java/nio/ByteBuffer.java

/*
 * Copyright (C) 2014 The Android Open Source Project
 * Copyright (c) 2000, 2008, 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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 */

// -- This file was mechanically generated: Do not edit! -- //

package java.nio;

import libcore.io.Memory;

/**
 * A byte buffer.
 *
 * <p> This class defines six categories of operations upon
 * byte buffers:
 *
 * <ul>
 *
 * <li><p> Absolute and relative {@link #get() </code><i>get</i><code>} and
 * {@link #put(byte) </code><i>put</i><code>} methods that read and write
 * single bytes; </p></li>
 *
 * <li><p> Relative {@link #get(byte[]) </code><i>bulk get</i><code>}
 * methods that transfer contiguous sequences of bytes from this buffer
 * into an array; </p></li>
 *
 * <li><p> Relative {@link #put(byte[]) </code><i>bulk put</i><code>}
 * methods that transfer contiguous sequences of bytes from a
 * byte array or some other byte
 * buffer into this buffer; </p></li>
 *
 * <li><p> Absolute and relative {@link #getChar() </code><i>get</i><code>}
 * and {@link #putChar(char) </code><i>put</i><code>} methods that read and
 * write values of other primitive types, translating them to and from
 * sequences of bytes in a particular byte order; </p></li>
 *
 * <li><p> Methods for creating <i><a href="#views">view buffers</a></i>,
 * which allow a byte buffer to be viewed as a buffer containing values of
 * some other primitive type; and </p></li>
 *
 *
 *
 * <li><p> Methods for {@link #compact </code>compacting<code>}, {@link
 * #duplicate </code>duplicating<code>}, and {@link #slice
 * </code>slicing<code>} a byte buffer.  </p></li>
 *
 * </ul>
 *
 * <p> Byte buffers can be created either by {@link #allocate
 * </code><i>allocation</i><code>}, which allocates space for the buffer's
 * content, or by {@link #wrap(byte[]) </code><i>wrapping</i><code>} an
 * existing byte array  into a buffer.
 *
 * <a name="direct">
 * <h4> Direct <i>vs.</i> non-direct buffers </h4>
 *
 * <p> A byte buffer is either <i>direct</i> or <i>non-direct</i>.  Given a
 * direct byte buffer, the Java virtual machine will make a best effort to
 * perform native I/O operations directly upon it.  That is, it will attempt to
 * avoid copying the buffer's content to (or from) an intermediate buffer
 * before (or after) each invocation of one of the underlying operating
 * system's native I/O operations.
 *
 * <p> A direct byte buffer may be created by invoking the {@link
 * #allocateDirect(int) allocateDirect} factory method of this class.  The
 * buffers returned by this method typically have somewhat higher allocation
 * and deallocation costs than non-direct buffers.  The contents of direct
 * buffers may reside outside of the normal garbage-collected heap, and so
 * their impact upon the memory footprint of an application might not be
 * obvious.  It is therefore recommended that direct buffers be allocated
 * primarily for large, long-lived buffers that are subject to the underlying
 * system's native I/O operations.  In general it is best to allocate direct
 * buffers only when they yield a measureable gain in program performance.
 *
 * <p> A direct byte buffer may also be created by {@link
 * java.nio.channels.FileChannel#map </code>mapping<code>} a region of a file
 * directly into memory.  An implementation of the Java platform may optionally
 * support the creation of direct byte buffers from native code via JNI.  If an
 * instance of one of these kinds of buffers refers to an inaccessible region
 * of memory then an attempt to access that region will not change the buffer's
 * content and will cause an unspecified exception to be thrown either at the
 * time of the access or at some later time.
 *
 * <p> Whether a byte buffer is direct or non-direct may be determined by
 * invoking its {@link #isDirect isDirect} method.  This method is provided so
 * that explicit buffer management can be done in performance-critical code.
 *
 * <a name="bin">
 * <h4> Access to binary data </h4>
 *
 * <p> This class defines methods for reading and writing values of all other
 * primitive types, except <tt>boolean</tt>.  Primitive values are translated
 * to (or from) sequences of bytes according to the buffer's current byte
 * order, which may be retrieved and modified via the {@link #order order}
 * methods.  Specific byte orders are represented by instances of the {@link
 * ByteOrder} class.  The initial order of a byte buffer is always {@link
 * ByteOrder#BIG_ENDIAN BIG_ENDIAN}.
 *
 * <p> For access to heterogeneous binary data, that is, sequences of values of
 * different types, this class defines a family of absolute and relative
 * <i>get</i> and <i>put</i> methods for each type.  For 32-bit floating-point
 * values, for example, this class defines:
 *
 * <blockquote><pre>
 * float  {@link #getFloat()}
 * float  {@link #getFloat(int) getFloat(int index)}
 *  void  {@link #putFloat(float) putFloat(float f)}
 *  void  {@link #putFloat(int, float) putFloat(int index, float f)}</pre></blockquote>
 *
 * <p> Corresponding methods are defined for the types <tt>char</tt>,
 * <tt>short</tt>, <tt>int</tt>, <tt>long</tt>, and <tt>double</tt>.  The index
 * parameters of the absolute <i>get</i> and <i>put</i> methods are in terms of
 * bytes rather than of the type being read or written.
 *
 * <a name="views">
 *
 * <p> For access to homogeneous binary data, that is, sequences of values of
 * the same type, this class defines methods that can create <i>views</i> of a
 * given byte buffer.  A <i>view buffer</i> is simply another buffer whose
 * content is backed by the byte buffer.  Changes to the byte buffer's content
 * will be visible in the view buffer, and vice versa; the two buffers'
 * position, limit, and mark values are independent.  The {@link
 * #asFloatBuffer() asFloatBuffer} method, for example, creates an instance of
 * the {@link FloatBuffer} class that is backed by the byte buffer upon which
 * the method is invoked.  Corresponding view-creation methods are defined for
 * the types <tt>char</tt>, <tt>short</tt>, <tt>int</tt>, <tt>long</tt>, and
 * <tt>double</tt>.
 *
 * <p> View buffers have three important advantages over the families of
 * type-specific <i>get</i> and <i>put</i> methods described above:
 *
 * <ul>
 *
 * <li><p> A view buffer is indexed not in terms of bytes but rather in terms
 * of the type-specific size of its values;  </p></li>
 *
 * <li><p> A view buffer provides relative bulk <i>get</i> and <i>put</i>
 * methods that can transfer contiguous sequences of values between a buffer
 * and an array or some other buffer of the same type; and  </p></li>
 *
 * <li><p> A view buffer is potentially much more efficient because it will
 * be direct if, and only if, its backing byte buffer is direct.  </p></li>
 *
 * </ul>
 *
 * <p> The byte order of a view buffer is fixed to be that of its byte buffer
 * at the time that the view is created.  </p>
 *
 * <h4> Invocation chaining </h4>
 *
 * <p> Methods in this class that do not otherwise have a value to return are
 * specified to return the buffer upon which they are invoked.  This allows
 * method invocations to be chained.
 *
 * The sequence of statements
 *
 * <blockquote><pre>
 * bb.putInt(0xCAFEBABE);
 * bb.putShort(3);
 * bb.putShort(45);</pre></blockquote>
 *
 * can, for example, be replaced by the single statement
 *
 * <blockquote><pre>
 * bb.putInt(0xCAFEBABE).putShort(3).putShort(45);</pre></blockquote>
 *
 * @author Mark Reinhold
 * @author JSR-51 Expert Group
 * @since 1.4
 */

