From 3ff95f3b0b1eed95aa6e4d6baa59c68a047072ea Mon Sep 17 00:00:00 2001
From: Stephen Kelly <steveire@gmail.com>
Date: Thu, 5 Mar 2015 23:14:27 +0100
Subject: [PATCH] cmAlgorithms: Add early return in cmRemoveIndices.

Avoid derefencing the iterator and segfaulting if the range
is empty.
---
 Source/cmAlgorithms.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Source/cmAlgorithms.h b/Source/cmAlgorithms.h
index b9d7e7889..be57da3dc 100644
--- a/Source/cmAlgorithms.h
+++ b/Source/cmAlgorithms.h
@@ -237,6 +237,11 @@ typename Range::const_iterator cmRemoveIndices(Range& r, InputRange const& rem)
 {
   typename InputRange::const_iterator remIt = rem.begin();
   typename InputRange::const_iterator remEnd = rem.end();
+  const typename Range::iterator rangeEnd = r.end();
+  if (remIt == remEnd)
+    {
+    return rangeEnd;
+    }
 
   typename Range::iterator writer = r.begin();
   std::advance(writer, *remIt);
@@ -244,7 +249,6 @@ typename Range::const_iterator cmRemoveIndices(Range& r, InputRange const& rem)
   typename InputRange::value_type prevRem = *remIt;
   ++remIt;
   size_t count = 1;
-  const typename Range::iterator rangeEnd = r.end();
   for ( ; writer != rangeEnd && remIt != remEnd; ++count, ++remIt)
     {
     std::advance(pivot, *remIt - prevRem);