content: /*
   * Copyright (C) 2014 The Android Open Source Project
   * Copyright (c) 2000, 2013, 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.
   */
  
  // -- This file was mechanically generated: Do not edit! -- //
  
  package java.nio;
  
  
  import java.io.IOException;
  import java.util.Spliterator;
  import java.util.stream.StreamSupport;
  import java.util.stream.IntStream;
  
  import dalvik.annotation.codegen.CovariantReturnType;
  
  
  /**
   * A char buffer.
   *
   * <p> This class defines four categories of operations upon
   * char buffers:
   *
   * <ul>
   *
   *   <li><p> Absolute and relative {@link #get() <i>get</i>} and
   *   {@link #put(char) <i>put</i>} methods that read and write
   *   single chars; </p></li>
   *
   *   <li><p> Relative {@link #get(char[]) <i>bulk get</i>}
   *   methods that transfer contiguous sequences of chars from this buffer
   *   into an array; and</p></li>
   *
   *   <li><p> Relative {@link #put(char[]) <i>bulk put</i>}
   *   methods that transfer contiguous sequences of chars from a
   *   char array,&#32;a&#32;string, or some other char
   *   buffer into this buffer;&#32;and </p></li>
   *
   *
   *   <li><p> Methods for {@link #compact compacting}, {@link
   *   #duplicate duplicating}, and {@link #slice slicing}
   *   a char buffer.  </p></li>
   *
   * </ul>
   *
   * <p> Char buffers can be created either by {@link #allocate
   * <i>allocation</i>}, which allocates space for the buffer's
   *
   *
   * content, by {@link #wrap(char[]) <i>wrapping</i>} an existing
   * char array or&#32;string into a buffer, or by creating a
   * <a href="ByteBuffer.html#views"><i>view</i></a> of an existing byte buffer.
   *
   *
  *
   *
   * <p> Like a byte buffer, a char buffer is either <a
   * href="ByteBuffer.html#direct"><i>direct</i> or <i>non-direct</i></a>.  A
   * char buffer created via the <tt>wrap</tt> methods of this class will
   * be non-direct.  A char buffer created as a view of a byte buffer will
   * be direct if, and only if, the byte buffer itself is direct.  Whether or not
   * a char buffer is direct may be determined by invoking the {@link
   * #isDirect isDirect} method.  </p>
   *
  *
   *
   * <p> This class implements the {@link CharSequence} interface so that
   * character buffers may be used wherever character sequences are accepted, for
   * example in the regular-expression package <tt>{@link java.util.regex}</tt>.
   * </p>
   *
   *
   *
   * <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>
   * cb.put("text/");
   * cb.put(subtype);
   * cb.put("; charset=");
   * cb.put(enc);</pre></blockquote>
   *
   * can, for example, be replaced by the single statement
   *
   * <blockquote><pre>
   * cb.put("text/").put(subtype).put("; charset=").put(enc);</pre></blockquote>
   *
   *
   *
   * @author Mark Reinhold
   * @author JSR-51 Expert Group
   * @since 1.4
   */
  
  public abstract class CharBuffer
      extends Buffer
      implements Comparable<CharBuffer>, Appendable, CharSequence, Readable
  {
  
      // 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 char[] 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
      //
      CharBuffer(int mark, int pos, int lim, int cap,   // package-private
                   char[] hb, int offset)
      {
          // Android-added: elementSizeShift parameter (log2 of element size).
          super(mark, pos, lim, cap, 1 /* elementSizeShift */);
          this.hb = hb;
          this.offset = offset;
      }
  
      // Creates a new buffer with the given mark, position, limit, and capacity
      //
      CharBuffer(int mark, int pos, int lim, int cap) { // package-private
          this(mark, pos, lim, cap, null, 0);
      }
  
  
      /**
       * Allocates a new char 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 backing array},
       * and its {@link #arrayOffset array offset} will be zero.
       *
       * @param  capacity
       *         The new buffer's capacity, in chars
       *
       * @return  The new char buffer
       *
       * @throws  IllegalArgumentException
       *          If the <tt>capacity</tt> is a negative integer
       */
      public static CharBuffer allocate(int capacity) {
          if (capacity < 0)
              throw new IllegalArgumentException();
          return new HeapCharBuffer(capacity, capacity);
      }
  