public abstract class ByteBuffer
        extends Buffer
        implements Comparable<ByteBuffer> {

    // These fields are declared here rather than in Heap-X-Buffer in order to
    // reduce the number of virtual method invocations needed to access these
    // values, which is especially costly when coding small buffers.
    //
    final byte[] hb;                  // Non-null only for heap buffers
    final int offset;
    boolean isReadOnly;                 // Valid only for heap buffers

    // Creates a new buffer with the given mark, position, limit, capacity,
    // backing array, and array offset
    //
    ByteBuffer(int mark, int pos, int lim, int cap,   // package-private
               byte[] hb, int offset) {
        super(mark, pos, lim, cap, 0);
        this.hb = hb;
        this.offset = offset;
    }

    // Creates a new buffer with the given mark, position, limit, and capacity
    //
    ByteBuffer(int mark, int pos, int lim, int cap) { // package-private
        this(mark, pos, lim, cap, null, 0);
    }


    /**
     * Allocates a new direct byte buffer.
     *
     * <p> The new buffer's position will be zero, its limit will be its
     * capacity, its mark will be undefined, and each of its elements will be
     * initialized to zero.  Whether or not it has a
     * {@link #hasArray </code>backing array<code>} is unspecified.
     *
     * @param capacity The new buffer's capacity, in bytes
     * @return The new byte buffer
     * @throws IllegalArgumentException If the <tt>capacity</tt> is a negative integer
     */
    public static ByteBuffer allocateDirect(int capacity) {
        if (capacity < 0) {
            throw new IllegalArgumentException("capacity < 0: " + capacity);
        }

        DirectByteBuffer.MemoryRef memoryRef = new DirectByteBuffer.MemoryRef(capacity);
        return new DirectByteBuffer(capacity, memoryRef);
    }


    /**
     * Allocates a new byte buffer.
     *
     * <p> The new buffer's position will be zero, its limit will be its
     * capacity, its mark will be undefined, and each of its elements will be
     * initialized to zero.  It will have a {@link #array
     * </code>backing array<code>}, and its {@link #arrayOffset </code>array
     * offset<code>} will be zero.
     *
     * @param capacity The new buffer's capacity, in bytes
     * @return The new byte buffer
     * @throws IllegalArgumentException If the <tt>capacity</tt> is a negative integer
     */
    public static ByteBuffer allocate(int capacity) {
        if (capacity < 0)
            throw new IllegalArgumentException();
        return new HeapByteBuffer(capacity, capacity);
    }

    /**
     * Wraps a byte array into a buffer.
     *
     * <p> The new buffer will be backed by the given byte array;
     * that is, modifications to the buffer will cause the array to be modified
     * and vice versa.  The new buffer's capacity will be
     * <tt>array.length</tt>, its position will be <tt>offset</tt>, its limit
     * will be <tt>offset + length</tt>, and its mark will be undefined.  Its
     * {@link #array </code>backing array<code>} will be the given array, and
     * its {@link #arrayOffset </code>array offset<code>} will be zero.  </p>
     *
     * @param array  The array that will back the new buffer
     * @param offset The offset of the subarray to be used; must be non-negative and
     *               no larger than <tt>array.length</tt>.  The new buffer's position
     *               will be set to this value.
     * @param length The length of the subarray to be used;
     *               must be non-negative and no larger than
     *               <tt>array.length - offset</tt>.
     *               The new buffer's limit will be set to <tt>offset + length</tt>.
     * @return The new byte buffer
     * @throws IndexOutOfBoundsException If the preconditions on the <tt>offset</tt> and
     *                                   <tt>length</tt>
     *                                   parameters do not hold
     */
    public static ByteBuffer wrap(byte[] array,
                                  int offset, int length) {
        try {
            return new HeapByteBuffer(array, offset, length);
        } catch (IllegalArgumentException x) {
            throw new IndexOutOfBoundsException();
        }
    }

