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
30package sun.misc;
31
32import java.io.EOFException;
33import java.io.IOException;
34import java.io.InputStream;
35import java.util.Arrays;
36
37public 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     */
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