jdk/src/share/classes/sun/nio/ch/NativeObject.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/sun/nio/ch/NativeObject.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,405 @@
+/*
+ * Copyright 2000-2002 Sun Microsystems, Inc.  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.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ */
+
+package sun.nio.ch;                                     // Formerly in sun.misc
+
+import java.nio.ByteOrder;
+import sun.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
+    private static int pageSize = -1;
+
+    /**
+     * Returns the page size of the underlying hardware.
+     *
+     * @return  The page size, in bytes
+     */
+    static int pageSize() {
+        if (pageSize == -1)
+            pageSize = unsafe.pageSize();
+        return pageSize;
+    }
+
+}