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 org.apache.james.mime4j.util.ByteArrayBuffer; |
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23 | |
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24 | import java.io.IOException; |
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25 | import java.io.InputStream; |
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26 | |
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27 | /** |
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28 | * Input buffer that can be used to search for patterns using Quick Search |
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29 | * algorithm in data read from an {@link InputStream}. |
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30 | */ |
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31 | public class BufferedLineReaderInputStream extends LineReaderInputStream { |
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32 | |
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33 | private boolean truncated; |
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34 | |
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35 | boolean tempBuffer = false; |
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36 | |
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37 | private byte[] origBuffer; |
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38 | private int origBufpos; |
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39 | private int origBuflen; |
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40 | |
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41 | private byte[] buffer; |
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42 | private int bufpos; |
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43 | private int buflen; |
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44 | |
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45 | private final int maxLineLen; |
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46 | |
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47 | public BufferedLineReaderInputStream( |
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48 | final InputStream instream, |
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49 | int buffersize, |
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50 | int maxLineLen) { |
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51 | super(instream); |
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52 | if (instream == null) { |
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53 | throw new IllegalArgumentException("Input stream may not be null"); |
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54 | } |
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55 | if (buffersize <= 0) { |
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56 | throw new IllegalArgumentException("Buffer size may not be negative or zero"); |
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57 | } |
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58 | this.buffer = new byte[buffersize]; |
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59 | this.bufpos = 0; |
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60 | this.buflen = 0; |
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61 | this.maxLineLen = maxLineLen; |
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62 | this.truncated = false; |
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63 | } |
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64 | |
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65 | public BufferedLineReaderInputStream( |
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66 | final InputStream instream, |
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67 | int buffersize) { |
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68 | this(instream, buffersize, -1); |
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69 | } |
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70 | |
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71 | private void expand(int newlen) { |
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72 | byte newbuffer[] = new byte[newlen]; |
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73 | int len = bufferLen(); |
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74 | if (len > 0) { |
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75 | System.arraycopy(this.buffer, this.bufpos, newbuffer, this.bufpos, len); |
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76 | } |
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77 | this.buffer = newbuffer; |
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78 | } |
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79 | |
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80 | public void ensureCapacity(int len) { |
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81 | if (len > this.buffer.length) { |
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82 | expand(len); |
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83 | } |
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84 | } |
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85 | |
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86 | public int fillBuffer() throws IOException { |
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87 | if (tempBuffer) { |
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88 | // we was on tempBuffer. |
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89 | // check that we completed the tempBuffer |
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90 | if (bufpos != buflen) throw new IllegalStateException("unread only works when a buffer is fully read before the next refill is asked!"); |
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91 | // restore the original buffer |
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92 | buffer = origBuffer; |
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93 | buflen = origBuflen; |
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94 | bufpos = origBufpos; |
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95 | tempBuffer = false; |
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96 | // return that we just read bufferLen data. |
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97 | return bufferLen(); |
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98 | } |
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99 | // compact the buffer if necessary |
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100 | if (this.bufpos > 0) { // could swtich to (this.buffer.length / 2) but needs a 4*boundary capacity, then (instead of 2). |
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101 | int len = bufferLen(); |
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102 | if (len > 0) { |
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103 | System.arraycopy(this.buffer, this.bufpos, this.buffer, 0, len); |
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104 | } |
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105 | this.bufpos = 0; |
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106 | this.buflen = len; |
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107 | } |
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108 | int l; |
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109 | int off = this.buflen; |
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110 | int len = this.buffer.length - off; |
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111 | l = in.read(this.buffer, off, len); |
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112 | if (l == -1) { |
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113 | return -1; |
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114 | } else { |
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115 | this.buflen = off + l; |
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116 | return l; |
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117 | } |
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118 | } |
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119 | |
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120 | private int bufferLen() { |
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121 | return this.buflen - this.bufpos; |
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122 | } |
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123 | |
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124 | public boolean hasBufferedData() { |
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125 | return bufferLen() > 0; |
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126 | } |
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127 | |
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128 | public void truncate() { |
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129 | clear(); |
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130 | this.truncated = true; |
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131 | } |
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132 | |
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133 | protected boolean readAllowed() { |
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134 | return !this.truncated; |
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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 (!readAllowed()) return -1; |
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140 | int noRead = 0; |
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141 | while (!hasBufferedData()) { |
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142 | noRead = fillBuffer(); |
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143 | if (noRead == -1) { |
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144 | return -1; |
