1 files changed, 43 insertions, 0 deletions
diff --git a/common/alsem.h b/common/alsem.h
new file mode 100644
index 00000000..9f72d1c6
--- /dev/null
+++ b/common/alsem.h
@@ -0,0 +1,43 @@
+#ifndef COMMON_ALSEM_H
+#define COMMON_ALSEM_H
+
+#if defined(__APPLE__)
+#include <AvailabilityMacros.h>
+#include <TargetConditionals.h>
+#if (((MAC_OS_X_VERSION_MIN_REQUIRED > 1050) && !defined(__ppc__)) || TARGET_OS_IOS || TARGET_OS_TV)
+#include <dispatch/dispatch.h>
+#define AL_APPLE_HAVE_DISPATCH 1
+#else
+#include <semaphore.h> /* Fallback option for Apple without a working libdispatch */
+#endif
+#elif !defined(_WIN32)
+#include <semaphore.h>
+#endif
+
+namespace al {
+
+class semaphore {
+#ifdef _WIN32
+    using native_type = void*;
+#elif defined(AL_APPLE_HAVE_DISPATCH)
+    using native_type = dispatch_semaphore_t;
+#else
+    using native_type = sem_t;
+#endif
+    native_type mSem;
+
+public:
+    semaphore(unsigned int initial=0);
+    semaphore(const semaphore&) = delete;
+    ~semaphore();
+
+    semaphore& operator=(const semaphore&) = delete;
+
+    void post();
+    void wait() noexcept;
+    bool try_wait() noexcept;
+};
+
+} // namespace al
+
+#endif /* COMMON_ALSEM_H */