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/*
 * Copyright 2004-2014 ICEsoft Technologies Canada Corp.
 *
 * Licensed 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.
 */

/*
 * 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 andd
 * limitations under the License.
 */
package org.icefaces.apache.commons.fileupload.util;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;


/**
 * An input stream, which limits its data size. This stream is
 * used, if the content length is unknown.
 */
public abstract class LimitedInputStream
        extends FilterInputStream implements Closeable {
    /**
     * The maximum size of an item, in bytes.
     */
    private long sizeMax;
    /**
     * The current number of bytes.
     */
    private long count;
    /**
     * Whether this stream is already closed.
     */
    private boolean closed;

    /**
     * Creates a new instance.
     * @param pIn The input stream, which shall be limited.
     * @param pSizeMax The limit; no more than this number of bytes
     *   shall be returned by the source stream.
     */
    public LimitedInputStream(InputStream pIn, long pSizeMax) {
        super(pIn);
        sizeMax = pSizeMax;
    }

    /**
     * Called to indicate, that the input streams limit has
     * been exceeded.
     * @param pSizeMax The input streams limit, in bytes.
     * @param pCount The actual number of bytes.
     * @throws IOException The called method is expected
     *   to raise an IOException.
     */
    protected abstract void raiseError(long pSizeMax, long pCount)
            throws IOException;

    /** Called to check, whether the input streams
     * limit is reached.
     * @throws IOException The given limit is exceeded.
     */
    private void checkLimit() throws IOException {
        if (count > sizeMax) {
            raiseError(sizeMax, count);
        }
    }

    /**
     * Reads the next byte of data from this input stream. The value
     * byte is returned as an int in the range
     * 0 to 255. If no byte is available
     * because the end of the stream has been reached, the value
     * -1 is returned. This method blocks until input data
     * is available, the end of the stream is detected, or an exception
     * is thrown.
     * 

* This method * simply performs in.read() and returns the result. * * @return the next byte of data, or -1 if the end of the * stream is reached. * @exception IOException if an I/O error occurs. * @see java.io.FilterInputStream#in */ public int read() throws IOException { int res = super.read(); if (res != -1) { count++; checkLimit(); } return res; } /** * Reads up to len bytes of data from this input stream * into an array of bytes. If len is not zero, the method * blocks until some input is available; otherwise, no * bytes are read and 0 is returned. *

* This method simply performs in.read(b, off, len) * and returns the result. * * @param b the buffer into which the data is read. * @param off The start offset in the destination array * b. * @param len the maximum number of bytes read. * @return the total number of bytes read into the buffer, or * -1 if there is no more data because the end of * the stream has been reached. * @exception NullPointerException If b is null. * @exception IndexOutOfBoundsException If off is negative, * len is negative, or len is greater than * b.length - off * @exception IOException if an I/O error occurs. * @see java.io.FilterInputStream#in */ public int read(byte[] b, int off, int len) throws IOException { int res = super.read(b, off, len); if (res > 0) { count += res; checkLimit(); } return res; } /** * Returns, whether this stream is already closed. * @return True, if the stream is closed, otherwise false. * @throws IOException An I/O error occurred. */ public boolean isClosed() throws IOException { return closed; } /** * Closes this input stream and releases any system resources * associated with the stream. * This * method simply performs in.close(). * * @exception IOException if an I/O error occurs. * @see java.io.FilterInputStream#in */ public void close() throws IOException { closed = true; super.close(); } }





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