mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
102 lines
3.5 KiB
C++
102 lines
3.5 KiB
C++
#ifndef SPROUT_MATH_LOGB_HPP
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#define SPROUT_MATH_LOGB_HPP
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#include <climits>
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#include <cfloat>
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#include <cstdint>
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#include <type_traits>
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#include <stdexcept>
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#include <sprout/config.hpp>
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#include <sprout/math/detail/config.hpp>
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#include <sprout/detail/pow.hpp>
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#include <sprout/math/log_a.hpp>
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#include <sprout/type_traits/enabler_if.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 T
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logb_impl_2_neg_lo(T x, T x0, T base, T exp) {
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return base < 1 ? sprout::math::detail::logb_impl_2_neg_lo(x, x0 * FLT_RADIX, x / (x0 / FLT_RADIX), exp - 1)
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: exp
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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logb_impl_2_neg_hi(T x, T x0, T base, T exp) {
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return !(base < FLT_RADIX) ? sprout::math::detail::logb_impl_2_neg_hi(x, x0 / FLT_RADIX, x / (x0 * FLT_RADIX), exp + 1)
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: exp
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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logb_impl_2_pos_lo(T x, T x0, T base, T exp) {
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return base < 1 ? sprout::math::detail::logb_impl_2_pos_lo(x, x0 * FLT_RADIX, x / (x0 / FLT_RADIX), exp + 1)
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: exp
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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logb_impl_2_pos_hi(T x, T x0, T base, T exp) {
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return !(base < FLT_RADIX) ? sprout::math::detail::logb_impl_2_pos_hi(x, x0 / FLT_RADIX, x / (x0 * FLT_RADIX), exp - 1)
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: exp
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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logb_impl_2(T x, T x0, T base, T exp) {
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return exp < 0
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? base < 1 ? sprout::math::detail::logb_impl_2_neg_lo(x, x0 * FLT_RADIX, x / (x0 / FLT_RADIX), exp - 1)
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: !(base < FLT_RADIX) ? sprout::math::detail::logb_impl_2_neg_hi(x, x0 / FLT_RADIX, x / (x0 * FLT_RADIX), exp + 1)
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: exp
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: base < 1 ? sprout::math::detail::logb_impl_2_pos_lo(x, x0 * FLT_RADIX, x / (x0 / FLT_RADIX), exp + 1)
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: !(base < FLT_RADIX) ? sprout::math::detail::logb_impl_2_pos_hi(x, x0 / FLT_RADIX, x / (x0 * FLT_RADIX), exp - 1)
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: exp
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;
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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logb_impl_1(T x, T x0, T exp) {
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return sprout::math::detail::logb_impl_2(x, x0, x / x0, exp);
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}
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template<typename T>
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inline SPROUT_CONSTEXPR T
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logb_impl(T x, T exp) {
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return std::numeric_limits<std::intmax_t>::max() < exp || std::numeric_limits<std::intmax_t>::min() > exp
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? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::domain_error("trunc: large float rounding."), exp)
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: sprout::math::detail::logb_impl_1(
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x, sprout::detail::pow_n(T(FLT_RADIX), static_cast<std::intmax_t>(exp)),
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static_cast<T>(static_cast<std::intmax_t>(exp))
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)
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;
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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 FloatType
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logb(FloatType x) {
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return x < 0 ? sprout::math::detail::logb_impl(-x, sprout::math::trunc(sprout::math::log_a(FloatType(FLT_RADIX), -x)))
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: sprout::math::detail::logb_impl(x, sprout::math::trunc(sprout::math::log_a(FloatType(FLT_RADIX), x)))
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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 double
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logb(IntType x) {
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return sprout::math::detail::logb(static_cast<double>(x));
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}
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} // namespace detail
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using NS_SPROUT_MATH_DETAIL::logb;
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} // namespace math
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using sprout::math::logb;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_LOGB_HPP
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