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.charset;
  
  import java.nio.Buffer;
  import java.nio.ByteBuffer;
  import java.nio.CharBuffer;
  import java.nio.BufferOverflowException;
  import java.nio.BufferUnderflowException;
  import java.lang.ref.WeakReference;
  import java.nio.charset.CoderMalfunctionError;                  // javadoc
  import java.util.Arrays;
  
  
  /**
   * An engine that can transform a sequence of sixteen-bit Unicode characters into a sequence of
   * bytes in a specific charset.
   *
   * <a name="steps"></a>
   *
   * <p> The input character sequence is provided in a character buffer or a series
   * of such buffers.  The output byte sequence is written to a byte buffer
   * or a series of such buffers.  An encoder should always be used by making
   * the following sequence of method invocations, hereinafter referred to as an
   * <i>encoding operation</i>:
   *
   * <ol>
   *
   *   <li><p> Reset the encoder via the {@link #reset reset} method, unless it
   *   has not been used before; </p></li>
   *
   *   <li><p> Invoke the {@link #encode encode} method zero or more times, as
   *   long as additional input may be available, passing <tt>false</tt> for the
   *   <tt>endOfInput</tt> argument and filling the input buffer and flushing the
   *   output buffer between invocations; </p></li>
   *
   *   <li><p> Invoke the {@link #encode encode} method one final time, passing
   *   <tt>true</tt> for the <tt>endOfInput</tt> argument; and then </p></li>
   *
   *   <li><p> Invoke the {@link #flush flush} method so that the encoder can
   *   flush any internal state to the output buffer. </p></li>
   *
   * </ol>
   *
   * Each invocation of the {@link #encode encode} method will encode as many
   * characters as possible from the input buffer, writing the resulting bytes
   * to the output buffer.  The {@link #encode encode} method returns when more
   * input is required, when there is not enough room in the output buffer, or
   * when an encoding error has occurred.  In each case a {@link CoderResult}
   * object is returned to describe the reason for termination.  An invoker can
   * examine this object and fill the input buffer, flush the output buffer, or
   * attempt to recover from an encoding error, as appropriate, and try again.
   *
   * <a name="ce"></a>
   *
   * <p> There are two general types of encoding errors.  If the input character
   * sequence is not a legal sixteen-bit Unicode sequence then the input is considered <i>malformed</i>.  If
   * the input character sequence is legal but cannot be mapped to a valid
   * byte sequence in the given charset then an <i>unmappable character</i> has been encountered.
   *
   * <a name="cae"></a>
   *
   * <p> How an encoding error is handled depends upon the action requested for
   * that type of error, which is described by an instance of the {@link
   * CodingErrorAction} class.  The possible error actions are to {@linkplain
   * CodingErrorAction#IGNORE ignore} the erroneous input, {@linkplain
   * CodingErrorAction#REPORT report} the error to the invoker via
   * the returned {@link CoderResult} object, or {@linkplain CodingErrorAction#REPLACE
   * replace} the erroneous input with the current value of the
   * replacement byte array.  The replacement
   *
  
   * is initially set to the encoder's default replacement, which often
   * (but not always) has the initial value&nbsp;<tt>{</tt>&nbsp;<tt>(byte)'?'</tt>&nbsp;<tt>}</tt>;
  
  
  
  
   *
   * its value may be changed via the {@link #replaceWith(byte[])
   * replaceWith} method.
   *
   * <p> The default action for malformed-input and unmappable-character errors
   * is to {@linkplain CodingErrorAction#REPORT report} them.  The
   * malformed-input error action may be changed via the {@link
   * #onMalformedInput(CodingErrorAction) onMalformedInput} method; the
   * unmappable-character action may be changed via the {@link
   * #onUnmappableCharacter(CodingErrorAction) onUnmappableCharacter} method.
   *
   * <p> This class is designed to handle many of the details of the encoding
   * process, including the implementation of error actions.  An encoder for a
   * specific charset, which is a concrete subclass of this class, need only
   * implement the abstract {@link #encodeLoop encodeLoop} method, which
   * encapsulates the basic encoding loop.  A subclass that maintains internal
   * state should, additionally, override the {@link #implFlush implFlush} and
   * {@link #implReset implReset} methods.
   *
   * <p> Instances of this class are not safe for use by multiple concurrent
   * threads.  </p>
   *
   *
   * @author Mark Reinhold
   * @author JSR-51 Expert Group
   * @since 1.4
   *
   * @see ByteBuffer
   * @see CharBuffer
   * @see Charset
   * @see CharsetDecoder
   */
  
