1 /* 2 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 /* 27 * @(#)LineInputStream.java 1.7 03/01/07 28 */ 29 30 31 32 package com.sun.xml.internal.messaging.saaj.packaging.mime.util; 33 34 import java.io.*; 35 36 /** 37 * This class is to support reading CRLF terminated lines that 38 * contain only US-ASCII characters from an input stream. Provides 39 * functionality that is similar to the deprecated 40 * <code>DataInputStream.readLine()</code>. Expected use is to read 41 * lines as String objects from a RFC822 stream. 42 * 43 * It is implemented as a FilterInputStream, so one can just wrap 44 * this class around any input stream and read bytes from this filter. 45 * 46 * @author John Mani 47 */ 48 49 public final class LineInputStream extends FilterInputStream { 50 51 private char[] lineBuffer = null; // reusable byte buffer 52 53 public LineInputStream(InputStream in) { 54 super(in); 55 } 56 57 /** 58 * Read a line containing only ASCII characters from the input 59 * stream. A line is terminated by a CR or NL or CR-NL sequence. 60 * A common error is a CR-CR-NL sequence, which will also terminate 61 * a line. 62 * The line terminator is not returned as part of the returned 63 * String. Returns null if no data is available. <p> 64 * 65 * This class is similar to the deprecated 66 * <code>DataInputStream.readLine()</code> 67 */ 68 public String readLine() throws IOException { 69 InputStream in = this.in; 70 char[] buf = lineBuffer; 71 72 if (buf == null) 73 buf = lineBuffer = new char[128]; 74 75 int c1; 76 int room = buf.length; 77 int offset = 0; 78 79 while ((c1 = in.read()) != -1) { 80 if (c1 == '\n') // Got NL, outa here. 81 break; 82 else if (c1 == '\r') { 83 // Got CR, is the next char NL ? 84 int c2 = in.read(); 85 if (c2 == '\r') // discard extraneous CR 86 c2 = in.read(); 87 if (c2 != '\n') { 88 // If not NL, push it back 89 if (!(in instanceof PushbackInputStream)) 90 in = this.in = new PushbackInputStream(in); 91 ((PushbackInputStream)in).unread(c2); 92 } 93 break; // outa here. 94 } 95 96 // Not CR, NL or CR-NL ... 97 // .. Insert the byte into our byte buffer 98 if (--room < 0) { // No room, need to grow. 99 buf = new char[offset + 128]; 100 room = buf.length - offset - 1; 101 System.arraycopy(lineBuffer, 0, buf, 0, offset); 102 lineBuffer = buf; 103 } 104 buf[offset++] = (char)c1; 105 } 106 107 if ((c1 == -1) && (offset == 0)) 108 return null; 109 110 return String.copyValueOf(buf, 0, offset); 111 } 112 }