1 | /*
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2 | * Copyright 2000-2005 The Apache Software Foundation
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3 | *
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4 | * Licensed under the Apache License, Version 2.0 (the "License");
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5 | * you may not use this file except in compliance with the License.
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6 | * You may obtain a copy of the License at
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7 | *
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8 | * http://www.apache.org/licenses/LICENSE-2.0
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9 | *
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10 | * Unless required by applicable law or agreed to in writing, software
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11 | * distributed under the License is distributed on an "AS IS" BASIS,
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12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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13 | * See the License for the specific language governing permissions and
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14 | * limitations under the License.
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15 | *
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16 | */
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17 |
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18 | /*
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19 | * This package is based on the work done by Timothy Gerard Endres
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20 | * ([email protected]) to whom the Ant project is very grateful for his great code.
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21 | */
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22 |
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23 | package org.apache.tools.tar;
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24 |
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25 | import java.io.FilterInputStream;
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26 | import java.io.IOException;
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27 | import java.io.InputStream;
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28 | import java.io.OutputStream;
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29 |
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30 | /**
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31 | * The TarInputStream reads a UNIX tar archive as an InputStream.
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32 | * methods are provided to position at each successive entry in
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33 | * the archive, and the read each entry as a normal input stream
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34 | * using read().
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35 | *
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36 | */
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37 | public class TarInputStream extends FilterInputStream {
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38 |
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39 | protected boolean debug;
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40 | protected boolean hasHitEOF;
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41 | protected int entrySize;
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42 | protected int entryOffset;
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43 | protected byte[] readBuf;
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44 | protected TarBuffer buffer;
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45 | protected TarEntry currEntry;
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46 | private boolean v7Format;
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47 |
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48 | /**
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49 | * This contents of this array is not used at all in this class,
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50 | * it is only here to avoid repreated object creation during calls
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51 | * to the no-arg read method.
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52 | */
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53 | protected byte[] oneBuf;
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54 |
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55 | /**
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56 | * Constructor for TarInputStream.
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57 | * @param is the input stream to use
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58 | */
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59 | public TarInputStream(InputStream is) {
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60 | this(is, TarBuffer.DEFAULT_BLKSIZE, TarBuffer.DEFAULT_RCDSIZE);
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61 | }
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62 |
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63 | /**
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64 | * Constructor for TarInputStream.
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65 | * @param is the input stream to use
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66 | * @param blockSize the block size to use
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67 | */
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68 | public TarInputStream(InputStream is, int blockSize) {
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69 | this(is, blockSize, TarBuffer.DEFAULT_RCDSIZE);
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70 | }
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71 |
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72 | /**
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73 | * Constructor for TarInputStream.
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74 | * @param is the input stream to use
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75 | * @param blockSize the block size to use
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76 | * @param recordSize the record size to use
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77 | */
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78 | public TarInputStream(InputStream is, int blockSize, int recordSize) {
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79 | super(is);
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80 |
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81 | this.buffer = new TarBuffer(is, blockSize, recordSize);
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82 | this.readBuf = null;
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83 | this.oneBuf = new byte[1];
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84 | this.debug = false;
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85 | this.hasHitEOF = false;
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86 | this.v7Format = false;
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87 | }
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88 |
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89 | /**
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90 | * Sets the debugging flag.
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91 | *
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92 | * @param debug True to turn on debugging.
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93 | */
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94 | public void setDebug(boolean debug) {
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95 | this.debug = debug;
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96 | this.buffer.setDebug(debug);
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97 | }
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98 |
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99 | /**
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100 | * Closes this stream. Calls the TarBuffer's close() method.
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101 | * @throws IOException on error
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102 | */
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103 | public void close() throws IOException {
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104 | this.buffer.close();
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105 | }
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106 |
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107 | /**
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108 | * Get the record size being used by this stream's TarBuffer.
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109 | *
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110 | * @return The TarBuffer record size.
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111 | */
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112 | public int getRecordSize() {
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113 | return this.buffer.getRecordSize();
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114 | }
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115 |
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116 | /**
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117 | * Get the available data that can be read from the current
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118 | * entry in the archive. This does not indicate how much data
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119 | * is left in the entire archive, only in the current entry.
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120 | * This value is determined from the entry's size header field
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121 | * and the amount of data already read from the current entry.
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122 | *
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123 | *
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124 | * @return The number of available bytes for the current entry.
