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- // Copyright (C) 2016-2018 T. Zachary Laine
- //
- // Distributed under the Boost Software License, Version 1.0. (See
- // accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- #include <boost/yap/expression.hpp>
- #include <algorithm>
- #include <cassert>
- #include <iostream>
- #include <vector>
- #include <boost/test/minimal.hpp>
- int allocations = 0;
- void * operator new(std::size_t size)
- {
- ++allocations;
- void * retval = malloc(size);
- if (!retval)
- throw std::bad_alloc();
- return retval;
- }
- void operator delete(void * ptr) noexcept { free(ptr); }
- template<boost::yap::expr_kind Kind, typename Tuple>
- struct lazy_vector_expr;
- struct take_nth
- {
- boost::yap::terminal<lazy_vector_expr, double> operator()(
- boost::yap::terminal<lazy_vector_expr, std::vector<double>> const &
- expr);
- std::size_t n;
- };
- template<boost::yap::expr_kind Kind, typename Tuple>
- struct lazy_vector_expr
- {
- static const boost::yap::expr_kind kind = Kind;
- Tuple elements;
- auto operator[](std::size_t n) const
- {
- return boost::yap::evaluate(boost::yap::transform(*this, take_nth{n}));
- }
- };
- BOOST_YAP_USER_BINARY_OPERATOR(plus, lazy_vector_expr, lazy_vector_expr)
- BOOST_YAP_USER_BINARY_OPERATOR(minus, lazy_vector_expr, lazy_vector_expr)
- boost::yap::terminal<lazy_vector_expr, double> take_nth::operator()(
- boost::yap::terminal<lazy_vector_expr, std::vector<double>> const & expr)
- {
- double x = boost::yap::value(expr)[n];
- return boost::yap::make_terminal<lazy_vector_expr, double>(std::move(x));
- }
- struct lazy_vector : lazy_vector_expr<
- boost::yap::expr_kind::terminal,
- boost::hana::tuple<std::vector<double>>>
- {
- lazy_vector() {}
- explicit lazy_vector(std::vector<double> && vec)
- {
- elements = boost::hana::tuple<std::vector<double>>(std::move(vec));
- }
- template<boost::yap::expr_kind Kind, typename Tuple>
- lazy_vector & operator+=(lazy_vector_expr<Kind, Tuple> const & rhs)
- {
- std::vector<double> & this_vec = boost::yap::value(*this);
- for (int i = 0, size = (int)this_vec.size(); i < size; ++i) {
- this_vec[i] += rhs[i];
- }
- return *this;
- }
- };
- int test_main(int, char * [])
- {
- lazy_vector v1{std::vector<double>(4, 1.0)};
- lazy_vector v2{std::vector<double>(4, 2.0)};
- lazy_vector v3{std::vector<double>(4, 3.0)};
- // Reset allocation count. There should be none from this point on.
- allocations = 0;
- double d1 = (v2 + v3)[2];
- std::cout << d1 << "\n";
- v1 += v2 - v3;
- std::cout << '{' << v1[0] << ',' << v1[1] << ',' << v1[2] << ',' << v1[3]
- << '}' << "\n";
- BOOST_CHECK(allocations == 0);
- return 0;
- }
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