1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18 package org.apache.commons.codec.binary;
19
20 import static org.apache.commons.codec.binary.BaseNCodec.EOF;
21
22 import java.io.FilterOutputStream;
23 import java.io.IOException;
24 import java.io.OutputStream;
25
26 import org.apache.commons.codec.binary.BaseNCodec.Context;
27
28 /**
29 * Abstract superclass for Base-N output streams.
30 *
31 * @since 1.5
32 * @version $Id: BaseNCodecOutputStream.html 891688 2013-12-24 20:49:46Z ggregory $
33 */
34 public class BaseNCodecOutputStream extends FilterOutputStream {
35
36 private final boolean doEncode;
37
38 private final BaseNCodec baseNCodec;
39
40 private final byte[] singleByte = new byte[1];
41
42 private final Context context = new Context();
43
44 // TODO should this be protected?
45 public BaseNCodecOutputStream(final OutputStream out, final BaseNCodec basedCodec, final boolean doEncode) {
46 super(out);
47 this.baseNCodec = basedCodec;
48 this.doEncode = doEncode;
49 }
50
51 /**
52 * Writes the specified <code>byte</code> to this output stream.
53 *
54 * @param i
55 * source byte
56 * @throws IOException
57 * if an I/O error occurs.
58 */
59 @Override
60 public void write(final int i) throws IOException {
61 singleByte[0] = (byte) i;
62 write(singleByte, 0, 1);
63 }
64
65 /**
66 * Writes <code>len</code> bytes from the specified <code>b</code> array starting at <code>offset</code> to this
67 * output stream.
68 *
69 * @param b
70 * source byte array
71 * @param offset
72 * where to start reading the bytes
73 * @param len
74 * maximum number of bytes to write
75 *
76 * @throws IOException
77 * if an I/O error occurs.
78 * @throws NullPointerException
79 * if the byte array parameter is null
80 * @throws IndexOutOfBoundsException
81 * if offset, len or buffer size are invalid
82 */
83 @Override
84 public void write(final byte b[], final int offset, final int len) throws IOException {
85 if (b == null) {
86 throw new NullPointerException();
87 } else if (offset < 0 || len < 0) {
88 throw new IndexOutOfBoundsException();
89 } else if (offset > b.length || offset + len > b.length) {
90 throw new IndexOutOfBoundsException();
91 } else if (len > 0) {
92 if (doEncode) {
93 baseNCodec.encode(b, offset, len, context);
94 } else {
95 baseNCodec.decode(b, offset, len, context);
96 }
97 flush(false);
98 }
99 }
100
101 /**
102 * Flushes this output stream and forces any buffered output bytes to be written out to the stream. If propagate is
103 * true, the wrapped stream will also be flushed.
104 *
105 * @param propagate
106 * boolean flag to indicate whether the wrapped OutputStream should also be flushed.
107 * @throws IOException
108 * if an I/O error occurs.
109 */
110 private void flush(final boolean propagate) throws IOException {
111 final int avail = baseNCodec.available(context);
112 if (avail > 0) {
113 final byte[] buf = new byte[avail];
114 final int c = baseNCodec.readResults(buf, 0, avail, context);
115 if (c > 0) {
116 out.write(buf, 0, c);
117 }
118 }
119 if (propagate) {
120 out.flush();
121 }
122 }
123
124 /**
125 * Flushes this output stream and forces any buffered output bytes to be written out to the stream.
126 *
127 * @throws IOException
128 * if an I/O error occurs.
129 */
130 @Override
131 public void flush() throws IOException {
132 flush(true);
133 }
134
135 /**
136 * Closes this output stream and releases any system resources associated with the stream.
137 *
138 * @throws IOException
139 * if an I/O error occurs.
140 */
141 @Override
142 public void close() throws IOException {
143 // Notify encoder of EOF (-1).
144 if (doEncode) {
145 baseNCodec.encode(singleByte, 0, EOF, context);
146 } else {
147 baseNCodec.decode(singleByte, 0, EOF, context);
148 }
149 flush();
150 out.close();
151 }
152
153 }