boost/accumulators/statistics/rolling_count.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // rolling_count.hpp
   3 //
   4 // Copyright 2008 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_ROLLING_COUNT_HPP_EAN_26_12_2008
   9 #define BOOST_ACCUMULATORS_STATISTICS_ROLLING_COUNT_HPP_EAN_26_12_2008
  10
  11 #include <boost/mpl/placeholders.hpp>
  12 #include <boost/accumulators/framework/accumulator_base.hpp>
  13 #include <boost/accumulators/framework/extractor.hpp>
  14 #include <boost/accumulators/numeric/functional.hpp>
  15 #include <boost/accumulators/framework/parameters/sample.hpp>
  16 #include <boost/accumulators/framework/depends_on.hpp>
  17 #include <boost/accumulators/statistics_fwd.hpp>
  18 #include <boost/accumulators/statistics/rolling_window.hpp>
  19
  20 namespace boost { namespace accumulators
  21 {
  22
  23 namespace impl
  24 {
  25
  26     ///////////////////////////////////////////////////////////////////////////////
  27     // rolling_count_impl
  28     //    returns the count of elements in the rolling window
  29     template<typename Sample>
  30     struct rolling_count_impl
  31       : accumulator_base
  32     {
  33         typedef std::size_t result_type;
  34
  35         rolling_count_impl(dont_care)
  36         {}
  37
  38         template<typename Args>
  39         result_type result(Args const &args) const
  40         {
  41             return static_cast<std::size_t>(rolling_window_plus1(args).size()) - is_rolling_window_plus1_full(args);
  42         }
  43     };
  44
  45 } // namespace impl
  46
  47 ///////////////////////////////////////////////////////////////////////////////
  48 // tag::rolling_count
  49 //
  50 namespace tag
  51 {
  52     struct rolling_count
  53       : depends_on< rolling_window_plus1 >
  54     {
  55         /// INTERNAL ONLY
  56         ///
  57         typedef accumulators::impl::rolling_count_impl< mpl::_1 > impl;
  58
  59         #ifdef BOOST_ACCUMULATORS_DOXYGEN_INVOKED
  60         /// tag::rolling_window::window_size named parameter
  61         static boost::parameter::keyword<tag::rolling_window_size> const window_size;
  62         #endif
  63     };
  64 } // namespace tag
  65
  66 ///////////////////////////////////////////////////////////////////////////////
  67 // extract::rolling_count
  68 //
  69 namespace extract
  70 {
  71     extractor<tag::rolling_count> const rolling_count = {};
  72 }
  73
  74 using extract::rolling_count;
  75
  76 }} // namespace boost::accumulators
  77
  78 #endif