mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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63 lines
1.9 KiB
C++
63 lines
1.9 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2014 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_DETAIL_POW_HPP
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#define SPROUT_DETAIL_POW_HPP
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/type_traits/is_int.hpp>
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#include <sprout/type_traits/is_uint.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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namespace sprout {
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namespace detail {
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template<typename T>
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inline SPROUT_CONSTEXPR T
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pow2(T const& x) {
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return x * x;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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pow3(T const& x) {
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return x * x * x;
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}
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template<typename T, typename IntType>
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inline SPROUT_CONSTEXPR T
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pow_n_impl(T const& x, IntType n) {
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return n == 1 ? x
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: n % 2 ? x * sprout::detail::pow2(sprout::detail::pow_n_impl(x, n / 2))
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: sprout::detail::pow2(sprout::detail::pow_n_impl(x, n / 2))
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;
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}
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template<
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typename T, typename UIntType,
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typename sprout::enabler_if<sprout::is_uint<UIntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR T
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pow_n(T const& x, UIntType n) {
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return n == 0 ? T(1)
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: sprout::detail::pow_n_impl(x, n)
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;
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}
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template<
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typename T, typename IntType,
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typename sprout::enabler_if<sprout::is_int<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR T
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pow_n(T const& x, IntType n) {
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return n == 0 ? T(1)
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: n > 0 ? sprout::detail::pow_n_impl(x, n)
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: T(1) / sprout::detail::pow_n_impl(x, -n)
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;
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}
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} // namespace detail
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} // namespace sprout
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#endif // #ifndef SPROUT_DETAIL_POW_HPP
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