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145 | } |
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146 | } |
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147 | return this.buffer[this.bufpos++] & 0xff; |
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148 | } |
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149 | |
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150 | @Override |
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151 | public int read(final byte[] b, int off, int len) throws IOException { |
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152 | if (!readAllowed()) return -1; |
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153 | if (b == null) { |
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154 | return 0; |
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155 | } |
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156 | int noRead = 0; |
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157 | while (!hasBufferedData()) { |
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158 | noRead = fillBuffer(); |
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159 | if (noRead == -1) { |
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160 | return -1; |
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161 | } |
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162 | } |
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163 | int chunk = bufferLen(); |
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164 | if (chunk > len) { |
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165 | chunk = len; |
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166 | } |
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167 | System.arraycopy(this.buffer, this.bufpos, b, off, chunk); |
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168 | this.bufpos += chunk; |
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169 | return chunk; |
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170 | } |
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171 | |
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172 | @Override |
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173 | public int read(final byte[] b) throws IOException { |
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174 | if (!readAllowed()) return -1; |
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175 | if (b == null) { |
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176 | return 0; |
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177 | } |
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178 | return read(b, 0, b.length); |
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179 | } |
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180 | |
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181 | @Override |
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182 | public boolean markSupported() { |
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183 | return false; |
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184 | } |
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185 | |
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186 | @Override |
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187 | public int readLine(final ByteArrayBuffer dst) |
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188 | throws MaxLineLimitException, IOException { |
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189 | if (dst == null) { |
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190 | throw new IllegalArgumentException("Buffer may not be null"); |
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191 | } |
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192 | if (!readAllowed()) return -1; |
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193 | |
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194 | int total = 0; |
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195 | boolean found = false; |
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196 | int bytesRead = 0; |
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197 | while (!found) { |
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198 | if (!hasBufferedData()) { |
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199 | bytesRead = fillBuffer(); |
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200 | if (bytesRead == -1) { |
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201 | break; |
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202 | } |
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203 | } |
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204 | int i = indexOf((byte)'\n'); |
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205 | int chunk; |
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206 | if (i != -1) { |
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207 | found = true; |
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208 | chunk = i + 1 - pos(); |
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209 | } else { |
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210 | chunk = length(); |
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211 | } |
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212 | if (chunk > 0) { |
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213 | dst.append(buf(), pos(), chunk); |
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214 | skip(chunk); |
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215 | total += chunk; |
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216 | } |
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217 | if (this.maxLineLen > 0 && dst.length() >= this.maxLineLen) { |
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218 | throw new MaxLineLimitException("Maximum line length limit exceeded"); |
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219 | } |
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220 | } |
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221 | if (total == 0 && bytesRead == -1) { |
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222 | return -1; |
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223 | } else { |
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224 | return total; |
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225 | } |
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226 | } |
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227 | |
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228 | /** |
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229 | * Implements quick search algorithm as published by |
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230 | * <p> |
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231 | * SUNDAY D.M., 1990, |
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232 | * A very fast substring search algorithm, |
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233 | * Communications of the ACM . 33(8):132-142. |
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234 | * </p> |
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235 | */ |
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236 | public int indexOf(final byte[] pattern, int off, int len) { |
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237 | if (pattern == null) { |
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238 | throw new IllegalArgumentException("Pattern may not be null"); |
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239 | } |
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240 | if (off < this.bufpos || len < 0 || off + len > this.buflen) { |
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241 | throw new IndexOutOfBoundsException("looking for "+off+"("+len+")"+" in "+bufpos+"/"+buflen); |
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242 | } |
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243 | if (len < pattern.length) { |
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244 | return -1; |
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245 | } |
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246 | |
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247 | int[] shiftTable = new int[256]; |
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248 | for (int i = 0; i < shiftTable.length; i++) { |
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249 | shiftTable[i] = pattern.length + 1; |
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250 | } |
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251 | for (int i = 0; i < pattern.length; i++) { |
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252 | int x = pattern[i] & 0xff; |
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253 | shiftTable[x] = pattern.length - i; |
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254 | } |
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255 | |
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256 | int j = 0; |
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257 | while (j <= len - pattern.length) { |
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258 | int cur = off + j; |
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259 | boolean match = true; |
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260 | for (int i = 0; i < pattern.length; i++) { |
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261 | if (this.buffer[cur + i] != pattern[i]) { |
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262 | match = false; |
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263 | break; |
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264 | } |
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265 | } |
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266 | if (match) { |
