Overload writeValue to allow forced write without response

When a characteristic is declared (Write | WriteWithoutResponse) the code always creates a request
and expects a response.
By setting withResponse=false the user can bypass the request and write a responseless command.

Reworks and supersedes #72

Author: facchinm

src/BLECharacteristic.cpp

@@ -234,22 +234,22 @@ int BLECharacteristic::readValue(int32_t& value)
   return readValue((uint8_t*)&value, sizeof(value));
 }
 
-int BLECharacteristic::writeValue(const uint8_t value[], int length)
+int BLECharacteristic::writeValue(const uint8_t value[], int length, bool withResponse)
 {
   if (_local) {
     return _local->writeValue(value, length);
   }
 
   if (_remote) {
-    return _remote->writeValue(value, length);
+    return _remote->writeValue(value, length, withResponse);
   }
 
   return 0;
 }
 
-int BLECharacteristic::writeValue(const void* value, int length)
+int BLECharacteristic::writeValue(const void* value, int length, bool withResponse)
 {
-  return writeValue((const uint8_t*)value, length);
+  return writeValue((const uint8_t*)value, length, withResponse);
 }
 
 int BLECharacteristic::writeValue(const char* value)

src/BLECharacteristic.h

@@ -68,8 +68,8 @@ class BLECharacteristic  {
   int readValue(uint32_t& value);
   int readValue(int32_t& value);
 
-  int writeValue(const uint8_t value[], int length);
-  int writeValue(const void* value, int length);
+  int writeValue(const uint8_t value[], int length, bool withResponse = true);
+  int writeValue(const void* value, int length, bool withResponse = true);
   int writeValue(const char* value);
   int writeValue(uint8_t value);
   int writeValue(int8_t value);

src/remote/BLERemoteCharacteristic.cpp

@@ -85,7 +85,7 @@ uint8_t BLERemoteCharacteristic::operator[] (int offset) const
   return 0;
 }
 
-int BLERemoteCharacteristic::writeValue(const uint8_t value[], int length)
+int BLERemoteCharacteristic::writeValue(const uint8_t value[], int length, bool withResponse)
 {
   if (!ATT.connected(_connectionHandle)) {
     return false;
@@ -104,7 +104,7 @@ int BLERemoteCharacteristic::writeValue(const uint8_t value[], int length)
     return 0;
   }
 
-  if (_properties & BLEWrite) {
+  if ((_properties & BLEWrite) && withResponse) {
     uint8_t resp[4];
     int respLength = ATT.writeReq(_connectionHandle, _valueHandle, value, length, resp);
 

src/remote/BLERemoteCharacteristic.h

@@ -38,7 +38,7 @@ class BLERemoteCharacteristic : public BLERemoteAttribute {
   int valueLength() const;
   uint8_t operator[] (int offset) const;
 
-  int writeValue(const uint8_t value[], int length);
+  int writeValue(const uint8_t value[], int length, bool withResponse = true);
   int writeValue(const char* value);
 
   bool valueUpdated();