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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
21
22 package org.apache.james.util.stream;
23
24 import java.io.FilterInputStream;
25 import java.io.IOException;
26 import java.io.InputStream;
27
28 /**
29 * Removes the dot-stuffing happening during the NNTP and SMTP message
30 * transfer
31 */
32 public class DotStuffingInputStream extends FilterInputStream {
33 /**
34 * An array to hold the last two bytes read off the stream.
35 * This allows the stream to detect '\r\n' sequences even
36 * when they occur across read boundaries.
37 */
38 protected int last[] = new int[2];
39
40 public DotStuffingInputStream(InputStream in) {
41 super(in);
42 last[0] = -1;
43 last[1] = -1;
44 }
45
46 /**
47 * Read through the stream, checking for '\r\n.'
48 *
49 * @return the byte read from the stream
50 */
51 public int read() throws IOException {
52 int b = in.read();
53 if (b == '.' && last[0] == '\r' && last[1] == '\n') {
54 //skip this '.' because it should have been stuffed
55 b = in.read();
56 }
57 last[0] = last[1];
58 last[1] = b;
59 return b;
60 }
61
62 /**
63 * Read through the stream, checking for '\r\n.'
64 *
65 * @param b the byte array into which the bytes will be read
66 * @param off the offset into the byte array where the bytes will be inserted
67 * @param len the maximum number of bytes to be read off the stream
68 * @return the number of bytes read
69 */
70 public int read(byte[] b, int off, int len) throws IOException {
71 if (b == null) {
72 throw new NullPointerException();
73 } else if ((off < 0) || (off > b.length) || (len < 0) ||
74 ((off + len) > b.length) || ((off + len) < 0)) {
75 throw new IndexOutOfBoundsException();
76 } else if (len == 0) {
77 return 0;
78 }
79
80 int c = read();
81 if (c == -1) {
82 return -1;
83 }
84 b[off] = (byte)c;
85
86 int i = 1;
87
88 for (; i < len ; i++) {
89 c = read();
90 if (c == -1) {
91 break;
92 }
93 if (b != null) {
94 b[off + i] = (byte)c;
95 }
96 }
97
98 return i;
99 }
100 }