minmax

// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2008-2009 Alexander Warg <warg@os.inf.tu-dresden.de>
 *     economic rights: Technische Universität Dresden (Germany)
 *
 * This file is part of TUD:OS and distributed under the terms of the
 * GNU General Public License 2.
 * Please see the COPYING-GPL-2 file for details.
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
 * the GNU General Public License.  This exception does not however
 * invalidate any other reasons why the executable file might be covered by
 * the GNU General Public License.
 */
#pragma once
 
#include "type_traits"
 
namespace cxx
{
  // trivial, used to terminate the variadic recursion
  template<typename A>
  constexpr A const &
  min(A const &a)
  { return a; }
 
  template<typename A, typename ...ARGS>
  constexpr A const &
  min(A const &a1, A const &a2, ARGS const &...a)
  {
    return min((a1 <= a2) ? a1 : a2, a...);
  }
 
  template<typename A, typename ...ARGS>
  constexpr A const &
  min(cxx::identity_t<A> const &a1,
      cxx::identity_t<A> const &a2,
      ARGS const &...a)
  {
    return min<A>((a1 <= a2) ? a1 : a2, a...);
  }
 
  // trivial, used to terminate the variadic recursion
  template<typename A>
  constexpr A const &
  max(A const &a)
  { return a; }
 
  template<typename A, typename ...ARGS>
  constexpr A const &
  max(A const &a1, A const &a2, ARGS const &...a)
  { return max((a1 >= a2) ? a1 : a2, a...); }
 
  template<typename A, typename ...ARGS>
  constexpr A const &
  max(cxx::identity_t<A> const &a1,
      cxx::identity_t<A> const &a2,
      ARGS const &...a)
  {
    return max<A>((a1 >= a2) ? a1 : a2, a...);
  }
 
  template< typename T1 >
  inline
  T1 clamp(T1 v, T1 lo, T1 hi)
  { return min(hi, max(lo, v)); }
};