/* Copyright (c) 2001-2018, The HSQL Development Group
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* 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
* ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
* 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;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.hsqldb.lib;
import java.io.
IOException;
import java.io.
InputStream;
// fredt@users - 1.9.0 corrected read(byte[], int, int)
/**
* Counts down from a specified value the number of bytes actually read
* from the wrapped InputStream. <p>
*
* Returns minus one (-1) early from readXXX methods if the count
* down reaches zero (0) before the end of the wrapped InputStream
* is encountered. <p>
*
* 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 Campbell Burnet (campbell-burnet@users dot sourceforge.net)
* @version 2.1.1
* @since 1.9.0
*/
public final class
CountdownInputStream extends
InputStream {
private long
m_count;
private
InputStream m_input;
public
CountdownInputStream(final
InputStream is) {
m_input =
is;
}
public int
read() throws
IOException {
if (
m_count <= 0) {
return -1;
}
final int
b =
m_input.
read();
if (
b >= 0) {
m_count--;
}
return
b;
}
public int
read(final byte[]
buf) throws
IOException {
if (
buf == null) {
throw new
NullPointerException();
}
if (
m_count <= 0) {
return -1;
}
int
len =
buf.length;
if (
len >
m_count) {
len = (int)
m_count;
}
final int
r =
m_input.
read(
buf, 0,
len);
if (
r > 0) {
m_count -=
r;
}
return
r;
}
public int
read(final byte[]
buf, final int
off,
int
len) throws
IOException {
if (
buf == null) {
throw new
NullPointerException();
}
if (
m_count <= 0) {
return -1;
}
if (
len >
m_count) {
len = (int)
m_count;
}
final int
r =
m_input.
read(
buf,
off,
len);
if (
r > 0) {
m_count -=
r;
}
return
r;
}
public void
close() throws
IOException {
m_input.
close();
}
public int
available() throws
IOException {
return
Math.
min(
m_input.
available(),
(int)
Math.
min(
Integer.
MAX_VALUE,
m_count));
}
public long
skip(long
count) throws
IOException {
return (
count <= 0) ? 0
:
m_input.
skip(
Math.
min(
m_count,
count));
}
public long
getCount() {
return
m_count;
}
public void
setCount(long
count) {
m_count =
count;
}
}