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    1   package org.apache.commons.net.io;
    2
    3   /* ====================================================================
    4    * The Apache Software License, Version 1.1
    5    *
    6    * Copyright (c) 2001 The Apache Software Foundation.  All rights
    7    * reserved.
    8    *
    9    * Redistribution and use in source and binary forms, with or without
    10   * modification, are permitted provided that the following conditions
    11   * are met:
    12   *
    13   * 1. Redistributions of source code must retain the above copyright
    14   *    notice, this list of conditions and the following disclaimer.
    15   *
    16   * 2. Redistributions in binary form must reproduce the above copyright
    17   *    notice, this list of conditions and the following disclaimer in
    18   *    the documentation and/or other materials provided with the
    19   *    distribution.
    20   *
    21   * 3. The end-user documentation included with the redistribution,
    22   *    if any, must include the following acknowledgment:
    23   *       "This product includes software developed by the
    24   *        Apache Software Foundation (http://www.apache.org/)."
    25   *    Alternately, this acknowledgment may appear in the software itself,
    26   *    if and wherever such third-party acknowledgments normally appear.
    27   *
    28   * 4. The names "Apache" and "Apache Software Foundation" and
    29   *    "Apache Commons" must not be used to endorse or promote products
    30   *    derived from this software without prior written permission. For
    31   *    written permission, please contact apache@apache.org.
    32   *
    33   * 5. Products derived from this software may not be called "Apache",
    34   *    nor may "Apache" appear in their name, without
    35   *    prior written permission of the Apache Software Foundation.
    36   *
    37   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    38   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    39   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    40   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
    41   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    42   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    43   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    44   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    45   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    46   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    47   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    48   * SUCH DAMAGE.
    49   * ====================================================================
    50   *
    51   * This software consists of voluntary contributions made by many
    52   * individuals on behalf of the Apache Software Foundation.  For more
    53   * information on the Apache Software Foundation, please see
    54   * <http://www.apache.org/>;.
    55   */
    56
    57  import java.io.FilterOutputStream;
    58  import java.io.IOException;
    59  import java.io.OutputStream;
    60
    61  /****
    62   * This class wraps an output stream, replacing all occurrences
    63   * of <CR><LF> (carriage return followed by a linefeed),
    64   * which is the NETASCII standard for representing a newline, with the
    65   * local line separator representation.  You would use this class to
    66   * implement ASCII file transfers requiring conversion from NETASCII.
    67   * <p>
    68   * Because of the translation process, a call to <code>flush()</code> will
    69   * not flush the last byte written if that byte was a carriage
    70   * return.  A call to <a href="#close"> close() </a>, however, will
    71   * flush the carriage return.
    72   * <p>
    73   * <p>
    74   * @author Daniel F. Savarese
    75   ***/
    76
    77  public final class FromNetASCIIOutputStream extends FilterOutputStream
    78  {
    79      private boolean __lastWasCR;
    80
    81      /****
    82       * Creates a FromNetASCIIOutputStream instance that wraps an existing
    83       * OutputStream.
    84       * <p>
    85       * @param output  The OutputStream to wrap.
    86       ***/
    87      public FromNetASCIIOutputStream(OutputStream output)
    88      {
    89          super(output);
    90          __lastWasCR = false;
    91      }
    92
    93
    94      private void __write(int ch) throws IOException
    95      {
    96          switch (ch)
    97          {
    98          case '\r':
    99              __lastWasCR = true;
    100             // Don't write anything.  We need to see if next one is linefeed
    101             break;
    102         case '\n':
    103             if (__lastWasCR)
    104             {
    105                 out.write(FromNetASCIIInputStream._lineSeparatorBytes);
    106                 __lastWasCR = false;
    107                 break;
    108             }
    109             __lastWasCR = false;
    110             out.write('\n');
    111             break;
    112         default:
    113             if (__lastWasCR)
    114             {
    115                 out.write('\r');
    116                 __lastWasCR = false;
    117             }
    118             out.write(ch);
    119             break;
    120         }
    121     }
    122
    123
    124     /****
    125      * Writes a byte to the stream.    Note that a call to this method
    126      * might not actually write a byte to the underlying stream until a
    127      * subsequent character is written, from which it can be determined if
    128      * a NETASCII line separator was encountered.
    129      * This is transparent to the programmer and is only mentioned for
    130      * completeness.
    131      * <p>
    132      * @param ch The byte to write.
    133      * @exception IOException If an error occurs while writing to the underlying
    134      *            stream.
    135      ***/
    136     public synchronized void write(int ch)
    137     throws IOException
    138     {
    139         if (FromNetASCIIInputStream._noConversionRequired)
    140         {
    141             out.write(ch);
    142             return ;
    143         }
    144
    145         __write(ch);
    146     }
    147
    148
    149     /****
    150      * Writes a byte array to the stream.
    151      * <p>
    152      * @param buffer  The byte array to write.
    153      * @exception IOException If an error occurs while writing to the underlying
    154      *            stream.
    155      ***/
    156     public synchronized void write(byte buffer[])
    157     throws IOException
    158     {
    159         write(buffer, 0, buffer.length);
    160     }
    161
    162
    163     /****
    164      * Writes a number of bytes from a byte array to the stream starting from
    165      * a given offset.
    166      * <p>
    167      * @param buffer  The byte array to write.
    168      * @param offset  The offset into the array at which to start copying data.
    169      * @param length  The number of bytes to write.
    170      * @exception IOException If an error occurs while writing to the underlying
    171      *            stream.
    172      ***/
    173     public synchronized void write(byte buffer[], int offset, int length)
    174     throws IOException
    175     {
    176         if (FromNetASCIIInputStream._noConversionRequired)
    177         {
    178             // FilterOutputStream method is very slow.
    179             //super.write(buffer, offset, length);
    180             out.write(buffer, offset, length);
    181             return ;
    182         }
    183
    184         while (length-- > 0)
    185             __write(buffer[offset++]);
    186     }
    187
    188
    189     /****
    190      * Closes the stream, writing all pending data.
    191      * <p>
    192      * @exception IOException  If an error occurs while closing the stream.
    193      ***/
    194     public synchronized void close()
    195     throws IOException
    196     {
    197         if (FromNetASCIIInputStream._noConversionRequired)
    198         {
    199             super.close();
    200             return ;
    201         }
    202
    203         if (__lastWasCR)
    204             out.write('\r');
    205         super.close();
    206     }
    207 }

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