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267 | return cur; |
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268 | } |
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269 | |
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270 | int pos = cur + pattern.length; |
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271 | if (pos >= this.buffer.length) { |
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272 | break; |
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273 | } |
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274 | int x = this.buffer[pos] & 0xff; |
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275 | j += shiftTable[x]; |
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276 | } |
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277 | return -1; |
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278 | } |
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279 | |
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280 | /** |
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281 | * Implements quick search algorithm as published by |
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282 | * <p> |
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283 | * SUNDAY D.M., 1990, |
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284 | * A very fast substring search algorithm, |
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285 | * Communications of the ACM . 33(8):132-142. |
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286 | * </p> |
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287 | */ |
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288 | public int indexOf(final byte[] pattern) { |
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289 | return indexOf(pattern, this.bufpos, this.buflen - this.bufpos); |
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290 | } |
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291 | |
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292 | public int indexOf(byte b, int off, int len) { |
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293 | if (off < this.bufpos || len < 0 || off + len > this.buflen) { |
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294 | throw new IndexOutOfBoundsException(); |
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295 | } |
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296 | for (int i = off; i < off + len; i++) { |
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297 | if (this.buffer[i] == b) { |
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298 | return i; |
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299 | } |
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300 | } |
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301 | return -1; |
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302 | } |
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303 | |
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304 | public int indexOf(byte b) { |
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305 | return indexOf(b, this.bufpos, bufferLen()); |
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306 | } |
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307 | |
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308 | public byte charAt(int pos) { |
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309 | if (pos < this.bufpos || pos > this.buflen) { |
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310 | throw new IndexOutOfBoundsException("looking for "+pos+" in "+bufpos+"/"+buflen); |
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311 | } |
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312 | return this.buffer[pos]; |
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313 | } |
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314 | |
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315 | protected byte[] buf() { |
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316 | return this.buffer; |
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317 | } |
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318 | |
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319 | protected int pos() { |
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320 | return this.bufpos; |
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321 | } |
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322 | |
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323 | protected int limit() { |
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324 | return this.buflen; |
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325 | } |
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326 | |
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327 | protected int length() { |
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328 | return bufferLen(); |
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329 | } |
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330 | |
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331 | public int capacity() { |
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332 | return this.buffer.length; |
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333 | } |
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334 | |
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335 | protected int skip(int n) { |
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336 | int chunk = Math.min(n, bufferLen()); |
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337 | this.bufpos += chunk; |
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338 | return chunk; |
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339 | } |
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340 | |
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341 | private void clear() { |
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342 | this.bufpos = 0; |
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343 | this.buflen = 0; |
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344 | } |
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345 | |
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346 | @Override |
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347 | public String toString() { |
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348 | StringBuilder buffer = new StringBuilder(); |
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349 | buffer.append("[pos: "); |
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350 | buffer.append(this.bufpos); |
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351 | buffer.append("]"); |
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352 | buffer.append("[limit: "); |
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353 | buffer.append(this.buflen); |
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354 | buffer.append("]"); |
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355 | buffer.append("["); |
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356 | for (int i = this.bufpos; i < this.buflen; i++) { |
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357 | buffer.append((char) this.buffer[i]); |
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358 | } |
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359 | buffer.append("]"); |
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360 | if (tempBuffer) { |
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361 | buffer.append("-ORIG[pos: "); |
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362 | buffer.append(this.origBufpos); |
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363 | buffer.append("]"); |
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364 | buffer.append("[limit: "); |
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365 | buffer.append(this.origBuflen); |
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366 | buffer.append("]"); |
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367 | buffer.append("["); |
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368 | for (int i = this.origBufpos; i < this.origBuflen; i++) { |
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369 | buffer.append((char) this.origBuffer[i]); |
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370 | } |
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371 | buffer.append("]"); |
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372 | } |
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373 | return buffer.toString(); |
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374 | } |
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375 | |
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376 | @Override |
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377 | public boolean unread(ByteArrayBuffer buf) { |
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378 | if (tempBuffer) return false; |
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379 | origBuffer = buffer; |
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380 | origBuflen = buflen; |
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381 | origBufpos = bufpos; |
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382 | bufpos = 0; |
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383 | buflen = buf.length(); |
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384 | buffer = buf.buffer(); |
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385 | tempBuffer = true; |
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386 | return true; |
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387 | } |
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388 | |
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389 | } |
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