      /**
       * Wraps a char array into a buffer.
       *
       * <p> The new buffer will be backed by the given char 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 backing array} will be the given array, and
       * its {@link #arrayOffset array offset} 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 char buffer
       *
       * @throws  IndexOutOfBoundsException
       *          If the preconditions on the <tt>offset</tt> and <tt>length</tt>
       *          parameters do not hold
       */
      public static CharBuffer wrap(char[] array,
                                      int offset, int length)
      {
          try {
              return new HeapCharBuffer(array, offset, length);
          } catch (IllegalArgumentException x) {
              throw new IndexOutOfBoundsException();
          }
      }
  
      /**
       * Wraps a char array into a buffer.
       *
       * <p> The new buffer will be backed by the given char 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 backing array} will be the
       * given array, and its {@link #arrayOffset array offset>} will
       * be zero.  </p>
       *
       * @param  array
       *         The array that will back this buffer
       *
       * @return  The new char buffer
       */
      public static CharBuffer wrap(char[] array) {
          return wrap(array, 0, array.length);
      }
  
  
      /**
       * Attempts to read characters into the specified character buffer.
       * The buffer is used as a repository of characters as-is: the only
       * changes made are the results of a put operation. No flipping or
       * rewinding of the buffer is performed.
       *
       * @param target the buffer to read characters into
       * @return The number of characters added to the buffer, or
       *         -1 if this source of characters is at its end
       * @throws IOException if an I/O error occurs
       * @throws NullPointerException if target is null
       * @throws ReadOnlyBufferException if target is a read only buffer
       * @since 1.5
       */
      public int read(CharBuffer target) throws IOException {
          // Determine the number of bytes n that can be transferred
          int targetRemaining = target.remaining();
          int remaining = remaining();
          if (remaining == 0)
              return -1;
          int n = Math.min(remaining, targetRemaining);
          int limit = limit();
          // Set source limit to prevent target overflow
          if (targetRemaining < remaining)
              limit(position() + n);
          try {
              if (n > 0)
                  target.put(this);
          } finally {
              limit(limit); // restore real limit
          }
          return n;
      }
  
      /**
       * Wraps a character sequence into a buffer.
       *
       * <p> The content of the new, read-only buffer will be the content of the
       * given character sequence.  The buffer's capacity will be
       * <tt>csq.length()</tt>, its position will be <tt>start</tt>, its limit
       * will be <tt>end</tt>, and its mark will be undefined.  </p>
       *
       * @param  csq
       *         The character sequence from which the new character buffer is to
       *         be created
       *
       * @param  start
       *         The index of the first character to be used;
       *         must be non-negative and no larger than <tt>csq.length()</tt>.
       *         The new buffer's position will be set to this value.
       *
       * @param  end
       *         The index of the character following the last character to be
       *         used; must be no smaller than <tt>start</tt> and no larger
       *         than <tt>csq.length()</tt>.
       *         The new buffer's limit will be set to this value.
       *
       * @return  The new character buffer
       *
       * @throws  IndexOutOfBoundsException
       *          If the preconditions on the <tt>start</tt> and <tt>end</tt>
       *          parameters do not hold
       */
      public static CharBuffer wrap(CharSequence csq, int start, int end) {
          try {
              return new StringCharBuffer(csq, start, end);
          } catch (IllegalArgumentException x) {
              throw new IndexOutOfBoundsException();
          }
      }
  
      /**
       * Wraps a character sequence into a buffer.
       *
       * <p> The content of the new, read-only buffer will be the content of the
       * given character sequence.  The new buffer's capacity and limit will be
       * <tt>csq.length()</tt>, its position will be zero, and its mark will be
       * undefined.  </p>
       *
       * @param  csq
       *         The character sequence from which the new character buffer is to
       *         be created
       *
       * @return  The new character buffer
       */
      public static CharBuffer wrap(CharSequence csq) {
          return wrap(csq, 0, csq.length());
      }
  