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125 | * @throws IOException for signature
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126 | */
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127 | public int available() throws IOException {
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128 | return this.entrySize - this.entryOffset;
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129 | }
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130 |
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131 | /**
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132 | * Skip bytes in the input buffer. This skips bytes in the
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133 | * current entry's data, not the entire archive, and will
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134 | * stop at the end of the current entry's data if the number
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135 | * to skip extends beyond that point.
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136 | *
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137 | * @param numToSkip The number of bytes to skip.
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138 | * @return the number actually skipped
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139 | * @throws IOException on error
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140 | */
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141 | public long skip(long numToSkip) throws IOException {
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142 | // REVIEW
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143 | // This is horribly inefficient, but it ensures that we
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144 | // properly skip over bytes via the TarBuffer...
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145 | //
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146 | byte[] skipBuf = new byte[8 * 1024];
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147 | long skip = numToSkip;
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148 | while (skip > 0) {
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149 | int realSkip = (int) (skip > skipBuf.length ? skipBuf.length : skip);
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150 | int numRead = this.read(skipBuf, 0, realSkip);
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151 | if (numRead == -1) {
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152 | break;
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153 | }
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154 | skip -= numRead;
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155 | }
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156 | return (numToSkip - skip);
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157 | }
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158 |
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159 | /**
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160 | * Since we do not support marking just yet, we return false.
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161 | *
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162 | * @return False.
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163 | */
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164 | public boolean markSupported() {
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165 | return false;
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166 | }
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167 |
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168 | /**
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169 | * Since we do not support marking just yet, we do nothing.
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170 | *
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171 | * @param markLimit The limit to mark.
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172 | */
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173 | public void mark(int markLimit) {
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174 | }
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175 |
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176 | /**
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177 | * Since we do not support marking just yet, we do nothing.
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178 | */
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179 | public void reset() {
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180 | }
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181 |
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182 | /**
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183 | * Get the next entry in this tar archive. This will skip
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184 | * over any remaining data in the current entry, if there
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185 | * is one, and place the input stream at the header of the
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186 | * next entry, and read the header and instantiate a new
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187 | * TarEntry from the header bytes and return that entry.
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188 | * If there are no more entries in the archive, null will
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189 | * be returned to indicate that the end of the archive has
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190 | * been reached.
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191 | *
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192 | * @return The next TarEntry in the archive, or null.
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193 | * @throws IOException on error
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194 | */
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195 | public TarEntry getNextEntry() throws IOException {
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196 | if (this.hasHitEOF) {
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197 | return null;
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198 | }
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199 |
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200 | if (this.currEntry != null) {
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201 | int numToSkip = this.entrySize - this.entryOffset;
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202 |
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203 | if (this.debug) {
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204 | System.err.println("TarInputStream: SKIP currENTRY '"
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205 | + this.currEntry.getName() + "' SZ "
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206 | + this.entrySize + " OFF "
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207 | + this.entryOffset + " skipping "
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208 | + numToSkip + " bytes");
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209 | }
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210 |
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211 | if (numToSkip > 0) {
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212 | this.skip(numToSkip);
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213 | }
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214 |
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215 | this.readBuf = null;
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216 | }
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217 |
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218 | byte[] headerBuf = this.buffer.readRecord();
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219 |
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220 | if (headerBuf == null) {
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221 | if (this.debug) {
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222 | System.err.println("READ NULL RECORD");
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223 | }
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224 | this.hasHitEOF = true;
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225 | } else if (this.buffer.isEOFRecord(headerBuf)) {
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226 | if (this.debug) {
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227 | System.err.println("READ EOF RECORD");
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228 | }
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229 | this.hasHitEOF = true;
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230 | }
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231 |
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232 | if (this.hasHitEOF) {
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233 | this.currEntry = null;
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234 | } else {
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235 | this.currEntry = new TarEntry(headerBuf);
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236 |
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237 | if (!(headerBuf[257] == 'u' && headerBuf[258] == 's'
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238 | && headerBuf[259] == 't' && headerBuf[260] == 'a'
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239 | && headerBuf[261] == 'r')) {
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240 | this.v7Format = true;
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241 | }
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242 |
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243 | if (this.debug) {
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244 | System.err.println("TarInputStream: SET CURRENTRY '"
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245 | + this.currEntry.getName()
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246 | + "' size = "
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247 | + this.currEntry.getSize());
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248 | }
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249 |
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250 | this.entryOffset = 0;
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251 |
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252 | // REVIEW How do we resolve this discrepancy?!
