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- /*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.apache.poi.util;
-
- import java.io.IOException;
- import java.io.InputStream;
-
- /**
- * This is a stream that will only supply bytes up to a certain length - if its
- * position goes above that, it will stop.
- * <p>
- * This is useful to wrap ServletInputStreams. The ServletInputStream will block
- * if you try to read content from it that isn't there, because it doesn't know
- * whether the content hasn't arrived yet or whether the content has finished.
- * So, one of these, initialized with the Content-length sent in the
- * ServletInputStream's header, will stop it blocking, providing it's been sent
- * with a correct content length.
- *
- * @version $Id$
- * @since Commons IO 2.0
- */
- public class BoundedInputStream extends InputStream {
-
- /** the wrapped input stream */
- private final InputStream in;
-
- /** the max length to provide */
- private final long max;
-
- /** the number of bytes already returned */
- private long pos = 0;
-
- /** the marked position */
- private long mark = -1;
-
- /** flag if close shoud be propagated */
- private boolean propagateClose = true;
-
- /**
- * Creates a new <code>BoundedInputStream</code> that wraps the given input
- * stream and limits it to a certain size.
- *
- * @param in The wrapped input stream
- * @param size The maximum number of bytes to return
- */
- public BoundedInputStream(InputStream in, long size) {
- // Some badly designed methods - eg the servlet API - overload length
- // such that "-1" means stream finished
- this.max = size;
- this.in = in;
- }
-
- /**
- * Creates a new <code>BoundedInputStream</code> that wraps the given input
- * stream and is unlimited.
- *
- * @param in The wrapped input stream
- */
- public BoundedInputStream(InputStream in) {
- this(in, -1);
- }
-
- /**
- * Invokes the delegate's <code>read()</code> method if
- * the current position is less than the limit.
- * @return the byte read or -1 if the end of stream or
- * the limit has been reached.
- * @throws IOException if an I/O error occurs
- */
- @Override
- public int read() throws IOException {
- if (max>=0 && pos==max) {
- return -1;
- }
- int result = in.read();
- pos++;
- return result;
- }
-
- /**
- * Invokes the delegate's <code>read(byte[])</code> method.
- * @param b the buffer to read the bytes into
- * @return the number of bytes read or -1 if the end of stream or
- * the limit has been reached.
- * @throws IOException if an I/O error occurs
- */
- @Override
- public int read(byte[] b) throws IOException {
- return this.read(b, 0, b.length);
- }
-
- /**
- * Invokes the delegate's <code>read(byte[], int, int)</code> method.
- * @param b the buffer to read the bytes into
- * @param off The start offset
- * @param len The number of bytes to read
- * @return the number of bytes read or -1 if the end of stream or
- * the limit has been reached.
- * @throws IOException if an I/O error occurs
- */
- @Override
- public int read(byte[] b, int off, int len) throws IOException {
- if (max>=0 && pos>=max) {
- return -1;
- }
- long maxRead = max>=0 ? Math.min(len, max-pos) : len;
- int bytesRead = in.read(b, off, (int)maxRead);
-
- if (bytesRead==-1) {
- return -1;
- }
-
- pos+=bytesRead;
- return bytesRead;
- }
-
- /**
- * Invokes the delegate's <code>skip(long)</code> method.
- * @param n the number of bytes to skip
- * @return the actual number of bytes skipped
- * @throws IOException if an I/O error occurs
- */
- @Override
- public long skip(long n) throws IOException {
- long toSkip = max>=0 ? Math.min(n, max-pos) : n;
- long skippedBytes = in.skip(toSkip);
- pos+=skippedBytes;
- return skippedBytes;
- }
-
- /**
- * {@inheritDoc}
- */
- @Override
- @SuppressForbidden("just delegating")
- public int available() throws IOException {
- if (max>=0 && pos>=max) {
- return 0;
- }
- return in.available();
- }
-
- /**
- * Invokes the delegate's <code>toString()</code> method.
- * @return the delegate's <code>toString()</code>
- */
- @Override
- public String toString() {
- return in.toString();
- }
-
- /**
- * Invokes the delegate's <code>close()</code> method
- * if {@link #isPropagateClose()} is <code>true</code>.
- * @throws IOException if an I/O error occurs
- */
- @Override
- public void close() throws IOException {
- if (propagateClose) {
- in.close();
- }
- }
-
- /**
- * Invokes the delegate's <code>reset()</code> method.
- * @throws IOException if an I/O error occurs
- */
- @Override
- public synchronized void reset() throws IOException {
- in.reset();
- pos = mark;
- }
-
- /**
- * Invokes the delegate's <code>mark(int)</code> method.
- * @param readlimit read ahead limit
- */
- @Override
- public synchronized void mark(int readlimit) {
- in.mark(readlimit);
- mark = pos;
- }
-
- /**
- * Invokes the delegate's <code>markSupported()</code> method.
- * @return true if mark is supported, otherwise false
- */
- @Override
- public boolean markSupported() {
- return in.markSupported();
- }
-
- /**
- * Indicates whether the {@link #close()} method
- * should propagate to the underling {@link InputStream}.
- *
- * @return <code>true</code> if calling {@link #close()}
- * propagates to the <code>close()</code> method of the
- * underlying stream or <code>false</code> if it does not.
- */
- public boolean isPropagateClose() {
- return propagateClose;
- }
-
- /**
- * Set whether the {@link #close()} method
- * should propagate to the underling {@link InputStream}.
- *
- * @param propagateClose <code>true</code> if calling
- * {@link #close()} propagates to the <code>close()</code>
- * method of the underlying stream or
- * <code>false</code> if it does not.
- */
- public void setPropagateClose(boolean propagateClose) {
- this.propagateClose = propagateClose;
- }
- }
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