    /**
     * Wraps a byte array into a buffer.
     *
     * <p> The new buffer will be backed by the given byte array;
     * that is, modifications to the buffer will cause the array to be modified
     * and vice versa.  The new buffer's capacity and limit will be
     * <tt>array.length</tt>, its position will be zero, and its mark will be
     * undefined.  Its {@link #array </code>backing array<code>} will be the
     * given array, and its {@link #arrayOffset </code>array offset<code>} will
     * be zero.  </p>
     *
     * @param array The array that will back this buffer
     * @return The new byte buffer
     */
    public static ByteBuffer wrap(byte[] array) {
        return wrap(array, 0, array.length);
    }


    /**
     * Creates a new byte buffer whose content is a shared subsequence of
     * this buffer's content.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer, and its mark
     * will be undefined.  The new buffer will be direct if, and only if, this
     * buffer is direct, and it will be read-only if, and only if, this buffer
     * is read-only.  </p>
     *
     * @return The new byte buffer
     */
    public abstract ByteBuffer slice();

    /**
     * Creates a new byte buffer that shares this buffer's content.
     *
     * <p> The content of the new buffer will be that of this buffer.  Changes
     * to this buffer's content will be visible in the new buffer, and vice
     * versa; the two buffers' position, limit, and mark values will be
     * independent.
     *
     * <p> The new buffer's capacity, limit, position, and mark values will be
     * identical to those of this buffer.  The new buffer will be direct if,
     * and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return The new byte buffer
     */
    public abstract ByteBuffer duplicate();

    /**
     * Creates a new, read-only byte buffer that shares this buffer's
     * content.
     *
     * <p> The content of the new buffer will be that of this buffer.  Changes
     * to this buffer's content will be visible in the new buffer; the new
     * buffer itself, however, will be read-only and will not allow the shared
     * content to be modified.  The two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's capacity, limit, position, and mark values will be
     * identical to those of this buffer.
     *
     * <p> If this buffer is itself read-only then this method behaves in
     * exactly the same way as the {@link #duplicate duplicate} method.  </p>
     *
     * @return The new, read-only byte buffer
     */
    public abstract ByteBuffer asReadOnlyBuffer();


    // -- Singleton get/put methods --

    /**
     * Relative <i>get</i> method.  Reads the byte at this buffer's
     * current position, and then increments the position. </p>
     *
     * @return The byte at the buffer's current position
     * @throws BufferUnderflowException If the buffer's current position is not smaller than its
     *                                  limit
     */
    public abstract byte get();

    /**
     * Relative <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes the given byte into this buffer at the current
     * position, and then increments the position. </p>
     *
     * @param b The byte to be written
     * @return This buffer
     * @throws BufferOverflowException If this buffer's current position is not smaller than its
     *                                 limit
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer put(byte b);

    /**
     * Absolute <i>get</i> method.  Reads the byte at the given
     * index. </p>
     *
     * @param index The index from which the byte will be read
     * @return The byte at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit
     */
    public abstract byte get(int index);

    /**
     * Absolute <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes the given byte into this buffer at the given
     * index. </p>
     *
     * @param index The index at which the byte will be written
     * @param b     The byte value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer put(int index, byte b);


    // -- Bulk get operations --

    /**
     * Relative bulk <i>get</i> method.
     *
     * <p> This method transfers bytes from this buffer into the given
     * destination array.  If there are fewer bytes remaining in the
     * buffer than are required to satisfy the request, that is, if
     * <tt>length</tt>&nbsp;<tt>&gt;</tt>&nbsp;<tt>remaining()</tt>, then no
     * bytes are transferred and a {@link BufferUnderflowException} is
     * thrown.
     *
     * <p> Otherwise, this method copies <tt>length</tt> bytes from this
     * buffer into the given array, starting at the current position of this
     * buffer and at the given offset in the array.  The position of this
     * buffer is then incremented by <tt>length</tt>.
     *
     * <p> In other words, an invocation of this method of the form
     * <tt>src.get(dst,&nbsp;off,&nbsp;len)</tt> has exactly the same effect as
     * the loop
     *
     * <pre>
     *     for (int i = off; i < off + len; i++)
     *         dst[i] = src.get(); </pre>
     *
     * except that it first checks that there are sufficient bytes in
     * this buffer and it is potentially much more efficient. </p>
     *
     * @param dst    The array into which bytes are to be written
     * @param offset The offset within the array of the first byte to be
     *               written; must be non-negative and no larger than
     *               <tt>dst.length</tt>
     * @param length The maximum number of bytes to be written to the given
     *               array; must be non-negative and no larger than
     *               <tt>dst.length - offset</tt>
     * @return This buffer
     * @throws BufferUnderflowException  If there are fewer than <tt>length</tt> bytes
     *                                   remaining in this buffer
     * @throws IndexOutOfBoundsException If the preconditions on the <tt>offset</tt> and
     *                                   <tt>length</tt>
     *                                   parameters do not hold
     */
    public ByteBuffer get(byte[] dst, int offset, int length) {
        checkBounds(offset, length, dst.length);
        if (length > remaining())
            throw new BufferUnderflowException();
        int end = offset + length;
        for (int i = offset; i < end; i++)
            dst[i] = get();
        return this;
    }

