/*
 * 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.commons.io.input;

import static org.apache.commons.io.IOUtils.EOF;

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

/**
 * A decorating input stream that counts the number of bytes that have passed
 * through the stream so far.
 * 

* A typical use case would be during debugging, to ensure that data is being * read as expected. * * @version $Id$ */ public class CountingInputStream extends ProxyInputStream { /** The count of bytes that have passed. */ private long count; /** * Constructs a new CountingInputStream. * * @param in the InputStream to delegate to */ public CountingInputStream(final InputStream in) { super(in); } //----------------------------------------------------------------------- /** * Skips the stream over the specified number of bytes, adding the skipped * amount to the count. * * @param length the number of bytes to skip * @return the actual number of bytes skipped * @throws IOException if an I/O error occurs * @see java.io.InputStream#skip(long) */ @Override public synchronized long skip(final long length) throws IOException { final long skip = super.skip(length); this.count += skip; return skip; } /** * Adds the number of read bytes to the count. * * @param n number of bytes read, or -1 if no more bytes are available * @since 2.0 */ @Override protected synchronized void afterRead(final int n) { if (n != EOF) { this.count += n; } } //----------------------------------------------------------------------- /** * The number of bytes that have passed through this stream. *

* NOTE: From v1.3 this method throws an ArithmeticException if the * count is greater than can be expressed by an int. * See {@link #getByteCount()} for a method using a long. * * @return the number of bytes accumulated * @throws ArithmeticException if the byte count is too large */ public int getCount() { final long result = getByteCount(); if (result > Integer.MAX_VALUE) { throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int"); } return (int) result; } /** * Set the byte count back to 0. *

* NOTE: From v1.3 this method throws an ArithmeticException if the * count is greater than can be expressed by an int. * See {@link #resetByteCount()} for a method using a long. * * @return the count previous to resetting * @throws ArithmeticException if the byte count is too large */ public int resetCount() { final long result = resetByteCount(); if (result > Integer.MAX_VALUE) { throw new ArithmeticException("The byte count " + result + " is too large to be converted to an int"); } return (int) result; } /** * The number of bytes that have passed through this stream. *

* NOTE: This method is an alternative for getCount() * and was added because that method returns an integer which will * result in incorrect count for files over 2GB. * * @return the number of bytes accumulated * @since 1.3 */ public synchronized long getByteCount() { return this.count; } /** * Set the byte count back to 0. *

* NOTE: This method is an alternative for resetCount() * and was added because that method returns an integer which will * result in incorrect count for files over 2GB. * * @return the count previous to resetting * @since 1.3 */ public synchronized long resetByteCount() { final long tmp = this.count; this.count = 0; return tmp; } }