From 330a033177bbb14396794fa829f5ca98fe912b46 Mon Sep 17 00:00:00 2001
From: jzmaddock <john@johnmaddock.co.uk>
Date: Wed, 22 Jan 2014 13:46:38 +0000
Subject: [PATCH] Tentative fix for case where a transformation of a NULL
 string is requested.

---
 include/boost/regex/v4/cpp_regex_traits.hpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/boost/regex/v4/cpp_regex_traits.hpp b/include/boost/regex/v4/cpp_regex_traits.hpp
index b81d8c84..72ea2b21 100644
--- a/include/boost/regex/v4/cpp_regex_traits.hpp
+++ b/include/boost/regex/v4/cpp_regex_traits.hpp
@@ -508,6 +508,10 @@ typename cpp_regex_traits_implementation<charT>::string_type
    // we adhere to gcc's (buggy) preconditions...
    //
    BOOST_ASSERT(*p2 == 0);
+   if(p1 == p2)
+   {
+      return string_type(p1, p2);
+   }
 
    string_type result;
    //
@@ -584,6 +588,11 @@ typename cpp_regex_traits_implementation<charT>::string_type
    // std::bad_alloc for certain arguments...
    //
    string_type result, result2;
+   if(p1 == p2)
+   {
+      result.assign(p1, p2);
+      return result;
+   }
 #ifndef BOOST_NO_EXCEPTIONS
    try{
 #endif