From 9883dacfe29ff811a3baae5be94db5bcd4e03c5a Mon Sep 17 00:00:00 2001
From: bolero-MURAKAMI <bolero.murakami@gmail.com>
Date: Mon, 5 Aug 2013 22:18:02 +0900
Subject: [PATCH] fix to_string(FloatType): support inf, NaN; bug(digit count)

---
 sprout/detail/math/float.hpp      | 38 ++++++++++----------
 sprout/string/float_to_string.hpp | 59 +++++++++++++++++++++----------
 2 files changed, 59 insertions(+), 38 deletions(-)

diff --git a/sprout/detail/math/float.hpp b/sprout/detail/math/float.hpp
index 159bb062..b52ede66 100644
--- a/sprout/detail/math/float.hpp
+++ b/sprout/detail/math/float.hpp
@@ -75,37 +75,37 @@ 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_impl(FloatType val) {
-			return val < 1 ? 0
-				: 1 + sprout::detail::float_digits_impl(val / 10)
-				;
-		}
-		template<typename FloatType>
-		inline SPROUT_CONSTEXPR int
 		float_digits(FloatType val) {
 			return val < 0
-				? val > -1 ? 1 : 1 + sprout::detail::float_digits_impl(-val / 10)
-				: val < 1 ? 1 : 1 + sprout::detail::float_digits_impl(val / 10)
+				? 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
 		//
-		template<
-			typename FloatType,
-			typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
-		>
+		template<typename FloatType>
 		inline SPROUT_CONSTEXPR int
 		float_digit_of_impl(FloatType val) {
 			return static_cast<int>((val - sprout::math::floor(val)) * 10);
 		}
-		template<typename FloatType>
+		template<
+			typename FloatType,
+			typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+		>
 		inline SPROUT_CONSTEXPR int
 		float_digit_at(FloatType val, int digits) {
 			return sprout::detail::float_digit_of_impl(val / sprout::detail::float_pow10<FloatType>(digits + 1));
@@ -114,15 +114,15 @@ namespace sprout {
 		//
 		// float_round_at
 		//
-		template<
-			typename FloatType,
-			typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
-		>
+		template<typename FloatType>
 		inline SPROUT_CONSTEXPR FloatType
 		float_round_impl(FloatType val, FloatType p10) {
 			return sprout::math::round(val * p10) / p10;
 		}
-		template<typename FloatType>
+		template<
+			typename FloatType,
+			typename sprout::enabler_if<std::is_floating_point<FloatType>::value>::type = sprout::enabler
+		>
 		inline SPROUT_CONSTEXPR FloatType
 		float_round_at(FloatType val, int digits) {
 			return sprout::detail::float_round_impl(val, sprout::detail::float_pow10<FloatType>(digits));
diff --git a/sprout/string/float_to_string.hpp b/sprout/string/float_to_string.hpp
index 572c81b0..092ed4d7 100644
--- a/sprout/string/float_to_string.hpp
+++ b/sprout/string/float_to_string.hpp
@@ -8,6 +8,9 @@
 #include <sprout/index_tuple/metafunction.hpp>
 #include <sprout/string/string.hpp>
 #include <sprout/type_traits/enabler_if.hpp>
+#include <sprout/math/isinf.hpp>
+#include <sprout/math/isnan.hpp>
+#include <sprout/math/signbit.hpp>
 #include <sprout/math/floor.hpp>
 #include <sprout/detail/char_conversion.hpp>
 #include <sprout/detail/math/int.hpp>
@@ -34,8 +37,9 @@ namespace sprout {
 		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_impl(FloatType val, bool negative, int digits, int v, sprout::index_tuple<Indexes...>) {
+			typedef sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value> type;
 			return negative
-				? sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value>{
+				? type{
 					{
 						static_cast<Elem>('-'),
 						(Indexes < digits ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, digits - 1 - Indexes))
@@ -47,7 +51,7 @@ namespace sprout {
 						},
 						static_cast<std::size_t>(digits + 2 + sprout::detail::decimal_places_length)
 					}
-				: sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value>{
+				: type{
 					{
 						(Indexes < digits ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, digits - 1 - Indexes))
 							: Indexes == digits ? static_cast<Elem>('.')
@@ -79,11 +83,19 @@ 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_at(val < 0 ? -val : val, sprout::detail::decimal_places_length),
-			val < 0,
-			sprout::detail::float_digits(val)
-			);
+		typedef sprout::basic_string<Elem, sprout::printed_float_digits<FloatType>::value> type;
+		return sprout::math::isinf(val) ? sprout::math::signbit(val)
+				? type{{static_cast<Elem>('-'), static_cast<Elem>('i'), static_cast<Elem>('n'), static_cast<Elem>('f')}, 4}
+				: type{{static_cast<Elem>('i'), static_cast<Elem>('n'), static_cast<Elem>('f')}, 3}
+			: sprout::math::isnan(val) ? sprout::math::signbit(val)
+				? type{{static_cast<Elem>('-'), static_cast<Elem>('n'), static_cast<Elem>('a'), static_cast<Elem>('n')}, 4}
+				: type{{static_cast<Elem>('n'), static_cast<Elem>('a'), static_cast<Elem>('n')}, 3}
+			: 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)
+				)
+			;
 	}
 
