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fix to_string(FloatType): for large float value

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This commit is contained in:
bolero-MURAKAMI 2013-08-06 00:05:45 +09:00
parent 9883dacfe2
commit fc5e510c3c
2 changed files with 67 additions and 41 deletions
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106
sprout/detail/math/float.hpp
View file

@ -7,41 +7,26 @@
#include <sprout/math/floor.hpp>
#include <sprout/math/round.hpp>
#include <sprout/type_traits/enabler_if.hpp>
#include <sprout/detail/pow.hpp>
namespace sprout {
namespace detail {
//
// float_pow10
//
template<typename FloatType>
inline SPROUT_CONSTEXPR FloatType
float_pow10_positive(int exponent) {
return exponent ? sprout::detail::float_pow10_positive<FloatType>(exponent - 1) * 10
: FloatType(1)
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR FloatType
float_pow10_negative(int exponent) {
return exponent ? sprout::detail::float_pow10_negative<FloatType>(exponent + 1) / 10
: FloatType(1)
;
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR FloatType
float_pow10(int exponent) {
return exponent < 0
? sprout::detail::float_pow10_negative<FloatType>(exponent)
: sprout::detail::float_pow10_positive<FloatType>(exponent)
;
return sprout::detail::pow_n(FloatType(10), exponent);
}
//
// float_exponent10
//
// !!!
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_exponent10_positive(FloatType val) {
@ -72,28 +57,6 @@ namespace sprout {
;
}
//
// float_digits
//
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_digits_impl(FloatType val, FloatType n) {
return val / n < 1 ? 0
: 1 + sprout::detail::float_digits_impl(val, n * FloatType(10))
;
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR int
float_digits(FloatType val) {
return val < 0
? val > -1 ? 1 : 1 + sprout::detail::float_digits_impl(-val, FloatType(10))
: val < 1 ? 1 : 1 + sprout::detail::float_digits_impl(val, FloatType(10))
;
}
//
// float_digit_at
//
@ -111,6 +74,69 @@ namespace sprout {
return sprout::detail::float_digit_of_impl(val / sprout::detail::float_pow10<FloatType>(digits + 1));
}
//
// float_digits
//
template<typename FloatType>
inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
float_digits_impl_1(sprout::pair<int, FloatType> const& current, FloatType val, int n) {
typedef sprout::pair<int, FloatType> type;
return (val / current.second) < 1 ? current
: n == 1 ? type(current.first + 1, current.second * FloatType(10))
: sprout::detail::float_digits_impl_1(
sprout::detail::float_digits_impl_1(
current,
val, n / 2
),
val, n - n / 2
)
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR sprout::pair<int, FloatType>
float_digits_impl(sprout::pair<int, FloatType> const& current, FloatType val, int n) {
return (val / current.second) < 1 ? current
: sprout::detail::float_digits_impl(
sprout::detail::float_digits_impl_1(
current,
val, n
),
val, n * 2
)
;
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR int
float_digits(FloatType val) {
typedef sprout::pair<int, FloatType> type;
return val < 0
? val > -1 ? 1 : sprout::detail::float_digits_impl(type(1, FloatType(10)), -val, 1).first
: val < 1 ? 1 : sprout::detail::float_digits_impl(type(1, FloatType(10)), val, 1).first
;
}
//
// float_digits_checked
//
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_digits_checked_impl(FloatType val, int digits) {
return val == 0 ? digits
: sprout::detail::float_digit_at(val, digits - 1) == 0 ? digits - 1 : digits
;
}
template<
typename FloatType,
typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
>
inline SPROUT_CONSTEXPR int
float_digits_checked(FloatType val) {
return sprout::detail::float_digits_checked_impl(val, sprout::detail::float_digits(val));
}
//
// float_round_at
//

2
sprout/string/float_to_string.hpp
View file

@ -93,7 +93,7 @@ namespace sprout {
: sprout::detail::float_to_string<Elem>(
sprout::detail::float_round_at(val < 0 ? -val : val, sprout::detail::decimal_places_length),
sprout::math::signbit(val),
sprout::detail::float_digits(val)
sprout::detail::float_digits_checked(val)
)
;
}