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// CheckedInputStream.java - Compute checksum of data being read.
/* Copyright (C) 1999 Free Software Foundation
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
package java.util.zip;
import java.io.FilterInputStream;
import java.io.InputStream;
import java.io.IOException;
/**
* @author Tom Tromey
* @date May 17, 1999
*/
/* Written using on-line Java Platform 1.2 API Specification
* and JCL book.
* Believed complete and correct.
*/
public class CheckedInputStream extends FilterInputStream
{
public CheckedInputStream (InputStream in, Checksum sum)
{
super (in);
this.sum = sum;
}
public Checksum getChecksum ()
{
return sum;
}
public int read () throws IOException
{
int x = in.read();
if (x != -1)
sum.update(x);
return x;
}
public int read (byte[] buf, int off, int len) throws IOException
{
int r = in.read(buf, off, len);
if (r != -1)
sum.update(buf, off, r);
return r;
}
public long skip (long n) throws IOException
{
if (n == 0)
return 0;
int min = (int) Math.min(n, 1024);
byte[] buf = new byte[min];
long s = 0;
while (n > 0)
{
int r = in.read(buf, 0, min);
if (r == -1)
break;
n -= r;
s += r;
sum.update(buf, 0, r);
}
return s;
}
// The checksum object.
private Checksum sum;
}
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