mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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76 lines
2.3 KiB
C++
76 lines
2.3 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_INTEGER_STATIC_POW_HPP
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#define SPROUT_INTEGER_STATIC_POW_HPP
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#include <type_traits>
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#include <sprout/config.hpp>
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namespace sprout {
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//
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// static_pow2
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//
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template<typename T, T X>
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struct static_pow2
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: public std::integral_constant<T, (1 << X)>
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{};
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namespace detail {
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template<typename T, T X, bool IsZero = (X == 0)>
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struct static_pow2m1;
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template<typename T, T X>
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struct static_pow2m1<T, X, true>
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: public std::integral_constant<T, 1>
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{};
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template<typename T, T X>
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struct static_pow2m1<T, X, false>
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: public std::integral_constant<T, ((((T(1) << (X - 1)) - 1) << 1) + 1)>
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{};
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} // namespace detail
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//
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// static_pow2m1
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//
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template<typename T, T X>
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struct static_pow2m1
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: public sprout::detail::static_pow2m1<T, X>
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{};
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namespace detail {
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template<typename T, T X, T Y, int K = (Y < 3 ? int(Y) : 3), bool IsOdd = (Y % 2 != 0)>
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struct static_pow;
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template<typename T, T X, T Y>
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struct static_pow<T, X, Y, 0, false>
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: public std::integral_constant<T, 1>
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{};
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template<typename T, T X, T Y>
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struct static_pow<T, X, Y, 1, true>
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: public std::integral_constant<T, X>
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{};
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template<typename T, T X, T Y>
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struct static_pow<T, X, Y, 2, false>
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: public std::integral_constant<T, X * X>
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{};
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template<typename T, T X, T Y, int K>
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struct static_pow<T, X, Y, K, false>
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: public sprout::detail::static_pow<T, sprout::detail::static_pow<T, X, Y / 2>::value, 2>
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{};
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template<typename T, T X, T Y, int K>
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struct static_pow<T, X, Y, K, true>
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: public std::integral_constant<T, X * sprout::detail::static_pow<T, X, Y - 1>::value>
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{};
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} // namespace detail
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//
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// static_pow
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//
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template<typename T, T X, T Y>
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struct static_pow
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: public sprout::detail::static_pow<T, X, Y>
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{};
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} // namespace sprout
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#endif // #ifndef SPROUT_INTEGER_STATIC_POW_HPP
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