Diff: atomic_bool.h

Revision:

0:25fedaa4b401

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/atomic_bool.h	Fri May 02 13:40:57 2014 +0000
@@ -0,0 +1,98 @@
+/* (C) 2014 Richard Thompson (Tomo2k)
+This software is Apache 2.0 licenced.
+*/
+#pragma once
+
+//! Atomic Boolean.
+//! Also provides test-and-set and test-and-clear methods.
+//! Interchangable with bool.\n
+//! Works by disabling then re-enabling interrupts.\n
+//! Do not use during ISR or when interrupts should remain disabled.
+class AtomicBool
+{
+public:
+    //! Create the boolean and set initial value from bool
+    //! @warning Construction is not guaranteed atomic! Interrupts may occur before construction completes.
+    AtomicBool(const bool initialValue) :
+        m_value(initialValue) {}
+
+    //! Create and set initial value from another AtomicBool.
+    //! This method guaranteed atomic.
+    AtomicBool(const AtomicBool &rhs) {
+        __disable_irq();
+        m_value = rhs.m_value;
+        __enable_irq();
+    }
+
+    // Assign to bool
+    void operator=(const bool &rhs) {
+        __disable_irq();
+        m_value = rhs;
+        __enable_irq();
+    }
+
+    // Assign to own type
+    void operator=(const AtomicBool &rhs) {
+        __disable_irq();
+        m_value = rhs.m_value;
+        __enable_irq();
+    }
+
+    inline bool operator==(const bool &rhs) const {
+        __disable_irq();
+        bool result(m_value == rhs);
+        __enable_irq();
+        return result;
+    }
+
+    inline bool operator!=(const bool &rhs) const {
+        __disable_irq();
+        bool result(m_value != rhs);
+        __enable_irq();
+        return result;
+    }
+
+    //! Test and set the bool
+    //! @returns true if bool was false before calling
+    inline bool testAndSet() {
+        __disable_irq();
+        bool result(!m_value);
+        m_value = true;
+        __enable_irq();
+        return result;
+    }
+
+    //! Test and clear the bool
+    //! @returns true if bool was true before calling
+    inline bool testAndClear() {
+        __disable_irq();
+        bool result(m_value);
+        m_value = false;
+        __enable_irq();
+        return result;
+    }
+
+    inline operator bool() const {
+        __disable_irq();
+        bool result(m_value);
+        __enable_irq();
+        return result;
+    }
+
+    bool operator==(const AtomicBool &rhs) const {
+        __disable_irq();
+        bool result(m_value == rhs.m_value);
+        __enable_irq();
+        return result;
+    }
+
+    bool operator!=(const AtomicBool &rhs) const {
+        __disable_irq();
+        bool result(m_value != rhs.m_value);
+        __enable_irq();
+        return result;
+    }
+
+private:
+    bool m_value;
+};