1 | /** |
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2 | * Licensed to the Apache Software Foundation (ASF) under one or more |
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3 | * contributor license agreements. See the NOTICE file distributed with this |
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4 | * work for additional information regarding copyright ownership. The ASF |
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5 | * licenses this file to you under the Apache License, Version 2.0 (the |
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6 | * "License"); you may not use this file except in compliance with the License. |
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7 | * You may obtain a copy of the License at |
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8 | * |
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9 | * http://www.apache.org/licenses/LICENSE-2.0 |
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10 | * |
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11 | * Unless required by applicable law or agreed to in writing, software |
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12 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
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13 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
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14 | * License for the specific language governing permissions and limitations under |
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15 | * the License. |
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16 | */ |
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17 | package org.apache.hadoop.io.file.tfile; |
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18 | |
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19 | import java.io.DataInputStream; |
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20 | import java.io.DataOutputStream; |
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21 | import java.io.IOException; |
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22 | import java.io.InputStream; |
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23 | import java.io.OutputStream; |
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24 | |
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25 | /** |
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26 | * Several related classes to support chunk-encoded sub-streams on top of a |
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27 | * regular stream. |
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28 | */ |
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29 | final class Chunk { |
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30 | |
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31 | /** |
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32 | * Prevent the instantiation of class. |
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33 | */ |
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34 | private Chunk() { |
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35 | // nothing |
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36 | } |
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37 | |
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38 | /** |
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39 | * Decoding a chain of chunks encoded through ChunkEncoder or |
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40 | * SingleChunkEncoder. |
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41 | */ |
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42 | static public class ChunkDecoder extends InputStream { |
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43 | private DataInputStream in = null; |
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44 | private boolean lastChunk; |
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45 | private int remain = 0; |
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46 | private boolean closed; |
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47 | |
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48 | public ChunkDecoder() { |
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49 | lastChunk = true; |
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50 | closed = true; |
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51 | } |
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52 | |
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53 | public void reset(DataInputStream downStream) { |
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54 | // no need to wind forward the old input. |
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55 | in = downStream; |
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56 | lastChunk = false; |
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57 | remain = 0; |
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58 | closed = false; |
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59 | } |
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60 | |
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61 | /** |
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62 | * Constructor |
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63 | * |
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64 | * @param in |
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65 | * The source input stream which contains chunk-encoded data |
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66 | * stream. |
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67 | */ |
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68 | public ChunkDecoder(DataInputStream in) { |
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69 | this.in = in; |
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70 | lastChunk = false; |
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71 | closed = false; |
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72 | } |
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73 | |
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74 | /** |
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75 | * Have we reached the last chunk. |
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76 | * |
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77 | * @return true if we have reached the last chunk. |
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78 | * @throws java.io.IOException |
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79 | */ |
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80 | public boolean isLastChunk() throws IOException { |
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81 | checkEOF(); |
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82 | return lastChunk; |
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83 | } |
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84 | |
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85 | /** |
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86 | * How many bytes remain in the current chunk? |
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87 | * |
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88 | * @return remaining bytes left in the current chunk. |
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89 | * @throws java.io.IOException |
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90 | */ |
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91 | public int getRemain() throws IOException { |
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92 | checkEOF(); |
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93 | return remain; |
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94 | } |
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95 | |
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96 | /** |
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97 | * Reading the length of next chunk. |
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98 | * |
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99 | * @throws java.io.IOException |
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100 | * when no more data is available. |
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101 | */ |
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102 | private void readLength() throws IOException { |
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103 | remain = Utils.readVInt(in); |
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104 | if (remain >= 0) { |
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105 | lastChunk = true; |
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106 | } else { |
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107 | remain = -remain; |
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108 | } |
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109 | } |
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110 | |
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111 | /** |
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112 | * Check whether we reach the end of the stream. |
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113 | * |
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114 | * @return false if the chunk encoded stream has more data to read (in which |
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115 | * case available() will be greater than 0); true otherwise. |
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116 | * @throws java.io.IOException |
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117 | * on I/O errors. |
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118 | */ |
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119 | private boolean checkEOF() throws IOException { |
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120 | if (isClosed()) return true; |
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121 | while (true) { |
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122 | if (remain > 0) return false; |
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123 | if (lastChunk) return true; |
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124 | readLength(); |
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125 | } |
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126 | } |
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127 | |
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128 | @Override |
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129 | /* |
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130 | * This method never blocks the caller. Returning 0 does not mean we reach |
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131 | * the end of the stream. |
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132 | */ |
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133 | public int available() { |
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134 | return remain; |
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135 | } |
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136 | |
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137 | @Override |
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138 | public int read() throws IOException { |
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139 | if (checkEOF()) return -1; |
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140 | int ret = in.read(); |
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141 | if (ret < 0) throw new IOException("Corrupted chunk encoding stream"); |
