Add iterator safety check in DoxygenParser::parse

If the code called by DoxygenParser::parse does not behave correctly,
it may move the iterator m_tokenListIt past the value endParsingIndex.
This was not caught by the previous checks and could lead to
dereferencing an invalid m_tokenListIt iterator value (and segfault).
This is now protected against by using a less than check in the while
loop instead of not equals.  A warning is also printed if
endParsingIndex is exceeded.

Source/Doxygen/doxyparser.cxx

@@ -971,7 +971,9 @@ DoxygenEntityList DoxygenParser::parse(TokenListCIt endParsingIndex, const Token
   std::string currPlainstringCommandType = root ? "partofdescription" : "plainstd::string";
   DoxygenEntityList aNewList;
 
-  while (m_tokenListIt != endParsingIndex) {
+  // Less than check (instead of not equal) is a safeguard in case the
+  // iterator is incremented past the end
+  while (m_tokenListIt < endParsingIndex) {
 
     Token currToken = *m_tokenListIt;
 
@@ -988,6 +990,10 @@ DoxygenEntityList DoxygenParser::parse(TokenListCIt endParsingIndex, const Token
       addCommand(currPlainstringCommandType, tokList, aNewList);
     }
 
+    // If addCommand above misbehaves, it can move the iterator past endParsingIndex
+    if (m_tokenListIt > endParsingIndex)
+      printListError(WARN_DOXYGEN_UNEXPECTED_ITERATOR_VALUE, "Unexpected iterator value in DoxygenParser::parse");
+
     if (endParsingIndex != tokList.end() && m_tokenListIt == tokList.end()) {
       // this could happen if we can't reach the original endParsingIndex
       printListError(WARN_DOXYGEN_UNEXPECTED_END_OF_COMMENT, "Unexpected end of Doxygen comment encountered.");

Source/Include/swigwarn.h

@@ -221,6 +221,7 @@
 #define WARN_DOXYGEN_HTML_ERROR               563
 #define WARN_DOXYGEN_COMMAND_ERROR            564
 #define WARN_DOXYGEN_UNKNOWN_CHARACTER        565
+#define WARN_DOXYGEN_UNEXPECTED_ITERATOR_VALUE  566
 
 /* -- Reserved (600-799) -- */