Allow for passing a custom pointer to callback function (defaults to sending "this", same as previously)

Clear receiveBufferIndex before calling callback function so that the callback function can call update() if needed and receive more data

Author: Louis Beaudoin

src/PacketSerial.h

@@ -54,7 +54,8 @@ class PacketSerial_
         _receiveBufferIndex(0),
         _stream(nullptr),
         _onPacketFunction(nullptr),
-        _onPacketFunctionWithSender(nullptr)
+        _onPacketFunctionWithSender(nullptr),
+        _senderPtr(nullptr)
     {
     }
 
@@ -224,18 +225,23 @@ class PacketSerial_
                                                             _receiveBufferIndex,
                                                             _decodeBuffer);
 
+                    // clear the index here so that the callback function can call update() if needed and receive more data
+                    _receiveBufferIndex = 0;
+                    _recieveBufferOverflow = false;
+
                     if (_onPacketFunction)
                     {
                         _onPacketFunction(_decodeBuffer, numDecoded);
                     }
                     else if (_onPacketFunctionWithSender)
                     {
-                        _onPacketFunctionWithSender(this, _decodeBuffer, numDecoded);
+                        _onPacketFunctionWithSender(_senderPtr, _decodeBuffer, numDecoded);
                     }
-                }
 
-                _receiveBufferIndex = 0;
-                _recieveBufferOverflow = false;
+                } else {
+                    _receiveBufferIndex = 0;
+                    _recieveBufferOverflow = false;
+                }
             }
             else
             {
@@ -302,6 +308,7 @@ class PacketSerial_
     {
         _onPacketFunction = onPacketFunction;
         _onPacketFunctionWithSender = nullptr;
+        _senderPtr = nullptr;
     }
 
     /// \brief Set the function that will receive decoded packets.
@@ -336,10 +343,12 @@ class PacketSerial_
     /// Setting a packet handler will remove all other packet handlers.
     ///
     /// \param onPacketFunctionWithSender A pointer to the packet handler function.
-    void setPacketHandler(PacketHandlerFunctionWithSender onPacketFunctionWithSender)
+    void setPacketHandler(PacketHandlerFunctionWithSender onPacketFunctionWithSender, void * senderPtr = NULL)
     {
         _onPacketFunction = nullptr;
         _onPacketFunctionWithSender = onPacketFunctionWithSender;
+        _senderPtr = senderPtr;
+        if(!senderPtr) _senderPtr = this;
     }
 
     /// \brief Check to see if the receive buffer overflowed.
@@ -384,6 +393,7 @@ class PacketSerial_
 
     PacketHandlerFunction _onPacketFunction = nullptr;
     PacketHandlerFunctionWithSender _onPacketFunctionWithSender = nullptr;
+    void* _senderPtr = nullptr;
 };