1 | /**************************************************************** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one * |
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3 | * or more contributor license agreements. See the NOTICE file * |
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4 | * distributed with this work for additional information * |
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5 | * regarding copyright ownership. The ASF licenses this file * |
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6 | * to you under the Apache License, Version 2.0 (the * |
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7 | * "License"); you may not use this file except in compliance * |
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8 | * with the License. You may obtain a copy of the License at * |
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9 | * * |
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10 | * http://www.apache.org/licenses/LICENSE-2.0 * |
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11 | * * |
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12 | * Unless required by applicable law or agreed to in writing, * |
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13 | * software distributed under the License is distributed on an * |
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14 | * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * |
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15 | * KIND, either express or implied. See the License for the * |
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16 | * specific language governing permissions and limitations * |
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17 | * under the License. * |
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18 | ****************************************************************/ |
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19 | |
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20 | package org.apache.james.mime4j.io; |
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21 | |
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22 | import java.io.IOException; |
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23 | import java.io.InputStream; |
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24 | import java.io.PushbackInputStream; |
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25 | |
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26 | /** |
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27 | * InputStream which converts <code>\r</code> |
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28 | * bytes not followed by <code>\n</code> and <code>\n</code> not |
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29 | * preceded by <code>\r</code> to <code>\r\n</code>. |
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30 | */ |
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31 | public class EOLConvertingInputStream extends InputStream { |
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32 | /** Converts single '\r' to '\r\n' */ |
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33 | public static final int CONVERT_CR = 1; |
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34 | /** Converts single '\n' to '\r\n' */ |
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35 | public static final int CONVERT_LF = 2; |
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36 | /** Converts single '\r' and '\n' to '\r\n' */ |
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37 | public static final int CONVERT_BOTH = 3; |
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38 | |
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39 | private PushbackInputStream in = null; |
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40 | private int previous = 0; |
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41 | private int flags = CONVERT_BOTH; |
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42 | |
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43 | /** |
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44 | * Creates a new <code>EOLConvertingInputStream</code> |
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45 | * instance converting bytes in the given <code>InputStream</code>. |
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46 | * The flag <code>CONVERT_BOTH</code> is the default. |
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47 | * |
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48 | * @param in the <code>InputStream</code> to read from. |
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49 | */ |
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50 | public EOLConvertingInputStream(InputStream in) { |
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51 | this(in, CONVERT_BOTH); |
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52 | } |
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53 | /** |
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54 | * Creates a new <code>EOLConvertingInputStream</code> |
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55 | * instance converting bytes in the given <code>InputStream</code>. |
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56 | * |
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57 | * @param in the <code>InputStream</code> to read from. |
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58 | * @param flags one of <code>CONVERT_CR</code>, <code>CONVERT_LF</code> or |
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59 | * <code>CONVERT_BOTH</code>. |
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60 | */ |
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61 | public EOLConvertingInputStream(InputStream in, int flags) { |
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62 | super(); |
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63 | |
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64 | this.in = new PushbackInputStream(in, 2); |
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65 | this.flags = flags; |
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66 | } |
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67 | |
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68 | /** |
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69 | * Closes the underlying stream. |
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70 | * |
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71 | * @throws IOException on I/O errors. |
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72 | */ |
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73 | @Override |
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74 | public void close() throws IOException { |
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75 | in.close(); |
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76 | } |
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77 | |
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78 | /** |
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79 | * @see java.io.InputStream#read() |
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80 | */ |
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81 | @Override |
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82 | public int read() throws IOException { |
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83 | int b = in.read(); |
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84 | |
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85 | if (b == -1) { |
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86 | return -1; |
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87 | } |
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88 | |
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89 | if ((flags & CONVERT_CR) != 0 && b == '\r') { |
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90 | int c = in.read(); |
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91 | if (c != -1) { |
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92 | in.unread(c); |
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93 | } |
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94 | if (c != '\n') { |
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95 | in.unread('\n'); |
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96 | } |
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97 | } else if ((flags & CONVERT_LF) != 0 && b == '\n' && previous != '\r') { |
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98 | b = '\r'; |
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99 | in.unread('\n'); |
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100 | } |
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101 | |
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102 | previous = b; |
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103 | |
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104 | return b; |
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105 | } |
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106 | |
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107 | } |
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