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253 | this.entrySize = (int) this.currEntry.getSize();
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254 | }
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255 |
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256 | if (this.currEntry != null && this.currEntry.isGNULongNameEntry()) {
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257 | // read in the name
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258 | StringBuffer longName = new StringBuffer();
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259 | byte[] buf = new byte[256];
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260 | int length = 0;
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261 | while ((length = read(buf)) >= 0) {
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262 | longName.append(new String(buf, 0, length));
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263 | }
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264 | getNextEntry();
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265 |
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266 | // remove trailing null terminator
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267 | if (longName.length() > 0
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268 | && longName.charAt(longName.length() - 1) == 0) {
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269 | longName.deleteCharAt(longName.length() - 1);
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270 | }
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271 | this.currEntry.setName(longName.toString());
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272 | }
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273 |
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274 | return this.currEntry;
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275 | }
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276 |
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277 | /**
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278 | * Reads a byte from the current tar archive entry.
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279 | *
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280 | * This method simply calls read( byte[], int, int ).
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281 | *
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282 | * @return The byte read, or -1 at EOF.
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283 | * @throws IOException on error
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284 | */
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285 | public int read() throws IOException {
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286 | int num = this.read(this.oneBuf, 0, 1);
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287 | return num == -1 ? -1 : ((int) this.oneBuf[0]) & 0xFF;
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288 | }
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289 |
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290 | /**
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291 | * Reads bytes from the current tar archive entry.
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292 | *
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293 | * This method is aware of the boundaries of the current
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294 | * entry in the archive and will deal with them as if they
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295 | * were this stream's start and EOF.
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296 | *
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297 | * @param buf The buffer into which to place bytes read.
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298 | * @param offset The offset at which to place bytes read.
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299 | * @param numToRead The number of bytes to read.
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300 | * @return The number of bytes read, or -1 at EOF.
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301 | * @throws IOException on error
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302 | */
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303 | public int read(byte[] buf, int offset, int numToRead) throws IOException {
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304 | int totalRead = 0;
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305 |
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306 | if (this.entryOffset >= this.entrySize) {
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307 | return -1;
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308 | }
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309 |
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310 | if ((numToRead + this.entryOffset) > this.entrySize) {
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311 | numToRead = (this.entrySize - this.entryOffset);
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312 | }
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313 |
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314 | if (this.readBuf != null) {
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315 | int sz = (numToRead > this.readBuf.length) ? this.readBuf.length
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316 | : numToRead;
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317 |
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318 | System.arraycopy(this.readBuf, 0, buf, offset, sz);
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319 |
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320 | if (sz >= this.readBuf.length) {
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321 | this.readBuf = null;
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322 | } else {
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323 | int newLen = this.readBuf.length - sz;
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324 | byte[] newBuf = new byte[newLen];
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325 |
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326 | System.arraycopy(this.readBuf, sz, newBuf, 0, newLen);
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327 |
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328 | this.readBuf = newBuf;
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329 | }
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330 |
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331 | totalRead += sz;
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332 | numToRead -= sz;
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333 | offset += sz;
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334 | }
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335 |
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336 | while (numToRead > 0) {
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337 | byte[] rec = this.buffer.readRecord();
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338 |
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339 | if (rec == null) {
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340 | // Unexpected EOF!
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341 | throw new IOException("unexpected EOF with " + numToRead
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342 | + " bytes unread");
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343 | }
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344 |
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345 | int sz = numToRead;
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346 | int recLen = rec.length;
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347 |
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348 | if (recLen > sz) {
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349 | System.arraycopy(rec, 0, buf, offset, sz);
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350 |
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351 | this.readBuf = new byte[recLen - sz];
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352 |
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353 | System.arraycopy(rec, sz, this.readBuf, 0, recLen - sz);
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354 | } else {
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355 | sz = recLen;
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356 |
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357 | System.arraycopy(rec, 0, buf, offset, recLen);
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358 | }
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359 |
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360 | totalRead += sz;
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361 | numToRead -= sz;
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362 | offset += sz;
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363 | }
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364 |
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365 | this.entryOffset += totalRead;
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366 |
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367 | return totalRead;
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368 | }
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369 |
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370 | /**
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371 | * Copies the contents of the current tar archive entry directly into
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372 | * an output stream.
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373 | *
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374 | * @param out The OutputStream into which to write the entry's data.
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375 | * @throws IOException on error
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376 | */
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377 | public void copyEntryContents(OutputStream out) throws IOException {
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378 | byte[] buf = new byte[32 * 1024];
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379 |
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380 | while (true) {
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381 | int numRead = this.read(buf, 0, buf.length);
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382 |
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383 | if (numRead == -1) {
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384 | break;
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385 | }
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386 |
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387 | out.write(buf, 0, numRead);
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388 | }
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389 | }
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390 | }
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