1 /************************************************************************
2 * Copyright (c) 2000-2006 The Apache Software Foundation. *
3 * All rights reserved. *
4 * ------------------------------------------------------------------- *
5 * Licensed under the Apache License, Version 2.0 (the "License"); you *
6 * may not use this file except in compliance with the License. You *
7 * 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 *
14 * implied. See the License for the specific language governing *
15 * permissions and limitations under the License. *
16 ***********************************************************************/
17
18 package org.apache.james.util;
19
20 import java.io.FilterInputStream;
21 import java.io.IOException;
22 import java.io.InputStream;
23
24 /***
25 * Removes the dot-stuffing happening during the NNTP and SMTP message
26 * transfer
27 */
28 public class DotStuffingInputStream extends FilterInputStream {
29 /***
30 * An array to hold the last two bytes read off the stream.
31 * This allows the stream to detect '\r\n' sequences even
32 * when they occur across read boundaries.
33 */
34 protected int last[] = new int[2];
35
36 public DotStuffingInputStream(InputStream in) {
37 super(in);
38 last[0] = -1;
39 last[1] = -1;
40 }
41
42 /***
43 * Read through the stream, checking for '\r\n.'
44 *
45 * @return the byte read from the stream
46 */
47 public int read() throws IOException {
48 int b = in.read();
49 if (b == '.' && last[0] == '\r' && last[1] == '\n') {
50
51 b = in.read();
52 }
53 last[0] = last[1];
54 last[1] = b;
55 return b;
56 }
57
58 /***
59 * Read through the stream, checking for '\r\n.'
60 *
61 * @param b the byte array into which the bytes will be read
62 * @param off the offset into the byte array where the bytes will be inserted
63 * @param len the maximum number of bytes to be read off the stream
64 * @return the number of bytes read
65 */
66 public int read(byte[] b, int off, int len) throws IOException {
67 if (b == null) {
68 throw new NullPointerException();
69 } else if ((off < 0) || (off > b.length) || (len < 0) ||
70 ((off + len) > b.length) || ((off + len) < 0)) {
71 throw new IndexOutOfBoundsException();
72 } else if (len == 0) {
73 return 0;
74 }
75
76 int c = read();
77 if (c == -1) {
78 return -1;
79 }
80 b[off] = (byte)c;
81
82 int i = 1;
83
84 for (; i < len ; i++) {
85 c = read();
86 if (c == -1) {
87 break;
88 }
89 if (b != null) {
90 b[off + i] = (byte)c;
91 }
92 }
93
94 return i;
95 }
96 }