From 5554910ec2573282a85e61736e96f48e5f550066 Mon Sep 17 00:00:00 2001
From: Ben Boeckel <ben.boeckel@kitware.com>
Date: Mon, 10 Feb 2014 01:39:33 -0500
Subject: [PATCH] cmSourceFileLocation: Avoid string allocation in extension
 checking

The substr call was causing excess allocations. Swap the cheaper
character check to be before the longer string comparison, now using the
prefix checking function.
---
 Source/cmSourceFileLocation.cxx | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Source/cmSourceFileLocation.cxx b/Source/cmSourceFileLocation.cxx
index c05020236..9c0b2c524 100644
--- a/Source/cmSourceFileLocation.cxx
+++ b/Source/cmSourceFileLocation.cxx
@@ -183,8 +183,9 @@ cmSourceFileLocation
   // Check if loc's name could possibly be extended to our name by
   // adding an extension.
   if(!(this->Name.size() > loc.Name.size() &&
-       this->Name.substr(0, loc.Name.size()) == loc.Name &&
-       this->Name[loc.Name.size()] == '.'))
+       this->Name[loc.Name.size()] == '.' &&
+       cmHasLiteralPrefixImpl(this->Name.c_str(),
+                              loc.Name.c_str(), loc.Name.size())))
     {
     return false;
     }