    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    /**
    038     * Increments the counter of already read bytes.
    039     * Doesn't increment if the EOF has been hit (read == -1)
    040     *
    041     * @param read the number of bytes read
    042     */
    043    protected final void count(final long read) {
    044        if (read != -1) {
    045            bytesRead += read;
    046        }
    047    }
    048
    049    /**
    050     * Returns the current number of bytes read from this stream.
    051     * @return the number of read bytes
    052     */
    053    public long getBytesRead() {
    054        return bytesRead;
    055    }
    056
    057    @Override
    058    public int read() throws IOException {
    059        final int r = in.read();
    060        if (r >= 0) {
    061            count(1);
    062        }
    063        return r;
    064    }
    065
    066    @Override
    067    public int read(final byte[] b) throws IOException {
    068        return read(b, 0, b.length);
    069    }
    070
    071    @Override
    072    public int read(final byte[] b, final int off, final int len) throws IOException {
    073        if (len == 0) {
    074            return 0;
    075        }
    076        final int r = in.read(b, off, len);
    077        if (r >= 0) {
    078            count(r);
    079        }
    080        return r;
    081    }
    082}