mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
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282 lines
8.1 KiB
C++
282 lines
8.1 KiB
C++
/*=============================================================================
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Copyright (c) 2011-2014 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_CSTDLIB_STR_TO_FLOAT_HPP
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#define SPROUT_CSTDLIB_STR_TO_FLOAT_HPP
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#include <cstddef>
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#include <cstdlib>
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#include <cmath>
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#include <type_traits>
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#include <sprout/config.hpp>
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#include <sprout/limits.hpp>
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#include <sprout/iterator/operation.hpp>
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#include <sprout/ctype/ascii.hpp>
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namespace sprout {
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namespace detail {
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl_scale(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0,
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std::size_t num_decimals = 0,
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long exponent = 0,
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long n = 0,
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FloatType p10 = FloatType(10)
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)
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{
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return n ? sprout::detail::str_to_float_impl_scale<FloatType>(
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str,
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negative,
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n & 1 ? (exponent < 0 ? number / p10 : number * p10) : number,
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num_digits,
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num_decimals,
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exponent,
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n >> 1,
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p10 * p10
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)
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: number
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl_exponent_2(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0,
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std::size_t num_decimals = 0,
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long exponent = 0
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)
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{
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return exponent >= sprout::numeric_limits<FloatType>::min_exponent
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&& exponent <= sprout::numeric_limits<FloatType>::max_exponent
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? sprout::detail::str_to_float_impl_scale<FloatType>(
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str,
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negative,
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number,
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num_digits,
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num_decimals,
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exponent,
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exponent < 0 ? -exponent : exponent
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)
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: HUGE_VAL
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl_exponent_1(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0,
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std::size_t num_decimals = 0,
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long exponent = 0,
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long n = 0
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)
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{
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typedef typename std::iterator_traits<CStrIterator>::value_type char_type;
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return sprout::ascii::isdigit(*str) ? sprout::detail::str_to_float_impl_exponent_1<FloatType>(
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sprout::next(str),
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negative,
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number,
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num_digits,
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num_decimals,
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exponent,
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n * 10 + (*str - static_cast<char_type>('0'))
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)
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: sprout::detail::str_to_float_impl_exponent_2<FloatType>(
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str,
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negative,
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number,
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num_digits,
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num_decimals,
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negative ? exponent + n : exponent - n
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)
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl_exponent(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0,
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std::size_t num_decimals = 0,
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long exponent = 0
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)
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{
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typedef typename std::iterator_traits<CStrIterator>::value_type char_type;
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return (*str == static_cast<char_type>('e') || *str == static_cast<char_type>('E'))
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? *sprout::next(str) == static_cast<char_type>('-')
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? sprout::detail::str_to_float_impl_exponent_1<FloatType>(
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sprout::next(str, 2),
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true,
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number,
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num_digits,
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num_decimals,
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exponent
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)
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: sprout::detail::str_to_float_impl_exponent_1<FloatType>(
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sprout::next(str, 2),
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false,
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number,
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num_digits,
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num_decimals,
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exponent
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)
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: sprout::detail::str_to_float_impl_exponent_2<FloatType>(
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str,
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negative,
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number,
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num_digits,
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num_decimals,
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exponent
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)
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl_decimal_1(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0,
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std::size_t num_decimals = 0,
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long exponent = 0
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)
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{
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return num_digits == 0 ? FloatType()
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: sprout::detail::str_to_float_impl_exponent<FloatType>(
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str,
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negative,
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negative ? -number : number,
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num_digits,
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num_decimals,
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exponent
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)
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl_decimal(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0,
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std::size_t num_decimals = 0,
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long exponent = 0
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)
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{
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typedef typename std::iterator_traits<CStrIterator>::value_type char_type;
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return sprout::ascii::isdigit(*str) ? sprout::detail::str_to_float_impl_decimal<FloatType>(
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sprout::next(str),
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negative,
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number * 10 + (*str - static_cast<char_type>('0')),
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num_digits + 1,
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num_decimals + 1,
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exponent
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)
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: sprout::detail::str_to_float_impl_decimal_1<FloatType>(
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str,
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negative,
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number,
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num_digits,
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num_decimals,
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exponent - num_decimals
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)
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float_impl(
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CStrIterator str,
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bool negative,
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FloatType number = FloatType(),
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std::size_t num_digits = 0
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)
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{
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typedef typename std::iterator_traits<CStrIterator>::value_type char_type;
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return sprout::ascii::isdigit(*str) ? sprout::detail::str_to_float_impl<FloatType>(
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sprout::next(str),
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negative,
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number * 10 + (*str - static_cast<char_type>('0')),
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num_digits + 1
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)
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: *str == static_cast<char_type>('.') ? sprout::detail::str_to_float_impl_decimal<FloatType>(
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sprout::next(str),
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negative,
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number,
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num_digits
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)
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: sprout::detail::str_to_float_impl_decimal_1<FloatType>(
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str,
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negative,
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number,
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num_digits
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)
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;
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}
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template<typename FloatType, typename CStrIterator>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float(CStrIterator str) {
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return sprout::ascii::isspace(*str)
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? sprout::detail::str_to_float<FloatType>(sprout::next(str))
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: *str == static_cast<typename std::iterator_traits<CStrIterator>::value_type>('-')
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? sprout::detail::str_to_float_impl<FloatType>(sprout::next(str), true)
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: *str == static_cast<typename std::iterator_traits<CStrIterator>::value_type>('+')
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? sprout::detail::str_to_float_impl<FloatType>(sprout::next(str), false)
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: sprout::detail::str_to_float_impl<FloatType>(str, false)
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;
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}
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template<typename FloatType, typename CStrIterator, typename CharPtr>
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inline SPROUT_CONSTEXPR FloatType
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str_to_float(CStrIterator str, CharPtr* endptr) {
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return !endptr ? sprout::detail::str_to_float<FloatType>(str)
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: std::is_same<typename std::remove_cv<FloatType>::type, float>::value ? std::strtof(&*str, endptr)
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: std::is_same<typename std::remove_cv<FloatType>::type, double>::value ? std::strtod(&*str, endptr)
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: std::strtold(&*str, endptr)
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;
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}
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} // namespace detail
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//
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// str_to_float
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//
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template<typename FloatType, typename Char>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_floating_point<FloatType>::value,
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FloatType
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>::type
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str_to_float(Char const* str, Char** endptr) {
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return sprout::detail::str_to_float<FloatType>(str, endptr);
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}
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template<typename FloatType, typename Char>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_floating_point<FloatType>::value,
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FloatType
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>::type
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str_to_float(Char const* str, std::nullptr_t) {
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return sprout::detail::str_to_float<FloatType>(str);
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}
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template<typename FloatType, typename Char>
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inline SPROUT_CONSTEXPR typename std::enable_if<
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std::is_floating_point<FloatType>::value,
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FloatType
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>::type
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str_to_float(Char const* str) {
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return sprout::detail::str_to_float<FloatType>(str);
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}
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} // namespace sprout
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#endif // #ifndef SPROUT_CSTDLIB_STR_TO_FLOAT_HPP
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