Intial checkin of 'clamp' algorithm

[SVN r54414]

include/boost/algorithm/clamp.hpp

@@ -0,0 +1,42 @@
+/* 
+   Copyright (c) Marshall Clow 2008.
+
+   Distributed under the Boost Software License, Version 1.0. (See accompanying
+   file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+ Revision history:
+   27 June 2009 mtc First version
+   
+*/
+
+/// \file clamp.hpp
+/// \brief Clamp algorithm
+/// \author Marshall Clow
+///
+/// Suggested by olafvdspek in https://svn.boost.org/trac/boost/ticket/3215
+
+#ifndef BOOST_ALGORITHM_CLAMP_HPP
+#define BOOST_ALGORITHM_CLAMP_HPP
+
+namespace boost { namespace algorithm {
+
+/// \fn clamp ( V lo, V hi, V val )
+/// \brief Returns the value "val" brought into the range [ lo, hi ]
+///          If the value is greater than "hi", return hi. If the value is
+///          less than "lo", return lo. Otherwise, return the original value.
+/// 
+/// \param lo    The low point of the range to be clamped to
+/// \param hi    The high point of the range to be clamped to
+/// \param val   The value to be clamped
+///
+  template<typename V> 
+  V clamp ( V lo, V hi, V val )
+  {
+    return val >= hi ? hi : val <= lo ? lo : val;
+//  Alternately, 
+//  return std::max ( std::min ( val, hi ), lo );
+  } 
+
+}}
+
+#endif // BOOST_ALGORITHM_CLAMP_HPP