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19 
20 package org.apache.james.mime4j;
21 
22 import java.io.IOException;
23 import 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  */
35 class 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      */
RootInputStream(InputStream is)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      */
getLineNumber()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      */
truncate()66     public void truncate() {
67         this.truncated = true;
68     }
69 
70     /**
71      * @see java.io.InputStream#read()
72      */
read()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      */
read(byte[] b, int off, int len)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      */
read(byte[] b)108     public int read(byte[] b) throws IOException {
109         return read(b, 0, b.length);
110     }
111 }