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merged #201

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This commit is contained in:
Niels 2016-04-03 14:08:38 +02:00
parent 04edafbddc
commit 9c233be567
9 changed files with 980 additions and 650 deletions
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2
README.md
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@ -402,7 +402,7 @@ I deeply appreciate the help of the following people.
- [406345](https://github.com/406345) fixed two small warnings.
- [Glen Fernandes](https://github.com/glenfe) noted a potential portability problem in the `has_mapped_type` function.
- [Corbin Hughes](https://github.com/nibroc) fixed some typos in the contribution guidelines.
- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers.
- [twelsby](https://github.com/twelsby) fixed the array subscript operator, an issue that failed the MSVC build, and floating-point parsing/dumping. He further added support for unsigned integer numbers and implemented better roundtrip support for parsed numbers.
- [Volker Diels-Grabsch](https://github.com/vog) fixed a link in the README file.
- [msm-](https://github.com/msm-) added support for american fuzzy lop.
- [Annihil](https://github.com/Annihil) fixed an example in the README file.

1255
src/json.hpp
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352
src/json.hpp.re2c
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@ -695,6 +695,74 @@ class basic_json
private:
/*!
@brief a type to hold JSON type information
This bitfield type holds information about JSON types. It is internally
used to hold the basic JSON type enumeration, as well as additional
information in the case of values that have been parsed from a string
including whether of not it was created directly or parsed, and in the
case of floating point numbers the number of significant figures in the
original representaiton and if it was in exponential form, if a '+' was
included in the exponent and the capitilization of the exponent marker.
The sole purpose of this information is to permit accurate round trips.
@since version 2.0.0
*/
union type_data_t
{
struct
{
/// the type of the value (@ref value_t)
uint16_t type : 4;
/// whether the number was parsed from a string
uint16_t parsed : 1;
/// whether parsed number contained an exponent ('e'/'E')
uint16_t has_exp : 1;
/// whether parsed number contained a plus in the exponent
uint16_t exp_plus : 1;
/// whether parsed number's exponent was capitalized ('E')
uint16_t exp_cap : 1;
/// the number of figures for a parsed number
uint16_t precision : 8;
} bits;
uint16_t data;
/// return the type as value_t
operator value_t() const
{
return static_cast<value_t>(bits.type);
}
/// test type for equality (ignore other fields)
bool operator==(const value_t& rhs) const
{
return static_cast<value_t>(bits.type) == rhs;
}
/// assignment
type_data_t& operator=(value_t rhs)
{
bits.type = static_cast<uint16_t>(rhs);
return *this;
}
/// construct from value_t
type_data_t(value_t t) noexcept
{
*reinterpret_cast<uint16_t*>(this) = 0;
bits.type = static_cast<uint16_t>(t);
}
/// default constructor
type_data_t() noexcept
{
data = 0;
bits.type = reinterpret_cast<uint16_t>(value_t::null);
}
};
/// helper for exception-safe object creation
template<typename T, typename... Args>
static T* create(Args&& ... args)
@ -6046,23 +6114,78 @@ class basic_json
case value_t::number_float:
{
// If the number is an integer then output as a fixed with with
// precision 1 to output "0.0", "1.0" etc as expected for some
// round trip tests otherwise 15 digits of precision allows
// round-trip IEEE 754 string->double->string; to be safe, we
// read this value from
// std::numeric_limits<number_float_t>::digits10
if (std::fmod(m_value.number_float, 1) == 0)
// buffer size: precision (2^8-1 = 255) + other ('-.e-xxx' = 7) + null (1)
char buf[263];
int len;
// check if number was parsed from a string
if (m_type.bits.parsed)
{
o << std::fixed << std::setprecision(1);
// check if parsed number had an exponent given
if (m_type.bits.has_exp)
{
// handle capitalization of the exponent
if (m_type.bits.exp_cap)
{
len = snprintf(buf, sizeof(buf), "%.*E", m_type.bits.precision, m_value.number_float) + 1;
}
else
{
len = snprintf(buf, sizeof(buf), "%.*e", m_type.bits.precision, m_value.number_float) + 1;
}
// remove '+' sign from the exponent if necessary
if (not m_type.bits.exp_plus)
{
if (len > static_cast<int>(sizeof(buf)))
{
len = sizeof(buf);
}
for (int i = 0; i < len; i++)
{
if (buf[i] == '+')
{
for (; i + 1 < len; i++)
{
buf[i] = buf[i + 1];
}
}
}
}
}
else
{
// no exponent - output as a decimal
snprintf(buf, sizeof(buf), "%.*f",
m_type.bits.precision, m_value.number_float);
}
}
else if (m_value.number_float == 0)
{
// special case for zero to get "0.0"/"-0.0"
if (std::signbit(m_value.number_float))
{
o << "-0.0";
}
else
{
o << "0.0";
}
return;
}
else
{
// std::defaultfloat not supported in gcc version < 5
o.unsetf(std::ios_base::floatfield);
o << std::setprecision(std::numeric_limits<double>::digits10);
// Otherwise 6, 15 or 16 digits of precision allows
// round-trip IEEE 754 string->float->string,
// string->double->string or string->long double->string;
// to be safe, we read this value from
// std::numeric_limits<number_float_t>::digits10
snprintf(buf, sizeof(buf), "%.*g",
std::numeric_limits<double>::digits10,
m_value.number_float);
}
o << m_value.number_float;
o << buf;
return;
}
@ -6086,7 +6209,7 @@ class basic_json
//////////////////////
/// the type of the current element
value_t m_type = value_t::null;
type_data_t m_type = value_t::null;
/// the value of the current element
json_value m_value = {};
@ -7558,124 +7681,145 @@ class basic_json
return std::strtof(reinterpret_cast<typename string_t::const_pointer>(m_start), endptr);
}
/*!
@brief static_cast between two types and indicate if it results in error
This function performs a `static_cast` between @a source and @a dest.
It then checks if a `static_cast` back to @a dest produces an error.
@param[in] source the value to cast from
@param[in, out] dest the value to cast to
@return true iff the cast was performed without error
*/
template <typename T_A, typename T_B>
static bool attempt_cast(T_A source, T_B& dest)
{
dest = static_cast<T_B>(source);
return (source == static_cast<T_A>(dest));
}
/*!
@brief return number value for number tokens
This function translates the last token into the most appropriate
number type (either integer, unsigned integer or floating point), which
is passed back to the caller via the result parameter. The pointer @a
m_start points to the beginning of the parsed number. We first examine
the first character to determine the sign of the number and then pass
this pointer to either @a std::strtoull (if positive) or @a
