mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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235 lines
7.3 KiB
C++
235 lines
7.3 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2015 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_FLOAT_HPP
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#define SPROUT_DETAIL_FLOAT_HPP
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/math/abs.hpp>
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#include <sprout/math/floor.hpp>
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#include <sprout/math/round.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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#include <sprout/detail/pow.hpp>
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namespace sprout {
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namespace detail {
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//
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// float_pow10
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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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float_pow10(int exponent) {
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return sprout::detail::pow_n(FloatType(10), exponent);
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}
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//
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// float_exponent10
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//
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template<typename FloatType>
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inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
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float_exponent10_positive_1(sprout::pair<int, FloatType> const& current, int n) {
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typedef sprout::pair<int, FloatType> type;
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return (current.second) < 10 ? current
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: n == 1 ? type(current.first + 1, current.second / 10)
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: sprout::detail::float_exponent10_positive_1(
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sprout::detail::float_exponent10_positive_1(
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current,
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n / 2
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),
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n - n / 2
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)
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;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
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float_exponent10_positive_0(sprout::pair<int, FloatType> const& current, int n) {
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return (current.second) < 10 ? current
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: sprout::detail::float_exponent10_positive_0(
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sprout::detail::float_exponent10_positive_1(
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current,
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n
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),
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n * 2
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)
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;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR int
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float_exponent10_positive(FloatType val) {
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typedef sprout::pair<int, FloatType> type;
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return float_exponent10_positive_0(type(val, 0), 1).first;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
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float_exponent10_negative_1(sprout::pair<int, FloatType> const& current, int n) {
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typedef sprout::pair<int, FloatType> type;
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return !((current.second) < 1) ? current
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: n == 1 ? type(current.first + 1, current.second * 10)
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: sprout::detail::float_exponent10_negative_1(
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sprout::detail::float_exponent10_negative_1(
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current,
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n / 2
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),
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n - n / 2
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)
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;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
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float_exponent10_negative_0(sprout::pair<int, FloatType> const& current, int n) {
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return !((current.second) < 1) ? current
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: sprout::detail::float_exponent10_negative_0(
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sprout::detail::float_exponent10_negative_1(
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current,
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n
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),
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n * 2
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)
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;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR int
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float_exponent10_negative(FloatType val) {
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typedef sprout::pair<int, FloatType> type;
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return float_exponent10_negative_0(type(val, 0), 1).first;
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}
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// !!! OLD:
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// template<typename FloatType>
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// inline SPROUT_CONSTEXPR int
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// float_exponent10_positive(FloatType val) {
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// return val < 10 ? 0
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// : 1 + sprout::detail::float_exponent10_positive(val / 10)
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// ;
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// }
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// template<typename FloatType>
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// inline SPROUT_CONSTEXPR int
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// float_exponent10_negative(FloatType val) {
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// return val < 1 ? 1 + sprout::detail::float_exponent10_negative(val * 10)
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// : 0
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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 int
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float_exponent10(FloatType val) {
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return val < 0
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? val > -1
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? sprout::detail::float_exponent10_negative(-val)
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: sprout::detail::float_exponent10_positive(-val)
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: val < 1
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? sprout::detail::float_exponent10_negative(val)
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: sprout::detail::float_exponent10_positive(val)
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;
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}
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//
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// float_digit_at
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//
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template<typename FloatType>
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inline SPROUT_CONSTEXPR int
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float_digit_of_impl(FloatType val) {
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return static_cast<int>((val - sprout::math::floor(val)) * 10);
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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 int
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float_digit_at(FloatType val, int digits) {
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return sprout::detail::float_digit_of_impl(val / sprout::detail::float_pow10<FloatType>(digits + 1));
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}
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//
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// float_digits
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//
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template<typename FloatType>
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inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
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float_digits_impl_1(sprout::pair<int, FloatType> const& current, FloatType val, int n) {
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typedef sprout::pair<int, FloatType> type;
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return (val / current.second) < 1 ? current
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: n == 1 ? type(current.first + 1, current.second * FloatType(10))
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: sprout::detail::float_digits_impl_1(
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sprout::detail::float_digits_impl_1(
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current,
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val, n / 2
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),
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val, n - n / 2
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)
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;
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}
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template<typename FloatType>
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inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
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float_digits_impl(sprout::pair<int, FloatType> const& current, FloatType val, int n) {
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return (val / current.second) < 1 ? current
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: sprout::detail::float_digits_impl(
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sprout::detail::float_digits_impl_1(
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current,
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val, n
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),
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val, n * 2
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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 int
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float_digits(FloatType val) {
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typedef sprout::pair<int, FloatType> type;
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return val < 0
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? val > -1 ? 1 : sprout::detail::float_digits_impl(type(1, FloatType(10)), -val, 1).first
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: val < 1 ? 1 : sprout::detail::float_digits_impl(type(1, FloatType(10)), val, 1).first
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;
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}
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//
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// float_digits_checked
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//
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template<typename FloatType>
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inline SPROUT_CONSTEXPR int
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float_digits_checked_impl(FloatType val, int digits) {
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return val == 0 ? digits
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: sprout::detail::float_digit_at(val, digits - 1) == 0 ? digits - 1 : digits
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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 int
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float_digits_checked(FloatType val) {
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return sprout::detail::float_digits_checked_impl(val, sprout::detail::float_digits(val));
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}
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//
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// float_round_at
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//
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template<typename FloatType>
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inline SPROUT_CONSTEXPR FloatType
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float_round_impl(FloatType val, FloatType p10) {
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return sprout::math::round(val * p10) / p10;
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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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float_round_at(FloatType val, int digits) {
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return sprout::detail::float_round_impl(val, sprout::detail::float_pow10<FloatType>(digits));
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}
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} // namespace detail
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} // namespace sprout
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#endif // #ifndef SPROUT_DETAIL_FLOAT_HPP
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