Mercurial > jmeCapture

     1 /*

     2  * @(#)SeekableByteArrayOutputStream.java  1.0  2010-12-27

     3  * 

     4  * Copyright © 2010 Werner Randelshofer, Immensee, Switzerland.

     5  * All rights reserved.

     6  * 

     7  * You may not use, copy or modify this file, except in compliance with the

     8  * license agreement you entered into with Werner Randelshofer.

     9  * For details see accompanying license terms.

    10  */

    11 

    12 package com.aurellem.capture;

    13 

    14 import java.io.ByteArrayOutputStream;

    15 import java.io.IOException;

    16 import java.io.OutputStream;

    17 import java.util.Arrays;

    18 import static java.lang.Math.*;

    19 /**

    20  * {@code SeekableByteArrayOutputStream}.

    21  *

    22  * @author Werner Randelshofer

    23  * @version 1.0 2010-12-27 Created.

    24  */

    25 public class SeekableByteArrayOutputStream extends ByteArrayOutputStream {

    26 

    27     /**

    28      * The current stream position.

    29      */

    30     private int pos;

    31 

    32     /**

    33      * Creates a new byte array output stream. The buffer capacity is

    34      * initially 32 bytes, though its size increases if necessary.

    35      */

    36     public SeekableByteArrayOutputStream() {

    37 	this(32);

    38     }

    39 

    40     /**

    41      * Creates a new byte array output stream, with a buffer capacity of

    42      * the specified size, in bytes.

    43      *

    44      * @param   size   the initial size.

    45      * @exception  IllegalArgumentException if size is negative.

    46      */

    47     public SeekableByteArrayOutputStream(int size) {

    48         if (size < 0) {

    49             throw new IllegalArgumentException("Negative initial size: "

    50                                                + size);

    51         }

    52 	buf = new byte[size];

    53     }

    54 

    55     /**

    56      * Writes the specified byte to this byte array output stream.

    57      *

    58      * @param   b   the byte to be written.

    59      */

    60     @Override

    61     public synchronized void write(int b) {

    62 	int newcount = max(pos + 1, count);

    63 	if (newcount > buf.length) {

    64             buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));

    65 	}

    66 	buf[pos++] = (byte)b;

    67 	count = newcount;

    68     }

    69 

    70     /**

    71      * Writes <code>len</code> bytes from the specified byte array

    72      * starting at offset <code>off</code> to this byte array output stream.

    73      *

    74      * @param   b     the data.

    75      * @param   off   the start offset in the data.

    76      * @param   len   the number of bytes to write.

    77      */

    78     @Override

    79     public synchronized void write(byte b[], int off, int len) {

    80 	if ((off < 0) || (off > b.length) || (len < 0) ||

    81             ((off + len) > b.length) || ((off + len) < 0)) {

    82 	    throw new IndexOutOfBoundsException();

    83 	} else if (len == 0) {

    84 	    return;

    85 	}

    86         int newcount = max(pos+len,count);

    87         if (newcount > buf.length) {

    88             buf = Arrays.copyOf(buf, Math.max(buf.length << 1, newcount));

    89         }

    90         System.arraycopy(b, off, buf, pos, len);

    91         pos+=len;

    92         count = newcount;

    93     }

    94 

    95     /**

    96      * Resets the <code>count</code> field of this byte array output

    97      * stream to zero, so that all currently accumulated output in the

    98      * output stream is discarded. The output stream can be used again,

    99      * reusing the already allocated buffer space.

   100      *

   101      * @see     java.io.ByteArrayInputStream#count

   102      */

   103     @Override

   104     public synchronized void reset() {

   105 	count = 0;

   106         pos=0;

   107     }

   108 

   109     /**

   110      * Sets the current stream position to the desired location.  The

   111      * next read will occur at this location.  The bit offset is set

   112      * to 0.

   113      *

   114      * <p> An <code>IndexOutOfBoundsException</code> will be thrown if

   115      * <code>pos</code> is smaller than the flushed position (as

   116      * returned by <code>getflushedPosition</code>).

   117      *

   118      * <p> It is legal to seek past the end of the file; an

   119      * <code>EOFException</code> will be thrown only if a read is

   120      * performed.

   121      *

   122      * @param pos a <code>long</code> containing the desired file

   123      * pointer position.

   124      *

   125      * @exception IndexOutOfBoundsException if <code>pos</code> is smaller

   126      * than the flushed position.

   127      * @exception IOException if any other I/O error occurs.

   128      */

   129     public void seek(long pos) throws IOException {

   130         this.pos = (int)pos;

   131     }

   132 

   133         /**

   134      * Returns the current byte position of the stream.  The next write

   135      * will take place starting at this offset.

   136      *

   137      * @return a long containing the position of the stream.

   138      *

   139      * @exception IOException if an I/O error occurs.

   140      */

   141     public long getStreamPosition() throws IOException {

   142         return pos;

   143     }

   144 

   145     /** Writes the contents of the byte array into the specified output

   146      * stream.

   147      * @param out

   148      */

   149     public void toOutputStream(OutputStream out) throws IOException {

   150         out.write(buf, 0, count);

   151     }

   152 

   153 }
author	Robert McIntyre <rlm@mit.edu>
date	Tue, 25 Oct 2011 11:55:55 -0700
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