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142 | --remain; |
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143 | return ret; |
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144 | } |
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145 | |
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146 | @Override |
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147 | public int read(byte[] b) throws IOException { |
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148 | return read(b, 0, b.length); |
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149 | } |
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150 | |
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151 | @Override |
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152 | public int read(byte[] b, int off, int len) throws IOException { |
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153 | if ((off | len | (off + len) | (b.length - (off + len))) < 0) { |
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154 | throw new IndexOutOfBoundsException(); |
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155 | } |
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156 | |
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157 | if (!checkEOF()) { |
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158 | int n = Math.min(remain, len); |
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159 | int ret = in.read(b, off, n); |
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160 | if (ret < 0) throw new IOException("Corrupted chunk encoding stream"); |
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161 | remain -= ret; |
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162 | return ret; |
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163 | } |
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164 | return -1; |
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165 | } |
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166 | |
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167 | @Override |
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168 | public long skip(long n) throws IOException { |
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169 | if (!checkEOF()) { |
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170 | long ret = in.skip(Math.min(remain, n)); |
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171 | remain -= ret; |
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172 | return ret; |
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173 | } |
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174 | return 0; |
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175 | } |
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176 | |
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177 | @Override |
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178 | public boolean markSupported() { |
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179 | return false; |
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180 | } |
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181 | |
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182 | public boolean isClosed() { |
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183 | return closed; |
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184 | } |
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185 | |
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186 | @Override |
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187 | public void close() throws IOException { |
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188 | if (closed == false) { |
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189 | try { |
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190 | while (!checkEOF()) { |
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191 | skip(Integer.MAX_VALUE); |
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192 | } |
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193 | } finally { |
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194 | closed = true; |
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195 | } |
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196 | } |
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197 | } |
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198 | } |
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199 | |
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200 | /** |
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201 | * Chunk Encoder. Encoding the output data into a chain of chunks in the |
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202 | * following sequences: -len1, byte[len1], -len2, byte[len2], ... len_n, |
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203 | * byte[len_n]. Where len1, len2, ..., len_n are the lengths of the data |
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204 | * chunks. Non-terminal chunks have their lengths negated. Non-terminal chunks |
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205 | * cannot have length 0. All lengths are in the range of 0 to |
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206 | * Integer.MAX_VALUE and are encoded in Utils.VInt format. |
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207 | */ |
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208 | static public class ChunkEncoder extends OutputStream { |
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209 | /** |
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210 | * The data output stream it connects to. |
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211 | */ |
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212 | private DataOutputStream out; |
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213 | |
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214 | /** |
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215 | * The internal buffer that is only used when we do not know the advertised |
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216 | * size. |
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217 | */ |
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218 | private byte buf[]; |
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219 | |
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220 | /** |
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221 | * The number of valid bytes in the buffer. This value is always in the |
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222 | * range <tt>0</tt> through <tt>buf.length</tt>; elements <tt>buf[0]</tt> |
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223 | * through <tt>buf[count-1]</tt> contain valid byte data. |
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224 | */ |
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225 | private int count; |
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226 | |
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227 | /** |
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228 | * Constructor. |
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229 | * |
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230 | * @param out |
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231 | * the underlying output stream. |
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232 | * @param buf |
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233 | * user-supplied buffer. The buffer would be used exclusively by |
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234 | * the ChunkEncoder during its life cycle. |
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235 | */ |
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236 | public ChunkEncoder(DataOutputStream out, byte[] buf) { |
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237 | this.out = out; |
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238 | this.buf = buf; |
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239 | this.count = 0; |
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240 | } |
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241 | |
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242 | /** |
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243 | * Write out a chunk. |
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244 | * |
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245 | * @param chunk |
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246 | * The chunk buffer. |
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247 | * @param offset |
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248 | * Offset to chunk buffer for the beginning of chunk. |
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249 | * @param len |
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250 | * @param last |
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251 | * Is this the last call to flushBuffer? |
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252 | */ |
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253 | private void writeChunk(byte[] chunk, int offset, int len, boolean last) |
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254 | throws IOException { |
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255 | if (last) { // always write out the length for the last chunk. |
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256 | Utils.writeVInt(out, len); |
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257 | if (len > 0) { |
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258 | out.write(chunk, offset, len); |
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259 | } |
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260 | } else { |
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261 | if (len > 0) { |
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262 | Utils.writeVInt(out, -len); |
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263 | out.write(chunk, offset, len); |
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264 | } |
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265 | } |
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266 | } |
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267 | |
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268 | /** |
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269 | * Write out a chunk that is a concatenation of the internal buffer plus |
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270 | * user supplied data. This will never be the last block. |
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271 | * |
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272 | * @param data |
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273 | * User supplied data buffer. |
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274 | * @param offset |
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275 | * Offset to user data buffer. |
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276 | * @param len |
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277 | * User data buffer size. |
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278 | */ |
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279 | private void writeBufData(byte[] data, int offset, int len) |
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280 | throws IOException { |
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281 | if (count + len > 0) { |
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282 | Utils.writeVInt(out, -(count + len)); |
