* tests/data/transform-lambda.cc: New. * tests/data/Makefile.am (EXTRA_PROGRAMS) (transform_lambda_SOURCES): New. (extra-check): New (phony) target. --- milena/ChangeLog | 9 +++ milena/tests/data/Makefile.am | 12 +++ milena/tests/data/transform-lambda.cc | 123 +++++++++++++++++++++++++++++++++ 3 files changed, 144 insertions(+), 0 deletions(-) create mode 100644 milena/tests/data/transform-lambda.cc diff --git a/milena/ChangeLog b/milena/ChangeLog index 5712ee9..65f6803 100644 --- a/milena/ChangeLog +++ b/milena/ChangeLog @@ -1,3 +1,12 @@ +2012-05-22 Roland Levillain <roland@lrde.epita.fr> + + Add an optional test to exercise mln::transform with lambdas. + + * tests/data/transform-lambda.cc: New. + * tests/data/Makefile.am (EXTRA_PROGRAMS) + (transform_lambda_SOURCES): New. + (extra-check): New (phony) target. + 2011-09-15 Guillaume Lazzara <z@lrde.epita.fr> Fix Scribo build system. diff --git a/milena/tests/data/Makefile.am b/milena/tests/data/Makefile.am index 205337e..269567b 100644 --- a/milena/tests/data/Makefile.am +++ b/milena/tests/data/Makefile.am @@ -74,3 +74,15 @@ MOSTLYCLEANFILES = \ median-out_line.pgm \ median-out_rect.pgm \ median_fast-out.pgm + + +# FIXME: We should introduce a conditional (e.g named HAVE_CXX_LAMBDA) +# to guard these lines, and make them actually part of the test suite +# if the C++ compiler found by `configure' supports lambda +# abstractions. +EXTRA_PROGRAMS = transform-lambda +transform_lambda_SOURCES = transform-lambda.cc + +.PHONY: extra-check +extra-check: transform-lambda + ./transform-lambda$(EXEEXT) diff --git a/milena/tests/data/transform-lambda.cc b/milena/tests/data/transform-lambda.cc new file mode 100644 index 0000000..25de53a --- /dev/null +++ b/milena/tests/data/transform-lambda.cc @@ -0,0 +1,123 @@ +// Copyright (C) 2012 EPITA Research and Development Laboratory (LRDE) +// +// This file is part of Olena. +// +// Olena is free software: you can redistribute it and/or modify it under +// the terms of the GNU General Public License as published by the Free +// Software Foundation, version 2 of the License. +// +// Olena 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 Olena. If not, see <http://www.gnu.org/licenses/>. +// +// As a special exception, you may use this file as part of a free +// software project 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. + +/// \file +/// Exercise mln::data::transform with a lambda abstraction. + +#include <type_traits> + +#include <mln/core/concept/function.hh> +#include <mln/fun/c.hh> + +#include <mln/core/image/image2d.hh> + +#include <mln/data/transform.hh> +#include <mln/debug/iota.hh> +#include <mln/debug/println.hh> + + +/*----------------. +| Lambda traits. | +`----------------*/ + +// Metaprogramming traits for the deduction of return and argument +// types of lambda asbtractions. Inspired from +// http://stackoverflow.com/questions/6512019/can-we-get-the-type-of-a-lambda-a... + +/// Deduce the type of \p F's first argument. +template <typename F> +struct first_arg_of +{ + template <typename Ret, typename A, typename... Rest> + static A + helper(Ret (F::*)(A, Rest...)); + + template <typename Ret, typename A, typename... Rest> + static A + helper(Ret (F::*)(A, Rest...) const); + + typedef decltype( helper(&F::operator()) ) type; +}; + +/// Deduce the type of \p F's first argument. +/// +/// This traits works with lambdas, whereas std::result_of does not. +template <typename F> +struct return_of +{ + template <typename Ret, typename A, typename... Rest> + static Ret + helper(Ret (F::*)(A, Rest...)); + + template <typename Ret, typename A, typename... Rest> + static Ret + helper(Ret (F::*)(A, Rest...) const); + + typedef decltype( helper(&F::operator()) ) type; +}; + + +/*---------------------. +| Conversion routine. | +`---------------------*/ + +/// Convert a lambda abstraction into a Milena function (functor). + +template <typename F> +auto +to_fun (F f) -> mln::fun::C< typename return_of<F>::type (*) (typename first_arg_of<F>::type) > +{ + return mln::fun::C< typename return_of<F>::type (*) (typename first_arg_of<F>::type) > (f); +} + + +/*-------. +| Test. | +`-------*/ + +int +main() +{ + using namespace mln; + + // FIXME: Replacing unsigned by int_u8 would trigger a bug here, as + // the (low quantization) implementation of data::transform would + // create values that would not fit in int_u8 (e.g. sqr(16) = 256). + typedef unsigned V; + typedef image2d<V> I; + + I input(3, 3); + debug::iota(input); + + auto sqr = [](V x) { return x * x; }; + + I output = data::transform(input, to_fun([](V x) { return x * x; })); + debug::println(output); + + // FIXME: Or use mln::test instead? + mln_piter_(I) p(output.domain()); + for_all(p) + mln_assertion(output(p) = math::sqr(input(p))); +} -- 1.7.2.5