Add filter pipe node

tpie/pipelining/filter.h

@@ -0,0 +1,74 @@
+// -*- mode: c++; tab-width: 4; indent-tabs-mode: t; eval: (progn (c-set-style "stroustrup") (c-set-offset 'innamespace 0)); -*-
+// vi:set ts=4 sts=4 sw=4 noet :
+// Copyright 2015 The TPIE development team
+// 
+// This file is part of TPIE.
+// 
+// TPIE is free software: you can redistribute it and/or modify it under
+// the terms of the GNU Lesser General Public License as published by the
+// Free Software Foundation, either version 3 of the License, or (at your
+// option) any later version.
+// 
+// TPIE 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 Lesser General Public
+// License for more details.
+// 
+// You should have received a copy of the GNU Lesser General Public License
+// along with TPIE.  If not, see <http://www.gnu.org/licenses/>
+
+#ifndef __TPIE_PIPELINING_FILTER_H__
+#define __TPIE_PIPELINING_FILTER_H__
+
+#include <tpie/pipelining/node.h>
+#include <tpie/pipelining/pipe_base.h>
+#include <tpie/pipelining/factory_helpers.h>
+#include <tpie/pipelining/node_name.h>
+
+namespace tpie {
+namespace pipelining {
+namespace bits {
+
+template <typename F>
+class filter_t {
+public:
+	template <typename dest_t>
+	class type: public node {
+	private:
+		F functor;
+		dest_t dest;
+	public:
+#ifdef TPIE_CPP_DECLTYPE
+		typedef typename std::decay<typename unary_traits<F>::argument_type>::type item_type;
+#else
+		typedef typename boost::template unary_traits<F>::argument_type item_type;
+#endif	
+		type(TPIE_RREF(dest_t) dest, const F & functor):
+			functor(functor), dest(TPIE_MOVE(dest)) {
+			set_name(bits::extract_pipe_name(typeid(F).name()), PRIORITY_NO_NAME);
+		}
+
+		void push(const item_type & item) {
+			if (functor(item))
+				dest.push(item);
+		}
+	};
+};
+
+} //namespace bits
+
+///////////////////////////////////////////////////////////////////////////////
+/// \brief Pipelining nodes that keeps only elements where functor evaluates
+// to true.
+/// the stream.
+/// \param f The filter to use
+///////////////////////////////////////////////////////////////////////////////
+template <typename F>
+pipe_middle<tempfactory_1<bits::filter_t<F>, F> > filter(const F & functor) {
+	return tempfactory_1<bits::filter_t<F>, F >(functor);
+}
+
+} //namespace pipelining
+} //namespace terrastream
+
+#endif //__TPIE_PIPELINING_FILTER_H__