mirror of
https://github.com/bolero-MURAKAMI/Sprout
synced 2024-11-12 21:09:01 +00:00
61 lines
2 KiB
C++
61 lines
2 KiB
C++
#ifndef SPROUT_MATH_ROUND_HPP
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#define SPROUT_MATH_ROUND_HPP
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#include <cstdint>
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#include <limits>
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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/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 FloatType>
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inline SPROUT_CONSTEXPR FloatType
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round_impl_positive(FloatType x, FloatType x0) {
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return x - x0 < FloatType(0.5) ? x0
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: x0 + 1
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;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR FloatType
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round_impl_nagative(FloatType x, FloatType x0) {
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return x0 - x < FloatType(0.5) ? x0
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: x0 - 1
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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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round(FloatType x) {
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return x == 0 ? FloatType(0)
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: x == std::numeric_limits<FloatType>::infinity() ? std::numeric_limits<FloatType>::infinity()
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: x == -std::numeric_limits<FloatType>::infinity() ? -std::numeric_limits<FloatType>::infinity()
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: std::numeric_limits<std::uintmax_t>::max() < x || std::numeric_limits<std::uintmax_t>::max() < -x
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? SPROUT_MATH_THROW_LARGE_FLOAT_ROUNDING(std::runtime_error("round: large float rounding."), x)
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: x < 0 ? sprout::math::detail::round_impl_nagative(x, -static_cast<FloatType>(static_cast<std::uintmax_t>(-x)))
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: sprout::math::detail::round_impl_positive(x, static_cast<FloatType>(static_cast<std::uintmax_t>(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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round(IntType x) {
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return sprout::math::detail::round(static_cast<double>(x));
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}
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} // namespace detail
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using NS_SPROUT_MATH_DETAIL::round;
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} // namespace math
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using sprout::math::round;
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} // namespace sprout
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#endif // #ifndef SPROUT_MATH_ROUND_HPP
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