boost/accumulators/statistics/count.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // count.hpp
   3 //
   4 //  Copyright 2005 Eric Niebler. Distributed under the Boost
   5 //  Software License, Version 1.0. (See accompanying file
   6 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef BOOST_ACCUMULATORS_STATISTICS_COUNT_HPP_EAN_28_10_2005
   9 #define BOOST_ACCUMULATORS_STATISTICS_COUNT_HPP_EAN_28_10_2005
  10
  11 #include <boost/mpl/always.hpp>
  12 #include <boost/accumulators/framework/accumulator_base.hpp>
  13 #include <boost/accumulators/framework/extractor.hpp>
  14 #include <boost/accumulators/framework/depends_on.hpp>
  15 #include <boost/accumulators/statistics_fwd.hpp>
  16
  17 namespace boost { namespace accumulators
  18 {
  19
  20 namespace impl
  21 {
  22
  23     ///////////////////////////////////////////////////////////////////////////////
  24     // count_impl
  25     struct count_impl
  26       : accumulator_base
  27     {
  28         // for boost::result_of
  29         typedef std::size_t result_type;
  30
  31         count_impl(dont_care)
  32           : cnt(0)
  33         {
  34         }
  35
  36         void operator ()(dont_care)
  37         {
  38             ++this->cnt;
  39         }
  40
  41         result_type result(dont_care) const
  42         {
  43             return this->cnt;
  44         }
  45
  46     private:
  47         std::size_t cnt;
  48     };
  49
  50 } // namespace impl
  51
  52 ///////////////////////////////////////////////////////////////////////////////
  53 // tag::count
  54 //
  55 namespace tag
  56 {
  57     struct count
  58       : depends_on<>
  59     {
  60         /// INTERNAL ONLY
  61         ///
  62         typedef mpl::always<accumulators::impl::count_impl> impl;
  63     };
  64 }
  65
  66 ///////////////////////////////////////////////////////////////////////////////
  67 // extract::count
  68 //
  69 namespace extract
  70 {
  71     extractor<tag::count> const count = {};
  72 }
  73
  74 using extract::count;
  75
  76 }} // namespace boost::accumulators
  77
  78 #endif