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comparison src/com/aurellem/capture/SeekableByteArrayOutputStream.java @ 3:a92de00f0414

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migrating files
author Robert McIntyre <rlm@mit.edu>
date Tue, 25 Oct 2011 11:55:55 -0700
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2:59509c585530 3:a92de00f0414
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 }