Fix bare pointer in topic_tools::ShapeShifter (#1722)

The Copy constructor and assignment operator on the ShapeShifter class
were wrong because the class was using a bare pointer for its internal
buffer.  This switches to using a std::vector, so the constructors are
automatically handled correctly.

tools/topic_tools/include/topic_tools/shape_shifter.h

@@ -99,10 +99,7 @@ class TOPIC_TOOLS_DECL ShapeShifter
   std::string md5, datatype, msg_def, latching;
   bool typed;
 
-  uint8_t *msgBuf;
-  uint32_t msgBufUsed;
-  uint32_t msgBufAlloc;
-
+  std::vector<uint8_t> msgBuf;
 };
 
 }
@@ -207,37 +204,33 @@ boost::shared_ptr<M> ShapeShifter::instantiate() const
 
   boost::shared_ptr<M> p(boost::make_shared<M>());
 
-  ros::serialization::IStream s(msgBuf, msgBufUsed);
+  // The IStream never modifies its data, and nothing else has access to this
+  // object, so the const_cast here is ok
+  ros::serialization::IStream s(const_cast<unsigned char*>(msgBuf.data()),
+                                msgBuf.size());
   ros::serialization::deserialize(s, *p);
 
   return p;
 }
 
 template<typename Stream>
 void ShapeShifter::write(Stream& stream) const {
-  if (msgBufUsed > 0)
-    memcpy(stream.advance(msgBufUsed), msgBuf, msgBufUsed);
+  if (msgBuf.size() > 0)
+    memcpy(stream.advance(msgBuf.size()), msgBuf.data(), msgBuf.size());
 }
 
 template<typename Stream>
 void ShapeShifter::read(Stream& stream)
 {
   stream.getLength();
   stream.getData();
-    
+
   // stash this message in our buffer
-  if (stream.getLength() > msgBufAlloc)
-  {
-    delete[] msgBuf;
-    msgBuf = new uint8_t[stream.getLength()];
-    msgBufAlloc = stream.getLength();
-  }
-  msgBufUsed = stream.getLength();
-  memcpy(msgBuf, stream.getData(), stream.getLength());
+  msgBuf.resize(stream.getLength());
+  memcpy(msgBuf.data(), stream.getData(), stream.getLength());
 }
 
 } // namespace topic_tools
 
 
 #endif
-

tools/topic_tools/src/shape_shifter.cpp

@@ -38,24 +38,9 @@ using namespace topic_tools;
 
 bool ShapeShifter::uses_old_API_ = false;
 
-ShapeShifter::ShapeShifter()
-  :  typed(false),
-     msgBuf(NULL),
-     msgBufUsed(0),
-     msgBufAlloc(0)
-{ 
-}
-
-
-ShapeShifter::~ShapeShifter()
-{
-  if (msgBuf)
-    delete[] msgBuf;
-
-  msgBuf = NULL;
-  msgBufAlloc = 0;
-}
+ShapeShifter::ShapeShifter() : typed(false) {}
 
+ShapeShifter::~ShapeShifter() {}
 
 std::string const& ShapeShifter::getDataType()          const { return datatype; }
 
@@ -88,6 +73,5 @@ ros::Publisher ShapeShifter::advertise(ros::NodeHandle& nh, const std::string& t
 
 uint32_t ShapeShifter::size() const
 {
-  return msgBufUsed;
+  return msgBuf.size();
 }
-