  public abstract class CharsetEncoder {
  
      private final Charset charset;
      private final float averageBytesPerChar;
      private final float maxBytesPerChar;
  
      private byte[] replacement;
      private CodingErrorAction malformedInputAction
          = CodingErrorAction.REPORT;
      private CodingErrorAction unmappableCharacterAction
          = CodingErrorAction.REPORT;
  
      // Internal states
      //
      private static final int ST_RESET   = 0;
      private static final int ST_CODING  = 1;
      private static final int ST_END     = 2;
      private static final int ST_FLUSHED = 3;
  
      private int state = ST_RESET;
  
      private static String stateNames[]
          = { "RESET", "CODING", "CODING_END", "FLUSHED" };
  
  
      /**
       * Initializes a new encoder.  The new encoder will have the given
       * bytes-per-char and replacement values.
       *
       * @param  cs
       *         The charset that created this encoder
       *
       * @param  averageBytesPerChar
       *         A positive float value indicating the expected number of
       *         bytes that will be produced for each input character
       *
       * @param  maxBytesPerChar
       *         A positive float value indicating the maximum number of
       *         bytes that will be produced for each input character
       *
       * @param  replacement
       *         The initial replacement; must not be <tt>null</tt>, must have
       *         non-zero length, must not be longer than maxBytesPerChar,
       *         and must be {@linkplain #isLegalReplacement legal}
       *
       * @throws  IllegalArgumentException
       *          If the preconditions on the parameters do not hold
       */
      protected
      CharsetEncoder(Charset cs,
                     float averageBytesPerChar,
                     float maxBytesPerChar,
                     byte[] replacement)
      {
          // BEGIN Android-added: A hidden constructor for the CharsetEncoderICU subclass.
          this(cs, averageBytesPerChar, maxBytesPerChar, replacement, false);
      }
  
      /**
       * This constructor is for subclasses to specify whether {@code replacement} can be used as it
       * is ("trusted"). If it is trusted, {@link #replaceWith(byte[])} and
       * {@link #implReplaceWith(byte[])} will not be called.
       * @hide
       */
      protected CharsetEncoder(Charset cs, float averageBytesPerChar, float maxBytesPerChar, byte[] replacement,
              boolean trusted)
      {
          // END Android-added: A hidden constructor for the CharsetEncoderICU subclass.
          this.charset = cs;
          if (averageBytesPerChar <= 0.0f)
              throw new IllegalArgumentException("Non-positive "
                                                 + "averageBytesPerChar");
          if (maxBytesPerChar <= 0.0f)
              throw new IllegalArgumentException("Non-positive "
                                                 + "maxBytesPerChar");
          if (!Charset.atBugLevel("1.4")) {
              if (averageBytesPerChar > maxBytesPerChar)
                  throw new IllegalArgumentException("averageBytesPerChar"
                                                     + " exceeds "
                                                     + "maxBytesPerChar");
          }
          this.replacement = replacement;
          this.averageBytesPerChar = averageBytesPerChar;
          this.maxBytesPerChar = maxBytesPerChar;
          // BEGIN Android-changed: Avoid calling replaceWith() for trusted subclasses.
          // replaceWith(replacement);
          if (!trusted) {
              replaceWith(replacement);
          }
          // END Android-changed: Avoid calling replaceWith() for trusted subclasses.
      }
  