    /**
     * Relative bulk <i>get</i> method.
     *
     * <p> This method transfers bytes from this buffer into the given
     * destination array.  An invocation of this method of the form
     * <tt>src.get(a)</tt> behaves in exactly the same way as the invocation
     *
     * <pre>
     *     src.get(a, 0, a.length) </pre>
     *
     * @return This buffer
     * @throws BufferUnderflowException If there are fewer than <tt>length</tt> bytes
     *                                  remaining in this buffer
     */
    public ByteBuffer get(byte[] dst) {
        return get(dst, 0, dst.length);
    }


    // -- Bulk put operations --

    /**
     * Relative bulk <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> This method transfers the bytes remaining in the given source
     * buffer into this buffer.  If there are more bytes remaining in the
     * source buffer than in this buffer, that is, if
     * <tt>src.remaining()</tt>&nbsp;<tt>&gt;</tt>&nbsp;<tt>remaining()</tt>,
     * then no bytes are transferred and a {@link
     * BufferOverflowException} is thrown.
     *
     * <p> Otherwise, this method copies
     * <i>n</i>&nbsp;=&nbsp;<tt>src.remaining()</tt> bytes from the given
     * buffer into this buffer, starting at each buffer's current position.
     * The positions of both buffers are then incremented by <i>n</i>.
     *
     * <p> In other words, an invocation of this method of the form
     * <tt>dst.put(src)</tt> has exactly the same effect as the loop
     *
     * <pre>
     *     while (src.hasRemaining())
     *         dst.put(src.get()); </pre>
     *
     * except that it first checks that there is sufficient space in this
     * buffer and it is potentially much more efficient. </p>
     *
     * @param src The source buffer from which bytes are to be read;
     *            must not be this buffer
     * @return This buffer
     * @throws BufferOverflowException  If there is insufficient space in this buffer
     *                                  for the remaining bytes in the source buffer
     * @throws IllegalArgumentException If the source buffer is this buffer
     * @throws ReadOnlyBufferException  If this buffer is read-only
     */
    public ByteBuffer put(ByteBuffer src) {
        if (!isAccessible()) {
            throw new IllegalStateException("buffer is inaccessible");
        }
        if (isReadOnly) {
            throw new ReadOnlyBufferException();
        }
        if (src == this) {
            throw new IllegalArgumentException();
        }
        int n = src.remaining();
        if (n > remaining()) {
            throw new BufferOverflowException();
        }

        if (this.hb != null && src.hb != null) {
            // System.arraycopy is intrinsified by art and therefore tiny bit faster than memmove
            System.arraycopy(src.hb, src.position() + src.arrayOffset(),
                             hb, position() + arrayOffset(), n);
        } else {
            // Use the buffer object (and the raw memory address) if it's direct buffer.
            // Note that isDirect() doesn't imply !hasArray(), ByteBuffer.allocateDirect allocated
            // bufferwill have a backing, non-gc-movable byte array. JNI allocated direct byte
            // buffers WILL NOT have backing array.
            final Object srcObject = src.isDirect() ? src : src.array();
            int srcOffset = src.position();
            if (!src.isDirect()) {
                srcOffset += src.arrayOffset();
            }

            final ByteBuffer dst = this;
            final Object dstObject = dst.isDirect() ? dst : dst.array();
            int dstOffset = dst.position();
            if (!dst.isDirect()) {
                dstOffset += dst.arrayOffset();
            }
            Memory.memmove(dstObject, dstOffset, srcObject, srcOffset, n);
        }
        src.position(src.limit());
        this.position(this.position() + n);
        return this;
    }

    /**
     * Relative bulk <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> This method transfers bytes into this buffer from the given
     * source array.  If there are more bytes to be copied from the array
     * than remain in this buffer, that is, if
     * <tt>length</tt>&nbsp;<tt>&gt;</tt>&nbsp;<tt>remaining()</tt>, then no
     * bytes are transferred and a {@link BufferOverflowException} is
     * thrown.
     *
     * <p> Otherwise, this method copies <tt>length</tt> bytes from the
     * given array into this buffer, starting at the given offset in the array
     * and at the current position of this buffer.  The position of this buffer
     * is then incremented by <tt>length</tt>.
     *
     * <p> In other words, an invocation of this method of the form
     * <tt>dst.put(src,&nbsp;off,&nbsp;len)</tt> has exactly the same effect as
     * the loop
     *
     * <pre>
     *     for (int i = off; i < off + len; i++)
     *         dst.put(a[i]); </pre>
     *
     * except that it first checks that there is sufficient space in this
     * buffer and it is potentially much more efficient. </p>
     *
     * @param src    The array from which bytes are to be read
     * @param offset The offset within the array of the first byte to be read;
     *               must be non-negative and no larger than <tt>array.length</tt>
     * @param length The number of bytes to be read from the given array;
     *               must be non-negative and no larger than
     *               <tt>array.length - offset</tt>
     * @return This buffer
     * @throws BufferOverflowException   If there is insufficient space in this buffer
     * @throws IndexOutOfBoundsException If the preconditions on the <tt>offset</tt> and
     *                                   <tt>length</tt>
     *                                   parameters do not hold
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public ByteBuffer put(byte[] src, int offset, int length) {
        checkBounds(offset, length, src.length);
        if (length > remaining())
            throw new BufferOverflowException();
        int end = offset + length;
        for (int i = offset; i < end; i++)
            this.put(src[i]);
        return this;
    }

