72 lines
1.4 KiB
C++
72 lines
1.4 KiB
C++
#pragma once
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#include <version>
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/*
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a simple semaphore interface.
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*/
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// note: __cpp_lib_semaphore will not be defined in some apple platforms
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// even if >= C++20.
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#if __has_include(<semaphore>) && defined(__cpp_lib_semaphore) && __cpp_lib_semaphore >= 201907L
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#define C10_SEMAPHORE_USE_STL
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#endif
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#ifdef C10_SEMAPHORE_USE_STL
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#include <semaphore>
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#else
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// To use moodycamel semaphore, we need to include the header file
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// for concurrentqueue first. Hiding implementation detail here.
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#ifdef BLOCK_SIZE
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#pragma push_macro("BLOCK_SIZE")
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#undef BLOCK_SIZE
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#include <moodycamel/concurrentqueue.h> // @manual
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#pragma pop_macro("BLOCK_SIZE")
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#else
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#include <moodycamel/concurrentqueue.h> // @manual
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#endif
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#include <moodycamel/lightweightsemaphore.h> // @manual
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#endif
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namespace c10 {
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class Semaphore {
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public:
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Semaphore(int32_t initial_count = 0) : impl_(initial_count) {}
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void release(int32_t n = 1) {
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#ifdef C10_SEMAPHORE_USE_STL
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impl_.release(n);
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#else
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impl_.signal(n);
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#endif
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}
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void acquire() {
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#ifdef C10_SEMAPHORE_USE_STL
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impl_.acquire();
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#else
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impl_.wait();
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#endif
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}
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bool tryAcquire() {
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#ifdef C10_SEMAPHORE_USE_STL
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return impl_.try_acquire();
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#else
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return impl_.tryWait();
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#endif
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}
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private:
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#ifdef C10_SEMAPHORE_USE_STL
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std::counting_semaphore<> impl_;
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#else
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moodycamel::LightweightSemaphore impl_;
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#endif
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};
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} // namespace c10
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#undef C10_SEMAPHORE_USE_STL
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