      /**
       * Initializes a new encoder.  The new encoder will have the given
       * bytes-per-char values and its replacement will be the
       * byte array <tt>{</tt>&nbsp;<tt>(byte)'?'</tt>&nbsp;<tt>}</tt>.
       *
       * @param  cs
       *         The charset that created this encoder
       *
       * @param  averageBytesPerChar
       *         A positive float value indicating the expected number of
       *         bytes that will be produced for each input character
       *
       * @param  maxBytesPerChar
       *         A positive float value indicating the maximum number of
       *         bytes that will be produced for each input character
       *
       * @throws  IllegalArgumentException
       *          If the preconditions on the parameters do not hold
       */
      protected CharsetEncoder(Charset cs,
                               float averageBytesPerChar,
                               float maxBytesPerChar)
      {
          this(cs,
               averageBytesPerChar, maxBytesPerChar,
               new byte[] { (byte)'?' });
      }
  
      /**
       * Returns the charset that created this encoder.
       *
       * @return  This encoder's charset
       */
      public final Charset charset() {
          return charset;
      }
  
      /**
       * Returns this encoder's replacement value.
       *
       * @return  This encoder's current replacement,
       *          which is never <tt>null</tt> and is never empty
       */
      public final byte[] replacement() {
  
  
  
  
          return Arrays.copyOf(replacement, replacement.length);
  
      }
  
      /**
       * Changes this encoder's replacement value.
       *
       * <p> This method invokes the {@link #implReplaceWith implReplaceWith}
       * method, passing the new replacement, after checking that the new
       * replacement is acceptable.  </p>
       *
       * @param  newReplacement  The replacement value
       *
  
  
  
  
  
       *         The new replacement; must not be <tt>null</tt>, must have
       *         non-zero length, must not be longer than the value returned by
       *         the {@link #maxBytesPerChar() maxBytesPerChar} method, and
       *         must be {@link #isLegalReplacement legal}
  
       *
       * @return  This encoder
       *
       * @throws  IllegalArgumentException
       *          If the preconditions on the parameter do not hold
       */
      public final CharsetEncoder replaceWith(byte[] newReplacement) {
          if (newReplacement == null)
              throw new IllegalArgumentException("Null replacement");
          int len = newReplacement.length;
          if (len == 0)
              throw new IllegalArgumentException("Empty replacement");
          if (len > maxBytesPerChar)
              throw new IllegalArgumentException("Replacement too long");
  
  
  
  
          if (!isLegalReplacement(newReplacement))
              throw new IllegalArgumentException("Illegal replacement");
          this.replacement = Arrays.copyOf(newReplacement, newReplacement.length);
  
          implReplaceWith(this.replacement);
          return this;
      }
  
      /**
       * Reports a change to this encoder's replacement value.
       *
       * <p> The default implementation of this method does nothing.  This method
       * should be overridden by encoders that require notification of changes to
       * the replacement.  </p>
       *
       * @param  newReplacement    The replacement value
       */
      protected void implReplaceWith(byte[] newReplacement) {
      }
  
  
  
      private WeakReference<CharsetDecoder> cachedDecoder = null;
  
      /**
       * Tells whether or not the given byte array is a legal replacement value
       * for this encoder.
       *
       * <p> A replacement is legal if, and only if, it is a legal sequence of
       * bytes in this encoder's charset; that is, it must be possible to decode
       * the replacement into one or more sixteen-bit Unicode characters.
       *
       * <p> The default implementation of this method is not very efficient; it
       * should generally be overridden to improve performance.  </p>
       *
       * @param  repl  The byte array to be tested
       *
       * @return  <tt>true</tt> if, and only if, the given byte array
       *          is a legal replacement value for this encoder
       */
      public boolean isLegalReplacement(byte[] repl) {
          WeakReference<CharsetDecoder> wr = cachedDecoder;
          CharsetDecoder dec = null;
          if ((wr == null) || ((dec = wr.get()) == null)) {
              dec = charset().newDecoder();
              dec.onMalformedInput(CodingErrorAction.REPORT);
              dec.onUnmappableCharacter(CodingErrorAction.REPORT);
              cachedDecoder = new WeakReference<CharsetDecoder>(dec);
          } else {
              dec.reset();
          }
          ByteBuffer bb = ByteBuffer.wrap(repl);
          CharBuffer cb = CharBuffer.allocate((int)(bb.remaining()
                                                    * dec.maxCharsPerByte()));
          CoderResult cr = dec.decode(bb, cb, true);
          return !cr.isError();
      }
  
