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.codec; |
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21 | |
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22 | import java.io.FilterOutputStream; |
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23 | import java.io.IOException; |
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24 | import java.io.OutputStream; |
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25 | |
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26 | /** |
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27 | * Performs Quoted-Printable encoding on an underlying stream. |
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28 | */ |
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29 | public class QuotedPrintableOutputStream extends FilterOutputStream { |
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30 | |
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31 | private static final int DEFAULT_BUFFER_SIZE = 1024 * 3; |
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32 | |
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33 | private static final byte TB = 0x09; |
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34 | private static final byte SP = 0x20; |
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35 | private static final byte EQ = 0x3D; |
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36 | private static final byte CR = 0x0D; |
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37 | private static final byte LF = 0x0A; |
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38 | private static final byte QUOTED_PRINTABLE_LAST_PLAIN = 0x7E; |
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39 | private static final int QUOTED_PRINTABLE_MAX_LINE_LENGTH = 76; |
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40 | private static final int QUOTED_PRINTABLE_OCTETS_PER_ESCAPE = 3; |
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41 | private static final byte[] HEX_DIGITS = { |
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42 | '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; |
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43 | |
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44 | private final byte[] outBuffer; |
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45 | private final boolean binary; |
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46 | |
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47 | private boolean pendingSpace; |
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48 | private boolean pendingTab; |
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49 | private boolean pendingCR; |
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50 | private int nextSoftBreak; |
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51 | private int outputIndex; |
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52 | |
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53 | private boolean closed = false; |
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54 | |
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55 | private byte[] singleByte = new byte[1]; |
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56 | |
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57 | public QuotedPrintableOutputStream(int bufsize, OutputStream out, boolean binary) { |
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58 | super(out); |
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59 | this.outBuffer = new byte[bufsize]; |
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60 | this.binary = binary; |
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61 | this.pendingSpace = false; |
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62 | this.pendingTab = false; |
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63 | this.pendingCR = false; |
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64 | this.outputIndex = 0; |
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65 | this.nextSoftBreak = QUOTED_PRINTABLE_MAX_LINE_LENGTH + 1; |
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66 | } |
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67 | |
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68 | public QuotedPrintableOutputStream(OutputStream out, boolean binary) { |
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69 | this(DEFAULT_BUFFER_SIZE, out, binary); |
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70 | } |
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71 | |
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72 | private void encodeChunk(byte[] buffer, int off, int len) throws IOException { |
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73 | for (int inputIndex = off; inputIndex < len + off; inputIndex++) { |
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74 | encode(buffer[inputIndex]); |
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75 | } |
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76 | } |
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77 | |
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78 | private void completeEncoding() throws IOException { |
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79 | writePending(); |
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80 | flushOutput(); |
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81 | } |
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82 | |
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83 | private void writePending() throws IOException { |
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84 | if (pendingSpace) { |
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85 | plain(SP); |
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86 | } else if (pendingTab) { |
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87 | plain(TB); |
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88 | } else if (pendingCR) { |
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89 | plain(CR); |
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90 | } |
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91 | clearPending(); |
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92 | } |
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93 | |
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94 | private void clearPending() throws IOException { |
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95 | pendingSpace = false; |
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96 | pendingTab = false; |
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97 | pendingCR = false; |
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98 | } |
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99 | |
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100 | private void encode(byte next) throws IOException { |
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101 | if (next == LF) { |
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102 | if (binary) { |
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103 | writePending(); |
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104 | escape(next); |
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105 | } else { |
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106 | if (pendingCR) { |
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107 | // Expect either space or tab pending |
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108 | // but not both |
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109 | if (pendingSpace) { |
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110 | escape(SP); |
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111 | } else if (pendingTab) { |
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112 | escape(TB); |
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113 | } |
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114 | lineBreak(); |
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115 | clearPending(); |
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116 | } else { |
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117 | writePending(); |
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118 | plain(next); |
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119 | } |
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120 | } |
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121 | } else if (next == CR) { |
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122 | if (binary) { |
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123 | escape(next); |
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124 | } else { |
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125 | pendingCR = true; |
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126 | } |
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127 | } else { |
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128 | writePending(); |
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129 | if (next == SP) { |
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130 | if (binary) { |
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131 | escape(next); |
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132 | } else { |
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133 | pendingSpace = true; |
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134 | } |
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135 | } else if (next == TB) { |
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136 | if (binary) { |
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137 | escape(next); |
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138 | } else { |
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139 | pendingTab = true; |
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140 | } |
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141 | } else if (next < SP) { |
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142 | escape(next); |
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143 | } else if (next > QUOTED_PRINTABLE_LAST_PLAIN) { |
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144 | escape(next); |
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145 | } else if (next == EQ) { |
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146 | escape(next); |
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147 | } else { |
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148 | plain(next); |
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149 | } |
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150 | } |
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151 | } |
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152 | |
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153 | private void plain(byte next) throws IOException { |
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154 | if (--nextSoftBreak <= 1) { |
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155 | softBreak(); |
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156 | } |
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157 | write(next); |
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158 | } |
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159 | |
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160 | private void escape(byte next) throws IOException { |
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161 | if (--nextSoftBreak <= QUOTED_PRINTABLE_OCTETS_PER_ESCAPE) { |
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162 | softBreak(); |
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163 | } |
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164 | |
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165 | int nextUnsigned = next & 0xff; |
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166 | |
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167 | write(EQ); |
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168 | --nextSoftBreak; |
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169 | write(HEX_DIGITS[nextUnsigned >> 4]); |
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170 | --nextSoftBreak; |
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171 | write(HEX_DIGITS[nextUnsigned % 0x10]); |
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172 | } |
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173 | |
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174 | private void write(byte next) throws IOException { |
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175 | outBuffer[outputIndex++] = next; |
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176 | if (outputIndex >= outBuffer.length) { |
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177 | flushOutput(); |
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178 | } |
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179 | } |
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180 | |
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181 | private void softBreak() throws IOException { |
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182 | write(EQ); |
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183 | lineBreak(); |
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184 | } |
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185 | |
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186 | private void lineBreak() throws IOException { |
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187 | write(CR); |
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188 | write(LF); |
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189 | nextSoftBreak = QUOTED_PRINTABLE_MAX_LINE_LENGTH; |
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190 | } |
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191 | |
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192 | void flushOutput() throws IOException { |
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193 | if (outputIndex < outBuffer.length) { |
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194 | out.write(outBuffer, 0, outputIndex); |
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195 | } else { |
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196 | out.write(outBuffer); |
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197 | } |
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198 | outputIndex = 0; |
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199 | } |
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200 | |
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201 | @Override |
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202 | public void close() throws IOException { |
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203 | if (closed) |
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204 | return; |
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205 | |
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206 | try { |
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207 | completeEncoding(); |
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208 | // do not close the wrapped stream |
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209 | } finally { |
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210 | closed = true; |
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211 | } |
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212 | } |
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213 | |
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214 | @Override |
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215 | public void flush() throws IOException { |
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216 | flushOutput(); |
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217 | } |
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218 | |
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219 | @Override |
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220 | public void write(int b) throws IOException { |
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221 | singleByte[0] = (byte) b; |
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222 | this.write(singleByte, 0, 1); |
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223 | } |
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224 | |
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225 | @Override |
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226 | public void write(byte[] b, int off, int len) throws IOException { |
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227 | if (closed) { |
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228 | throw new IOException("Stream has been closed"); |
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229 | } |
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230 | encodeChunk(b, off, len); |
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231 | } |
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232 | |
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233 | } |
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