Breaking: Use std::vector instead of std::map in client classes (#46)

* Exchange map for vector, saving 1,076 bytes of program memory and 5,024 bytes of heap for a small device (LYWSD03MMC)

* Removing m_characteristicMapByHandle (using the handles form m_characteristicVector instead) saving in total (compared to the current master) 1,508 bytes of program memory and 6,500 bytes of heap for a small device (LYWSD03MMC)

* Change NimBLEScan container from std::map to std::vector

* Add function to get advertised device by address

* Update documentation

src/NimBLERemoteCharacteristic.cpp

@@ -157,10 +157,9 @@ int NimBLERemoteCharacteristic::descriptorDiscCB(uint16_t conn_handle,
 
     switch (error->status) {
         case 0: {
-            // Found a descriptor - add it to the map
+            // Found a descriptor - add it to the vector
             NimBLERemoteDescriptor* pNewRemoteDescriptor = new NimBLERemoteDescriptor(characteristic, dsc);
-            characteristic->m_descriptorMap.insert(std::pair<std::string, NimBLERemoteDescriptor*>(pNewRemoteDescriptor->getUUID().toString(), pNewRemoteDescriptor));
-
+            characteristic->m_descriptorVector.push_back(pNewRemoteDescriptor);
             break;
         }
         case BLE_HS_EDONE:{
@@ -212,15 +211,15 @@ bool NimBLERemoteCharacteristic::retrieveDescriptors(uint16_t endHdl) {
     }
 
     return true;
-    NIMBLE_LOGD(LOG_TAG, "<< retrieveDescriptors(): Found %d descriptors.", m_descriptorMap.size());
+    NIMBLE_LOGD(LOG_TAG, "<< retrieveDescriptors(): Found %d descriptors.", m_descriptorVector.size());
 } // getDescriptors
 
 
 /**
- * @brief Retrieve the map of descriptors keyed by UUID.
- */
-std::map<std::string, NimBLERemoteDescriptor*>* NimBLERemoteCharacteristic::getDescriptors() {
-    return &m_descriptorMap;
+ * @brief Retrieve the vector of descriptors.
+ */ 
+std::vector<NimBLERemoteDescriptor*>* NimBLERemoteCharacteristic::getDescriptors() {
+    return &m_descriptorVector;
 } // getDescriptors
 
 
@@ -248,12 +247,12 @@ uint16_t NimBLERemoteCharacteristic::getDefHandle() {
  */
 NimBLERemoteDescriptor* NimBLERemoteCharacteristic::getDescriptor(const NimBLEUUID &uuid) {
     NIMBLE_LOGD(LOG_TAG, ">> getDescriptor: uuid: %s", uuid.toString().c_str());
-    std::string v = uuid.toString();
-    for (auto &myPair : m_descriptorMap) {
-        if (myPair.first == v) {
-            NIMBLE_LOGD(LOG_TAG, "<< getDescriptor: found");
-            return myPair.second;
-        }
+
+    for(auto &it: m_descriptorVector) {
+          if(it->getUUID() == uuid) {
+              NIMBLE_LOGD(LOG_TAG, "<< getDescriptor: found");
+              return it;
+          }
     }
     NIMBLE_LOGD(LOG_TAG, "<< getDescriptor: Not found");
     return nullptr;
@@ -444,19 +443,18 @@ bool NimBLERemoteCharacteristic::registerForNotify(notify_callback notifyCallbac
 
 
 /**
- * @brief Delete the descriptors in the descriptor map.
- * We maintain a map called m_descriptorMap that contains pointers to BLERemoteDescriptors
- * object references.  Since we allocated these in this class, we are also responsible for deleteing
- * them.  This method does just that.
+ * @brief Delete the descriptors in the descriptor vector.
+ * We maintain a vector called m_descriptorVector that contains pointers to BLERemoteDescriptors
+ * object references. Since we allocated these in this class, we are also responsible for deleteing
+ * them. This method does just that.
  * @return N/A.
  */
 void NimBLERemoteCharacteristic::removeDescriptors() {
-    // Iterate through all the descriptors releasing their storage and erasing them from the map.
-    for (auto &myPair : m_descriptorMap) {
-       m_descriptorMap.erase(myPair.first);
-       delete myPair.second;
+    // Iterate through all the descriptors releasing their storage and erasing them from the vector.
+    for(auto &it: m_descriptorVector) {
+        delete it;
     }
-    m_descriptorMap.clear();   // Technically not neeeded, but just to be sure.
+    m_descriptorVector.clear();
 } // removeCharacteristics
 
 
@@ -478,8 +476,8 @@ std::string NimBLERemoteCharacteristic::toString() {
     snprintf(val, sizeof(val), "%02x", m_charProp);
     res += val;
 
-    for (auto &myPair : m_descriptorMap) {
-        res += "\n" + myPair.second->toString();
+    for(auto &it: m_descriptorVector) {
+        res += "\n" + it->toString();
     }
 
     return res;
@@ -645,8 +643,8 @@ size_t NimBLERemoteCharacteristic::getDataLength() {
 
 
 void NimBLERemoteCharacteristic::releaseSemaphores() {
-    for (auto &dPair : m_descriptorMap) {
-        dPair.second->releaseSemaphores();
+    for (auto &it: m_descriptorVector) {
+        it->releaseSemaphores();
     }
     m_semaphoreWriteCharEvt.give(1);
     m_semaphoreGetDescEvt.give(1);