  
  
      /**
       * Returns this encoder's current action for malformed-input errors.
       *
       * @return The current malformed-input action, which is never <tt>null</tt>
       */
      public CodingErrorAction malformedInputAction() {
          return malformedInputAction;
      }
  
      /**
       * Changes this encoder's action for malformed-input errors.
       *
       * <p> This method invokes the {@link #implOnMalformedInput
       * implOnMalformedInput} method, passing the new action.  </p>
       *
       * @param  newAction  The new action; must not be <tt>null</tt>
       *
       * @return  This encoder
       *
       * @throws IllegalArgumentException
       *         If the precondition on the parameter does not hold
       */
      public final CharsetEncoder onMalformedInput(CodingErrorAction newAction) {
          if (newAction == null)
              throw new IllegalArgumentException("Null action");
          malformedInputAction = newAction;
          implOnMalformedInput(newAction);
          return this;
      }
  
      /**
       * Reports a change to this encoder's malformed-input action.
       *
       * <p> The default implementation of this method does nothing.  This method
       * should be overridden by encoders that require notification of changes to
       * the malformed-input action.  </p>
       *
       * @param  newAction  The new action
       */
      protected void implOnMalformedInput(CodingErrorAction newAction) { }
  
      /**
       * Returns this encoder's current action for unmappable-character errors.
       *
       * @return The current unmappable-character action, which is never
       *         <tt>null</tt>
       */
      public CodingErrorAction unmappableCharacterAction() {
          return unmappableCharacterAction;
      }
  
      /**
       * Changes this encoder's action for unmappable-character errors.
       *
       * <p> This method invokes the {@link #implOnUnmappableCharacter
       * implOnUnmappableCharacter} method, passing the new action.  </p>
       *
       * @param  newAction  The new action; must not be <tt>null</tt>
       *
       * @return  This encoder
       *
       * @throws IllegalArgumentException
       *         If the precondition on the parameter does not hold
       */
      public final CharsetEncoder onUnmappableCharacter(CodingErrorAction
                                                        newAction)
      {
          if (newAction == null)
              throw new IllegalArgumentException("Null action");
          unmappableCharacterAction = newAction;
          implOnUnmappableCharacter(newAction);
          return this;
      }
  
      /**
       * Reports a change to this encoder's unmappable-character action.
       *
       * <p> The default implementation of this method does nothing.  This method
       * should be overridden by encoders that require notification of changes to
       * the unmappable-character action.  </p>
       *
       * @param  newAction  The new action
       */
      protected void implOnUnmappableCharacter(CodingErrorAction newAction) { }
  
      /**
       * Returns the average number of bytes that will be produced for each
       * character of input.  This heuristic value may be used to estimate the size
       * of the output buffer required for a given input sequence.
       *
       * @return  The average number of bytes produced
       *          per character of input
       */
      public final float averageBytesPerChar() {
          return averageBytesPerChar;
      }
  
      /**
       * Returns the maximum number of bytes that will be produced for each
       * character of input.  This value may be used to compute the worst-case size
       * of the output buffer required for a given input sequence.
       *
       * @return  The maximum number of bytes that will be produced per
       *          character of input
       */
      public final float maxBytesPerChar() {
          return maxBytesPerChar;
      }
  
