1 /*
2  * Copyright (c) 2009, Oracle and/or its affiliates. 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.  Oracle designates this
8  * particular file as subject to the "Classpath" exception as provided
9  * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 
26 /**
27  * IOUtils: A collection of IO-related public static methods.
28  */
29 
30 package sun.misc;
31 
32 import java.io.EOFException;
33 import java.io.IOException;
34 import java.io.InputStream;
35 import java.util.Arrays;
36 
37 public class IOUtils {
38 
39     /**
40      * Read up to <code>length</code> of bytes from <code>in</code>
41      * until EOF is detected.
42      * @param in input stream, must not be null
43      * @param length number of bytes to read, -1 or Integer.MAX_VALUE means
44      *        read as much as possible
45      * @param readAll if true, an EOFException will be thrown if not enough
46      *        bytes are read. Ignored when length is -1 or Integer.MAX_VALUE
47      * @return bytes read
48      * @throws IOException Any IO error or a premature EOF is detected
49      */
readFully(InputStream is, int length, boolean readAll)50     public static byte[] readFully(InputStream is, int length, boolean readAll)
51             throws IOException {
52         byte[] output = {};
53         if (length == -1) length = Integer.MAX_VALUE;
54         int pos = 0;
55         while (pos < length) {
56             int bytesToRead;
57             if (pos >= output.length) { // Only expand when there's no room
58                 bytesToRead = Math.min(length - pos, output.length + 1024);
59                 if (output.length < pos + bytesToRead) {
60                     output = Arrays.copyOf(output, pos + bytesToRead);
61                 }
62             } else {
63                 bytesToRead = output.length - pos;
64             }
65             int cc = is.read(output, pos, bytesToRead);
66             if (cc < 0) {
67                 if (readAll && length != Integer.MAX_VALUE) {
68                     throw new EOFException("Detect premature EOF");
69                 } else {
70                     if (output.length != pos) {
71                         output = Arrays.copyOf(output, pos);
72                     }
73                     break;
74                 }
75             }
76             pos += cc;
77         }
78         return output;
79     }
80 }
81