Add a simple midi queue class code

Signed-off-by: falkTX <falktx@falktx.com>

source/native-plugins/midi-queue.hpp

@@ -0,0 +1,139 @@
+/*
+ * MIDI Event Queue
+ * Copyright (C) 2012-2020 Filipe Coelho <falktx@falktx.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * For a full copy of the GNU General Public License see the COPYING file
+ */
+
+#ifndef MIDI_QUEUE_HPP_INCLUDED
+#define MIDI_QUEUE_HPP_INCLUDED
+
+#include "CarlaMutex.hpp"
+
+template<uint16_t MAX_SIZE>
+class MIDIEventQueue
+{
+public:
+    MIDIEventQueue() noexcept
+        : index(0),
+          empty(true),
+          full(false),
+          mutex() {}
+
+    bool isEmpty() const noexcept
+    {
+        return empty;
+    }
+
+    bool isNotEmpty() const noexcept
+    {
+        return !empty;
+    }
+
+    bool isFull() const noexcept
+    {
+        return full;
+    }
+
+    CarlaMutex& getMutex() noexcept
+    {
+        return mutex;
+    }
+
+    bool put(unsigned char d1, unsigned char d2, unsigned char d3)
+    {
+        CARLA_SAFE_ASSERT_RETURN(d1 != 0, false);
+
+        if (full)
+            return false;
+
+        for (unsigned short i=0; i < MAX_SIZE; i++)
+        {
+            if (data[i].d1 == 0)
+            {
+                data[i].d1 = d1;
+                data[i].d2 = d2;
+                data[i].d3 = d3;
+                empty = false;
+                full  = (i == MAX_SIZE-1);
+                break;
+            }
+        }
+
+        return true;
+    }
+
+    bool get(uint8_t& d1, uint8_t& d2, uint8_t& d3)
+    {
+        if (empty)
+            return false;
+
+        full = false;
+
+        if (data[index].d1 == 0)
+        {
+            index = 0;
+            empty = true;
+
+            return false;
+        }
+
+        d1 = data[index].d1;
+        d2 = data[index].d2;
+        d3 = data[index].d3;
+
+        data[index].d1 = data[index].d2 = data[index].d3 = 0;
+        empty = false;
+        ++index;
+
+        return true;
+    }
+
+    bool tryToCopyDataFrom(MIDIEventQueue& queue) noexcept
+    {
+        const CarlaMutexTryLocker cml(queue.mutex);
+
+        if (cml.wasNotLocked())
+            return false;
+
+        // copy data from queue
+        carla_copyStruct(data, queue.data);
+        index = queue.index;
+        empty = queue.empty;
+        full  = queue.full;
+
+        // reset queque
+        carla_zeroStruct(queue.data);
+        queue.index = 0;
+        queue.empty = true;
+        queue.full  = false;
+
+        return true;
+    }
+
+private:
+    struct MIDIEvent {
+        uint8_t d1, d2, d3;
+
+        MIDIEvent() noexcept
+            : d1(0), d2(0), d3(0) {}
+    };
+
+    MIDIEvent data[MAX_SIZE];
+    uint16_t index;
+    volatile bool empty, full;
+
+    CarlaMutex mutex;
+};
+
+#endif // MIDI_QUEUE_HPP_INCLUDED