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 }