[10] | 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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