  
      /**
       * Creates a new char 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 chars 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 char buffer
       */
      public abstract CharBuffer slice();
  
      /**
       * Creates a new char 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 char buffer
       */
      public abstract CharBuffer duplicate();
  
      /**
       * Creates a new, read-only char 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 char buffer
       */
      public abstract CharBuffer asReadOnlyBuffer();
  
  
      // -- Singleton get/put methods --
  
      /**
       * Relative <i>get</i> method.  Reads the char at this buffer's
       * current position, and then increments the position.
       *
       * @return  The char at the buffer's current position
       *
       * @throws  BufferUnderflowException
       *          If the buffer's current position is not smaller than its limit
       */
      public abstract char get();
  
      /**
       * Relative <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> Writes the given char into this buffer at the current
       * position, and then increments the position. </p>
       *
       * @param  c
       *         The char 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 CharBuffer put(char c);
  
      /**
       * Absolute <i>get</i> method.  Reads the char at the given
       * index.
       *
       * @param  index
       *         The index from which the char will be read
       *
       * @return  The char at the given index
       *
       * @throws  IndexOutOfBoundsException
       *          If <tt>index</tt> is negative
       *          or not smaller than the buffer's limit
       */
      public abstract char get(int index);
  
      /**
       * Absolute <i>get</i> method.  Reads the char at the given
       * index without any validation of the index.
       *
       * @param  index
       *         The index from which the char will be read
       *
       * @return  The char at the given index
       */
      abstract char getUnchecked(int index);   // package-private
  
      /**
       * Absolute <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> Writes the given char into this buffer at the given
       * index. </p>
       *
       * @param  index
       *         The index at which the char will be written
       *
       * @param  c
       *         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
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       */
      public abstract CharBuffer put(int index, char c);
  
  
      // -- Bulk get operations --
  
      /**
       * Relative bulk <i>get</i> method.
       *
       * <p> This method transfers chars from this buffer into the given
       * destination array.  If there are fewer chars 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
       * chars are transferred and a {@link BufferUnderflowException} is
       * thrown.
       *
       * <p> Otherwise, this method copies <tt>length</tt> chars 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>{@code
       *     for (int i = off; i < off + len; i++)
       *         dst[i] = src.get();
       * }</pre>
       *
       * except that it first checks that there are sufficient chars in
       * this buffer and it is potentially much more efficient.
       *
       * @param  dst
       *         The array into which chars are to be written
       *
       * @param  offset
       *         The offset within the array of the first char to be
       *         written; must be non-negative and no larger than
       *         <tt>dst.length</tt>
       *
       * @param  length
       *         The maximum number of chars 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> chars
       *          remaining in this buffer
       *
       * @throws  IndexOutOfBoundsException
       *          If the preconditions on the <tt>offset</tt> and <tt>length</tt>
       *          parameters do not hold
       */
      public CharBuffer get(char[] 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 chars 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>
       *
       * @param   dst
       *          The destination array
       *
       * @return  This buffer
       *
       * @throws  BufferUnderflowException
       *          If there are fewer than <tt>length</tt> chars
       *          remaining in this buffer
       */
      public CharBuffer get(char[] 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 chars remaining in the given source
       * buffer into this buffer.  If there are more chars 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 chars are transferred and a {@link
       * BufferOverflowException} is thrown.
       *
       * <p> Otherwise, this method copies
       * <i>n</i>&nbsp;=&nbsp;<tt>src.remaining()</tt> chars 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.
       *
       * @param  src
       *         The source buffer from which chars 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 chars in the source buffer
       *
       * @throws  IllegalArgumentException
       *          If the source buffer is this buffer
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       */
      public CharBuffer put(CharBuffer src) {
          if (src == this)
              throw new IllegalArgumentException();
          if (isReadOnly())
              throw new ReadOnlyBufferException();
          int n = src.remaining();
          if (n > remaining())
              throw new BufferOverflowException();
          for (int i = 0; i < n; i++)
              put(src.get());
          return this;
      }
  