      /**
       * Encodes as many characters as possible from the given input buffer,
       * writing the results to the given output buffer.
       *
       * <p> The buffers are read from, and written to, starting at their current
       * positions.  At most {@link Buffer#remaining in.remaining()} characters
       * will be read and at most {@link Buffer#remaining out.remaining()}
       * bytes will be written.  The buffers' positions will be advanced to
       * reflect the characters read and the bytes written, but their marks and
       * limits will not be modified.
       *
       * <p> In addition to reading characters from the input buffer and writing
       * bytes to the output buffer, this method returns a {@link CoderResult}
       * object to describe its reason for termination:
       *
       * <ul>
       *
       *   <li><p> {@link CoderResult#UNDERFLOW} indicates that as much of the
       *   input buffer as possible has been encoded.  If there is no further
       *   input then the invoker can proceed to the next step of the
       *   <a href="#steps">encoding operation</a>.  Otherwise this method
       *   should be invoked again with further input.  </p></li>
       *
       *   <li><p> {@link CoderResult#OVERFLOW} indicates that there is
       *   insufficient space in the output buffer to encode any more characters.
       *   This method should be invoked again with an output buffer that has
       *   more {@linkplain Buffer#remaining remaining} bytes. This is
       *   typically done by draining any encoded bytes from the output
       *   buffer.  </p></li>
       *
       *   <li><p> A {@linkplain CoderResult#malformedForLength
       *   malformed-input} result indicates that a malformed-input
       *   error has been detected.  The malformed characters begin at the input
       *   buffer's (possibly incremented) position; the number of malformed
       *   characters may be determined by invoking the result object's {@link
       *   CoderResult#length() length} method.  This case applies only if the
       *   {@linkplain #onMalformedInput malformed action} of this encoder
       *   is {@link CodingErrorAction#REPORT}; otherwise the malformed input
       *   will be ignored or replaced, as requested.  </p></li>
       *
       *   <li><p> An {@linkplain CoderResult#unmappableForLength
       *   unmappable-character} result indicates that an
       *   unmappable-character error has been detected.  The characters that
       *   encode the unmappable character begin at the input buffer's (possibly
       *   incremented) position; the number of such characters may be determined
       *   by invoking the result object's {@link CoderResult#length() length}
       *   method.  This case applies only if the {@linkplain #onUnmappableCharacter
       *   unmappable action} of this encoder is {@link
       *   CodingErrorAction#REPORT}; otherwise the unmappable character will be
       *   ignored or replaced, as requested.  </p></li>
       *
       * </ul>
       *
       * In any case, if this method is to be reinvoked in the same encoding
       * operation then care should be taken to preserve any characters remaining
       * in the input buffer so that they are available to the next invocation.
       *
       * <p> The <tt>endOfInput</tt> parameter advises this method as to whether
       * the invoker can provide further input beyond that contained in the given
       * input buffer.  If there is a possibility of providing additional input
       * then the invoker should pass <tt>false</tt> for this parameter; if there
       * is no possibility of providing further input then the invoker should
       * pass <tt>true</tt>.  It is not erroneous, and in fact it is quite
       * common, to pass <tt>false</tt> in one invocation and later discover that
       * no further input was actually available.  It is critical, however, that
       * the final invocation of this method in a sequence of invocations always
       * pass <tt>true</tt> so that any remaining unencoded input will be treated
       * as being malformed.
       *
       * <p> This method works by invoking the {@link #encodeLoop encodeLoop}
       * method, interpreting its results, handling error conditions, and
       * reinvoking it as necessary.  </p>
       *
       *
       * @param  in
       *         The input character buffer
       *
       * @param  out
       *         The output byte buffer
       *
       * @param  endOfInput
       *         <tt>true</tt> if, and only if, the invoker can provide no
       *         additional input characters beyond those in the given buffer
       *
       * @return  A coder-result object describing the reason for termination
       *
       * @throws  IllegalStateException
       *          If an encoding operation is already in progress and the previous
       *          step was an invocation neither of the {@link #reset reset}
       *          method, nor of this method with a value of <tt>false</tt> for
       *          the <tt>endOfInput</tt> parameter, nor of this method with a
       *          value of <tt>true</tt> for the <tt>endOfInput</tt> parameter
       *          but a return value indicating an incomplete encoding operation
       *
       * @throws  CoderMalfunctionError
       *          If an invocation of the encodeLoop method threw
       *          an unexpected exception
       */
      public final CoderResult encode(CharBuffer in, ByteBuffer out,
                                      boolean endOfInput)
      {
          int newState = endOfInput ? ST_END : ST_CODING;
          if ((state != ST_RESET) && (state != ST_CODING)
              && !(endOfInput && (state == ST_END)))
              throwIllegalStateException(state, newState);
          state = newState;
  
