From 038ae17545335e5d1b33746b0193e85ee9f584fe Mon Sep 17 00:00:00 2001
From: Carl Hetherington <cth@carlh.net>
Date: Mon, 5 Jan 2015 23:05:29 +0000
Subject: Thought-necessary protection of TransferFunction::lut() for access
 from multiple threads.

---
 src/transfer_function.cc | 4 ++++
 src/transfer_function.h  | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/transfer_function.cc b/src/transfer_function.cc
index d889cbbc..8a844d9b 100644
--- a/src/transfer_function.cc
+++ b/src/transfer_function.cc
@@ -33,6 +33,8 @@ TransferFunction::TransferFunction (bool inverse)
 
 TransferFunction::~TransferFunction ()
 {
+	boost::mutex::scoped_lock lm (_mutex);
+
 	for (map<int, double*>::const_iterator i = _luts.begin(); i != _luts.end(); ++i) {
 		delete[] i->second;
 	}
@@ -43,6 +45,8 @@ TransferFunction::~TransferFunction ()
 double const *
 TransferFunction::lut (int bit_depth) const
 {
+	boost::mutex::scoped_lock lm (_mutex);
+	
 	map<int, double*>::const_iterator i = _luts.find (bit_depth);
 	if (i != _luts.end ()) {
 		return i->second;
diff --git a/src/transfer_function.h b/src/transfer_function.h
index 16d00c1a..4105f3d4 100644
--- a/src/transfer_function.h
+++ b/src/transfer_function.h
@@ -22,6 +22,7 @@
 
 #include <boost/noncopyable.hpp>
 #include <boost/shared_ptr.hpp>
+#include <boost/thread/mutex.hpp>
 #include <map>
 
 namespace dcp {
@@ -43,8 +44,10 @@ protected:
 
 	bool _inverse;
 
-private:	
+private:
 	mutable std::map<int, double*> _luts;
+	/** mutex to protect _luts */
+	mutable boost::mutex _mutex;
 };
 
 }
-- 
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