      /**
       * Relative bulk <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> This method transfers chars into this buffer from the given
       * source array.  If there are more chars 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
       * chars are transferred and a {@link BufferOverflowException} is
       * thrown.
       *
       * <p> Otherwise, this method copies <tt>length</tt> chars 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>{@code
       *     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.
       *
       * @param  src
       *         The array from which chars are to be read
       *
       * @param  offset
       *         The offset within the array of the first char to be read;
       *         must be non-negative and no larger than <tt>array.length</tt>
       *
       * @param  length
       *         The number of chars 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 CharBuffer put(char[] 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
       * char 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>
       *
       * @param   src
       *          The source array
       *
       * @return  This buffer
       *
       * @throws  BufferOverflowException
       *          If there is insufficient space in this buffer
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       */
      public final CharBuffer put(char[] src) {
          return put(src, 0, src.length);
      }
  
  
      /**
       * Relative bulk <i>put</i> method&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> This method transfers chars from the given string into this
       * buffer.  If there are more chars to be copied from the string than
       * remain in this buffer, that is, if
       * <tt>end&nbsp;-&nbsp;start</tt>&nbsp;<tt>&gt;</tt>&nbsp;<tt>remaining()</tt>,
       * then no chars are transferred and a {@link
       * BufferOverflowException} is thrown.
       *
       * <p> Otherwise, this method copies
       * <i>n</i>&nbsp;=&nbsp;<tt>end</tt>&nbsp;-&nbsp;<tt>start</tt> chars
       * from the given string into this buffer, starting at the given
       * <tt>start</tt> index and at the current position of this buffer.  The
       * position of this buffer is then incremented by <i>n</i>.
       *
       * <p> In other words, an invocation of this method of the form
       * <tt>dst.put(src,&nbsp;start,&nbsp;end)</tt> has exactly the same effect
       * as the loop
       *
       * <pre>{@code
       *     for (int i = start; i < end; i++)
       *         dst.put(src.charAt(i));
       * }</pre>
       *
       * except that it first checks that there is sufficient space in this
       * buffer and it is potentially much more efficient.
       *
       * @param  src
       *         The string from which chars are to be read
       *
       * @param  start
       *         The offset within the string of the first char to be read;
       *         must be non-negative and no larger than
       *         <tt>string.length()</tt>
       *
       * @param  end
       *         The offset within the string of the last char to be read,
       *         plus one; must be non-negative and no larger than
       *         <tt>string.length()</tt>
       *
       * @return  This buffer
       *
       * @throws  BufferOverflowException
       *          If there is insufficient space in this buffer
       *
       * @throws  IndexOutOfBoundsException
       *          If the preconditions on the <tt>start</tt> and <tt>end</tt>
       *          parameters do not hold
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       */
      public CharBuffer put(String src, int start, int end) {
          checkBounds(start, end - start, src.length());
  
          // BEGIN Android-added: Don't check readonly/overflow if there's nothing to write.
          // This is questionable behaviour but code expects it.
          if (start == end) {
              return this;
          }
          // END Android-added: Don't check readonly/overflow if there's nothing to write.
  
          if (isReadOnly())
              throw new ReadOnlyBufferException();
          if (end - start > remaining())
              throw new BufferOverflowException();
          for (int i = start; i < end; i++)
              this.put(src.charAt(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 string
       * into this buffer.  An invocation of this method of the form
       * <tt>dst.put(s)</tt> behaves in exactly the same way as the invocation
       *
       * <pre>
       *     dst.put(s, 0, s.length()) </pre>
       *
       * @param   src
       *          The source string
       *
       * @return  This buffer
       *
       * @throws  BufferOverflowException
       *          If there is insufficient space in this buffer
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       */
      public final CharBuffer put(String src) {
          return put(src, 0, src.length());
      }
  
  
      // -- Other stuff --
  
      /**
       * Tells whether or not this buffer is backed by an accessible char
       * 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 char 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 char[] 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;
      }
  
      // BEGIN Android-added: covariant overloads of *Buffer methods that return this.
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer position(int newPosition) {
          return super.position(newPosition);
      }
  
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer limit(int newLimit) {
          return super.limit(newLimit);
      }
  
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer mark() {
          return super.mark();
      }
  
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer reset() {
          return super.reset();
      }
  
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer clear() {
          return super.clear();
      }
  
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer flip() {
          return super.flip();
      }
  
      @CovariantReturnType(returnType = CharBuffer.class, presentAfter = 28)
      @Override
      public Buffer rewind() {
          return super.rewind();
      }
      // END Android-added: covariant overloads of *Buffer methods that return this.
  
