1 files changed, 34 insertions, 0 deletions
diff --git a/include/libcamera/base/semaphore.h b/include/libcamera/base/semaphore.h
new file mode 100644
index 00000000..c8e62e3e
--- /dev/null
+++ b/include/libcamera/base/semaphore.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * semaphore.h - General-purpose counting semaphore
+ */
+#ifndef __LIBCAMERA_BASE_SEMAPHORE_H__
+#define __LIBCAMERA_BASE_SEMAPHORE_H__
+
+#include <condition_variable>
+
+#include <libcamera/base/thread.h>
+
+namespace libcamera {
+
+class Semaphore
+{
+public:
+	Semaphore(unsigned int n = 0);
+
+	unsigned int available();
+	void acquire(unsigned int n = 1);
+	bool tryAcquire(unsigned int n = 1);
+	void release(unsigned int n = 1);
+
+private:
+	Mutex mutex_;
+	std::condition_variable cv_;
+	unsigned int available_;
+};
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_BASE_SEMAPHORE_H__ */