boost/range/size.hpp

   1 // Boost.Range library
   2 //
   3 //  Copyright Thorsten Ottosen 2003-2004. Use, modification and
   4 //  distribution is subject to the Boost Software License, Version
   5 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
   6 //  http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // For more information, see http://www.boost.org/libs/range/
   9 //
  10
  11 #ifndef BOOST_RANGE_SIZE_HPP
  12 #define BOOST_RANGE_SIZE_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif
  17
  18 #include <boost/range/begin.hpp>
  19 #include <boost/range/end.hpp>
  20 #include <boost/range/difference_type.hpp>
  21 #include <boost/assert.hpp>
  22
  23 namespace boost
  24 {
  25
  26     template< class T >
  27     inline BOOST_DEDUCED_TYPENAME range_difference<T>::type size( const T& r )
  28     {
  29         BOOST_ASSERT( (boost::end( r ) - boost::begin( r )) >= 0 &&
  30                       "reachability invariant broken!" );
  31         return boost::end( r ) - boost::begin( r );
  32     }
  33
  34 } // namespace 'boost'
  35
  36 #endif