    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one
    003 * or more contributor license agreements.  See the NOTICE file
    004 * distributed with this work for additional information
    005 * regarding copyright ownership.  The ASF licenses this file
    006 * to you under the Apache License, Version 2.0 (the
    007 * "License"); you may not use this file except in compliance
    008 * with the License.  You may obtain a copy of the License at
    009 *
    010 * http://www.apache.org/licenses/LICENSE-2.0
    011 *
    012 * Unless required by applicable law or agreed to in writing,
    013 * software distributed under the License is distributed on an
    014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    015 * KIND, either express or implied.  See the License for the
    016 * specific language governing permissions and limitations
    017 * under the License.
    018 */
    019package org.apache.commons.compress.utils;
    020
    021import java.io.FilterInputStream;
    022import java.io.IOException;
    023import java.io.InputStream;
    024
    025/**
    026 * Input stream that tracks the number of bytes read.
    027 * @since 1.3
    028 * @NotThreadSafe
    029 */
    030public class CountingInputStream extends FilterInputStream {
    031    private long bytesRead;
    032
    033    public CountingInputStream(final InputStream in) {
    034        super(in);
    035    }
    036
    037    @Override
    038    public int read() throws IOException {
    039        final int r = in.read();
    040        if (r >= 0) {
    041            count(1);
    042        }
    043        return r;
    044    }
    045
    046    @Override
    047    public int read(final byte[] b) throws IOException {
    048        return read(b, 0, b.length);
    049    }
    050
    051    @Override
    052    public int read(final byte[] b, final int off, final int len) throws IOException {
    053        if (len == 0) {
    054            return 0;
    055        }
    056        final int r = in.read(b, off, len);
    057        if (r >= 0) {
    058            count(r);
    059        }
    060        return r;
    061    }
    062
    063    /**
    064     * Increments the counter of already read bytes.
    065     * Doesn't increment if the EOF has been hit (read == -1)
    066     *
    067     * @param read the number of bytes read
    068     */
    069    protected final void count(final long read) {
    070        if (read != -1) {
    071            bytesRead += read;
    072        }
    073    }
    074
    075    /**
    076     * Returns the current number of bytes read from this stream.
    077     * @return the number of read bytes
    078     */
    079    public long getBytesRead() {
    080        return bytesRead;
    081    }
    082}