diff --git a/src/json.hpp b/src/json.hpp
index 9c0df9d497..0509e45649 100644
--- a/src/json.hpp
+++ b/src/json.hpp
@@ -8800,64 +8800,149 @@ class basic_json
return result;
}
- /*!
- @brief parse floating point number
+ // non locale aware isdigit
+ // Microsoft in 1252 codepage and others may classify additional single-byte characters as digits using std::isdigit
+ constexpr bool nl_isdigit(const char c) const
+ {
+ return c >= '0' and c <= '9';
+ }
- This function (and its overloads) serves to select the most approprate
- standard floating point number parsing function based on the type
- supplied via the first parameter. Set this to @a
- static_cast<number_float_t*>(nullptr).
+ /*!
+ @brief parse string to floating point number
- @param[in] type the @ref number_float_t in use
+ This function is a partial reimplementation of the strtold in order to meet needs of JSON number
- @param[in,out] endptr recieves a pointer to the first character after
- the number
+ @param[in] str the string we will parse
@return the floating point number
*/
- long double str_to_float_t(long double* /* type */, char** endptr) const
+ long double strtojnum(const char *str) const
{
- return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
- }
+ long double result = 0;
+ char cp = *str;
+ int exp = 0; // exponent
+ {
+ const bool negative_sign = cp == '-';
- /*!
- @brief parse floating point number
+ if (cp == '-' or cp == '+')
+ {
+ ++str;
+ }
- This function (and its overloads) serves to select the most approprate
- standard floating point number parsing function based on the type
- supplied via the first parameter. Set this to @a
- static_cast<number_float_t*>(nullptr).
+ // read in fractional part of number, until an 'e' is reached.
+ // count digits after decimal point.
+ while (nl_isdigit(cp = *str))
+ {
+ result = result * 10 + (cp - '0');
+ ++str;
+ }
- @param[in] type the @ref number_float_t in use
+ if (cp == '.')
+ {
+ while (nl_isdigit(cp = *++str))
+ {
+ result = result * 10 + (cp - '0');
+ --exp;
+ }
+ }
- @param[in,out] endptr recieves a pointer to the first character after
- the number
+ // if negative number, reverse sign
+ if (negative_sign)
+ {
+ result *= -1;
+ }
+ }
- @return the floating point number
- */
- double str_to_float_t(double* /* type */, char** endptr) const
- {
- return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
- }
+ // read in explicit exponent and calculate real exponent.
+ if (*str == 'e' or *str == 'E')
+ {
+ cp = *++str;
- /*!
- @brief parse floating point number
+ const bool negative_exp = cp == '-'; // read in exponent sign (+/-)
+ const bool plus_or_minus = (cp == '-' or cp == '+');
+ if (plus_or_minus)
+ {
+ cp = *++str;
+ }
- This function (and its overloads) serves to select the most approprate
- standard floating point number parsing function based on the type
- supplied via the first parameter. Set this to @a
- static_cast<number_float_t*>(nullptr).
+ int count = 0; // exponent calculation
+ if (not nl_isdigit(cp))
+ {
+ if (plus_or_minus)
+ {
+ *--str;
+ }
- @param[in] type the @ref number_float_t in use
+ *--str;
+ goto skip_loop;
+ }
- @param[in,out] endptr recieves a pointer to the first character after
- the number
+ while (nl_isdigit(cp))
+ {
+ constexpr int imax = std::numeric_limits<int>::max();
- @return the floating point number
- */
- float str_to_float_t(float* /* type */, char** endptr) const
- {
- return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+ if ((imax - std::abs(exp) - (cp - '0')) / 10 > count)
+ {
+ count *= 10;
+ count += cp - '0';
+ }
+ else
+ {
+ count = imax - exp;
+ break;
+ }
+
+ cp = *++str;
+ }
+skip_loop:
+ exp += negative_exp ? -count : count;
+ }
+
+ // adjust number by powers of ten specified by format and exponent.
+ constexpr std::array<long double, 9> powerof10 = {
+ {1.e1L, 1.e2L, 1.e4L, 1.e8L, 1.e16L, 1.e32L, 1.e64L, 1.e128L, 1.e256L}
+ };
+
+ // round to INF if our exponent is larger than representable number
+ if (exp > std::numeric_limits<long double>::max_exponent10)
+ {
+ constexpr long double inf = std::numeric_limits<long double>::infinity();
+ result = (result < 0) ? -inf : inf;
+ }
+ // round to zero if our exponent is smaller than representable number
+ else if (exp < std::numeric_limits<long double>::min_exponent10)
+ {
+ result = 0.0L;
+ }
+ // iteratively divide result for negative exp
+ else if (exp < 0)
+ {
+ // make exp positive for loop below
+ exp *= -1;
+
+ // check enabled exp bits on lookup powerof10 lookup table
+ for (std::size_t count = 0; exp; ++count, exp >>= 1)
+ {
+ if (exp & 1)
+ {
+ result /= powerof10[count];
+ }
+ }
+ }
+ // iteratively multiply result for positive exp
+ else
+ {
+ // check enabled exp bits on lookup powerof10 lookup table
+ for (std::size_t count = 0; exp; ++count, exp >>= 1)
+ {
+ if (exp & 1)
+ {
+ result *= powerof10[count];
+ }
+ }
+ }
+
+ return result;
}
/*!
@@ -8958,8 +9043,8 @@ class basic_json
}
else
{
- // parse with strtod
- result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
+ // convert string by json number format to floating point
+ result.m_value.number_float = strtojnum(reinterpret_cast<typename string_t::const_pointer>(m_start));
}
// save the type
diff --git a/src/json.hpp.re2c b/src/json.hpp.re2c
index 656e13b319..99631bbae2 100644
--- a/src/json.hpp.re2c
+++ b/src/json.hpp.re2c
@@ -8097,64 +8097,149 @@ class basic_json
return result;
}
- /*!