std::strtoll (if negative), both of which set @a endptr to the first
character past the converted number. If this pointer is not the same as
@a m_cursor, then either more or less characters have been used during
the comparison.
number type (either integer, unsigned integer or floating point),
which is passed back to the caller via the result parameter.
This can happen for inputs like "01" which will be treated like number
0 followed by number 1. This will also occur for valid floating point
inputs like "12e3" will be incorrectly read as 12. Numbers that are too
large or too small for a signed/unsigned long long will cause a range
error (@a errno set to ERANGE). The parsed number is cast to a @ref
number_integer_t/@ref number_unsigned_t using the helper function @ref
attempt_cast, which returns @a false if the cast could not be peformed
without error.
This function parses the integer component up to the radix point or
exponent while collecting information about the 'floating point
representation', which it stores in the result parameter. If there is
no radix point or exponent, and the number can fit into a
@ref number_integer_t or @ref number_unsigned_t then it sets the
result parameter accordingly.
In any of these cases (more/less characters read, range error or a cast
error) the pointer is passed to @a std:strtod, which also sets @a
endptr to the first character past the converted number. The resulting
@ref number_float_t is then cast to a @ref number_integer_t/@ref
number_unsigned_t using @ref attempt_cast and if no error occurs is
stored in that form, otherwise it is stored as a @ref number_float_t.
The 'floating point representation' includes the number of significant
figures after the radix point, whether the number is in exponential
or decimal form, the capitalization of the exponent marker, and if the
optional '+' is present in the exponent. This information is necessary
to perform accurate round trips of floating point numbers.
A final comparison is made of @a endptr and if still not the same as
@ref m_cursor a bad input is assumed and @a result parameter is set to
NAN.
If the number is a floating point number the number is then parsed
using @a std:strtod (or @a std:strtof or @a std::strtold).
@param[out] result @ref basic_json object to receive the number, or NAN
if the conversion read past the current token. The latter case needs to
be treated by the caller function.
@param[out] result @ref basic_json object to receive the number, or
NAN if the conversion read past the current token. The latter case
needs to be treated by the caller function.
*/
void get_number(basic_json& result) const
{
typename string_t::value_type* endptr;
assert(m_start != nullptr);
errno = 0;
// attempt to parse it as an integer - first checking for a
// negative number
if (*reinterpret_cast<typename string_t::const_pointer>(m_start) != '-')
const lexer::lexer_char_t* curptr = m_start;
// remember this number was parsed (for later serialization)
result.m_type.bits.parsed = true;
// 'found_radix_point' will be set to 0xFF upon finding a radix
// point and later used to mask in/out the precision depending
// whether a radix is found i.e. 'precision &= found_radix_point'
uint8_t found_radix_point = 0;
uint8_t precision = 0;
// accumulate the integer conversion result (unsigned for now)
number_unsigned_t value = 0;
// maximum absolute value of the relevant integer type
number_unsigned_t max;
// temporarily store the type to avoid unecessary bitfield access
value_t type;
// look for sign
if (*curptr == '-')
{
// positive, parse with strtoull and attempt cast to
// number_unsigned_t
if (attempt_cast(std::strtoull(reinterpret_cast<typename string_t::const_pointer>(m_start), &endptr,
10), result.m_value.number_unsigned))
{
result.m_type = value_t::number_unsigned;
}
else
{
// cast failed due to overflow - store as float
result.m_type = value_t::number_float;
}
type = value_t::number_integer;
max = static_cast<uint64_t>(std::numeric_limits<number_integer_t>::max()) + 1;
curptr++;
}
else
{
// Negative, parse with strtoll and attempt cast to
// number_integer_t
if (attempt_cast(std::strtoll(reinterpret_cast<typename string_t::const_pointer>(m_start), &endptr,
10), result.m_value.number_integer))
type = value_t::number_unsigned;
max = static_cast<uint64_t>(std::numeric_limits<number_unsigned_t>::max());
if (*curptr == '+')
{
result.m_type = value_t::number_integer;
}
else
{
// cast failed due to overflow - store as float
result.m_type = value_t::number_float;
curptr++;
}
}
// check the end of the number was reached and no range error
// occurred
if (reinterpret_cast<lexer_char_t*>(endptr) != m_cursor || errno == ERANGE)
// count the significant figures
for (; curptr < m_cursor; curptr++)
{
result.m_type = value_t::number_float;
// quickly skip tests if a digit
if (*curptr < '0' || *curptr > '9')
{
if (*curptr == '.')
{
// don't count '.' but change to float
type = value_t::number_float;
// reset precision count
precision = 0;
found_radix_point = 0xFF;
continue;
}
// assume exponent (if not then will fail parse): change to
// float, stop counting and record exponent details
type = value_t::number_float;
result.m_type.bits.has_exp = true;
// exponent capitalization
result.m_type.bits.exp_cap = (*curptr == 'E');
// exponent '+' sign
result.m_type.bits.exp_plus = (*(++curptr) == '+');
break;
}
// skip if definitely not an integer
if (type != value_t::number_float)
{
// multiply last value by ten and add the new digit
auto temp = value * 10 + *curptr - 0x30;
// test for overflow
if (temp < value || temp > max)
{
// overflow
type = value_t::number_float;
}
else
{
// no overflow - save it
value = temp;
}
}
++precision;
}
if (result.m_type == value_t::number_float)
{
// either the number won't fit in an integer (range error from
// strtoull/strtoll or overflow on cast) or there was something
// else after the number, which could be an exponent
// If no radix point was found then precision would now be set to
// the number of digits, which is wrong - clear it.
result.m_type.bits.precision = precision & found_radix_point;
// save the value (if not a float)
if (type == value_t::number_unsigned)
{
result.m_value.number_unsigned = value;
}
else if (type == value_t::number_integer)
{
result.m_value.number_integer = -static_cast<number_integer_t>(value);
}
else
{
// parse with strtod
result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), &endptr);
// anything after the number is an error
if (reinterpret_cast<lexer_char_t*>(endptr) != m_cursor)
{
throw std::invalid_argument(std::string("parse error - ") + get_token() + " is not a number");
}
result.m_value.number_float = str_to_float_t(static_cast<number_float_t*>(nullptr), NULL);
}
// save the type
result.m_type = type;
}
private:

