From ed48905c5e44ef35402daa98a6a8661a46e53a93 Mon Sep 17 00:00:00 2001
From: John Maddock <john@johnmaddock.co.uk>
Date: Wed, 11 Jun 2003 12:11:17 +0000
Subject: [PATCH] Added check for invalid regular expression in matching code.

[SVN r18777]
---
 include/boost/regex/v4/perl_matcher_common.hpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/boost/regex/v4/perl_matcher_common.hpp b/include/boost/regex/v4/perl_matcher_common.hpp
index d339f907..c3ce7d7b 100644
--- a/include/boost/regex/v4/perl_matcher_common.hpp
+++ b/include/boost/regex/v4/perl_matcher_common.hpp
@@ -41,7 +41,13 @@ perl_matcher<BidiIterator, Allocator, traits, Allocator2>::perl_matcher(BidiIter
       next_count(&rep_obj), rep_obj(&next_count)
 { 
    typedef typename regex_iterator_traits<BidiIterator>::iterator_category category;
-
+   
+   if(e.empty())
+   {
+      // precondition failure: e is not a valid regex.
+      std::invalid_argument ex("Invalid regular expression object");
+      boost::throw_exception(ex);
+   }
    pstate = 0;
    m_match_flags = f;
    icase = re.flags() & regex_constants::icase;