          for (;;) {
  
              CoderResult cr;
              try {
                  cr = encodeLoop(in, out);
              } catch (BufferUnderflowException x) {
                  throw new CoderMalfunctionError(x);
              } catch (BufferOverflowException x) {
                  throw new CoderMalfunctionError(x);
              }
  
              if (cr.isOverflow())
                  return cr;
  
              if (cr.isUnderflow()) {
                  if (endOfInput && in.hasRemaining()) {
                      cr = CoderResult.malformedForLength(in.remaining());
                      // Fall through to malformed-input case
                  } else {
                      return cr;
                  }
              }
  
              CodingErrorAction action = null;
              if (cr.isMalformed())
                  action = malformedInputAction;
              else if (cr.isUnmappable())
                  action = unmappableCharacterAction;
              else
                  assert false : cr.toString();
  
              if (action == CodingErrorAction.REPORT)
                  return cr;
  
              if (action == CodingErrorAction.REPLACE) {
                  if (out.remaining() < replacement.length)
                      return CoderResult.OVERFLOW;
                  out.put(replacement);
              }
  
              if ((action == CodingErrorAction.IGNORE)
                  || (action == CodingErrorAction.REPLACE)) {
                  // Skip erroneous input either way
                  in.position(in.position() + cr.length());
                  continue;
              }
  
              assert false;
          }
  
      }
  
      /**
       * Flushes this encoder.
       *
       * <p> Some encoders maintain internal state and may need to write some
       * final bytes to the output buffer once the overall input sequence has
       * been read.
       *
       * <p> Any additional output is written to the output buffer beginning at
       * its current position.  At most {@link Buffer#remaining out.remaining()}
       * bytes will be written.  The buffer's position will be advanced
       * appropriately, but its mark and limit will not be modified.
       *
       * <p> If this method completes successfully then it returns {@link
       * CoderResult#UNDERFLOW}.  If there is insufficient room in the output
       * buffer then it returns {@link CoderResult#OVERFLOW}.  If this happens
       * then this method must be invoked again, with an output buffer that has
       * more room, in order to complete the current <a href="#steps">encoding
       * operation</a>.
       *
       * <p> If this encoder has already been flushed then invoking this method
       * has no effect.
       *
       * <p> This method invokes the {@link #implFlush implFlush} method to
       * perform the actual flushing operation.  </p>
       *
       * @param  out
       *         The output byte buffer
       *
       * @return  A coder-result object, either {@link CoderResult#UNDERFLOW} or
       *          {@link CoderResult#OVERFLOW}
       *
       * @throws  IllegalStateException
       *          If the previous step of the current encoding operation was an
       *          invocation neither of the {@link #flush flush} method nor of
       *          the three-argument {@link
       *          #encode(CharBuffer,ByteBuffer,boolean) encode} method
       *          with a value of <tt>true</tt> for the <tt>endOfInput</tt>
       *          parameter
       */
      public final CoderResult flush(ByteBuffer out) {
          if (state == ST_END) {
              CoderResult cr = implFlush(out);
              if (cr.isUnderflow())
                  state = ST_FLUSHED;
              return cr;
          }
  
          if (state != ST_FLUSHED)
              throwIllegalStateException(state, ST_FLUSHED);
  
          return CoderResult.UNDERFLOW; // Already flushed
      }
  
      /**
       * Flushes this encoder.
       *
       * <p> The default implementation of this method does nothing, and always
       * returns {@link CoderResult#UNDERFLOW}.  This method should be overridden
       * by encoders that may need to write final bytes to the output buffer
       * once the entire input sequence has been read. </p>
       *
       * @param  out
       *         The output byte buffer
       *
       * @return  A coder-result object, either {@link CoderResult#UNDERFLOW} or
       *          {@link CoderResult#OVERFLOW}
       */
      protected CoderResult implFlush(ByteBuffer out) {
          return CoderResult.UNDERFLOW;
      }
  
