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19 
20 
21 package org.apache.james.mime4j.util;
22 
23 import java.io.InputStream;
24 import java.io.IOException;
25 
26 public class PartialInputStream extends PositionInputStream {
27     private final long limit;
28 
PartialInputStream(InputStream inputStream, long offset, long length)29     public PartialInputStream(InputStream inputStream, long offset, long length) throws IOException {
30         super(inputStream);
31         inputStream.skip(offset);
32         this.limit = offset + length;
33     }
34 
available()35     public int available() throws IOException {
36         return Math.min(super.available(), getBytesLeft());
37     }
38 
read()39     public int read() throws IOException {
40         if (limit > position)
41             return super.read();
42         else
43             return -1;
44     }
45 
read(byte b[])46     public int read(byte b[]) throws IOException {
47         return read(b, 0, b.length);
48     }
49 
read(byte b[], int off, int len)50     public int read(byte b[], int off, int len) throws IOException {
51         len = Math.min(len, getBytesLeft());
52         return super.read(b, off, len);    //To change body of overridden methods use File | Settings | File Templates.
53     }
54 
skip(long n)55     public long skip(long n) throws IOException {
56         n = Math.min(n, getBytesLeft());
57         return super.skip(n);    //To change body of overridden methods use File | Settings | File Templates.
58     }
59 
getBytesLeft()60     private int getBytesLeft() {
61         return (int)Math.min(Integer.MAX_VALUE, limit - position);
62     }
63 }
64