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Merge bc53b798e6 into a29fcae409

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Jett LaRue 2016-10-26 17:20:57 +00:00 committed by GitHub
commit 703d0395c4
2 changed files with 260 additions and 90 deletions
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175
src/json.hpp
View File

@ -8800,64 +8800,149 @@ basic_json_parser_63:
return result; return result;
} }
/*! // non locale aware isdigit
@brief parse floating point number // 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
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).
@param[in] type the @ref number_float_t in use
@param[in,out] endptr recieves a pointer to the first character after
the number
@return the floating point number
*/
long double str_to_float_t(long double* /* type */, char** endptr) const
{ {
return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr); return c >= '0' and c <= '9';
} }
/*! /*!
@brief parse floating point number @brief parse string to floating point number
This function (and its overloads) serves to select the most approprate This function is a partial reimplementation of the strtold in order to meet needs of JSON number
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).
@param[in] type the @ref number_float_t in use @param[in] str the string we will parse
@param[in,out] endptr recieves a pointer to the first character after
the number
@return the floating point number @return the floating point number
*/ */
double str_to_float_t(double* /* type */, char** endptr) const long double strtojnum(const char *str) const
{ {
return std::strtod(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 == '-';
/*! if (cp == '-' or cp == '+')
@brief parse floating point number {
++str;
}
This function (and its overloads) serves to select the most approprate // read in fractional part of number, until an 'e' is reached.
standard floating point number parsing function based on the type // count digits after decimal point.
supplied via the first parameter. Set this to @a while (nl_isdigit(cp = *str))
static_cast<number_float_t*>(nullptr). {
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 // if negative number, reverse sign
the number if (negative_sign)
{
result *= -1;
}
}
@return the floating point number // read in explicit exponent and calculate real exponent.
*/ if (*str == 'e' or *str == 'E')
float str_to_float_t(float* /* type */, char** endptr) const {
{ cp = *++str;
return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
const bool negative_exp = cp == '-'; // read in exponent sign (+/-)
const bool plus_or_minus = (cp == '-' or cp == '+');
if (plus_or_minus)
{
cp = *++str;
}
int count = 0; // exponent calculation
if (not nl_isdigit(cp))
{
if (plus_or_minus)
{
*--str;
}
*--str;
goto skip_loop;
}
while (nl_isdigit(cp))
{
constexpr int imax = std::numeric_limits<int>::max();
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 @@ basic_json_parser_63:
} }
else else
{ {
// parse with strtod // convert string by json number format to floating point
result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL); result.m_value.number_float = strtojnum(reinterpret_cast<typename string_t::const_pointer>(m_start));
} }
// save the type // save the type

175
src/json.hpp.re2c
View File

@ -8097,64 +8097,149 @@ class basic_json
return result; return result;
} }
/*! // non locale aware isdigit
@brief parse floating point number // 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
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).
@param[in] type the @ref number_float_t in use
@param[in,out] endptr recieves a pointer to the first character after
the number
@return the floating point number
*/
long double str_to_float_t(long double* /* type */, char** endptr) const
{ {
return std::strtold(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr); return c >= '0' and c <= '9';
} }
/*! /*!
@brief parse floating point number @brief parse string to floating point number
This function (and its overloads) serves to select the most approprate This function is a partial reimplementation of the strtold in order to meet needs of JSON number
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).
@param[in] type the @ref number_float_t in use @param[in] str the string we will parse
@param[in,out] endptr recieves a pointer to the first character after
the number
@return the floating point number @return the floating point number
*/ */
double str_to_float_t(double* /* type */, char** endptr) const long double strtojnum(const char *str) const
{ {
return std::strtod(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 == '-';
/*! if (cp == '-' or cp == '+')
@brief parse floating point number {
++str;
}
This function (and its overloads) serves to select the most approprate // read in fractional part of number, until an 'e' is reached.
standard floating point number parsing function based on the type // count digits after decimal point.
supplied via the first parameter. Set this to @a while (nl_isdigit(cp = *str))
static_cast<number_float_t*>(nullptr). {
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 // if negative number, reverse sign
the number if (negative_sign)
{
result *= -1;
}
}
@return the floating point number // read in explicit exponent and calculate real exponent.
*/ if (*str == 'e' or *str == 'E')
float str_to_float_t(float* /* type */, char** endptr) const {
{ cp = *++str;
return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
const bool negative_exp = cp == '-'; // read in exponent sign (+/-)
const bool plus_or_minus = (cp == '-' or cp == '+');
if (plus_or_minus)
{
cp = *++str;
}
int count = 0; // exponent calculation
if (not nl_isdigit(cp))
{
if (plus_or_minus)
{
*--str;
}
*--str;
goto skip_loop;
}
while (nl_isdigit(cp))
{
constexpr int imax = std::numeric_limits<int>::max();
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 else
{ {
// parse with strtod // convert string by json number format to floating point
result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL); result.m_value.number_float = strtojnum(reinterpret_cast<typename string_t::const_pointer>(m_start));
} }
// save the type // save the type