Relocate Adafruit BLE code (#14530)

drivers/bluetooth/ringbuffer.hpp

@@ -0,0 +1,66 @@
+#pragma once
+// A simple ringbuffer holding Size elements of type T
+template <typename T, uint8_t Size>
+class RingBuffer {
+ protected:
+  T buf_[Size];
+  uint8_t head_{0}, tail_{0};
+ public:
+  inline uint8_t nextPosition(uint8_t position) {
+    return (position + 1) % Size;
+  }
+
+  inline uint8_t prevPosition(uint8_t position) {
+    if (position == 0) {
+      return Size - 1;
+    }
+    return position - 1;
+  }
+
+  inline bool enqueue(const T &item) {
+    static_assert(Size > 1, "RingBuffer size must be > 1");
+    uint8_t next = nextPosition(head_);
+    if (next == tail_) {
+      // Full
+      return false;
+    }
+
+    buf_[head_] = item;
+    head_ = next;
+    return true;
+  }
+
+  inline bool get(T &dest, bool commit = true) {
+    auto tail = tail_;
+    if (tail == head_) {
+      // No more data
+      return false;
+    }
+
+    dest = buf_[tail];
+    tail = nextPosition(tail);
+
+    if (commit) {
+      tail_ = tail;
+    }
+    return true;
+  }
+
+  inline bool empty() const { return head_ == tail_; }
+
+  inline uint8_t size() const {
+    int diff = head_ - tail_;
+    if (diff >= 0) {
+      return diff;
+    }
+    return Size + diff;
+  }
+
+  inline T& front() {
+    return buf_[tail_];
+  }
+
+  inline bool peek(T &item) {
+    return get(item, false);
+  }
+};