1 /*
2 * Copyright 1996-2006 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package java.util.zip;
27
28 import java.io.FilterOutputStream;
29 import java.io.OutputStream;
30 import java.io.InputStream;
31 import java.io.IOException;
32
33 /**
34 * This class implements an output stream filter for compressing data in
35 * the "deflate" compression format. It is also used as the basis for other
36 * types of compression filters, such as GZIPOutputStream.
37 *
38 * @see Deflater
39 * @author David Connelly
40 */
41 public
42 class DeflaterOutputStream extends FilterOutputStream {
43 /**
44 * Compressor for this stream.
45 */
46 protected Deflater def;
47
48 /**
49 * Output buffer for writing compressed data.
50 */
51 protected byte[] buf;
52
53 /**
54 * Indicates that the stream has been closed.
55 */
56
57 private boolean closed = false;
58
59 /**
60 * Creates a new output stream with the specified compressor and
61 * buffer size.
62 * @param out the output stream
63 * @param def the compressor ("deflater")
64 * @param size the output buffer size
65 * @exception IllegalArgumentException if size is <= 0
66 */
67 public DeflaterOutputStream(OutputStream out, Deflater def, int size) {
68 super(out);
69 if (out == null || def == null) {
70 throw new NullPointerException();
71 } else if (size <= 0) {
72 throw new IllegalArgumentException("buffer size <= 0");
73 }
74 this.def = def;
75 buf = new byte[size];
76 }
77
78 /**
79 * Creates a new output stream with the specified compressor and
80 * a default buffer size.
81 * @param out the output stream
82 * @param def the compressor ("deflater")
83 */
84 public DeflaterOutputStream(OutputStream out, Deflater def) {
85 this(out, def, 512);
86 }
87
88 boolean usesDefaultDeflater = false;
89
90 /**
91 * Creates a new output stream with a default compressor and buffer size.
92 * @param out the output stream
93 */
94 public DeflaterOutputStream(OutputStream out) {
95 this(out, new Deflater());
96 usesDefaultDeflater = true;
97 }
98
99 /**
100 * Writes a byte to the compressed output stream. This method will
101 * block until the byte can be written.
102 * @param b the byte to be written
103 * @exception IOException if an I/O error has occurred
104 */
105 public void write(int b) throws IOException {
106 byte[] buf = new byte[1];
107 buf[0] = (byte)(b & 0xff);
108 write(buf, 0, 1);
109 }
110
111 /**
112 * Writes an array of bytes to the compressed output stream. This
113 * method will block until all the bytes are written.
114 * @param b the data to be written
115 * @param off the start offset of the data
116 * @param len the length of the data
117 * @exception IOException if an I/O error has occurred
118 */
119 public void write(byte[] b, int off, int len) throws IOException {
120 if (def.finished()) {
121 throw new IOException("write beyond end of stream");
122 }
123 if ((off | len | (off + len) | (b.length - (off + len))) < 0) {
124 throw new IndexOutOfBoundsException();
125 } else if (len == 0) {
126 return;
127 }
128 if (!def.finished()) {
129 // Deflate no more than stride bytes at a time. This avoids
130 // excess copying in deflateBytes (see Deflater.c)
131 int stride = buf.length;
132 for (int i = 0; i < len; i+= stride) {
133 def.setInput(b, off + i, Math.min(stride, len - i));
134 while (!def.needsInput()) {
135 deflate();
136 }
137 }
138 }
139 }
140
141 /**
142 * Finishes writing compressed data to the output stream without closing
143 * the underlying stream. Use this method when applying multiple filters
144 * in succession to the same output stream.
145 * @exception IOException if an I/O error has occurred
146 */
147 public void finish() throws IOException {
148 if (!def.finished()) {
149 def.finish();
150 while (!def.finished()) {
151 deflate();
152 }
153 }
154 }
155
156 /**
157 * Writes remaining compressed data to the output stream and closes the
158 * underlying stream.
159 * @exception IOException if an I/O error has occurred
160 */
161 public void close() throws IOException {
162 if (!closed) {
163 finish();
164 if (usesDefaultDeflater)
165 def.end();
166 out.close();
167 closed = true;
168 }
169 }
170
171 /**
172 * Writes next block of compressed data to the output stream.
173 * @throws IOException if an I/O error has occurred
174 */
175 protected void deflate() throws IOException {
176 int len = def.deflate(buf, 0, buf.length);
177 if (len > 0) {
178 out.write(buf, 0, len);
179 }
180 }
181 }
Save This Page