      /**
       * Compacts this buffer&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> The chars between the buffer's current position and its limit,
       * if any, are copied to the beginning of the buffer.  That is, the
       * char at index <i>p</i>&nbsp;=&nbsp;<tt>position()</tt> is copied
       * to index zero, the char at index <i>p</i>&nbsp;+&nbsp;1 is copied
       * to index one, and so forth until the char 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 chars 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>
       *
  
       *
       * @return  This buffer
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       */
      public abstract CharBuffer compact();
  
      /**
       * Tells whether or not this char buffer is direct.
       *
       * @return  <tt>true</tt> if, and only if, this buffer is direct
       */
      public abstract boolean isDirect();
  
  
      /**
       * Returns the current hash code of this buffer.
       *
       * <p> The hash code of a char 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 char buffers are equal if, and only if,
       *
       * <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 char 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 CharBuffer))
              return false;
          CharBuffer that = (CharBuffer)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(char x, char y) {
  
  
          return x == y;
  
      }
  
      /**
       * Compares this buffer to another.
       *
       * <p> Two char 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 char} elements are compared as if by invoking
       * {@link Character#compare(char,char)}.
  
       *
       * <p> A char 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(CharBuffer 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(char x, char y) {
  
  
          return Character.compare(x, y);
  
      }
  
      // -- Other char stuff --
  
  
      /**
       * Returns a string containing the characters in this buffer.
       *
       * <p> The first character of the resulting string will be the character at
       * this buffer's position, while the last character will be the character
       * at index <tt>limit()</tt>&nbsp;-&nbsp;1.  Invoking this method does not
       * change the buffer's position. </p>
       *
       * @return  The specified string
       */
      public String toString() {
          return toString(position(), limit());
      }
  
      abstract String toString(int start, int end);       // package-private
  
  
      // --- Methods to support CharSequence ---
  
      /**
       * Returns the length of this character buffer.
       *
       * <p> When viewed as a character sequence, the length of a character
       * buffer is simply the number of characters between the position
       * (inclusive) and the limit (exclusive); that is, it is equivalent to
       * <tt>remaining()</tt>. </p>
       *
       * @return  The length of this character buffer
       */
      public final int length() {
          return remaining();
      }
  
      /**
       * Reads the character at the given index relative to the current
       * position.
       *
       * @param  index
       *         The index of the character to be read, relative to the position;
       *         must be non-negative and smaller than <tt>remaining()</tt>
       *
       * @return  The character at index
       *          <tt>position()&nbsp;+&nbsp;index</tt>
       *
       * @throws  IndexOutOfBoundsException
       *          If the preconditions on <tt>index</tt> do not hold
       */
      public final char charAt(int index) {
          return get(position() + checkIndex(index, 1));
      }
  
      /**
       * Creates a new character buffer that represents the specified subsequence
       * of this buffer, relative to the current position.
       *
       * <p> The new buffer will share this buffer's content; that is, if the
       * content of this buffer is mutable then modifications to one buffer will
       * cause the other to be modified.  The new buffer's capacity will be that
       * of this buffer, its position will be
       * <tt>position()</tt>&nbsp;+&nbsp;<tt>start</tt>, and its limit will be
       * <tt>position()</tt>&nbsp;+&nbsp;<tt>end</tt>.  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>
       *
       * @param  start
       *         The index, relative to the current position, of the first
       *         character in the subsequence; must be non-negative and no larger
       *         than <tt>remaining()</tt>
       *
       * @param  end
       *         The index, relative to the current position, of the character
       *         following the last character in the subsequence; must be no
       *         smaller than <tt>start</tt> and no larger than
       *         <tt>remaining()</tt>
       *
       * @return  The new character buffer
       *
       * @throws  IndexOutOfBoundsException
       *          If the preconditions on <tt>start</tt> and <tt>end</tt>
       *          do not hold
       */
      public abstract CharBuffer subSequence(int start, int end);
  