 	namespace detail {
@@ -111,8 +123,9 @@ namespace sprout {
 		template<typename Elem, typename FloatType, sprout::index_t... Indexes>
 		inline SPROUT_CONSTEXPR sprout::basic_string<Elem, sprout::printed_float_exp_digits<FloatType>::value>
 		float_to_string_exp(FloatType val, bool negative, int exponent10, int e10_digits, sprout::index_tuple<Indexes...>) {
+			typedef sprout::basic_string<Elem, sprout::printed_float_exp_digits<FloatType>::value> type;
 			return negative
-				? sprout::basic_string<Elem, sprout::printed_float_exp_digits<FloatType>::value>{
+				? type{
 					{
 						static_cast<Elem>('-'),
 						(Indexes == 0 ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, 0))
@@ -128,7 +141,7 @@ namespace sprout {
 						},
 						static_cast<std::size_t>(5 + sprout::detail::decimal_places_length + e10_digits)
 					}
-				: sprout::basic_string<Elem, sprout::printed_float_exp_digits<FloatType>::value>{
+				: type{
 					{
 						(Indexes == 0 ? sprout::detail::int_to_char<Elem>(sprout::detail::float_digit_at(val, 0))
 							: Indexes == 1 ? static_cast<Elem>('.')
@@ -156,16 +169,24 @@ namespace sprout {
 	>
 	inline SPROUT_CONSTEXPR sprout::basic_string<Elem, sprout::printed_float_exp_digits<FloatType>::value>
 	float_to_string_exp(FloatType val) {
-		return sprout::detail::float_to_string_exp<Elem>(
-			sprout::detail::float_round_at(
-				(val < 0 ? -val : val) / sprout::detail::float_pow10<FloatType>(sprout::detail::float_exponent10(val)),
-				sprout::detail::decimal_places_length
-				),
-			val < 0,
-			sprout::detail::float_exponent10(val),
-			NS_SSCRISK_CEL_OR_SPROUT::max(sprout::detail::int_digits(sprout::detail::float_exponent10(val)), 2),
-			sprout::make_index_tuple<sprout::printed_float_exp_digits<FloatType>::value - 1>::make()
-			);
+		typedef sprout::basic_string<Elem, sprout::printed_float_exp_digits<FloatType>::value> type;
+		return sprout::math::isinf(val) ? sprout::math::signbit(val)
+				? type{{static_cast<Elem>('-'), static_cast<Elem>('i'), static_cast<Elem>('n'), static_cast<Elem>('f')}, 4}
+				: type{{static_cast<Elem>('i'), static_cast<Elem>('n'), static_cast<Elem>('f')}, 3}
+			: sprout::math::isnan(val) ? sprout::math::signbit(val)
+				? type{{static_cast<Elem>('-'), static_cast<Elem>('n'), static_cast<Elem>('a'), static_cast<Elem>('n')}, 4}
+				: type{{static_cast<Elem>('n'), static_cast<Elem>('a'), static_cast<Elem>('n')}, 3}
+			: sprout::detail::float_to_string_exp<Elem>(
+				sprout::detail::float_round_at(
+					(val < 0 ? -val : val) / sprout::detail::float_pow10<FloatType>(sprout::detail::float_exponent10(val)),
+					sprout::detail::decimal_places_length
+					),
+				sprout::math::signbit(val),
+				sprout::detail::float_exponent10(val),
+				NS_SSCRISK_CEL_OR_SPROUT::max(sprout::detail::int_digits(sprout::detail::float_exponent10(val)), 2),
+				sprout::make_index_tuple<sprout::printed_float_exp_digits<FloatType>::value - 1>::make()
+				)
+			;
 	}
 
 	//