/* Copyright (c) 2001-2009, The HSQL Development Group
* All rights reserved.
*
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* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* Neither the name of the HSQL Development Group nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.io.IOException;
import java.io.InputStream;
/**
* Counts down from a specified value the number of bytes actually read
* from the wrapped InputStream.
*
* Returns minus one (-1) early from readXXX methods if the count
* down reaches zero (0) before the end of the wrapped InputStream
* is encountered.
*
* This class is especially useful when a fixed number of bytes is to be read
* from an InputStream that is in turn to be used as the source for an
* {@link java.io.InputStreamReader InputStreamReader}.
*
* @author boucherb@users
* @version 1.8.x
* @since 1.8.x
*/
public final class CountdownInputStream extends InputStream {
private long count;
private InputStream input;
public CountdownInputStream(final InputStream is) {
this.input = is;
}
public int read() throws IOException {
if (this.count <= 0) {
return -1;
}
final int b = this.input.read();
if (b >= 0) {
this.count--;
}
return b;
}
public int read(final byte[] buf) throws IOException {
if (this.count <= 0) {
return -1;
}
int len = buf.length;
if (len > this.count) {
len = (int) this.count;
}
final int r = this.input.read(buf, 0, len);
if (r > 0) {
this.count -= r;
}
return r;
}
public int read(final byte[] buf, final int off,
int len) throws IOException {
if (this.count <= 0) {
return -1;
}
if (len > this.count) {
len = (int) this.count;
}
final int r = this.input.read(buf, 0, len);
if (r > 0) {
this.count -= r;
}
return r;
}
public void close() throws IOException {
this.input.close();
}
public long getCount() {
return this.count;
}
public void setCount(long count) {
this.count = count;
}
}