Cast and smart pointer improvements. (#1893)

* cpp casts

* Changed layerOldData to use unique_ptr

Author: Dimi1010

Packet++/src/Packet.cpp

@@ -15,6 +15,7 @@
 #include "Logger.h"
 #include <numeric>
 #include <sstream>
+#include <memory>
 #ifdef _MSC_VER
 #	include <time.h>
 #	include "SystemUtils.h"
@@ -294,7 +295,7 @@ namespace pcpp
 
 		// first, get ptr and data length of the raw packet
 		const uint8_t* dataPtr = m_RawPacket->getRawData();
-		size_t dataLen = (size_t)m_RawPacket->getRawDataLen();
+		size_t dataLen = static_cast<size_t>(m_RawPacket->getRawDataLen());
 
 		// if a packet trailer exists, get its length
 		size_t packetTrailerLen = 0;
@@ -306,7 +307,7 @@ namespace pcpp
 		while (curLayer != nullptr)
 		{
 			// set data ptr to layer
-			curLayer->m_Data = (uint8_t*)dataPtr;
+			curLayer->m_Data = const_cast<uint8_t*>(dataPtr);
 
 			// there is an assumption here that the packet trailer, if exists, corresponds to the L2 (data link) layers.
 			// so if there is a packet trailer and this layer is L2 (data link), set its data length to contain the
@@ -427,16 +428,15 @@ namespace pcpp
 		// before removing the layer's data, copy it so it can be later assigned as the removed layer's data
 		size_t headerLen = layer->getHeaderLen();
 		size_t layerOldDataSize = headerLen;
-		uint8_t* layerOldData = new uint8_t[layerOldDataSize];
-		memcpy(layerOldData, layer->m_Data, layerOldDataSize);
+		auto layerOldData = std::make_unique<uint8_t[]>(layerOldDataSize);
+		memcpy(layerOldData.get(), layer->m_Data, layerOldDataSize);
 
 		// remove data from raw packet
 		size_t numOfBytesToRemove = headerLen;
 		int indexOfDataToRemove = layer->m_Data - m_RawPacket->getRawData();
 		if (!m_RawPacket->removeData(indexOfDataToRemove, numOfBytesToRemove))
 		{
 			PCPP_LOG_ERROR("Couldn't remove data from packet");
-			delete[] layerOldData;
 			return false;
 		}
 
@@ -463,15 +463,15 @@ namespace pcpp
 
 		// first, get ptr and data length of the raw packet
 		const uint8_t* dataPtr = m_RawPacket->getRawData();
-		size_t dataLen = (size_t)m_RawPacket->getRawDataLen();
+		size_t dataLen = static_cast<size_t>(m_RawPacket->getRawDataLen());
 
 		curLayer = m_FirstLayer;
 
 		// go over all layers from the first layer to the last layer and set the data ptr and data length for each one
 		while (curLayer != nullptr)
 		{
 			// set data ptr to layer
-			curLayer->m_Data = (uint8_t*)dataPtr;
+			curLayer->m_Data = const_cast<uint8_t*>(dataPtr);
 
 			// there is an assumption here that the packet trailer, if exists, corresponds to the L2 (data link) layers.
 			// so if there is a packet trailer and this layer is L2 (data link), set its data length to contain the
@@ -494,14 +494,13 @@ namespace pcpp
 		if (tryToDelete && layer->m_IsAllocatedInPacket)
 		{
 			delete layer;
-			delete[] layerOldData;
 		}
 		// if layer was not allocated by this packet or the tryToDelete is not set, detach it from the packet so it can
 		// be reused
 		else
 		{
 			layer->m_Packet = nullptr;
-			layer->m_Data = layerOldData;
+			layer->m_Data = layerOldData.release();
 			layer->m_DataLen = layerOldDataSize;
 		}