  
      // --- Methods to support Appendable ---
  
      /**
       * Appends the specified character sequence  to this
       * buffer&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> An invocation of this method of the form <tt>dst.append(csq)</tt>
       * behaves in exactly the same way as the invocation
       *
       * <pre>
       *     dst.put(csq.toString()) </pre>
       *
       * <p> Depending on the specification of <tt>toString</tt> for the
       * character sequence <tt>csq</tt>, the entire sequence may not be
       * appended.  For instance, invoking the {@link CharBuffer#toString()
       * toString} method of a character buffer will return a subsequence whose
       * content depends upon the buffer's position and limit.
       *
       * @param  csq
       *         The character sequence to append.  If <tt>csq</tt> is
       *         <tt>null</tt>, then the four characters <tt>"null"</tt> are
       *         appended to this character buffer.
       *
       * @return  This buffer
       *
       * @throws  BufferOverflowException
       *          If there is insufficient space in this buffer
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       *
       * @since  1.5
       */
      public CharBuffer append(CharSequence csq) {
          if (csq == null)
              return put("null");
          else
              return put(csq.toString());
      }
  
      /**
       * Appends a subsequence of the  specified character sequence  to this
       * buffer&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> An invocation of this method of the form <tt>dst.append(csq, start,
       * end)</tt> when <tt>csq</tt> is not <tt>null</tt>, behaves in exactly the
       * same way as the invocation
       *
       * <pre>
       *     dst.put(csq.subSequence(start, end).toString()) </pre>
       *
       * @param  csq
       *         The character sequence from which a subsequence will be
       *         appended.  If <tt>csq</tt> is <tt>null</tt>, then characters
       *         will be appended as if <tt>csq</tt> contained the four
       *         characters <tt>"null"</tt>.
       *
       * @return  This buffer
       *
       * @throws  BufferOverflowException
       *          If there is insufficient space in this buffer
       *
       * @throws  IndexOutOfBoundsException
       *          If <tt>start</tt> or <tt>end</tt> are negative, <tt>start</tt>
       *          is greater than <tt>end</tt>, or <tt>end</tt> is greater than
       *          <tt>csq.length()</tt>
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       *
       * @since  1.5
       */
      public CharBuffer append(CharSequence csq, int start, int end) {
          CharSequence cs = (csq == null ? "null" : csq);
          return put(cs.subSequence(start, end).toString());
      }
  
      /**
       * Appends the specified char  to this
       * buffer&nbsp;&nbsp;<i>(optional operation)</i>.
       *
       * <p> An invocation of this method of the form <tt>dst.append(c)</tt>
       * behaves in exactly the same way as the invocation
       *
       * <pre>
       *     dst.put(c) </pre>
       *
       * @param  c
       *         The 16-bit char to append
       *
       * @return  This buffer
       *
       * @throws  BufferOverflowException
       *          If there is insufficient space in this buffer
       *
       * @throws  ReadOnlyBufferException
       *          If this buffer is read-only
       *
       * @since  1.5
       */
      public CharBuffer append(char c) {
          return put(c);
      }
  
  
      // -- Other byte stuff: Access to binary data --
  
  
      /**
       * Retrieves this buffer's byte order.
       *
       * <p> The byte order of a char buffer created by allocation or by
       * wrapping an existing <tt>char</tt> array is the {@link
       * ByteOrder#nativeOrder native order} of the underlying
       * hardware.  The byte order of a char buffer created as a <a
       * href="ByteBuffer.html#views">view</a> of a byte buffer is that of the
       * byte buffer at the moment that the view is created.  </p>
       *
       * @return  This buffer's byte order
       */
      public abstract ByteOrder order();
  
      @Override
      public IntStream chars() {
          return StreamSupport.intStream(() -> new CharBufferSpliterator(this),
              Buffer.SPLITERATOR_CHARACTERISTICS, false);
      }
  }
  