Diff: Blynk_v0_3_7/Blynk/utility/BlynkFifo2.h

Revision:

0:740c1eb2df13

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Blynk_v0_3_7/Blynk/utility/BlynkFifo2.h	Thu Jun 23 11:16:14 2016 +0000
@@ -0,0 +1,152 @@
+/**
+ * @file       BlynkFifo.h
+ * @author     Volodymyr Shymanskyy
+ * @license    This project is released under the MIT License (MIT)
+ * @copyright  Copyright (c) 2015 Volodymyr Shymanskyy
+ * @date       Feb 2015
+ * @brief      FIFO implementation
+ *
+ */
+
+#ifndef BlynkFifo_h
+#define BlynkFifo_h
+
+#include <utility/BlynkUtility.h>
+
+template <class T, unsigned N>
+class BlynkFifo
+{
+public:
+    BlynkFifo()
+    {
+        clear();
+    }
+
+    void clear()
+    {
+        _r = 0;
+        _w = 0;
+    }
+
+    ~BlynkFifo(void)
+    {}
+
+    // writing thread/context API
+    //-------------------------------------------------------------
+
+    bool writeable(void)
+    {
+        return free() > 0;
+    }
+
+    int free(void)
+    {
+        int s = _r - _w;
+        if (s <= 0)
+            s += N;
+        return s - 1;
+    }
+
+    T put(const T& c)
+    {
+        int i = _w;
+        int j = i;
+        i = _inc(i);
+        while (i == _r) // = !writeable()
+            /* nothing / just wait */;
+        _b[j] = c;
+        _w = i;
+        return c;
+    }
+
+    int put(const T* p, int n, bool t = false)
+    {
+        int c = n;
+        while (c)
+        {
+            int f;
+            while ((f = free()) == 0) // wait for space
+            {
+                if (!t) return n - c; // no more space and not blocking
+                /* nothing / just wait */;
+            }
+            // check free space
+            if (c < f) f = c;
+            int w = _w;
+            int m = N - w;
+            // check wrap
+            if (f > m) f = m;
+            memcpy(&_b[w], p, f);
+            _w = _inc(w, f);
+            c -= f;
+            p += f;
+        }
+        return n - c;
+    }
+
+    // reading thread/context API
+    // --------------------------------------------------------
+
+    bool readable(void)
+    {
+        return (_r != _w);
+    }
+
+    size_t size(void)
+    {
+        int s = _w - _r;
+        if (s < 0)
+            s += N;
+        return s;
+    }
+
+    T get(void)
+    {
+        int r = _r;
+        while (r == _w) // = !readable()
+            /* nothing / just wait */;
+        T t = _b[r];
+        _r = _inc(r);
+        return t;
+    }
+
+    int get(T* p, int n, bool t = false)
+    {
+        int c = n;
+        while (c)
+        {
+            int f;
+            for (;;) // wait for data
+            {
+                f = size();
+                if (f)  break;        // free space
+                if (!t) return n - c; // no space and not blocking
+                /* nothing / just wait */;
+            }
+            // check available data
+            if (c < f) f = c;
+            int r = _r;
+            int m = N - r;
+            // check wrap
+            if (f > m) f = m;
+            memcpy(p, &_b[r], f);
+            _r = _inc(r, f);
+            c -= f;
+            p += f;
+        }
+        return n - c;
+    }
+
+private:
+    inline int _inc(int i, int n = 1)
+    {
+        return (i + n) % N;
+    }
+
+    T             _b[N];
+    volatile int  _w;
+    volatile int  _r;
+};
+
+#endif
+