    /**
     * Relative bulk <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> This method transfers the entire content of the given source
     * byte array into this buffer.  An invocation of this method of the
     * form <tt>dst.put(a)</tt> behaves in exactly the same way as the
     * invocation
     *
     * <pre>
     *     dst.put(a, 0, a.length) </pre>
     *
     * @return This buffer
     * @throws BufferOverflowException If there is insufficient space in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public final ByteBuffer put(byte[] src) {
        return put(src, 0, src.length);
    }


    // -- Other stuff --

    /**
     * Tells whether or not this buffer is backed by an accessible byte
     * array.
     *
     * <p> If this method returns <tt>true</tt> then the {@link #array() array}
     * and {@link #arrayOffset() arrayOffset} methods may safely be invoked.
     * </p>
     *
     * @return <tt>true</tt> if, and only if, this buffer
     * is backed by an array and is not read-only
     */
    public final boolean hasArray() {
        return (hb != null) && !isReadOnly();
    }

    /**
     * Returns the byte array that backs this
     * buffer&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Modifications to this buffer's content will cause the returned
     * array's content to be modified, and vice versa.
     *
     * <p> Invoke the {@link #hasArray hasArray} method before invoking this
     * method in order to ensure that this buffer has an accessible backing
     * array.  </p>
     *
     * @return The array that backs this buffer
     * @throws ReadOnlyBufferException       If this buffer is backed by an array but is read-only
     * @throws UnsupportedOperationException If this buffer is not backed by an accessible array
     */
    public final byte[] array() {
        if (hb == null)
            throw new UnsupportedOperationException();
        if (isReadOnly)
            throw new ReadOnlyBufferException();
        return hb;
    }

    /**
     * Returns the offset within this buffer's backing array of the first
     * element of the buffer&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> If this buffer is backed by an array then buffer position <i>p</i>
     * corresponds to array index <i>p</i>&nbsp;+&nbsp;<tt>arrayOffset()</tt>.
     *
     * <p> Invoke the {@link #hasArray hasArray} method before invoking this
     * method in order to ensure that this buffer has an accessible backing
     * array.  </p>
     *
     * @return The offset within this buffer's array
     * of the first element of the buffer
     * @throws ReadOnlyBufferException       If this buffer is backed by an array but is read-only
     * @throws UnsupportedOperationException If this buffer is not backed by an accessible array
     */
    public final int arrayOffset() {
        if (hb == null)
            throw new UnsupportedOperationException();
        if (isReadOnly)
            throw new ReadOnlyBufferException();
        return offset;
    }

    /**
     * Compacts this buffer&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> The bytes between the buffer's current position and its limit,
     * if any, are copied to the beginning of the buffer.  That is, the
     * byte at index <i>p</i>&nbsp;=&nbsp;<tt>position()</tt> is copied
     * to index zero, the byte at index <i>p</i>&nbsp;+&nbsp;1 is copied
     * to index one, and so forth until the byte at index
     * <tt>limit()</tt>&nbsp;-&nbsp;1 is copied to index
     * <i>n</i>&nbsp;=&nbsp;<tt>limit()</tt>&nbsp;-&nbsp;<tt>1</tt>&nbsp;-&nbsp;<i>p</i>.
     * The buffer's position is then set to <i>n+1</i> and its limit is set to
     * its capacity.  The mark, if defined, is discarded.
     *
     * <p> The buffer's position is set to the number of bytes copied,
     * rather than to zero, so that an invocation of this method can be
     * followed immediately by an invocation of another relative <i>put</i>
     * method. </p>
     *
     *
     *
     * <p> Invoke this method after writing data from a buffer in case the
     * write was incomplete.  The following loop, for example, copies bytes
     * from one channel to another via the buffer <tt>buf</tt>:
     *
     * <blockquote><pre>
     * buf.clear();          // Prepare buffer for use
     * while (in.read(buf) >= 0 || buf.position != 0) {
     *     buf.flip();
     *     out.write(buf);
     *     buf.compact();    // In case of partial write
     * }</pre></blockquote>
     *
     * @return This buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer compact();

    /**
     * Tells whether or not this byte buffer is direct. </p>
     *
     * @return <tt>true</tt> if, and only if, this buffer is direct
     */
    public abstract boolean isDirect();


    /**
     * Returns a string summarizing the state of this buffer.  </p>
     *
     * @return A summary string
     */
    public String toString() {
        StringBuffer sb = new StringBuffer();
        sb.append(getClass().getName());
        sb.append("[pos=");
        sb.append(position());
        sb.append(" lim=");
        sb.append(limit());
        sb.append(" cap=");
        sb.append(capacity());
        sb.append("]");
        return sb.toString();
    }


    /**
     * Returns the current hash code of this buffer.
     *
     * <p> The hash code of a byte buffer depends only upon its remaining
     * elements; that is, upon the elements from <tt>position()</tt> up to, and
     * including, the element at <tt>limit()</tt>&nbsp;-&nbsp;<tt>1</tt>.
     *
     * <p> Because buffer hash codes are content-dependent, it is inadvisable
     * to use buffers as keys in hash maps or similar data structures unless it
     * is known that their contents will not change.  </p>
     *
     * @return The current hash code of this buffer
     */
    public int hashCode() {
        int h = 1;
        int p = position();
        for (int i = limit() - 1; i >= p; i--)
            h = 31 * h + (int) get(i);
        return h;
    }

