[Olena-patches] proto-1.0 77: Add function composition

Index: ChangeLog from Simon Odou &lt;simon(a)lrde.epita.fr&gt; * oln/makefile.src: Add compose.hh. * oln/core/compose.hh: New. core/compose.hh | 170 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ makefile.src | 3 2 files changed, 172 insertions(+), 1 deletion(-) Index: oln/makefile.src --- oln/makefile.src (revision 76) +++ oln/makefile.src (working copy) @@ -45,8 +45,9 @@ core/abstract/point.hh \ core/abstract/size.hh \ core/abstract/neighborhood.hh \ - core/abstract/window.hh \ + core/abstract/struct_elt.hh \ core/coord.hh \ + core/compose.hh \ core/properties.hh \ core/value_box.hh \ fancy/iota.hh \ Index: oln/core/compose.hh --- oln/core/compose.hh (revision 0) +++ oln/core/compose.hh (revision 0) @@ -0,0 +1,170 @@ +// Copyright (C) 2001, 2004 EPITA Research and Development Laboratory +// +// This file is part of the Olena Library. This library is free +// software; you can redistribute it and/or modify it under the terms +// of the GNU General Public License version 2 as published by the +// Free Software Foundation. +// +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +// General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with this library; see the file COPYING. If not, write to +// the Free Software Foundation, 59 Temple Place - Suite 330, Boston, +// MA 02111-1307, USA. +// +// 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. + +#ifndef OLENA_CORE_COMPOSE_HH +# define OLENA_CORE_COMPOSE_HH + +# include <functional> + +namespace oln { + + namespace internal { + + /*! \class compose_uu_ + ** + ** The operator () of this class performs a composition between + ** two unary functors \a F1 & \a F2. + */ + + template< class F1, class F2 > + struct compose_uu_ : + public std::unary_function <typename F2::argument_type, + typename F1::result_type> + { + typedef compose_uu_ self_type; + + typename self_type::result_type + operator()(typename self_type::argument_type arg) const + { + return f1_(f2_(arg)); + } + + compose_uu_(const F1& f1, const F2& f2) : f1_(f1), f2_(f2) {} + + private: + + const F1 f1_; + const F2 f2_; + + }; + + /*! \class compose_ub_ + ** + ** The operator () of this class performs a composition between + ** a unary functor \a F1 and a binary functor \a F2. + */ + + + template< class F1, class F2 > + struct compose_ub_ : + public std::binary_function <typename F2::first_argument_type, + typename F2::second_argument_type, + typename F1::result_type> + { + typedef compose_ub_ self_type; + + typename self_type::result_type + operator()(typename self_type::first_argument_type arg1, + typename self_type::second_argument_type arg2) const + { + return f1_(f2_(arg1, arg2)); + } + + compose_ub_(const F1& f1, const F2& f2) : f1_(f1), f2_(f2) {} + + private: + + const F1 f1_; + const F2 f2_; + + }; + + /*! \class compose_bu_ + ** + ** The operator () of this class performs a composition between + ** a binary functor \a F1 and an unary functor \a F2. + */ + + template< class F1, class F2 > + struct compose_bu_ : + public std::binary_function <typename F2::argument_type, + typename F2::argument_type, + typename F1::result_type> + { + typedef compose_bu_ self_type; + + typename self_type::result_type + operator()(typename self_type::first_argument_type arg1, + typename self_type::second_argument_type arg2) const + { + return f1_(f2_(arg1), f2_(arg2)); + } + + compose_bu_(const F1& f1, const F2& f2) : f1_(f1), f2_(f2) {} + + private: + + const F1 f1_; + const F2 f2_; + + }; + + } + + + /// Compose two unary functors \a F1 & \a F2. + template<class UF1, class UF2> + internal::compose_uu_<UF1, UF2> + compose_uu(const UF1& f1, const UF2& f2) + { + return internal::compose_uu_<UF1, UF2>(f1, f2); + } + + /// Compose a unary functor \a F1 with a binary functor \a F2. + template<class UF1, class BF2> + internal::compose_ub_<UF1, BF2> + compose_ub(const UF1& f1, const BF2& f2) + { + return internal::compose_ub_<UF1, BF2>(f1, f2); + } + + /// Compose a binary functor \a F1 and an unary functor \a F2. + template<class BF1, class UF2> + internal::compose_bu_<BF1, UF2> + compose_bu(const BF1& f1, const UF2& f2) + { + return internal::compose_bu_<BF1, UF2>(f1, f2); + } + + /*! \class f_identity + ** + ** This functor returns its argument. + */ + + template<class T> + struct f_identity : std::unary_function<T, T> + { + T + operator()(T t) const + { + return t; + } + }; + +} // end of oln + +#endif // OLENA_CORE_COMPOSE_HH