1 /*****************************************************************
2 * Licensed to the Apache Software Foundation (ASF) under one *
3 * or more contributor license agreements. See the NOTICE file *
4 * distributed with this work for additional information *
5 * regarding copyright ownership. The ASF licenses this file *
6 * to you under the Apache License, Version 2.0 (the *
7 * "License"); you may not use this file except in compliance *
8 * with the License. You may obtain a copy of the License at *
9 * *
10 * http://www.apache.org/licenses/LICENSE-2.0 *
11 * *
12 * Unless required by applicable law or agreed to in writing, *
13 * software distributed under the License is distributed on an *
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
15 * KIND, either express or implied. See the License for the *
16 * specific language governing permissions and limitations *
17 * under the License. *
18 ****************************************************************/
19
20 package org.apache.james.util;
21
22 import java.io.FilterInputStream;
23 import java.io.IOException;
24 import java.io.InputStream;
25
26 /***
27 * Removes the dot-stuffing happening during the NNTP and SMTP message
28 * transfer
29 */
30 public class DotStuffingInputStream extends FilterInputStream {
31 /***
32 * An array to hold the last two bytes read off the stream.
33 * This allows the stream to detect '\r\n' sequences even
34 * when they occur across read boundaries.
35 */
36 protected int last[] = new int[2];
37
38 public DotStuffingInputStream(InputStream in) {
39 super(in);
40 last[0] = -1;
41 last[1] = -1;
42 }
43
44 /***
45 * Read through the stream, checking for '\r\n.'
46 *
47 * @return the byte read from the stream
48 */
49 public int read() throws IOException {
50 int b = in.read();
51 if (b == '.' && last[0] == '\r' && last[1] == '\n') {
52
53 b = in.read();
54 }
55 last[0] = last[1];
56 last[1] = b;
57 return b;
58 }
59
60 /***
61 * Read through the stream, checking for '\r\n.'
62 *
63 * @param b the byte array into which the bytes will be read
64 * @param off the offset into the byte array where the bytes will be inserted
65 * @param len the maximum number of bytes to be read off the stream
66 * @return the number of bytes read
67 */
68 public int read(byte[] b, int off, int len) throws IOException {
69 if (b == null) {
70 throw new NullPointerException();
71 } else if ((off < 0) || (off > b.length) || (len < 0) ||
72 ((off + len) > b.length) || ((off + len) < 0)) {
73 throw new IndexOutOfBoundsException();
74 } else if (len == 0) {
75 return 0;
76 }
77
78 int c = read();
79 if (c == -1) {
80 return -1;
81 }
82 b[off] = (byte)c;
83
84 int i = 1;
85
86 for (; i < len ; i++) {
87 c = read();
88 if (c == -1) {
89 break;
90 }
91 if (b != null) {
92 b[off + i] = (byte)c;
93 }
94 }
95
96 return i;
97 }
98 }