    /**
     * Tells whether or not this buffer is equal to another object.
     *
     * <p> Two byte buffers are equal if, and only if,
     *
     * <p><ol>
     *
     * <li><p> They have the same element type,  </p></li>
     *
     * <li><p> They have the same number of remaining elements, and
     * </p></li>
     *
     * <li><p> The two sequences of remaining elements, considered
     * independently of their starting positions, are pointwise equal.
     *
     *
     *
     *
     *
     *
     *
     * </p></li>
     *
     * </ol>
     *
     * <p> A byte buffer is not equal to any other type of object.  </p>
     *
     * @param ob The object to which this buffer is to be compared
     * @return <tt>true</tt> if, and only if, this buffer is equal to the
     * given object
     */
    public boolean equals(Object ob) {
        if (this == ob)
            return true;
        if (!(ob instanceof ByteBuffer))
            return false;
        ByteBuffer that = (ByteBuffer) ob;
        if (this.remaining() != that.remaining())
            return false;
        int p = this.position();
        for (int i = this.limit() - 1, j = that.limit() - 1; i >= p; i--, j--)
            if (!equals(this.get(i), that.get(j)))
                return false;
        return true;
    }

    private static boolean equals(byte x, byte y) {


        return x == y;

    }

    /**
     * Compares this buffer to another.
     *
     * <p> Two byte buffers are compared by comparing their sequences of
     * remaining elements lexicographically, without regard to the starting
     * position of each sequence within its corresponding buffer.
     *
     *
     *
     *
     *
     *
     *
     *
     * Pairs of {@code byte} elements are compared as if by invoking
     * {@link Byte#compare(byte, byte)}.
     *
     *
     * <p> A byte buffer is not comparable to any other type of object.
     *
     * @return A negative integer, zero, or a positive integer as this buffer
     * is less than, equal to, or greater than the given buffer
     */
    public int compareTo(ByteBuffer that) {
        int n = this.position() + Math.min(this.remaining(), that.remaining());
        for (int i = this.position(), j = that.position(); i < n; i++, j++) {
            int cmp = compare(this.get(i), that.get(j));
            if (cmp != 0)
                return cmp;
        }
        return this.remaining() - that.remaining();
    }

    private static int compare(byte x, byte y) {


        return Byte.compare(x, y);

    }

    // -- Other char stuff --


    // -- Other byte stuff: Access to binary data --


    boolean bigEndian                                   // package-private
            = true;
    boolean nativeByteOrder                             // package-private
            = (Bits.byteOrder() == ByteOrder.BIG_ENDIAN);

    /**
     * Retrieves this buffer's byte order.
     *
     * <p> The byte order is used when reading or writing multibyte values, and
     * when creating buffers that are views of this byte buffer.  The order of
     * a newly-created byte buffer is always {@link ByteOrder#BIG_ENDIAN
     * BIG_ENDIAN}.  </p>
     *
     * @return This buffer's byte order
     */
    public final ByteOrder order() {
        return bigEndian ? ByteOrder.BIG_ENDIAN : ByteOrder.LITTLE_ENDIAN;
    }

    /**
     * Modifies this buffer's byte order.  </p>
     *
     * @param bo The new byte order,
     *           either {@link ByteOrder#BIG_ENDIAN BIG_ENDIAN}
     *           or {@link ByteOrder#LITTLE_ENDIAN LITTLE_ENDIAN}
     * @return This buffer
     */
    public final ByteBuffer order(ByteOrder bo) {
        bigEndian = (bo == ByteOrder.BIG_ENDIAN);
        nativeByteOrder =
                (bigEndian == (Bits.byteOrder() == ByteOrder.BIG_ENDIAN));
        return this;
    }

    // Unchecked accessors, for use by ByteBufferAs-X-Buffer classes
    //
    abstract byte _get(int i);                          // package-private

    abstract void _put(int i, byte b);                  // package-private


    /**
     * Relative <i>get</i> method for reading a char value.
     *
     * <p> Reads the next two bytes at this buffer's current position,
     * composing them into a char value according to the current byte order,
     * and then increments the position by two.  </p>
     *
     * @return The char value at the buffer's current position
     * @throws BufferUnderflowException If there are fewer than two bytes
     *                                  remaining in this buffer
     */
    public abstract char getChar();

    /**
     * Relative <i>put</i> method for writing a char
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes two bytes containing the given char value, in the
     * current byte order, into this buffer at the current position, and then
     * increments the position by two.  </p>
     *
     * @param value The char value to be written
     * @return This buffer
     * @throws BufferOverflowException If there are fewer than two bytes
     *                                 remaining in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer putChar(char value);

    /**
     * Absolute <i>get</i> method for reading a char value.
     *
     * <p> Reads two bytes at the given index, composing them into a
     * char value according to the current byte order.  </p>
     *
     * @param index The index from which the bytes will be read
     * @return The char value at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus one
     */
    public abstract char getChar(int index);

    char getCharUnchecked(int index) {
        throw new UnsupportedOperationException();
    }

    void getUnchecked(int pos, char[] dst, int dstOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Absolute <i>put</i> method for writing a char
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes two bytes containing the given char value, in the
     * current byte order, into this buffer at the given index.  </p>
     *
     * @param index The index at which the bytes will be written
     * @param value The char value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus one
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer putChar(int index, char value);

    void putCharUnchecked(int index, char value) {
        throw new UnsupportedOperationException();
    }

    void putUnchecked(int pos, char[] dst, int srcOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Creates a view of this byte buffer as a char buffer.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer divided by
     * two, and its mark will be undefined.  The new buffer will be direct
     * if, and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return A new char buffer
     */
    public abstract CharBuffer asCharBuffer();