- @brief parse floating point number
+ // non locale aware isdigit
+ // Microsoft in 1252 codepage and others may classify additional single-byte characters as digits using std::isdigit
+ constexpr bool nl_isdigit(const char c) const
+ {
+ return c >= '0' and c <= '9';
+ }
- This function (and its overloads) serves to select the most approprate
- standard floating point number parsing function based on the type
- supplied via the first parameter. Set this to @a
- static_cast<number_float_t*>(nullptr).
+ /*!
+ @brief parse string to floating point number
- @param[in] type the @ref number_float_t in use
+ This function is a partial reimplementation of the strtold in order to meet needs of JSON number
- @param[in,out] endptr recieves a pointer to the first character after
- the number
+ @param[in] str the string we will parse
@return the floating point number
*/
- long double str_to_float_t(long double* /* type */, char** endptr) const
+ long double strtojnum(const char *str) const
{
- return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
- }
+ long double result = 0;
+ char cp = *str;
+ int exp = 0; // exponent
+ {
+ const bool negative_sign = cp == '-';
- /*!
- @brief parse floating point number
+ if (cp == '-' or cp == '+')
+ {
+ ++str;
+ }
- This function (and its overloads) serves to select the most approprate
- standard floating point number parsing function based on the type
- supplied via the first parameter. Set this to @a
- static_cast<number_float_t*>(nullptr).
+ // read in fractional part of number, until an 'e' is reached.
+ // count digits after decimal point.
+ while (nl_isdigit(cp = *str))
+ {
+ result = result * 10 + (cp - '0');
+ ++str;
+ }
- @param[in] type the @ref number_float_t in use
+ if (cp == '.')
+ {
+ while (nl_isdigit(cp = *++str))
+ {
+ result = result * 10 + (cp - '0');
+ --exp;
+ }
+ }
- @param[in,out] endptr recieves a pointer to the first character after
- the number
+ // if negative number, reverse sign
+ if (negative_sign)
+ {
+ result *= -1;
+ }
+ }
- @return the floating point number
- */
- double str_to_float_t(double* /* type */, char** endptr) const
- {
- return std::strtod(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
- }
+ // read in explicit exponent and calculate real exponent.
+ if (*str == 'e' or *str == 'E')
+ {
+ cp = *++str;
- /*!
- @brief parse floating point number
+ const bool negative_exp = cp == '-'; // read in exponent sign (+/-)
+ const bool plus_or_minus = (cp == '-' or cp == '+');
+ if (plus_or_minus)
+ {
+ cp = *++str;
+ }
- This function (and its overloads) serves to select the most approprate
- standard floating point number parsing function based on the type
- supplied via the first parameter. Set this to @a
- static_cast<number_float_t*>(nullptr).
+ int count = 0; // exponent calculation
+ if (not nl_isdigit(cp))
+ {
+ if (plus_or_minus)
+ {
+ *--str;
+ }
- @param[in] type the @ref number_float_t in use
+ *--str;
+ goto skip_loop;
+ }
- @param[in,out] endptr recieves a pointer to the first character after
- the number
+ while (nl_isdigit(cp))
+ {
+ constexpr int imax = std::numeric_limits<int>::max();
- @return the floating point number
- */
- float str_to_float_t(float* /* type */, char** endptr) const
- {
- return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
+ if ((imax - std::abs(exp) - (cp - '0')) / 10 > count)
+ {
+ count *= 10;
+ count += cp - '0';
+ }
+ else
+ {
+ count = imax - exp;
+ break;
+ }
+
+ cp = *++str;
+ }
+skip_loop:
+ exp += negative_exp ? -count : count;
+ }
+
+ // adjust number by powers of ten specified by format and exponent.
+ constexpr std::array<long double, 9> powerof10 = {
+ {1.e1L, 1.e2L, 1.e4L, 1.e8L, 1.e16L, 1.e32L, 1.e64L, 1.e128L, 1.e256L}
+ };
+
+ // round to INF if our exponent is larger than representable number
+ if (exp > std::numeric_limits<long double>::max_exponent10)
+ {
+ constexpr long double inf = std::numeric_limits<long double>::infinity();
+ result = (result < 0) ? -inf : inf;
+ }
+ // round to zero if our exponent is smaller than representable number
+ else if (exp < std::numeric_limits<long double>::min_exponent10)
+ {
+ result = 0.0L;
+ }
+ // iteratively divide result for negative exp
+ else if (exp < 0)
+ {
+ // make exp positive for loop below
+ exp *= -1;
+
+ // check enabled exp bits on lookup powerof10 lookup table
+ for (std::size_t count = 0; exp; ++count, exp >>= 1)
+ {
+ if (exp & 1)
+ {
+ result /= powerof10[count];
+ }
+ }
+ }
+ // iteratively multiply result for positive exp
+ else
+ {
+ // check enabled exp bits on lookup powerof10 lookup table
+ for (std::size_t count = 0; exp; ++count, exp >>= 1)
+ {
+ if (exp & 1)
+ {
+ result *= powerof10[count];
+ }
+ }
+ }
+
+ return result;
}
/*!
@@ -8255,8 +8340,8 @@ class basic_json
}
else
{
- // parse with strtod
- result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
+ // convert string by json number format to floating point
+ result.m_value.number_float = strtojnum(reinterpret_cast<typename string_t::const_pointer>(m_start));
}
// save the type