Improve BLE interface

Use uint64_t as interface between NimBLE client and SensiScan
as we only convert it into a invalid string and back into an
uint64_t.

Add constructor and destructure to NimBLE client to better
represent the life-cycle of this class.

Remove squash method from SensiScan as it is not required anymore.

src/BleClientCallback.h

@@ -5,7 +5,7 @@ class BleClientCallback {
   public:
     virtual ~BleClientCallback() = default;
 
-    virtual void onAdvertisementReceived(std::string address, std::string name,
+    virtual void onAdvertisementReceived(uint64_t address, std::string name,
                                          std::string data) = 0;
 };
 

src/NimBleClient.cpp

@@ -1,8 +1,23 @@
 #include "NimBleClient.h"
 
+NimBleClient::NimBleClient() : _callback(nullptr) {
+    // CONFIG_BTDM_SCAN_DUPL_TYPE_DATA_DEVICE (2)
+    // Filter by address and data, advertisements from the same address will be
+    // reported only once, except if the data in the advertisement has changed,
+    // then it will be reported again.
+    NimBLEDevice::setScanFilterMode(CONFIG_BTDM_SCAN_DUPL_TYPE_DATA_DEVICE);
+    NimBLEDevice::setScanDuplicateCacheSize(200);
+    NimBLEDevice::init("");
+    _bleScan = NimBLEDevice::getScan();
+    setupBleScans();
+}
+
+NimBleClient::~NimBleClient() {
+    _bleScan->stop();
+}
+
 void NimBleClient::begin(BleClientCallback* callback) {
     _callback = callback;
-    setupBleScans();
     startBleScans();
 }
 
@@ -15,18 +30,18 @@ void NimBleClient::keepAlive() {
     }
 }
 
-
 void NimBleClient::onResult(NimBLEAdvertisedDevice* advertisedDevice) {
     if (!advertisedDevice->haveManufacturerData()) {
         return;
     }
 
     // MAC address contains 6 bytes of MAC address (in reversed order)
-    // (Note: advertisedDevice->getAddress().toString() seems broken)
     const uint8_t* bleMACAddress = advertisedDevice->getAddress().getNative();
-    std::string address;
-    for (int i = 5; i >= 0; i--) {
-        address.push_back(static_cast<char>(bleMACAddress[i]));
+    uint64_t address = 0;
+    size_t address_size = 6;
+    // reverse MAC address and store it as 64-bit unsigned int
+    for (int ix = 0; ix < address_size; ix++) {
+        address = (address << 8) | bleMACAddress[address_size - 1 - ix];
     }
 
     std::string name = advertisedDevice->haveName()
@@ -38,16 +53,6 @@ void NimBleClient::onResult(NimBLEAdvertisedDevice* advertisedDevice) {
 }
 
 void NimBleClient::setupBleScans() {
-    // CONFIG_BTDM_SCAN_DUPL_TYPE_DATA_DEVICE (2)
-    // Filter by address and data, advertisements from the same address will be
-    // reported only once, except if the data in the advertisement has changed,
-    // then it will be reported again.
-    NimBLEDevice::setScanFilterMode(CONFIG_BTDM_SCAN_DUPL_TYPE_DATA_DEVICE);
-    NimBLEDevice::setScanDuplicateCacheSize(200);
-    NimBLEDevice::init("");
-
-    // create new scan
-    _bleScan = NimBLEDevice::getScan();
     // Activate callback on advertisement update
     _bleScan->setAdvertisedDeviceCallbacks(this, true);
     // Set active scanning, this will get more data from the advertiser.

src/NimBleClient.h

@@ -8,7 +8,8 @@ class __attribute__((unused)) NimBleClient
     : public BleClient,
       public NimBLEAdvertisedDeviceCallbacks {
   public:
-    NimBleClient() : _bleScan(nullptr), _callback(nullptr) {};
+    NimBleClient();
+    ~NimBleClient();
     void begin(BleClientCallback* callback) override;
     void keepAlive() override;
 

src/Sensirion_upt_ble_auto_detection.cpp

@@ -1,4 +1,5 @@
 #include "Sensirion_upt_ble_auto_detection.h"
+#include "Arduino.h"
 #include "NimBleClient.h"
 
 const int COMPANY_ID_FILTER = 54534;
@@ -20,19 +21,16 @@ __attribute__((unused)) void SensiScan::keepAlive() {
     _bleClient->keepAlive();
 }
 
-void SensiScan::onAdvertisementReceived(const std::string address,
-                                        std::string name, std::string data) {
+void SensiScan::onAdvertisementReceived(uint64_t address, std::string name,
+                                        std::string data) {
     uint16_t companyId = (uint16_t)data[0] << 8 | (uint8_t)data[1];
     if (companyId != COMPANY_ID_FILTER) {
         return;
     }
 
-    // Get MAC address as uint64_t
-    uint64_t deviceID = squashMACAddress(address);
-
     // Build MetaData
     MetaData metaData;
-    metaData.deviceID = deviceID;
+    metaData.deviceID = address;
     metaData.deviceType.bleGadgetType =
         bleGadgetTypeFromCompleteLocalName(name.c_str());
     metaData.platform = DevicePlatform::BLE;
@@ -48,20 +46,6 @@ void SensiScan::onAdvertisementReceived(const std::string address,
     _sampleCache[getDeviceId(data)] = samples;
 }
 
-/**
- * @brief squash std::string address to a uint64_t
- * @note MAC address is comprised of 6 bytes
- */
-uint64_t SensiScan::squashMACAddress(const std::string& macAddressString) {
-
-    uint64_t deviceID = static_cast<unsigned char>(macAddressString[0]);
-    for (size_t i = 1; i < 6; i++) {
-        deviceID = (deviceID << 8) | macAddressString[i];
-    }
-
-    return deviceID;
-}
-
 /**
  * @brief last two digits of MAC address uniquely define a device
  */

src/Sensirion_upt_ble_auto_detection.h

@@ -20,9 +20,8 @@ class __attribute__((unused)) SensiScan: public BleClientCallback {
   private:
     BleClient* _bleClient;
     std::map<uint16_t, std::vector<Measurement>> _sampleCache;
-    void onAdvertisementReceived(std::string address, std::string name,
+    void onAdvertisementReceived(uint64_t address, std::string name,
                                  std::string data) override;
-    static uint64_t squashMACAddress(const std::string& macAddressString);
     static uint16_t getDeviceId(const std::string& data);
     static uint8_t decodeData(const MetaData& metaData, const std::string& data,
                               std::vector<Measurement>& samples);