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     17  * under the License.                                           *
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     19 
     20 package org.apache.james.mime4j;
     21 
     22 import java.io.IOException;
     23 import java.io.InputStream;
     24 import java.io.PushbackInputStream;
     25 
     26 /**
     27  * InputStream which converts <code>\r</code>
     28  * bytes not followed by <code>\n</code> and <code>\n</code> not
     29  * preceded by <code>\r</code> to <code>\r\n</code>.
     30  *
     31  *
     32  * @version $Id: EOLConvertingInputStream.java,v 1.4 2004/11/29 13:15:42 ntherning Exp $
     33  */
     34 public class EOLConvertingInputStream extends InputStream {
     35     /** Converts single '\r' to '\r\n' */
     36     public static final int CONVERT_CR   = 1;
     37     /** Converts single '\n' to '\r\n' */
     38     public static final int CONVERT_LF   = 2;
     39     /** Converts single '\r' and '\n' to '\r\n' */
     40     public static final int CONVERT_BOTH = 3;
     41 
     42     private PushbackInputStream in = null;
     43     private int previous = 0;
     44     private int flags = CONVERT_BOTH;
     45     private int size = 0;
     46     private int pos = 0;
     47     private int nextTenPctPos;
     48     private int tenPctSize;
     49     private Callback callback;
     50 
     51     public interface Callback {
     52         public void report(int bytesRead);
     53     }
     54 
     55     /**
     56      * Creates a new <code>EOLConvertingInputStream</code>
     57      * instance converting bytes in the given <code>InputStream</code>.
     58      * The flag <code>CONVERT_BOTH</code> is the default.
     59      *
     60      * @param in the <code>InputStream</code> to read from.
     61      */
     62     public EOLConvertingInputStream(InputStream _in) {
     63         super();
     64         in = new PushbackInputStream(_in, 2);
     65     }
     66 
     67     /**
     68      * Creates a new <code>EOLConvertingInputStream</code>
     69      * instance converting bytes in the given <code>InputStream</code>.
     70      *
     71      * @param _in the <code>InputStream</code> to read from.
     72      * @param _size the size of the input stream (need not be exact)
     73      * @param _callback a callback reporting when each 10% of stream's size is reached
     74      */
     75     public EOLConvertingInputStream(InputStream _in, int _size, Callback _callback) {
     76         this(_in);
     77         size = _size;
     78         tenPctSize = size / 10;
     79         nextTenPctPos = tenPctSize;
     80         callback = _callback;
     81     }
     82 
     83     /**
     84      * Closes the underlying stream.
     85      *
     86      * @throws IOException on I/O errors.
     87      */
     88     public void close() throws IOException {
     89         in.close();
     90     }
     91 
     92     private int readByte() throws IOException {
     93         int b = in.read();
     94         if (b != -1) {
     95             if (callback != null && pos++ == nextTenPctPos) {
     96                 nextTenPctPos += tenPctSize;
     97                 if (callback != null) {
     98                     callback.report(pos);
     99                 }
    100             }
    101         }
    102         return b;
    103     }
    104 
    105     private void unreadByte(int c) throws IOException {
    106         in.unread(c);
    107         pos--;
    108     }
    109 
    110     /**
    111      * @see java.io.InputStream#read()
    112      */
    113     public int read() throws IOException {
    114         int b = readByte();
    115 
    116         if (b == -1) {
    117             pos = size;
    118             return -1;
    119         }
    120 
    121         if ((flags & CONVERT_CR) != 0 && b == '\r') {
    122             int c = readByte();
    123             if (c != -1) {
    124                 unreadByte(c);
    125             }
    126             if (c != '\n') {
    127                 unreadByte('\n');
    128             }
    129         } else if ((flags & CONVERT_LF) != 0 && b == '\n' && previous != '\r') {
    130             b = '\r';
    131             unreadByte('\n');
    132         }
    133 
    134         previous = b;
    135 
    136         return b;
    137     }
    138 
    139 }
    140