Sprout/sprout/random/unique_seed.hpp
2016-03-19 00:21:43 +09:00

74 lines
2.3 KiB
C++

/*=============================================================================
Copyright (c) 2011-2016 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_UNIQUE_SEED_HPP
#define SPROUT_RANDOM_UNIQUE_SEED_HPP
#include <cstdint>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/workaround/std/cstddef.hpp>
#include <sprout/array/array.hpp>
#include <sprout/functional/hash.hpp>
#include <sprout/preprocessor/unique_string.hpp>
namespace sprout {
//
// make_seed
//
template<typename T>
SPROUT_CONSTEXPR std::uint_least32_t
make_seed(T const& v) {
return static_cast<std::uint_least32_t>(sprout::to_hash(v));
}
namespace detail {
template<std::size_t N, typename T, typename... Args>
SPROUT_CONSTEXPR typename std::enable_if<
sizeof...(Args) + 1 == N,
sprout::array<std::uint_least32_t, N>
>::type
make_seed_seq_impl(T const&, std::size_t seed, Args const&... args) {
return sprout::array<std::uint_least32_t, N>{{args..., static_cast<std::uint_least32_t>(seed)}};
}
template<std::size_t N, typename T, typename... Args>
SPROUT_CONSTEXPR typename std::enable_if<
sizeof...(Args) + 1 != N,
sprout::array<std::uint_least32_t, N>
>::type
make_seed_seq_impl(T const& v, std::size_t seed, Args const&... args) {
return sprout::detail::make_seed_seq_impl<N>(v, sprout::hash_combine(seed, v), args..., static_cast<std::uint_least32_t>(seed));
}
} // namespace detail
//
// make_seed_seq
//
template<std::size_t N, typename T>
SPROUT_CONSTEXPR sprout::array<std::uint_least32_t, N>
make_seed_seq(T const& v) {
return sprout::detail::make_seed_seq_impl<N>(v, sprout::to_hash(v));
}
} // namespace sprout
//
// SPROUT_UNIQUE_SEED_
//
#define SPROUT_UNIQUE_SEED_(N) \
(::sprout::make_seed(SPROUT_PP_UNIQUE_STRING_(N)))
//
// SPROUT_UNIQUE_SEED
//
#define SPROUT_UNIQUE_SEED \
(::sprout::make_seed(SPROUT_PP_UNIQUE_STRING))
//
// SPROUT_UNIQUE_SEED_SEQ
//
#define SPROUT_UNIQUE_SEED_SEQ(N) (::sprout::make_seed_seq<N>(SPROUT_PP_UNIQUE_STRING))
#endif // #ifndef SPROUT_RANDOM_UNIQUE_SEED_HPP