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283 | out.write(buf, 0, count); |
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284 | count = 0; |
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285 | out.write(data, offset, len); |
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286 | } |
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287 | } |
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288 | |
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289 | /** |
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290 | * Flush the internal buffer. |
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291 | * |
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292 | * Is this the last call to flushBuffer? |
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293 | * |
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294 | * @throws java.io.IOException |
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295 | */ |
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296 | private void flushBuffer() throws IOException { |
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297 | if (count > 0) { |
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298 | writeChunk(buf, 0, count, false); |
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299 | count = 0; |
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300 | } |
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301 | } |
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302 | |
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303 | @Override |
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304 | public void write(int b) throws IOException { |
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305 | if (count >= buf.length) { |
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306 | flushBuffer(); |
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307 | } |
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308 | buf[count++] = (byte) b; |
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309 | } |
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310 | |
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311 | @Override |
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312 | public void write(byte b[]) throws IOException { |
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313 | write(b, 0, b.length); |
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314 | } |
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315 | |
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316 | @Override |
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317 | public void write(byte b[], int off, int len) throws IOException { |
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318 | if ((len + count) >= buf.length) { |
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319 | /* |
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320 | * If the input data do not fit in buffer, flush the output buffer and |
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321 | * then write the data directly. In this way buffered streams will |
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322 | * cascade harmlessly. |
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323 | */ |
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324 | writeBufData(b, off, len); |
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325 | return; |
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326 | } |
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327 | |
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328 | System.arraycopy(b, off, buf, count, len); |
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329 | count += len; |
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330 | } |
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331 | |
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332 | @Override |
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333 | public void flush() throws IOException { |
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334 | flushBuffer(); |
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335 | out.flush(); |
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336 | } |
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337 | |
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338 | @Override |
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339 | public void close() throws IOException { |
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340 | if (buf != null) { |
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341 | try { |
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342 | writeChunk(buf, 0, count, true); |
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343 | } finally { |
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344 | buf = null; |
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345 | out = null; |
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346 | } |
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347 | } |
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348 | } |
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349 | } |
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350 | |
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351 | /** |
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352 | * Encode the whole stream as a single chunk. Expecting to know the size of |
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353 | * the chunk up-front. |
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354 | */ |
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355 | static public class SingleChunkEncoder extends OutputStream { |
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356 | /** |
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357 | * The data output stream it connects to. |
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358 | */ |
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359 | private final DataOutputStream out; |
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360 | |
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361 | /** |
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362 | * The remaining bytes to be written. |
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363 | */ |
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364 | private int remain; |
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365 | private boolean closed = false; |
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366 | |
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367 | /** |
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368 | * Constructor. |
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369 | * |
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370 | * @param out |
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371 | * the underlying output stream. |
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372 | * @param size |
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373 | * The total # of bytes to be written as a single chunk. |
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374 | * @throws java.io.IOException |
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375 | * if an I/O error occurs. |
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376 | */ |
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377 | public SingleChunkEncoder(DataOutputStream out, int size) |
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378 | throws IOException { |
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379 | this.out = out; |
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380 | this.remain = size; |
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381 | Utils.writeVInt(out, size); |
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382 | } |
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383 | |
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384 | @Override |
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385 | public void write(int b) throws IOException { |
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386 | if (remain > 0) { |
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387 | out.write(b); |
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388 | --remain; |
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389 | } else { |
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390 | throw new IOException("Writing more bytes than advertised size."); |
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391 | } |
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392 | } |
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393 | |
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394 | @Override |
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395 | public void write(byte b[]) throws IOException { |
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396 | write(b, 0, b.length); |
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397 | } |
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398 | |
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399 | @Override |
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400 | public void write(byte b[], int off, int len) throws IOException { |
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401 | if (remain >= len) { |
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402 | out.write(b, off, len); |
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403 | remain -= len; |
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404 | } else { |
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405 | throw new IOException("Writing more bytes than advertised size."); |
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406 | } |
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407 | } |
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408 | |
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409 | @Override |
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410 | public void flush() throws IOException { |
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411 | out.flush(); |
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412 | } |
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413 | |
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414 | @Override |
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415 | public void close() throws IOException { |
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416 | if (closed == true) { |
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417 | return; |
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418 | } |
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419 | |
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420 | try { |
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421 | if (remain > 0) { |
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422 | throw new IOException("Writing less bytes than advertised size."); |
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423 | } |
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424 | } finally { |
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425 | closed = true; |
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426 | } |
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427 | } |
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428 | } |
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429 | } |
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