added data structures

added audio support
added rfid support
added spi support

data/RingBuffer.h

@@ -0,0 +1,79 @@
+#ifndef RINGBUFFER_H
+#define RINGBUFFER_H
+
+template <typename Scalar, int size> class RingBuffer {
+
+private:
+
+	Scalar data[size];
+
+	volatile size_t head;
+	volatile size_t tail;
+	volatile size_t used;
+
+public:
+
+	void init() {
+		head = 0;
+		tail = 0;
+		used = 0;
+	}
+
+	/** add one value to the buffer */
+	void addBlocking(const Scalar value) {
+
+		while (used == size) {os_delay_us(1000);}
+
+		data[head] = value;
+		head = (head + 1) % size;
+		++used;
+	}
+
+	/** add one value to the buffer */
+	void addIgnore(const Scalar value) {
+
+		if (used == size) {return;}
+
+		data[head] = value;
+		head = (head + 1) % size;
+		++used;
+	}
+
+	/** add multiple values to the buffer */
+	void add(const Scalar* value, const size_t len) {
+		for (size_t i = 0; i < len; ++i) {
+			add(value[i]);
+		}
+	}
+
+	/** anything available? */
+	bool hasNext() const {
+		return used != 0;
+	}
+
+	Scalar get() {
+		const Scalar res = data[tail];
+		tail = (tail + 1) % size;
+		--used;
+		return res;
+	}
+
+	const Scalar& getConst() {
+		const uint8_t idx = tail;
+		tail = (tail + 1) % size;
+		--used;
+		return data[idx];
+	}
+
+//	/** true if the buffer is currently empty */
+//	bool isEmpty() const {
+//		return head == tail;
+//	}
+
+	size_t getNumUsed() const {
+		return used;
+	}
+
+};
+
+#endif // RINGBUFFER_H