(int offset) {
	return unsafe.getChar(offset + address);
	}

	/**
	* Writes a char at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the char
	*
	* @param value
	* The char value to be written
	*/
	final void putChar(int offset, char value) {
	unsafe.putChar(offset + address, value);
	}

	/**
	* Reads an int starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the int
	*
	* @return The int value read
	*/
	final int getInt(int offset) {
	return unsafe.getInt(offset + address);
	}

	/**
	* Writes an int at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the int
	*
	* @param value
	* The int value to be written
	*/
	final void putInt(int offset, int value) {
	unsafe.putInt(offset + address, value);
	}

	/**
	* Reads a long starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the long
	*
	* @return The long value read
	*/
	final long getLong(int offset) {
	return unsafe.getLong(offset + address);
	}

	/**
	* Writes a long at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the long
	*
	* @param value
	* The long value to be written
	*/
	final void putLong(int offset, long value) {
	unsafe.putLong(offset + address, value);
	}

	/**
	* Reads a float starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the float
	*
	* @return The float value read
	*/
	final float getFloat(int offset) {
	return unsafe.getFloat(offset + address);
	}

	/**
	* Writes a float at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the float
	*
	* @param value
	* The float value to be written
	*/
	final void putFloat(int offset, float value) {
	unsafe.putFloat(offset + address, value);
	}

	/**
	* Reads a double starting at the given offset from base of this native
	* object.
	*
	* @param offset
	* The offset at which to read the double
	*
	* @return The double value read
	*/
	final double getDouble(int offset) {
	return unsafe.getDouble(offset + address);
	}

	/**
	* Writes a double at the specified offset from this native object's
	* base address.
	*
	* @param offset
	* The offset at which to write the double
	*
	* @param value
	* The double value to be written
	*/
	final void putDouble(int offset, double value) {
	unsafe.putDouble(offset + address, value);
	}

	/**
	* Returns the native architecture's address size in bytes.
	*
	* @return The address size of the native architecture
	*/
	static int addressSize() {
	return unsafe.addressSize();
	}

	// Cache for byte order
	private static ByteOrder byteOrder = null;

	/**
	* Returns the byte order of the underlying hardware.
	*
	* @return An instance of {@link java.nio.ByteOrder}
	*/
	static ByteOrder byteOrder() {
	if (byteOrder != null)
	return byteOrder;
	long a = unsafe.allocateMemory(8);
	try {
	unsafe.putLong(a, 0x0102030405060708L);
	byte b = unsafe.getByte(a);
	switch (b) {
	case 0x01: byteOrder = ByteOrder.BIG_ENDIAN; break;
	case 0x08: byteOrder = ByteOrder.LITTLE_ENDIAN; break;
	default:
	assert false;
	}
	} finally {
	unsafe.freeMemory(a);
	}
	return byteOrder;
	}

	/**
	* Cache for page size.
	* Lazily initialized via a data race; safe because ints are atomic.
	*/
	private static int pageSize = -1;

	/**
	* Returns the page size of the underlying hardware.
	*
	* @return The page size, in bytes
	*/
	static int pageSize() {
	int value = pageSize;
	if (value == -1)
	pageSize = value = unsafe.pageSize();
	return value;
	}

	}

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