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add detail/float.hpp

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This commit is contained in:
bolero-MURAKAMI 2012-04-18 17:46:27 +09:00
parent 22f13db2a0
commit 80763fd432
2 changed files with 124 additions and 54 deletions
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60
sprout/string/float_to_string.hpp
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@ -9,6 +9,7 @@
#include <sprout/string/string.hpp>
#include <sprout/utility/enabler_if.hpp>
#include <sprout/detail/char_conversion.hpp>
#include <sprout/detail/float.hpp>
namespace sprout {
namespace detail {
@ -27,64 +28,15 @@ namespace sprout {
{};
namespace detail {
template<typename FloatType>
inline SPROUT_CONSTEXPR FloatType
float_pow10(int exponent) {
return exponent ? FloatType(10) * sprout::detail::float_pow10<FloatType>(exponent - 1)
: FloatType(1)
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_digits_impl(FloatType val) {
return !(val < 1 && val > -1) ? 1 + sprout::detail::float_digits_impl(val / 10)
: 0
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_digits(FloatType val) {
return !(val < 1 && val > -1) ? 1 + sprout::detail::float_digits_impl(val / 10)
: 1
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_digit_of_impl(FloatType val) {
using std::floor;
return static_cast<int>((val - floor(val)) * 10);
}
template<typename FloatType>
inline SPROUT_CONSTEXPR int
float_digit_of(FloatType val, int digits) {
return digits < 0 ? sprout::detail::float_digit_of_impl(val * sprout::detail::float_pow10<FloatType>(-digits - 1))
: sprout::detail::float_digit_of_impl(val / sprout::detail::float_pow10<FloatType>(digits + 1))
;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR FloatType
float_round_impl(FloatType val, FloatType p10) {
using std::round;
return round(val * p10) / p10;
}
template<typename FloatType>
inline SPROUT_CONSTEXPR FloatType
float_round(FloatType val, int digits) {
return sprout::detail::float_round_impl(val, sprout::detail::float_pow10<FloatType>(digits));
}
template<typename Elem, typename FloatType, sprout::index_t... Indexes>
inline SPROUT_CONSTEXPR sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value>
float_to_string(FloatType val, bool negative, int digits, sprout::index_tuple<Indexes...>) {
return negative ? sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value>{
{
static_cast<Elem>('-'),
(Indexes < digits ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_of(val, digits - 1 - Indexes))
(Indexes < digits ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, digits - 1 - Indexes))
: Indexes == digits ? static_cast<Elem>('.')
: Indexes < digits + 1 + sprout::detail::decimal_places_length ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_of(val, digits - Indexes))
: Indexes < digits + 1 + sprout::detail::decimal_places_length ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, digits - Indexes))
: Elem()
)...
},
@ -92,9 +44,9 @@ namespace sprout {
}
: sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value>{
{
(Indexes < digits ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_of(val, digits - 1 - Indexes))
(Indexes < digits ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, digits - 1 - Indexes))
: Indexes == digits ? static_cast<Elem>('.')
: Indexes < digits + 1 + sprout::detail::decimal_places_length ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_of(val, digits - Indexes))
: Indexes < digits + 1 + sprout::detail::decimal_places_length ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, digits - Indexes))
: Elem()
)...
},
@ -115,7 +67,7 @@ namespace sprout {
inline SPROUT_CONSTEXPR sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value>
float_to_string(FloatType val) {
return sprout::detail::float_to_string<Elem>(
sprout::detail::float_round(val < 0 ? -val : val, sprout::detail::decimal_places_length),
sprout::detail::float_round_at(val < 0 ? -val : val, sprout::detail::decimal_places_length),
val < 0,
sprout::detail::float_digits(val),
sprout::index_range<0, sprout::printed_float_digits<FloatType>::value - 1>::make()