mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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114 lines
4.3 KiB
C++
114 lines
4.3 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2013 Bolero MURAKAMI
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https://github.com/bolero-MURAKAMI/Sprout
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#ifndef SPROUT_RANDOM_DETAIL_SEED_IMPL_HPP
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#define SPROUT_RANDOM_DETAIL_SEED_IMPL_HPP
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#include <cstdint>
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#include <stdexcept>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/iterator/next.hpp>
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#include <sprout/array.hpp>
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#include <sprout/pit.hpp>
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#include <sprout/random/detail/const_mod.hpp>
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#include <sprout/detail/integer/static_log2.hpp>
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namespace sprout {
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namespace random {
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namespace detail {
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template<typename IntType, IntType m>
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struct seed_log
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: public std::conditional<
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m == 0,
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std::integral_constant<int, sprout::numeric_limits<IntType>::digits>,
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std::integral_constant<int, sprout::detail::static_log2<m>::value>
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>::type
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{};
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template<typename IntType, IntType m, int log>
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struct seed_k
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: public std::integral_constant<
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int,
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(log + ((~(IntType(2) << (log - 1)) & m)? 32 : 31)) / 32
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>
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{};
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template<typename IntType, IntType m, int log, int k, typename Array>
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inline SPROUT_CONSTEXPR IntType
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seed_one_int_impl(Array const& arr, IntType s, int j) {
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return j < k ? sprout::random::detail::seed_one_int_impl<IntType, m, k>(
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arr,
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sprout::random::detail::const_mod<IntType, m>::mult_add(
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IntType(1) << 32 * j,
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sprout::random::detail::const_mod<IntType, m>::apply(IntType(arr[j + 3])),
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s
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),
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j + 1
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)
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: s
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;
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}
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template<typename IntType, IntType m, typename Sseq>
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inline SPROUT_CONSTEXPR IntType
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seed_one_int(Sseq const& seq) {
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typedef typename sprout::random::detail::seed_log<IntType, m>::type log_t;
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typedef typename sprout::random::detail::seed_k<IntType, m, log_t::value>::type k_t;
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return sprout::random::detail::seed_one_int_impl<IntType, m, k_t::value>(
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seq.generate(sprout::pit<sprout::array<std::uint_least32_t, log_t::value / 32 + 4> >()),
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0, 0
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);
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}
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template<typename IntType, IntType m, typename Sseq>
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inline SPROUT_CXX14_CONSTEXPR IntType
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seed_one_int(Sseq& seq) {
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typedef typename sprout::random::detail::seed_log<IntType, m>::type log_t;
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typedef typename sprout::random::detail::seed_k<IntType, m, log_t::value>::type k_t;
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sprout::array<std::uint_least32_t, log_t::value / 32 + 4> arr{{}};
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seq.generate(arr.begin(), arr.begin() + (k_t::value + 3));
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IntType s = 0;
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for (int j = 0; j < k_t::value; ++j) {
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IntType digit = sprout::random::detail::const_mod<IntType, m>::apply(IntType(arr[j + 3]));
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IntType mult = IntType(1) << 32 * j;
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s = sprout::random::detail::const_mod<IntType, m>::mult_add(mult, digit, s);
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}
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return s;
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}
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template<typename IntType, IntType m, int log, int k, typename InputIterator>
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inline SPROUT_CONSTEXPR IntType
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get_one_int_impl(InputIterator first, InputIterator last, IntType s, int j) {
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return j < k
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? first != last
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? sprout::random::detail::get_one_int_impl<IntType, m, k>(
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sprout::next(first), last,
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sprout::random::detail::const_mod<IntType, m>::mult_add(
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IntType(1) << 32 * j,
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sprout::random::detail::const_mod<IntType, m>::apply(IntType(*first)),
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s
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),
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j + 1
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)
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: throw std::invalid_argument("Not enough elements in call to seed.")
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: s
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;
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}
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template<typename IntType, IntType m, typename InputIterator>
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inline SPROUT_CONSTEXPR IntType
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get_one_int(InputIterator first, InputIterator last) {
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typedef typename sprout::random::detail::seed_log<IntType, m>::type log_t;
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typedef typename sprout::random::detail::seed_k<IntType, m, log_t::value>::type k_t;
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return sprout::random::detail::get_one_int_impl<IntType, m, k_t::value>(
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first, last,
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0, 0
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);
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}
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} // namespace detail
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} // namespace random
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} // namespace sprout
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#endif // #ifndef SPROUT_RANDOM_DETAIL_SEED_IMPL_HPP
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