      /**
       * Resets this encoder, clearing any internal state.
       *
       * <p> This method resets charset-independent state and also invokes the
       * {@link #implReset() implReset} method in order to perform any
       * charset-specific reset actions.  </p>
       *
       * @return  This encoder
       *
       */
      public final CharsetEncoder reset() {
          implReset();
          state = ST_RESET;
          return this;
      }
  
      /**
       * Resets this encoder, clearing any charset-specific internal state.
       *
       * <p> The default implementation of this method does nothing.  This method
       * should be overridden by encoders that maintain internal state.  </p>
       */
      protected void implReset() { }
  
      /**
       * Encodes one or more characters into one or more bytes.
       *
       * <p> This method encapsulates the basic encoding loop, encoding as many
       * characters as possible until it either runs out of input, runs out of room
       * in the output buffer, or encounters an encoding error.  This method is
       * invoked by the {@link #encode encode} method, which handles result
       * interpretation and error recovery.
       *
       * <p> The buffers are read from, and written to, starting at their current
       * positions.  At most {@link Buffer#remaining in.remaining()} characters
       * will be read, and at most {@link Buffer#remaining out.remaining()}
       * bytes will be written.  The buffers' positions will be advanced to
       * reflect the characters read and the bytes written, but their marks and
       * limits will not be modified.
       *
       * <p> This method returns a {@link CoderResult} object to describe its
       * reason for termination, in the same manner as the {@link #encode encode}
       * method.  Most implementations of this method will handle encoding errors
       * by returning an appropriate result object for interpretation by the
       * {@link #encode encode} method.  An optimized implementation may instead
       * examine the relevant error action and implement that action itself.
       *
       * <p> An implementation of this method may perform arbitrary lookahead by
       * returning {@link CoderResult#UNDERFLOW} until it receives sufficient
       * input.  </p>
       *
       * @param  in
       *         The input character buffer
       *
       * @param  out
       *         The output byte buffer
       *
       * @return  A coder-result object describing the reason for termination
       */
      protected abstract CoderResult encodeLoop(CharBuffer in,
                                                ByteBuffer out);
  
      /**
       * Convenience method that encodes the remaining content of a single input
       * character buffer into a newly-allocated byte buffer.
       *
       * <p> This method implements an entire <a href="#steps">encoding
       * operation</a>; that is, it resets this encoder, then it encodes the
       * characters in the given character buffer, and finally it flushes this
       * encoder.  This method should therefore not be invoked if an encoding
       * operation is already in progress.  </p>
       *
       * @param  in
       *         The input character buffer
       *
       * @return A newly-allocated byte buffer containing the result of the
       *         encoding operation.  The buffer's position will be zero and its
       *         limit will follow the last byte written.
       *
       * @throws  IllegalStateException
       *          If an encoding operation is already in progress
       *
       * @throws  MalformedInputException
       *          If the character sequence starting at the input buffer's current
       *          position is not a legal sixteen-bit Unicode sequence and the current malformed-input action
       *          is {@link CodingErrorAction#REPORT}
       *
       * @throws  UnmappableCharacterException
       *          If the character sequence starting at the input buffer's current
       *          position cannot be mapped to an equivalent byte sequence and
       *          the current unmappable-character action is {@link
       *          CodingErrorAction#REPORT}
       */
      public final ByteBuffer encode(CharBuffer in)
          throws CharacterCodingException
      {
          int n = (int)(in.remaining() * averageBytesPerChar());
          ByteBuffer out = ByteBuffer.allocate(n);
  
