1 | // Copyright (c) 2013 by István Váradi
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2 |
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3 | // This file is part of VSCPL, a simple cross-platform utility library
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4 |
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5 | // Redistribution and use in source and binary forms, with or without
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6 | // modification, are permitted provided that the following conditions are met:
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7 |
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8 | // 1. Redistributions of source code must retain the above copyright notice, this
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9 | // list of conditions and the following disclaimer.
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10 | // 2. Redistributions in binary form must reproduce the above copyright notice,
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11 | // this list of conditions and the following disclaimer in the documentation
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12 | // and/or other materials provided with the distribution.
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13 |
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14 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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15 | // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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16 | // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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17 | // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
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18 | // ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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19 | // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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20 | // LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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21 | // ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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22 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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23 | // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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24 |
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25 | // The views and conclusions contained in the software and documentation are those
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26 | // of the authors and should not be interpreted as representing official policies,
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27 | // either expressed or implied, of the FreeBSD Project.
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28 |
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29 | #ifndef HU_VARADIISTVAN_SCPL_IO_BLOCKINGSTREAM_H
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30 | #define HU_VARADIISTVAN_SCPL_IO_BLOCKINGSTREAM_H
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31 | //------------------------------------------------------------------------------
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32 |
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33 | #include "Failable.h"
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34 |
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35 | #include "BufferedStream.h"
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36 | #include "WaitableEvent.h"
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37 |
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38 | #include <cstdlib>
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39 |
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40 | //------------------------------------------------------------------------------
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41 |
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42 | namespace hu { namespace varadiistvan { namespace scpl { namespace io {
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43 |
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44 | //------------------------------------------------------------------------------
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45 |
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46 | /**
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47 | * Wrapper for a buffered stream, which an event and provides
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48 | * blocking, but interruptible read() and write() operations.
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49 | *
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50 | * The class is designed in a way, that it expects its constructed
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51 | * instances to be called only from a single thread at a time, except
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52 | * for the interrupt() function, which may be called from another
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53 | * thread anytime.
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54 | */
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55 | class BlockingStream : public Failable
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56 | {
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57 | private:
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58 | /**
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59 | * The buffered stream used.
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60 | */
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61 | BufferedStream& stream;
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62 |
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63 | /**
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64 | * The waitable event.
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65 | */
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66 | WaitableEvent event;
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67 |
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68 | /**
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69 | * Indicate if we are interrupted.
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70 | */
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71 | bool interrupted;
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72 |
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73 | /**
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74 | * The offset in the buffer of the reading stream.
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75 | */
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76 | size_t readingOffset;
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77 |
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78 | /**
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79 | * Indicate if the end-of-file has been reached while reading.
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80 | */
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81 | bool eof;
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82 |
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83 | public:
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84 | /**
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85 | * Construct the blocking stream for the given buffered stream.
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86 | *
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87 | * The stream must have a waiter which is used for waiting.
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88 | */
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89 | BlockingStream(BufferedStream& stream);
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90 |
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91 | /**
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92 | * Determine if the stream has neither failed nor been
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93 | * interrupted.
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94 | */
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95 | operator bool() const;
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96 |
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97 | /**
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98 | * Interrupt the stream. Pending or future read and write calls
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99 | * will return indicating error. The isInterrupted() function can
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100 | * be used to check if the stream was interrupted or not.
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101 | */
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102 | void interrupt();
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103 |
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104 | /**
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105 | * Indicate if the stream is interrupted or not.
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106 | */
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107 | bool isInterrupted();
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108 |
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109 | /**
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110 | * Read the given number of bytes into the given buffer.
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111 | *
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112 | * @return if the reading has succeeded
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113 | */
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114 | bool read(void* dest, size_t length);
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115 |
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116 | /**
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117 | * Skip the given number of bytes.
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118 | */
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119 | bool skip(size_t length);
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120 |
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121 | /**
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122 | * Write the given number of bytes from the given buffer. The data
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123 | * may not be written to the underlying stream fully, so if you
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124 | * want to make sure that it is sent, call flush() afterwards.
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125 | *
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126 | * @return true on success, false on error.
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127 | */
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128 | bool write(const void* src, size_t length);
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129 |
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130 | /**
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131 | * Flush anything written so far into the buffer, but not to the
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132 | * underlying stream.
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133 | *
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134 | * @return whether the operation has succeeded.
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135 | */
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136 | bool flush();
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137 |
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138 | private:
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139 | /**
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140 | * Fill the buffer with data from the stream.
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141 | */
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142 | bool fill();
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143 |
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144 | /**
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145 | * Check for the stream being interrupted.
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146 | *
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147 | * @return if the stream is interrupted, false otherwise
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148 | */
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149 | bool checkInterrupted();
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150 | };
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151 |
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152 | //------------------------------------------------------------------------------
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153 | // Inline definitions
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154 | //------------------------------------------------------------------------------
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155 |
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156 | inline BlockingStream::BlockingStream(BufferedStream& stream) :
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157 | stream(stream),
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158 | event(stream.getWaiter()),
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159 | interrupted(false),
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160 | readingOffset(0),
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161 | eof(false)
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162 | {
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163 | }
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164 |
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165 | //------------------------------------------------------------------------------
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166 |
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167 | inline BlockingStream::operator bool() const
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168 | {
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169 | return !failed() && !interrupted && !eof;
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170 | }
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171 |
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172 | //------------------------------------------------------------------------------
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173 |
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174 | inline void BlockingStream::interrupt()
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175 | {
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176 | event.fire();
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177 | }
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178 |
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179 | //------------------------------------------------------------------------------
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180 |
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181 | inline bool BlockingStream::isInterrupted()
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182 | {
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183 | return interrupted;
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184 | }
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185 |
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186 | //------------------------------------------------------------------------------
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187 |
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188 | } /* namespace hu::varadiistvan::scpl::io */ } /* namespace hu::varadiistvan::scpl */ } /* namespace hu::varadiistvan */ } /* namespace hu */
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189 |
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190 | //------------------------------------------------------------------------------
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191 | #endif // HU_VARADIISTVAN_SCPL_IO_BLOCKINGSTREAM_H
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192 |
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193 | // Local Variables:
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194 | // mode: C++
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195 | // c-basic-offset: 4
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196 | // indent-tabs-mode: nil
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197 | // End:
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