illegal memory overwrite in TMemberInspector::TParentBuf::Append

TMemberInspector::TParentBuf::Append looks like this:

   // Add "add" to string

   if (!add || !add[0]) return;

   Ssiz_t addlen = strlen(add);

   fBuf.reserve(fLen + addlen);

   const char* i = add;

   while (*i) {

      fBuf[fLen++] = *i;

      ++i;

   }

   fBuf[fLen] = 0;

First of all, it's not legal to write to memory through the indexing operator of a vector if it has only been reserved, you need to do resize() for that. I presume you're trying to skip the initialization here.

Second, the resize/reserve should be 'fLen + addlen + 1' to allow that write of '\0' if fLen is 0. I understand the thinking here otherwise, namely that once a +1 is done, you don't need it anymore for any subsequent Append, as you're just overwriting the old '\0'. But if you don't do it on fLen == 0, then it never happens.