    /**
     * Relative <i>get</i> method for reading a short value.
     *
     * <p> Reads the next two bytes at this buffer's current position,
     * composing them into a short value according to the current byte order,
     * and then increments the position by two.  </p>
     *
     * @return The short value at the buffer's current position
     * @throws BufferUnderflowException If there are fewer than two bytes
     *                                  remaining in this buffer
     */
    public abstract short getShort();

    /**
     * Relative <i>put</i> method for writing a short
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes two bytes containing the given short value, in the
     * current byte order, into this buffer at the current position, and then
     * increments the position by two.  </p>
     *
     * @param value The short value to be written
     * @return This buffer
     * @throws BufferOverflowException If there are fewer than two bytes
     *                                 remaining in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer putShort(short value);

    /**
     * Absolute <i>get</i> method for reading a short value.
     *
     * <p> Reads two bytes at the given index, composing them into a
     * short value according to the current byte order.  </p>
     *
     * @param index The index from which the bytes will be read
     * @return The short value at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus one
     */
    public abstract short getShort(int index);

    short getShortUnchecked(int index) {
        throw new UnsupportedOperationException();
    }

    void getUnchecked(int pos, short[] dst, int dstOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Absolute <i>put</i> method for writing a short
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes two bytes containing the given short value, in the
     * current byte order, into this buffer at the given index.  </p>
     *
     * @param index The index at which the bytes will be written
     * @param value The short value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus one
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer putShort(int index, short value);

    void putShortUnchecked(int index, short value) {
        throw new UnsupportedOperationException();
    }

    void putUnchecked(int pos, short[] dst, int srcOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Creates a view of this byte buffer as a short buffer.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer divided by
     * two, and its mark will be undefined.  The new buffer will be direct
     * if, and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return A new short buffer
     */
    public abstract ShortBuffer asShortBuffer();


    /**
     * Relative <i>get</i> method for reading an int value.
     *
     * <p> Reads the next four bytes at this buffer's current position,
     * composing them into an int value according to the current byte order,
     * and then increments the position by four.  </p>
     *
     * @return The int value at the buffer's current position
     * @throws BufferUnderflowException If there are fewer than four bytes
     *                                  remaining in this buffer
     */
    public abstract int getInt();

    /**
     * Relative <i>put</i> method for writing an int
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes four bytes containing the given int value, in the
     * current byte order, into this buffer at the current position, and then
     * increments the position by four.  </p>
     *
     * @param value The int value to be written
     * @return This buffer
     * @throws BufferOverflowException If there are fewer than four bytes
     *                                 remaining in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer putInt(int value);

    /**
     * Absolute <i>get</i> method for reading an int value.
     *
     * <p> Reads four bytes at the given index, composing them into a
     * int value according to the current byte order.  </p>
     *
     * @param index The index from which the bytes will be read
     * @return The int value at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus three
     */
    public abstract int getInt(int index);

    int getIntUnchecked(int index) {
        throw new UnsupportedOperationException();
    }

    void getUnchecked(int pos, int[] dst, int dstOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Absolute <i>put</i> method for writing an int
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes four bytes containing the given int value, in the
     * current byte order, into this buffer at the given index.  </p>
     *
     * @param index The index at which the bytes will be written
     * @param value The int value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus three
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer putInt(int index, int value);

    void putIntUnchecked(int index, int value) {
        throw new UnsupportedOperationException();
    }

    void putUnchecked(int pos, int[] dst, int srcOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Creates a view of this byte buffer as an int buffer.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer divided by
     * four, and its mark will be undefined.  The new buffer will be direct
     * if, and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return A new int buffer
     */
    public abstract IntBuffer asIntBuffer();


    /**
     * Relative <i>get</i> method for reading a long value.
     *
     * <p> Reads the next eight bytes at this buffer's current position,
     * composing them into a long value according to the current byte order,
     * and then increments the position by eight.  </p>
     *
     * @return The long value at the buffer's current position
     * @throws BufferUnderflowException If there are fewer than eight bytes
     *                                  remaining in this buffer
     */
    public abstract long getLong();

    /**
     * Relative <i>put</i> method for writing a long
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes eight bytes containing the given long value, in the
     * current byte order, into this buffer at the current position, and then
     * increments the position by eight.  </p>
     *
     * @param value The long value to be written
     * @return This buffer
     * @throws BufferOverflowException If there are fewer than eight bytes
     *                                 remaining in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer putLong(long value);

    /**
     * Absolute <i>get</i> method for reading a long value.
     *
     * <p> Reads eight bytes at the given index, composing them into a
     * long value according to the current byte order.  </p>
     *
     * @param index The index from which the bytes will be read
     * @return The long value at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus seven
     */
    public abstract long getLong(int index);

    long getLongUnchecked(int index) {
        throw new UnsupportedOperationException();
    }

    void getUnchecked(int pos, long[] dst, int dstOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Absolute <i>put</i> method for writing a long
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes eight bytes containing the given long value, in the
     * current byte order, into this buffer at the given index.  </p>
     *
     * @param index The index at which the bytes will be written
     * @param value The long value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus seven
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer putLong(int index, long value);

    void putLongUnchecked(int index, long value) {
        throw new UnsupportedOperationException();
    }

    void putUnchecked(int pos, long[] dst, int srcOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Creates a view of this byte buffer as a long buffer.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer divided by
     * eight, and its mark will be undefined.  The new buffer will be direct
     * if, and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return A new long buffer
     */
    public abstract LongBuffer asLongBuffer();


