Class ByteArrayInStream

1	/*
2	* Copyright (c) 2016 Vivid Solutions.
3	*
4	* All rights reserved. This program and the accompanying materials
5	* are made available under the terms of the Eclipse Public License 2.0
6	* and Eclipse Distribution License v. 1.0 which accompanies this distribution.
7	* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v20.html
8	* and the Eclipse Distribution License is available at
9	*
10	* http://www.eclipse.org/org/documents/edl-v10.php.
11	*/
12	package org.locationtech.jts.io;
13
14	/**
15	* Allows an array of bytes to be used as an {@link InStream}.
16	* To optimize memory usage, instances can be reused
17	* with different byte arrays.
18	*/
19	public class ByteArrayInStream
20	implements InStream
21	{
22	/*
23	* Implementation improvement suggested by Andrea Aime - Dec 15 2007
24	*/
25
26	private byte[] buffer;
27	private int position;
28
29	/**
30	* Creates a new stream based on the given buffer.
31	*
32	* @param buffer the bytes to read
33	*/
34	public ByteArrayInStream(final byte[] buffer) {
35	setBytes(buffer);
36	}
37
38	/**
39	* Sets this stream to read from the given buffer
40	*
41	* @param buffer the bytes to read
42	*/
43	public void setBytes(final byte[] buffer) {
44	this.buffer = buffer;
45	this.position = 0;
46	}
47
48	/**
49	* Reads up to <tt>buf.length</tt> bytes from the stream
50	* into the given byte buffer.
51	*
52	* @param buf the buffer to place the read bytes into
53	*/
54	public void read(final byte[] buf) {
55	int numToRead = buf.length;
56	// don't try and copy past the end of the input
57	if ((position + numToRead) > buffer.length) {
58	numToRead = buffer.length - position;
59	System.arraycopy(buffer, position, buf, 0, numToRead);
60	// zero out the unread bytes
61	for (int i = numToRead; i < buf.length; i++) {
62	buf[i] = 0;
63	}
64	}
65	else {
66	System.arraycopy(buffer, position, buf, 0, numToRead);
67	}
68	position += numToRead;
69	}
70	}
71