Make it more idiot-proof

Comms to NINA are now automatically started when needed.

The example should be a bit clearer now.

examples/multiplication/multiplication.ino

@@ -7,32 +7,28 @@
 
 #include <FastBLE.h>
 
-void setup() {
-}
+void setup() {}
 
-BLE::Output<uint64_t> out;
+BLETypes::Output<uint64_t> out;
 
-/* 
- * Callback that is later attached to one input Characteristic of the Service 
- */
+// Input characteristics accept writes with a length corresponding to the callback's argument
+// In this case four bytes
 void cb(int32_t x) {
   out.write((int64_t)x << 8);
 }
 
 void loop() {
-  /*
-   * FastBLE object's constructors may only be called after the Arduino library has initialized itself.
-   * That makes them inconvenient to initialize in setup, so I've hijacked loop instead.
-   */
-  BLE ble;
-  out = BLE::Output<uint64_t>(UUID_128(0x2d, 0x71, 0xa2, 0x59, 0xb4, 0x58, 0xc8, 0x12, 0x99, 0x99, 0x43, 0x95, 0x12, 0x2f, 0x46, 0x59));
+  // Outputs and inputs may only be added after the Arduino libraries have started up i.e. not in global scope
+  out = BLE.add_output<uint64_t>(UUID_128(0x2d, 0x71, 0xa2, 0x59, 0xb4, 0x58, 0xc8, 0x12, 0x99, 0x99, 0x43, 0x95, 0x12, 0x2f, 0x46, 0x59));
+
+  auto in = BLE.make_input(UUID_128(0x2a, 0x71, 0xa2, 0x59, 0xb4, 0x58, 0xc8, 0x12, 0x99, 0x99, 0x43, 0x95, 0x12, 0x2f, 0x46, 0x59), cb);
 
-  BLE::Input<int32_t> in(UUID_128(0x2a, 0x71, 0xa2, 0x59, 0xb4, 0x58, 0xc8, 0x12, 0x99, 0x99, 0x43, 0x95, 0x12, 0x2f, 0x46, 0x59), cb);
-  BLE::IInput* inputs[] = { &in };
+  // I do initialization in loop because this array must live as long as the program
+  BLETypes::IInput* inputs[] = { &in };
 
-  ble.start(UUID_128(0x2c, 0x71, 0xa2, 0x59, 0xb4, 0x58, 0xc8, 0x12, 0x99, 0x99, 0x43, 0x95, 0x12, 0x2f, 0xED, 0xFE), inputs);
+  BLE.start(UUID_128(0x2c, 0x71, 0xa2, 0x59, 0xb4, 0x58, 0xc8, 0x12, 0x99, 0x99, 0x43, 0x95, 0x12, 0x2f, 0xED, 0xFE), inputs);
 
   while(true) {
-    ble.poll();
+    BLE.poll();
   }
 }

src/FastBLE.h

@@ -5,29 +5,16 @@
 
 #define UUID_128(bytes...) (ble_uuid_any_t){ .u128 = { u: {type: BLE_UUID_TYPE_128}, value: { bytes } } }
 
-extern uint16_t output_count;
-extern uint16_t input_count;
+class BLEClass;
 
-class BLE {
-public:
+namespace BLETypes {
   template <typename T>
   class Output {
     uint16_t _n;
+    Output(uint16_t x) : _n(x) {}
+    friend BLEClass;
   public:
     Output() {}
-
-    Output(ble_uuid_any_t id) {
-      _n = output_count++;
-
-      SetupMessage msg
-        {
-        type: BLE_CREATE_OUTPUT,
-        uuid: id,
-        length: sizeof(T),
-        };
-      Serial2.write((uint8_t*)&msg, sizeof(SetupMessage));
-    };
-
     void write(T obj) {
       Serial2.write((uint8_t*)&_n, 2);
       Serial2.write((uint8_t*)&obj, sizeof(T));
@@ -37,7 +24,7 @@ class BLE {
   class IInput {
     virtual void receive();
     virtual void setup();
-    friend BLE;
+    friend BLEClass;
   };
 
   template <typename T>
@@ -60,14 +47,45 @@ class BLE {
       Serial2.readBytes((uint8_t*)&x, sizeof(T));
       _cb(x);
     }
-  public:
-    Input(ble_uuid_any_t id, void (*cb)(T)) : _cb(cb), _uuid(id) { input_count++; };
+
+    Input(ble_uuid_any_t id, void (*cb)(T)) : _cb(cb), _uuid(id) {};
+    friend BLEClass;
   };
+}
 
-  BLE();
-  void start(ble_uuid_any_t, IInput**);
+class BLEClass {
+public:
+  template <typename T>
+  BLETypes::Output<T> add_output(ble_uuid_any_t id) {
+    init_if_not_initialized();
+
+    SetupMessage msg
+      {
+      type: BLE_CREATE_OUTPUT,
+      uuid: id,
+      length: sizeof(T),
+      };
+    Serial2.write((uint8_t*)&msg, sizeof(SetupMessage));
+
+    return { _output_count++ };
+  }
+
+  template <typename T>
+  BLETypes::Input<T> make_input(ble_uuid_any_t id, void (*cb)(T)) {
+    _input_count++;
+    return { id, cb };
+  };
+
+  void start(ble_uuid_any_t, BLETypes::IInput**);
   void poll();
 
 private:
-  IInput** _inputs;
+  bool _initialized = false;
+  void init_if_not_initialized();
+
+  uint16_t _output_count = 0;
+  uint16_t _input_count = 0;
+  BLETypes::IInput** _inputs;
 };
+
+extern BLEClass BLE;

src/FastBle.cpp

@@ -1,9 +1,13 @@
 #include "FastBLE.h"
 
-uint16_t output_count = 0;
-uint16_t input_count = 0;
+BLEClass BLE;
+
+void BLEClass::init_if_not_initialized() {
+  if (_initialized) {
+    return;
+  }
+  _initialized = true;
 
-BLE::BLE() {
   // reset Nina
   pinMode(NINA_RESETN, OUTPUT);
   digitalWrite(NINA_RESETN, HIGH);
@@ -15,10 +19,12 @@ BLE::BLE() {
   while(!Serial2);
 }
 
-void BLE::start(ble_uuid_any_t svc_id, IInput** inputs) {
+void BLEClass::start(ble_uuid_any_t svc_id, BLETypes::IInput** inputs) {
+  init_if_not_initialized();
+
   _inputs = inputs;
 
-  for (uint16_t i = 0; i < input_count; i++) {
+  for (uint16_t i = 0; i < _input_count; i++) {
     inputs[i]->setup();
   }
 
@@ -30,7 +36,7 @@ void BLE::start(ble_uuid_any_t svc_id, IInput** inputs) {
   Serial2.write((uint8_t*)&msg, sizeof(SetupMessage));
 }
 
-void BLE::poll() {
+void BLEClass::poll() {
   if (Serial2.available() >= 2) {
     uint16_t input_no;
     Serial2.readBytes((uint8_t*)&input_no, 2);