    /**
     * Relative <i>get</i> method for reading a float value.
     *
     * <p> Reads the next four bytes at this buffer's current position,
     * composing them into a float value according to the current byte order,
     * and then increments the position by four.  </p>
     *
     * @return The float value at the buffer's current position
     * @throws BufferUnderflowException If there are fewer than four bytes
     *                                  remaining in this buffer
     */
    public abstract float getFloat();

    /**
     * Relative <i>put</i> method for writing a float
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes four bytes containing the given float value, in the
     * current byte order, into this buffer at the current position, and then
     * increments the position by four.  </p>
     *
     * @param value The float value to be written
     * @return This buffer
     * @throws BufferOverflowException If there are fewer than four bytes
     *                                 remaining in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer putFloat(float value);

    /**
     * Absolute <i>get</i> method for reading a float value.
     *
     * <p> Reads four bytes at the given index, composing them into a
     * float value according to the current byte order.  </p>
     *
     * @param index The index from which the bytes will be read
     * @return The float value at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus three
     */
    public abstract float getFloat(int index);

    float getFloatUnchecked(int index) {
        throw new UnsupportedOperationException();
    }

    void getUnchecked(int pos, float[] dst, int dstOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Absolute <i>put</i> method for writing a float
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes four bytes containing the given float value, in the
     * current byte order, into this buffer at the given index.  </p>
     *
     * @param index The index at which the bytes will be written
     * @param value The float value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus three
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer putFloat(int index, float value);

    void putFloatUnchecked(int index, float value) {
        throw new UnsupportedOperationException();
    }

    void putUnchecked(int pos, float[] dst, int srcOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Creates a view of this byte buffer as a float buffer.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer divided by
     * four, and its mark will be undefined.  The new buffer will be direct
     * if, and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return A new float buffer
     */
    public abstract FloatBuffer asFloatBuffer();


    /**
     * Relative <i>get</i> method for reading a double value.
     *
     * <p> Reads the next eight bytes at this buffer's current position,
     * composing them into a double value according to the current byte order,
     * and then increments the position by eight.  </p>
     *
     * @return The double value at the buffer's current position
     * @throws BufferUnderflowException If there are fewer than eight bytes
     *                                  remaining in this buffer
     */
    public abstract double getDouble();

    /**
     * Relative <i>put</i> method for writing a double
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes eight bytes containing the given double value, in the
     * current byte order, into this buffer at the current position, and then
     * increments the position by eight.  </p>
     *
     * @param value The double value to be written
     * @return This buffer
     * @throws BufferOverflowException If there are fewer than eight bytes
     *                                 remaining in this buffer
     * @throws ReadOnlyBufferException If this buffer is read-only
     */
    public abstract ByteBuffer putDouble(double value);

    /**
     * Absolute <i>get</i> method for reading a double value.
     *
     * <p> Reads eight bytes at the given index, composing them into a
     * double value according to the current byte order.  </p>
     *
     * @param index The index from which the bytes will be read
     * @return The double value at the given index
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus seven
     */
    public abstract double getDouble(int index);

    double getDoubleUnchecked(int index) {
        throw new UnsupportedOperationException();
    }

    void getUnchecked(int pos, double[] dst, int dstOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Absolute <i>put</i> method for writing a double
     * value&nbsp;&nbsp;<i>(optional operation)</i>.
     *
     * <p> Writes eight bytes containing the given double value, in the
     * current byte order, into this buffer at the given index.  </p>
     *
     * @param index The index at which the bytes will be written
     * @param value The double value to be written
     * @return This buffer
     * @throws IndexOutOfBoundsException If <tt>index</tt> is negative
     *                                   or not smaller than the buffer's limit,
     *                                   minus seven
     * @throws ReadOnlyBufferException   If this buffer is read-only
     */
    public abstract ByteBuffer putDouble(int index, double value);

    void putDoubleUnchecked(int index, double value) {
        throw new UnsupportedOperationException();
    }

    void putUnchecked(int pos, double[] dst, int srcOffset, int length) {
        throw new UnsupportedOperationException();
    }

    /**
     * Creates a view of this byte buffer as a double buffer.
     *
     * <p> The content of the new buffer will start at this buffer's current
     * position.  Changes to this buffer's content will be visible in the new
     * buffer, and vice versa; the two buffers' position, limit, and mark
     * values will be independent.
     *
     * <p> The new buffer's position will be zero, its capacity and its limit
     * will be the number of bytes remaining in this buffer divided by
     * eight, and its mark will be undefined.  The new buffer will be direct
     * if, and only if, this buffer is direct, and it will be read-only if, and
     * only if, this buffer is read-only.  </p>
     *
     * @return A new double buffer
     */
    public abstract DoubleBuffer asDoubleBuffer();

    /**
     * @hide
     */
    public boolean isAccessible() {
        return true;
    }

    /**
     * @hide
     */
    public void setAccessible(boolean value) {
        throw new UnsupportedOperationException();
    }
}