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annotate src/goodjava/io/FixedLengthInputStream.java @ 1490:9a2a2181a58f

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FixedLengthInputStream
author Franklin Schmidt <fschmidt@gmail.com>
date Sat, 02 May 2020 20:42:28 -0600
parents src/goodjava/io/LimitedInputStream.java@1f41e5921090
children 91c167099462
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.FilterInputStream;
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5 import java.io.IOException;
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6 import java.io.EOFException;
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7
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8
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9 public class FixedLengthInputStream extends FilterInputStream {
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10 protected long left;
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11
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12 public FixedLengthInputStream(InputStream in, long len) {
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13 super(in);
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14 if( len < 0 )
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15 throw new IllegalArgumentException("len can't be negative");
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16 this.left = len;
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17 }
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18
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19 public synchronized int read() throws IOException {
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20 if( left == 0 )
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21 return -1;
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22 int n = super.read();
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23 if( n == -1 )
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24 throw new EOFException();
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25 left--;
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26 return n;
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27 }
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29 public synchronized int read(byte[] b, int off, int len) throws IOException {
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30 if( len == 0 )
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31 return 0;
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32 if( left == 0 )
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33 return -1;
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34 if( len > left )
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35 len = (int)left;
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36 int n = super.read(b,off,len);
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37 if( n == -1 )
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38 throw new EOFException();
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39 left -= n;
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40 return n;
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41 }
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43 public synchronized long skip(long n) throws IOException {
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44 if( n > left )
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45 n = left;
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46 n = in.skip(n);
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47 left -= n;
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48 return n;
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49 }
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50
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51 public synchronized int available() throws IOException {
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52 int n = in.available();
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53 if( n > left )
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54 n = (int)left;
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55 return n;
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56 }
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57
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58 public void mark(int readlimit) {}
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59
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60 public void reset() throws IOException {
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61 throw new IOException("not supported");
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62 }
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63
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64 public boolean markSupported() {
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65 return false;
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66 }
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67
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68 }