J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1997-1999 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 sun.rmi.log; |
| 27 | |
| 28 | import java.io.*; |
| 29 | |
| 30 | public |
| 31 | class LogInputStream extends InputStream { |
| 32 | private InputStream in; |
| 33 | private int length; |
| 34 | |
| 35 | /** |
| 36 | * Creates a log input file with the specified system dependent |
| 37 | * file descriptor. |
| 38 | * @param fd the system dependent file descriptor |
| 39 | * @param length the total number of bytes allowed to be read |
| 40 | * @exception IOException If an I/O error has occurred. |
| 41 | */ |
| 42 | public LogInputStream(InputStream in, int length) throws IOException { |
| 43 | this.in = in; |
| 44 | this.length = length; |
| 45 | } |
| 46 | |
| 47 | /** |
| 48 | * Reads a byte of data. This method will block if no input is |
| 49 | * available. |
| 50 | * @return the byte read, or -1 if the end of the log or end of the |
| 51 | * stream is reached. |
| 52 | * @exception IOException If an I/O error has occurred. |
| 53 | */ |
| 54 | public int read() throws IOException { |
| 55 | if (length == 0) |
| 56 | return -1; |
| 57 | int c = in.read(); |
| 58 | length = (c != -1) ? length - 1 : 0; |
| 59 | return c; |
| 60 | } |
| 61 | |
| 62 | /** |
| 63 | * Reads data into an array of bytes. |
| 64 | * This method blocks until some input is available. |
| 65 | * @param b the buffer into which the data is read |
| 66 | * @return the actual number of bytes read, or -1 if the end of the log |
| 67 | * or end of the stream is reached. |
| 68 | * @exception IOException If an I/O error has occurred. |
| 69 | */ |
| 70 | public int read(byte b[]) throws IOException { |
| 71 | return read(b, 0, b.length); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Reads data into an array of bytes. |
| 76 | * This method blocks until some input is available. |
| 77 | * @param b the buffer into which the data is read |
| 78 | * @param off the start offset of the data |
| 79 | * @param len the maximum number of bytes read |
| 80 | * @return the actual number of bytes read, or -1 if the end of the log or |
| 81 | * end of the stream is reached. |
| 82 | * @exception IOException If an I/O error has occurred. |
| 83 | */ |
| 84 | public int read(byte b[], int off, int len) throws IOException { |
| 85 | if (length == 0) |
| 86 | return -1; |
| 87 | len = (length < len) ? length : len; |
| 88 | int n = in.read(b, off, len); |
| 89 | length = (n != -1) ? length - n : 0; |
| 90 | return n; |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Skips n bytes of input. |
| 95 | * @param n the number of bytes to be skipped |
| 96 | * @return the actual number of bytes skipped. |
| 97 | * @exception IOException If an I/O error has occurred. |
| 98 | */ |
| 99 | public long skip(long n) throws IOException { |
| 100 | if (n > Integer.MAX_VALUE) |
| 101 | throw new IOException("Too many bytes to skip - " + n); |
| 102 | if (length == 0) |
| 103 | return 0; |
| 104 | n = (length < n) ? length : n; |
| 105 | n = in.skip(n); |
| 106 | length -= n; |
| 107 | return n; |
| 108 | } |
| 109 | |
| 110 | /** |
| 111 | * Returns the number of bytes that can be read without blocking. |
| 112 | * @return the number of available bytes, which is initially |
| 113 | * equal to the file size. |
| 114 | */ |
| 115 | public int available() throws IOException { |
| 116 | int avail = in.available(); |
| 117 | return (length < avail) ? length : avail; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Closes the input stream. No further input can be read. |
| 122 | * the stream. |
| 123 | */ |
| 124 | public void close() { |
| 125 | length = 0; |
| 126 | } |
| 127 | |
| 128 | /** |
| 129 | * Closes the stream when garbage is collected. |
| 130 | */ |
| 131 | protected void finalize() throws IOException { |
| 132 | close(); |
| 133 | } |
| 134 | } |