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 ****************************************************************/
019
020package org.apache.james.mime4j.io;
021
022import java.io.FilterInputStream;
023import java.io.IOException;
024import java.io.InputStream;
025
026/**
027 * <code>InputStream</code> used by the parser to wrap the original user
028 * supplied stream. This stream keeps track of the current line number.
029 */
030public class LineNumberInputStream extends FilterInputStream implements
031        LineNumberSource {
032    private int lineNumber = 1;
033
034    /**
035     * Creates a new <code>LineNumberInputStream</code>.
036     *
037     * @param is
038     *            the stream to read from.
039     */
040    public LineNumberInputStream(InputStream is) {
041        super(is);
042    }
043
044    public int getLineNumber() {
045        return lineNumber;
046    }
047
048    @Override
049    public int read() throws IOException {
050        int b = in.read();
051        if (b == '\n') {
052            lineNumber++;
053        }
054        return b;
055    }
056
057    @Override
058    public int read(byte[] b, int off, int len) throws IOException {
059        int n = in.read(b, off, len);
060        for (int i = off; i < off + n; i++) {
061            if (b[i] == '\n') {
062                lineNumber++;
063            }
064        }
065        return n;
066    }
067}