1 /* 2 * Copyright (c) 1997, 2017, 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 * @return line. 69 * 70 * @throws IOException if an I/O error occurs. 71 */ 72 public String readLine() throws IOException { 73 InputStream in = this.in; 74 char[] buf = lineBuffer; 75 76 if (buf == null) 77 buf = lineBuffer = new char[128]; 78 79 int c1; 80 int room = buf.length; 81 int offset = 0; 82 83 while ((c1 = in.read()) != -1) { 84 if (c1 == '\n') // Got NL, outa here. 85 break; 86 else if (c1 == '\r') { 87 // Got CR, is the next char NL ? 88 int c2 = in.read(); 89 if (c2 == '\r') // discard extraneous CR 90 c2 = in.read(); 91 if (c2 != '\n') { 92 // If not NL, push it back 93 if (!(in instanceof PushbackInputStream)) 94 in = this.in = new PushbackInputStream(in); 95 ((PushbackInputStream)in).unread(c2); 96 } 97 break; // outa here. 98 } 99 100 // Not CR, NL or CR-NL ... 101 // .. Insert the byte into our byte buffer 102 if (--room < 0) { // No room, need to grow. 103 buf = new char[offset + 128]; 104 room = buf.length - offset - 1; 105 System.arraycopy(lineBuffer, 0, buf, 0, offset); 106 lineBuffer = buf; 107 } 108 buf[offset++] = (char)c1; 109 } 110 111 if ((c1 == -1) && (offset == 0)) 112 return null; 113 114 return String.copyValueOf(buf, 0, offset); 115 } 116 }