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
20package org.apache.james.mime4j;
21
22import java.io.IOException;
23import java.io.InputStream;
24
25/**
26 * <code>InputStream</code> used by the parser to wrap the original user
27 * supplied stream. This stream keeps track of the current line number and
28 * can also be truncated. When truncated the stream will appear to have
29 * reached end of file. This is used by the parser's
30 * {@link org.apache.james.mime4j.MimeStreamParser#stop()} method.
31 *
32 *
33 * @version $Id: RootInputStream.java,v 1.2 2004/10/02 12:41:10 ntherning Exp $
34 */
35class RootInputStream extends InputStream {
36    private InputStream is = null;
37    private int lineNumber = 1;
38    private int prev = -1;
39    private boolean truncated = false;
40
41    /**
42     * Creates a new <code>RootInputStream</code>.
43     *
44     * @param in the stream to read from.
45     */
46    public RootInputStream(InputStream is) {
47        this.is = is;
48    }
49
50    /**
51     * Gets the current line number starting at 1
52     * (the number of <code>\r\n</code> read so far plus 1).
53     *
54     * @return the current line number.
55     */
56    public int getLineNumber() {
57        return lineNumber;
58    }
59
60    /**
61     * Truncates this <code>InputStream</code>. After this call any
62     * call to {@link #read()}, {@link #read(byte[]) or
63     * {@link #read(byte[], int, int)} will return
64     * -1 as if end-of-file had been reached.
65     */
66    public void truncate() {
67        this.truncated = true;
68    }
69
70    /**
71     * @see java.io.InputStream#read()
72     */
73    public int read() throws IOException {
74        if (truncated) {
75            return -1;
76        }
77
78        int b = is.read();
79        if (prev == '\r' && b == '\n') {
80            lineNumber++;
81        }
82        prev = b;
83        return b;
84    }
85
86    /**
87     *
88     * @see java.io.InputStream#read(byte[], int, int)
89     */
90    public int read(byte[] b, int off, int len) throws IOException {
91        if (truncated) {
92            return -1;
93        }
94
95        int n = is.read(b, off, len);
96        for (int i = off; i < off + n; i++) {
97            if (prev == '\r' && b[i] == '\n') {
98                lineNumber++;
99            }
100            prev = b[i];
101        }
102        return n;
103    }
104
105    /**
106     * @see java.io.InputStream#read(byte[])
107     */
108    public int read(byte[] b) throws IOException {
109        return read(b, 0, b.length);
110    }
111}
112