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annotate src/goodjava/io/FixedLengthInputStream.java @ 1494:91c167099462

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more io
author Franklin Schmidt <fschmidt@gmail.com>
date Sun, 03 May 2020 11:51:31 -0600
parents 9a2a2181a58f
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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1 package goodjava.io;
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2
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3 import java.io.InputStream;
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4 import java.io.IOException;
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5 import java.io.EOFException;
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6
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7
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8 public class FixedLengthInputStream extends NoMarkInputStream {
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9 protected long left;
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10
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11 public FixedLengthInputStream(InputStream in, long len) {
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12 super(in);
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13 if( len < 0 )
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14 throw new IllegalArgumentException("len can't be negative");
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15 this.left = len;
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16 }
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17
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18 public int read() throws IOException {
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19 if( left == 0 )
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20 return -1;
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21 int n = in.read();
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22 if( n == -1 )
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23 throw new EOFException();
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24 left--;
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25 return n;
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26 }
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27
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28 public int read(byte[] b, int off, int len) throws IOException {
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29 if( len == 0 )
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30 return 0;
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31 if( left == 0 )
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32 return -1;
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33 if( len > left )
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34 len = (int)left;
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35 int n = in.read(b,off,len);
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36 if( n == -1 )
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37 throw new EOFException();
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38 left -= n;
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39 return n;
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40 }
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41
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42 public long skip(long n) throws IOException {
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43 if( n > left )
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44 n = left;
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45 n = in.skip(n);
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46 left -= n;
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47 return n;
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48 }
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49
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50 public int available() throws IOException {
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51 int n = in.available();
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52 if( n > left )
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53 n = (int)left;
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54 return n;
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55 }
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57 }