Added methods + example to retrive local MAC for BT

libraries/BluetoothSerial/examples/GetLocalMAC/GetLocalMAC.ino

@@ -0,0 +1,46 @@
+// This example demonstrates usage of BluetoothSerial method to retrieve MAC address of local BT device in various formats.
+// By Tomas Pilny - 2023
+
+#include "BluetoothSerial.h"
+
+String device_name = "ESP32-example";
+
+#if !defined(CONFIG_BT_ENABLED) || !defined(CONFIG_BLUEDROID_ENABLED)
+#error Bluetooth is not enabled! Please run `make menuconfig` to and enable it
+#endif
+
+#if !defined(CONFIG_BT_SPP_ENABLED)
+#error Serial Bluetooth not available or not enabled. It is only available for the ESP32 chip.
+#endif
+
+BluetoothSerial SerialBT;
+
+void setup() {
+  Serial.begin(115200);
+  SerialBT.begin(device_name); //Bluetooth device name
+
+  uint8_t mac_arr[6]; // Byte array to hold the MAC address from getBtAddress()
+  BTAddress mac_obj; // Object holding instance of BTAddress with the MAC (for more details see libraries/BluetoothSerial/src/BTAddress.h)
+  std::string mac_str; // String holding the text version of MAC in format AA:BB:CC:DD:EE:FF
+
+  SerialBT.getBtAddress(mac_arr); // Fill in the array
+  mac_obj = SerialBT.getBtAddressObject(); // Instantiate the object
+  mac_str = SerialBT.getBtAddressString(); // Copy the string
+
+  Serial.print("This device is instantiated with name "); Serial.println(device_name);
+
+  Serial.print("The mac address using byte array: ");
+  for(int i = 0; i < ESP_BD_ADDR_LEN-1; i++){
+    Serial.print(mac_arr[i], HEX); Serial.print(":");
+  }
+  Serial.println(mac_arr[ESP_BD_ADDR_LEN-1], HEX);
+
+  Serial.print("The mac address using BTAddress object using default method `toString()`: "); Serial.println(mac_obj.toString().c_str());
+  Serial.print("The mac address using BTAddress object using method `toString(true)`\n\twhich prints the MAC with capital letters: "); Serial.println(mac_obj.toString(true).c_str()); // This actually what is used inside the getBtAddressString()
+
+  Serial.print("The mac address using string: "); Serial.println(mac_str.c_str());
+}
+
+void loop(){
+
+}

libraries/BluetoothSerial/src/BTAddress.cpp

@@ -86,19 +86,25 @@ esp_bd_addr_t *BTAddress::getNative() const {
 
 /**
  * @brief Convert a BT address to a string.
- *
- * A string representation of an address is in the format:
- *
+ * @param [in] capital changes the letter size
+ * By default the parameter `capital` == false and the string representation of an address is in the format:
  * ```
  * xx:xx:xx:xx:xx:xx
  * ```
- *
+ * When the parameter `caputal` == true the format uses capital letters:
+ * ```
+ * XX:XX:XX:XX:XX:XX
+ * ```
  * @return The string representation of the address.
  */
-std::string BTAddress::toString() const {
+std::string BTAddress::toString(bool capital) const {
 	auto size = 18;
 	char *res = (char*)malloc(size);
-	snprintf(res, size, "%02x:%02x:%02x:%02x:%02x:%02x", m_address[0], m_address[1], m_address[2], m_address[3], m_address[4], m_address[5]);
+  if(capital){
+    snprintf(res, size, "%02X:%02X:%02X:%02X:%02X:%02X", m_address[0], m_address[1], m_address[2], m_address[3], m_address[4], m_address[5]);
+  }else{
+    snprintf(res, size, "%02x:%02x:%02x:%02x:%02x:%02x", m_address[0], m_address[1], m_address[2], m_address[3], m_address[4], m_address[5]);
+  }
 	std::string ret(res);
 	free(res);
 	return ret;

libraries/BluetoothSerial/src/BTAddress.h

@@ -29,7 +29,7 @@ class BTAddress {
 	operator bool () const;
 
 	esp_bd_addr_t* getNative() const;
-	std::string    toString() const;
+	std::string    toString(bool capital = false) const;
 
 private:
 	esp_bd_addr_t m_address;

libraries/BluetoothSerial/src/BluetoothSerial.cpp

@@ -661,8 +661,6 @@ static bool _init_bt(const char *deviceName)
         }
     }
 
-    // Why only master need this?  Slave need this during pairing as well
-//    if (_isMaster && esp_bt_gap_register_callback(esp_bt_gap_cb) != ESP_OK) {
     if (esp_bt_gap_register_callback(esp_bt_gap_cb) != ESP_OK) {
         log_e("gap register failed");
         return false;
@@ -1183,4 +1181,18 @@ std::map<int, std::string> BluetoothSerial::getChannels(const BTAddress &remoteA
     return sdpRecords;
 }
 
+void BluetoothSerial::getBtAddress(uint8_t *mac){
+   const uint8_t *dev_mac = esp_bt_dev_get_address();
+   memcpy(mac, dev_mac, ESP_BD_ADDR_LEN);
+}
+
+BTAddress BluetoothSerial::getBtAddressObject(){
+  uint8_t mac_arr[ESP_BD_ADDR_LEN];
+  getBtAddress(mac_arr);
+  return BTAddress(mac_arr);
+}
+
+std::string BluetoothSerial::getBtAddressString(){
+  return getBtAddressObject().toString(true);
+}
 #endif

libraries/BluetoothSerial/src/BluetoothSerial.h

@@ -85,6 +85,9 @@ class BluetoothSerial: public Stream
         const int MAX_INQ_TIME = (ESP_BT_GAP_MAX_INQ_LEN * INQ_TIME);
 
         operator bool() const;
+        void getBtAddress(uint8_t *mac);
+        BTAddress getBtAddressObject();
+        std::string getBtAddressString();
     private:
         String local_name;
         int timeoutTicks=0;