mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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61 lines
2.2 KiB
C++
61 lines
2.2 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_MATH_FLOAT_SIG_EXP_HPP
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#define SPROUT_MATH_FLOAT_SIG_EXP_HPP
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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/detail/pow.hpp>
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#include <sprout/math/detail/config.hpp>
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#include <sprout/math/isnan.hpp>
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#include <sprout/math/ilogb.hpp>
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#include <sprout/type_traits/enabler_if.hpp>
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#include <sprout/utility/pair/pair.hpp>
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namespace sprout {
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namespace math {
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namespace detail {
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template<typename T>
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inline SPROUT_CONSTEXPR sprout::pair<T, int>
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float_sig_exp_impl(T x, int exp) {
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typedef sprout::pair<T, int> type;
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return type(x / sprout::detail::pow_n(T(sprout::numeric_limits<T>::radix), exp), exp);
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}
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} // namespace detail
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//
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// float_sig_exp
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//
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template<
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typename FloatType,
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typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR sprout::pair<FloatType, int>
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float_sig_exp(FloatType x) {
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typedef sprout::pair<FloatType, int> type;
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return sprout::math::isnan(x) ? type(x, 0)
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: x == sprout::numeric_limits<FloatType>::infinity() ? type(sprout::numeric_limits<FloatType>::infinity(), 0)
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: x == -sprout::numeric_limits<FloatType>::infinity() ? type(-sprout::numeric_limits<FloatType>::infinity(), 0)
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: x == 0 ? type(x, 0)
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: sprout::math::detail::float_sig_exp_impl(x, sprout::math::ilogb(x) + 1)
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;
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}
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template<
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typename IntType,
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typename sprout::enabler_if<std::is_integral<IntType>::value>::type = sprout::enabler
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>
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inline SPROUT_CONSTEXPR sprout::pair<double, int>
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float_sig_exp(IntType x) {
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return sprout::math::float_sig_exp(static_cast<double>(x));
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}
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} // namespace math
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using sprout::math::float_sig_exp;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_FLOAT_SIG_EXP_HPP
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