1 2 #ifndef BOOST_MPL_COUNT_IF_HPP_INCLUDED 3 #define BOOST_MPL_COUNT_IF_HPP_INCLUDED 4 5 // Copyright Aleksey Gurtovoy 2000-2002 6 // 7 // Distributed under the Boost Software License, Version 1.0. 8 // (See accompanying file LICENSE_1_0.txt or copy at 9 // http://www.boost.org/LICENSE_1_0.txt) 10 // 11 // See http://www.boost.org/libs/mpl for documentation. 12 13 // $Id$ 14 // $Date$ 15 // $Revision$ 16 17 #include <boost/mpl/fold.hpp> 18 #include <boost/mpl/next.hpp> 19 #include <boost/mpl/integral_c.hpp> 20 #include <boost/mpl/identity.hpp> 21 #include <boost/mpl/eval_if.hpp> 22 #include <boost/mpl/apply.hpp> 23 #include <boost/mpl/aux_/msvc_eti_base.hpp> 24 #include <boost/mpl/aux_/na_spec.hpp> 25 #include <boost/mpl/aux_/lambda_support.hpp> 26 #include <boost/mpl/aux_/config/forwarding.hpp> 27 28 namespace boost { namespace mpl { 29 30 namespace aux { 31 32 template< typename Predicate > 33 struct next_if 34 { 35 template< 36 typename N 37 , typename T 38 > 39 struct apply 40 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING) 41 : eval_if< 42 typename apply1<Predicate,T>::type 43 , next<N> 44 , identity<N> 45 > 46 { 47 #else 48 { 49 typedef typename eval_if< 50 typename apply1<Predicate,T>::type 51 , next<N> 52 , identity<N> 53 >::type type; 54 #endif 55 }; 56 }; 57 58 } // namespace aux 59 60 61 template< 62 typename BOOST_MPL_AUX_NA_PARAM(Sequence) 63 , typename BOOST_MPL_AUX_NA_PARAM(Predicate) 64 > 65 struct count_if 66 : aux::msvc_eti_base< typename fold< 67 Sequence 68 , integral_c<unsigned long,0> 69 , protect< aux::next_if<Predicate> > 70 >::type > 71 { 72 BOOST_MPL_AUX_LAMBDA_SUPPORT(2,count_if,(Sequence,Predicate)) 73 }; 74 75 BOOST_MPL_AUX_NA_SPEC(2, count_if) 76 77 }} 78 79 #endif // BOOST_MPL_COUNT_IF_HPP_INCLUDED 80