Allow setting advertising parameters multiple time

If the new value for the parameter is not valid, because too large, then
the old value will remain the actual value of the parameter.

Author: polldo

src/BLEAdvertisingData.cpp

@@ -26,6 +26,7 @@ BLEAdvertisingData::BLEAdvertisingData() :
   _rawData(NULL),
   _rawDataLength(0),
   _advertisedServiceUuid(NULL),
+  _advertisedServiceUuidLength(0),
   _manufacturerData(NULL),
   _manufacturerDataLength(0),
   _manufacturerCompanyId(0),
@@ -43,10 +44,11 @@ BLEAdvertisingData::~BLEAdvertisingData()
 {
 }
 
-inline bool BLEAdvertisingData::updateRemainingLength(int fieldLength)
+inline bool BLEAdvertisingData::updateRemainingLength(int oldFieldLength, int newFieldLength)
 {
-  if (fieldLength <= _remainingLength) {
-    _remainingLength -= fieldLength;
+  int updatedRemaining = _remainingLength + (oldFieldLength - newFieldLength);
+  if (updatedRemaining >= 0) {
+    _remainingLength = updatedRemaining;
     return true;
   }
   return false;
@@ -75,6 +77,7 @@ void BLEAdvertisingData::clear()
   _manufacturerDataLength = 0;
   _hasManufacturerCompanyId = false;
   _advertisedServiceUuid = NULL;
+  _advertisedServiceUuidLength = 0;
   _serviceData = NULL;
   _serviceDataLength = 0;
 }
@@ -92,6 +95,7 @@ void BLEAdvertisingData::copy(const BLEAdvertisingData& adv)
   _manufacturerCompanyId = adv._manufacturerCompanyId;
   _hasManufacturerCompanyId = adv._hasManufacturerCompanyId;
   _advertisedServiceUuid = adv._advertisedServiceUuid;
+  _advertisedServiceUuidLength = adv._advertisedServiceUuidLength;
   _serviceDataUuid = adv._serviceDataUuid;
   _serviceData = adv._serviceData;
   _serviceDataLength = adv._serviceDataLength;
@@ -106,9 +110,11 @@ BLEAdvertisingData& BLEAdvertisingData::operator=(const BLEAdvertisingData &othe
 bool BLEAdvertisingData::setAdvertisedServiceUuid(const char* advertisedServiceUuid)
 {
   BLEUuid uuid(advertisedServiceUuid);
-  bool success = updateRemainingLength(uuid.length() + AD_FIELD_OVERHEAD);
+  int previousLength = (_advertisedServiceUuidLength > 0) ? (_advertisedServiceUuidLength + AD_FIELD_OVERHEAD) : 0;
+  bool success = updateRemainingLength(previousLength, (uuid.length() + AD_FIELD_OVERHEAD));
   if (success) {
     _advertisedServiceUuid = advertisedServiceUuid;
+    _advertisedServiceUuidLength = uuid.length();
   }
   return success;
 }
@@ -120,7 +126,14 @@ bool BLEAdvertisingData::setAdvertisedService(const BLEService& service)
 
 bool BLEAdvertisingData::setManufacturerData(const uint8_t manufacturerData[], int manufacturerDataLength)
 {
-  bool success = updateRemainingLength(manufacturerDataLength + AD_FIELD_OVERHEAD);
+  int previousLength = 0;
+  if (_manufacturerDataLength) {
+    previousLength = _manufacturerDataLength + AD_FIELD_OVERHEAD;
+    if (_hasManufacturerCompanyId) {
+      previousLength += sizeof(_manufacturerCompanyId);
+    }
+  }
+  bool success = updateRemainingLength(previousLength, (manufacturerDataLength + AD_FIELD_OVERHEAD));
   if (success) {
     _manufacturerData = manufacturerData;
     _manufacturerDataLength = manufacturerDataLength;
@@ -131,7 +144,14 @@ bool BLEAdvertisingData::setManufacturerData(const uint8_t manufacturerData[], i
 
 bool BLEAdvertisingData::setManufacturerData(const uint16_t companyId, const uint8_t manufacturerData[], int manufacturerDataLength)
 {
-  bool success = updateRemainingLength(manufacturerDataLength + sizeof(companyId) + AD_FIELD_OVERHEAD);
+  int previousLength = 0;
+  if (_manufacturerDataLength) {
+    previousLength = _manufacturerDataLength + AD_FIELD_OVERHEAD;
+    if (_hasManufacturerCompanyId) {
+      previousLength += sizeof(_manufacturerCompanyId);
+    }
+  }
+  bool success = updateRemainingLength(previousLength, (manufacturerDataLength + sizeof(companyId) + AD_FIELD_OVERHEAD));
   if (success) {
     _manufacturerData = manufacturerData;
     _manufacturerDataLength = manufacturerDataLength;
@@ -143,7 +163,8 @@ bool BLEAdvertisingData::setManufacturerData(const uint16_t companyId, const uin
 
 bool BLEAdvertisingData::setAdvertisedServiceData(uint16_t uuid, const uint8_t data[], int length)
 {
-  bool success = updateRemainingLength(length + sizeof(uuid) + AD_FIELD_OVERHEAD);
+  int previousLength = (_serviceDataLength > 0) ? (_serviceDataLength + sizeof(uuid) + AD_FIELD_OVERHEAD) : 0;
+  bool success = updateRemainingLength(previousLength, (length + sizeof(uuid) + AD_FIELD_OVERHEAD));
   if (success) {
     _serviceDataUuid = uuid;
     _serviceData = data;
@@ -154,7 +175,8 @@ bool BLEAdvertisingData::setAdvertisedServiceData(uint16_t uuid, const uint8_t d
 
 bool BLEAdvertisingData::setLocalName(const char *localName)
 {
-  bool success = updateRemainingLength(strlen(localName) + AD_FIELD_OVERHEAD);
+  int previousLength = (_localName && strlen(_localName) > 0) ? (strlen(_localName) + AD_FIELD_OVERHEAD) : 0;
+  bool success = updateRemainingLength(previousLength, (strlen(localName) + AD_FIELD_OVERHEAD));
   if (success) {
     _localName = localName;
   }
@@ -183,7 +205,8 @@ bool BLEAdvertisingData::setRawData(const BLEAdvertisingRawData& rawData)
 
 bool BLEAdvertisingData::setFlags(uint8_t flags)
 {
-  bool success = updateRemainingLength(sizeof(flags) + AD_FIELD_OVERHEAD);
+  int previousLength = (_hasFlags) ? (sizeof(_flags) + AD_FIELD_OVERHEAD) : 0;
+  bool success = updateRemainingLength(previousLength, (sizeof(flags) + AD_FIELD_OVERHEAD));
   if (success) {
     _hasFlags = true;
     _flags = flags;

src/BLEAdvertisingData.h

@@ -80,7 +80,7 @@ class BLEAdvertisingData {
   bool hasFlags() const;
 
 private:
-  bool updateRemainingLength(int fieldLength);
+  bool updateRemainingLength(int oldFieldLength, int newFieldLength);
 
   bool addAdvertisedServiceUuid(const char* advertisedServiceUuid);
   bool addManufacturerData(const uint8_t manufacturerData[], int manufacturerDataLength);
@@ -111,6 +111,7 @@ class BLEAdvertisingData {
   bool _hasManufacturerCompanyId;
 
   const char* _advertisedServiceUuid; 
+  int _advertisedServiceUuidLength;
   uint16_t _serviceDataUuid;
   const uint8_t* _serviceData;
   int _serviceDataLength;