Rename beast sources for consistency

modules/beast_core/memory/AtomicState.h

@@ -0,0 +1,101 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef BEAST_ATOMICSTATE_H_INCLUDED
+#define BEAST_ATOMICSTATE_H_INCLUDED
+
+/*============================================================================*/
+/**
+    A thread safe state variable.
+
+    This provides a simplified interface to an integer used to control atomic
+    state transitions. A state is distinguished by a single integer value.
+
+    @ingroup beast_core
+*/
+class BEAST_API AtomicState
+{
+public:
+    /** Create a new state with an optional starting value.
+
+        @param initialState The initial state.
+    */
+
+
+    explicit AtomicState (const int initialState = 0) noexcept
+:
+    m_value (initialState)
+    {
+    }
+
+    /** Retrieve the current state.
+
+        This converts the object to an integer reflecting the current state.
+
+        Note that other threads may change the value immediately after this
+        function returns. The caller is responsible for synchronizing.
+
+        @return The state at the time of the call.
+    */
+    inline operator int () const
+    {
+        return m_value.get ();
+    }
+
+    /** Attempt a state transition.
+
+        The current state is compared to `from`, and if the comparison is
+        successful the state becomes `to`. The entire operation is atomic.
+
+        @param from   The current state, for comparison.
+
+        @param to     The desired new state.
+
+        @return       true if the state transition succeeded.
+    */
+    inline bool tryChangeState (const int from, const int to) noexcept
+    {
+        return m_value.compareAndSetBool (to, from);
+    }
+
+    /** Perform a state transition.
+
+        This attempts to change the state and generates a diagnostic on
+        failure. This routine can be used instead of tryChangeState()
+        when program logic requires that the state change must succeed.
+
+        @param from   The required current state.
+
+        @param to     The new state.
+    */
+    inline void changeState (const int from, const int to) noexcept
+    {
+#if BEAST_DEBUG
+        const bool success = tryChangeState (from, to);
+        bassert (success);
+#else
+        tryChangeState (from, to);
+#endif
+    }
+
+private:
+    Atomic <int> m_value;
+};
+
+#endif