Java tutorial
/* * 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.compress.utils; import java.io.FilterInputStream; import java.io.IOException; import java.io.InputStream; /** * Stream that tracks the number of bytes read. * @since 1.3 * @NotThreadSafe */ public class CountingInputStream extends FilterInputStream { private long bytesRead; public CountingInputStream(final InputStream in) { super(in); } @Override public int read() throws IOException { final int r = in.read(); if (r >= 0) { count(1); } return r; } @Override public int read(final byte[] b) throws IOException { return read(b, 0, b.length); } @Override public int read(final byte[] b, final int off, final int len) throws IOException { final int r = in.read(b, off, len); if (r >= 0) { count(r); } return r; } /** * Increments the counter of already read bytes. * Doesn't increment if the EOF has been hit (read == -1) * * @param read the number of bytes read */ protected final void count(final long read) { if (read != -1) { bytesRead += read; } } /** * Returns the current number of bytes read from this stream. * @return the number of read bytes */ public long getBytesRead() { return bytesRead; } }