Sprout/sprout/random/generate_array.hpp
2019-01-07 17:47:17 +09:00

90 lines
3.9 KiB
C++

/*=============================================================================
Copyright (c) 2011-2019 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
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)
=============================================================================*/
#ifndef SPROUT_RANDOM_GENERATE_ARRAY_HPP
#define SPROUT_RANDOM_GENERATE_ARRAY_HPP
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/array/array.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/utility/pair/pair.hpp>
#include <sprout/random/results.hpp>
#include <sprout/generator/results.hpp>
namespace sprout {
namespace random {
//
// generate_array
//
template<std::size_t N, typename RandomNumberGenerator>
inline SPROUT_CXX14_CONSTEXPR sprout::array<typename RandomNumberGenerator::result_type, N>
generate_array(RandomNumberGenerator& rng) {
sprout::array<typename RandomNumberGenerator::result_type, N> result{{}};
for (std::size_t i = 0; i != N; ++i) {
result[i] = rng();
}
return result;
}
template<std::size_t N, typename RandomNumberGenerator, typename Distribution>
inline SPROUT_CXX14_CONSTEXPR sprout::array<typename std::remove_reference<Distribution>::type::result_type, N>
generate_array(RandomNumberGenerator& rng, Distribution&& dist) {
sprout::array<typename std::remove_reference<Distribution>::type::result_type, N> result{{}};
for (std::size_t i = 0; i != N; ++i) {
result[i] = SPROUT_FORWARD(Distribution, dist)(rng);
}
return result;
}
namespace detail {
template<std::size_t N, typename RandomNumberGenerator, typename Random, typename... Args>
static SPROUT_CONSTEXPR typename std::enable_if<
(sizeof...(Args) + 1 == N),
sprout::pair<
sprout::array<typename sprout::generators::results::generated_value<RandomNumberGenerator const>::type, N>,
typename sprout::generators::results::next_generator<RandomNumberGenerator const>::type
> const
>::type generate_array_impl(Random const& rnd, Args const&... args) {
typedef sprout::pair<
sprout::array<typename sprout::generators::results::generated_value<RandomNumberGenerator const>::type, N>,
typename sprout::generators::results::next_generator<RandomNumberGenerator const>::type
> const pair_type;
return pair_type{
sprout::array<typename RandomNumberGenerator::result_type, N>{{args..., sprout::random::result(rnd)}},
sprout::random::next(rnd)
};
}
template<std::size_t N, typename RandomNumberGenerator, typename Random, typename... Args>
static SPROUT_CONSTEXPR typename std::enable_if<
(sizeof...(Args) + 1 < N),
sprout::pair<
sprout::array<typename sprout::generators::results::generated_value<RandomNumberGenerator const>::type, N>,
typename sprout::generators::results::next_generator<RandomNumberGenerator const>::type
> const
>::type generate_array_impl(Random const& rnd, Args const&... args) {
return sprout::random::detail::generate_array_impl<N, RandomNumberGenerator>(
sprout::random::next(rnd)(),
args..., sprout::random::result(rnd)
);
}
} // namespace detail
//
// generate_array
//
template<std::size_t N, typename RandomNumberGenerator>
inline SPROUT_CONSTEXPR sprout::pair<
sprout::array<typename sprout::generators::results::generated_value<RandomNumberGenerator const>::type, N>,
typename sprout::generators::results::next_generator<RandomNumberGenerator const>::type
> const
generate_array(RandomNumberGenerator const& rng) {
return sprout::random::detail::generate_array_impl<N, RandomNumberGenerator>(rng());
}
} // namespace random
} // namespace sprout
#endif // #ifndef SPROUT_RANDOM_GENERATE_ARRAY_HPP