1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * https://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 implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.io.input;
18
19 import static org.apache.commons.io.IOUtils.CR;
20 import static org.apache.commons.io.IOUtils.EOF;
21 import static org.apache.commons.io.IOUtils.LF;
22
23 import java.io.IOException;
24 import java.io.InputStream;
25
26 /**
27 * A filtering input stream that ensures the content will have Windows line endings, CRLF.
28 *
29 * @since 2.5
30 */
31 public class WindowsLineEndingInputStream extends AbstractLineEndingInputStream {
32
33 private boolean injectSlashLf;
34
35 /**
36 * Constructs an input stream that filters another stream.
37 *
38 * @param in The input stream to wrap.
39 * @param lineFeedAtEos true to ensure that the stream ends with CRLF.
40 */
41 public WindowsLineEndingInputStream(final InputStream in, final boolean lineFeedAtEos) {
42 super(in, lineFeedAtEos);
43 }
44
45 /**
46 * Handles the end of stream condition.
47 *
48 * @return The next char to output to the stream.
49 */
50 private int handleEos() {
51 if (!lineFeedAtEos) {
52 return EOF;
53 }
54 if (!atSlashLf && !atSlashCr) {
55 atSlashCr = true;
56 return CR;
57 }
58 if (!atSlashLf) {
59 atSlashCr = false;
60 atSlashLf = true;
61 return LF;
62 }
63 return EOF;
64 }
65
66 /**
67 * {@inheritDoc}
68 */
69 @Override
70 public synchronized int read() throws IOException {
71 if (atEos) {
72 return handleEos();
73 }
74 if (injectSlashLf) {
75 injectSlashLf = false;
76 return LF;
77 }
78 final boolean prevWasSlashR = atSlashCr;
79 final int target = in.read();
80 atEos = target == EOF;
81 if (!atEos) {
82 atSlashCr = target == CR;
83 atSlashLf = target == LF;
84 }
85 if (atEos) {
86 return handleEos();
87 }
88 if (target == LF && !prevWasSlashR) {
89 injectSlashLf = true;
90 return CR;
91 }
92 return target;
93 }
94 }