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1 /* |
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2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 /* FROM mail.jar */ |
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27 package com.sun.xml.internal.org.jvnet.mimepull; |
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28 |
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29 import java.io.*; |
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30 |
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31 /** |
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32 * This class is to support reading CRLF terminated lines that |
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33 * contain only US-ASCII characters from an input stream. Provides |
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34 * functionality that is similar to the deprecated |
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35 * <code>DataInputStream.readLine()</code>. Expected use is to read |
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36 * lines as String objects from a RFC822 stream. |
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37 * |
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38 * It is implemented as a FilterInputStream, so one can just wrap |
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39 * this class around any input stream and read bytes from this filter. |
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40 * |
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41 * @author John Mani |
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42 */ |
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43 |
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44 final class LineInputStream extends FilterInputStream { |
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45 |
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46 private char[] lineBuffer = null; // reusable byte buffer |
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47 private static int MAX_INCR = 1024*1024; // 1MB |
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48 |
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49 public LineInputStream(InputStream in) { |
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50 super(in); |
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51 } |
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52 |
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53 /** |
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54 * Read a line containing only ASCII characters from the input |
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55 * stream. A line is terminated by a CR or NL or CR-NL sequence. |
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56 * A common error is a CR-CR-NL sequence, which will also terminate |
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57 * a line. |
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58 * The line terminator is not returned as part of the returned |
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59 * String. Returns null if no data is available. <p> |
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60 * |
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61 * This class is similar to the deprecated |
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62 * <code>DataInputStream.readLine()</code> |
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63 */ |
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64 public String readLine() throws IOException { |
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65 //InputStream in = this.in; |
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66 char[] buf = lineBuffer; |
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67 |
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68 if (buf == null) { |
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69 buf = lineBuffer = new char[128]; |
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70 } |
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71 |
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72 int c1; |
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73 int room = buf.length; |
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74 int offset = 0; |
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75 |
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76 while ((c1 = in.read()) != -1) { |
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77 if (c1 == '\n') { |
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78 break; |
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79 } else if (c1 == '\r') { |
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80 // Got CR, is the next char NL ? |
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81 boolean twoCRs = false; |
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82 if (in.markSupported()) { |
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83 in.mark(2); |
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84 } |
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85 int c2 = in.read(); |
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86 if (c2 == '\r') { // discard extraneous CR |
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87 twoCRs = true; |
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88 c2 = in.read(); |
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89 } |
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90 if (c2 != '\n') { |
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91 /* |
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92 * If the stream supports it (which we hope will always |
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93 * be the case), reset to after the first CR. Otherwise, |
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94 * we wrap a PushbackInputStream around the stream so we |
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95 * can unread the characters we don't need. The only |
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96 * problem with that is that the caller might stop |
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97 * reading from this LineInputStream, throw it away, |
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98 * and then start reading from the underlying stream. |
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99 * If that happens, the pushed back characters will be |
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100 * lost forever. |
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101 */ |
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102 if (in.markSupported()) { |
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103 in.reset(); |
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104 } else { |
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105 if (!(in instanceof PushbackInputStream)) { |
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106 in /*= this.in*/ = new PushbackInputStream(in, 2); |
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107 } |
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108 if (c2 != -1) { |
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109 ((PushbackInputStream)in).unread(c2); |
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110 } |
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111 if (twoCRs) { |
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112 ((PushbackInputStream)in).unread('\r'); |
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113 } |
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114 } |
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115 } |
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116 break; // outa here. |
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117 } |
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118 |
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119 // Not CR, NL or CR-NL ... |
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120 // .. Insert the byte into our byte buffer |
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121 if (--room < 0) { // No room, need to grow. |
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122 if (buf.length < MAX_INCR) { |
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123 buf = new char[buf.length * 2]; |
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124 } else { |
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125 buf = new char[buf.length + MAX_INCR]; |
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126 } |
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127 room = buf.length - offset - 1; |
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128 System.arraycopy(lineBuffer, 0, buf, 0, offset); |
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129 lineBuffer = buf; |
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130 } |
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131 buf[offset++] = (char)c1; |
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132 } |
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133 |
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134 if ((c1 == -1) && (offset == 0)) { |
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135 return null; |
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136 } |
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137 |
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138 return String.copyValueOf(buf, 0, offset); |
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139 } |
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140 } |