70 lines
2.5 KiB
C++
70 lines
2.5 KiB
C++
// Fig. 17.16: SynchronizedBuffer.h
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// SynchronizedBuffer using two binary_semaphores to
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// maintain synchronized access to a shared mutable int.
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#pragma once
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#include <fmt/format.h>
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#include <iostream>
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#include <semaphore>
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#include <string>
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using namespace std::string_literals;
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class SynchronizedBuffer {
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public:
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// place value into m_buffer
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void put(int value) {
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// acquire m_produce semaphore to be able to write to m_buffer
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m_produce.acquire(); // blocks if it's not the producer's turn
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m_buffer = value; // write to m_buffer
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m_occupied = true;
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std::cout << fmt::format("{:<40}{}\t\t{}\n",
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"Producer writes "s + std::to_string(value),
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m_buffer, m_occupied);
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m_consume.release(); // allow consumer to read
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}
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// return value from m_buffer
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int get() {
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int value; // will store the value returned by get
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// acquire m_consume semaphore to be able to read from m_buffer
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m_consume.acquire(); // blocks if it's not the consumer's turn
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value = m_buffer; // read from m_buffer
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m_occupied = false;
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std::cout << fmt::format("{:<40}{}\t\t{}\n",
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"Consumer reads "s + std::to_string(m_buffer),
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m_buffer, m_occupied);
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m_produce.release(); // allow producer to write
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return value;
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}
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private:
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std::binary_semaphore m_produce{1}; // producer can produce
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std::binary_semaphore m_consume{0}; // consumer can't consume
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bool m_occupied{false};
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int m_buffer{-1}; // shared by producer and consumer threads
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};
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/************************************************************************
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* (C) Copyright 1992-2022 by Deitel & Associates, Inc. and *
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* Pearson Education, Inc. All Rights Reserved. *
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* *
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* DISCLAIMER: The authors and publisher of this book have used their *
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* best efforts in preparing the book. These efforts include the *
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* development, research, and testing of the theories and programs *
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* to determine their effectiveness. The authors and publisher make *
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* no warranty of any kind, expressed or implied, with regard to these *
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* programs or to the documentation contained in these books. The *
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* authors and publisher shall not be liable in any event for *
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* incidental or consequential damages in connection with, or arising *
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* out of, the furnishing, performance, or use of these programs. *
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***********************************************************************/
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