          if ((n == 0) && (in.remaining() == 0))
              return out;
          reset();
          for (;;) {
              CoderResult cr = in.hasRemaining() ?
                  encode(in, out, true) : CoderResult.UNDERFLOW;
              if (cr.isUnderflow())
                  cr = flush(out);
  
              if (cr.isUnderflow())
                  break;
              if (cr.isOverflow()) {
                  n = 2*n + 1;    // Ensure progress; n might be 0!
                  ByteBuffer o = ByteBuffer.allocate(n);
                  out.flip();
                  o.put(out);
                  out = o;
                  continue;
              }
              cr.throwException();
          }
          out.flip();
          return out;
      }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
      private boolean canEncode(CharBuffer cb) {
          if (state == ST_FLUSHED)
              reset();
          else if (state != ST_RESET)
              throwIllegalStateException(state, ST_CODING);
  
          // BEGIN Android-added: Fast path handling for empty buffers.
          // Empty buffers can always be "encoded".
          if (!cb.hasRemaining()) {
              return true;
          }
          // END Android-added: Fast path handling for empty buffers.
  
          CodingErrorAction ma = malformedInputAction();
          CodingErrorAction ua = unmappableCharacterAction();
          try {
              onMalformedInput(CodingErrorAction.REPORT);
              onUnmappableCharacter(CodingErrorAction.REPORT);
              encode(cb);
          } catch (CharacterCodingException x) {
              return false;
          } finally {
              onMalformedInput(ma);
              onUnmappableCharacter(ua);
              reset();
          }
          return true;
      }
  
      /**
       * Tells whether or not this encoder can encode the given character.
       *
       * <p> This method returns <tt>false</tt> if the given character is a
       * surrogate character; such characters can be interpreted only when they
       * are members of a pair consisting of a high surrogate followed by a low
       * surrogate.  The {@link #canEncode(CharSequence)
       * canEncode(CharSequence)} method may be used to test whether or not a
       * character sequence can be encoded.
       *
       * <p> This method may modify this encoder's state; it should therefore not
       * be invoked if an <a href="#steps">encoding operation</a> is already in
       * progress.
       *
       * <p> The default implementation of this method is not very efficient; it
       * should generally be overridden to improve performance.  </p>
       *
       * @param   c
       *          The given character
       *
       * @return  <tt>true</tt> if, and only if, this encoder can encode
       *          the given character
       *
       * @throws  IllegalStateException
       *          If an encoding operation is already in progress
       */
      public boolean canEncode(char c) {
          CharBuffer cb = CharBuffer.allocate(1);
          cb.put(c);
          cb.flip();
          return canEncode(cb);
      }
  
      /**
       * Tells whether or not this encoder can encode the given character
       * sequence.
       *
       * <p> If this method returns <tt>false</tt> for a particular character
       * sequence then more information about why the sequence cannot be encoded
       * may be obtained by performing a full <a href="#steps">encoding
       * operation</a>.
       *
       * <p> This method may modify this encoder's state; it should therefore not
       * be invoked if an encoding operation is already in progress.
       *
       * <p> The default implementation of this method is not very efficient; it
       * should generally be overridden to improve performance.  </p>
       *
       * @param   cs
       *          The given character sequence
       *
       * @return  <tt>true</tt> if, and only if, this encoder can encode
       *          the given character without throwing any exceptions and without
       *          performing any replacements
       *
       * @throws  IllegalStateException
       *          If an encoding operation is already in progress
       */
      public boolean canEncode(CharSequence cs) {
          CharBuffer cb;
          if (cs instanceof CharBuffer)
              cb = ((CharBuffer)cs).duplicate();
          else
              // Android-removed: An unnecessary call to toString().
              // cb = CharBuffer.wrap(cs.toString());
              cb = CharBuffer.wrap(cs);
          return canEncode(cb);
      }
  
  
  
  
      private void throwIllegalStateException(int from, int to) {
          throw new IllegalStateException("Current state = " + stateNames[from]
                                          + ", new state = " + stateNames[to]);
      }
  
  }
  