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    
020    package org.apache.james.mime4j.io;
021    
022    import java.io.FilterInputStream;
023    import java.io.IOException;
024    import 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     */
030    public 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    }