| /* |
| * 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; |
| |
| /** 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; might be fewer than requested |
| * @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 = IOUtils.skipFully(in, 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; |
| } |
| } |