1
test/json_roundtrip/roundtrip28.json Normal file
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@ -0,0 +1 @@
[4.940656458412e-324]

1
test/json_roundtrip/roundtrip29.json Normal file
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@ -0,0 +1 @@
[2.2250738585072e-308]

1
test/json_roundtrip/roundtrip30.json Normal file
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@ -0,0 +1 @@
[1.2345E-30]

1
test/json_roundtrip/roundtrip31.json Normal file
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@ -0,0 +1 @@
[1.2345E+30]

1
test/json_roundtrip/roundtrip32.json Normal file
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@ -0,0 +1 @@
[1.2345e+30]

16
test/unit.cpp
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@ -9776,7 +9776,8 @@ TEST_CASE("parser class")
CHECK_THROWS_AS(json::parser("-0e-:").parse(), std::invalid_argument);
CHECK_THROWS_AS(json::parser("-0f").parse(), std::invalid_argument);
CHECK_THROWS_WITH(json::parser("01").parse(), "parse error - 0 is not a number");
CHECK_THROWS_WITH(json::parser("01").parse(),
"parse error - unexpected number literal; expected end of input");
CHECK_THROWS_WITH(json::parser("--1").parse(), "parse error - unexpected '-'");
CHECK_THROWS_WITH(json::parser("1.").parse(),
"parse error - unexpected '.'; expected end of input");
@ -11823,10 +11824,15 @@ TEST_CASE("compliance tests from nativejson-benchmark")
"test/json_roundtrip/roundtrip21.json",
"test/json_roundtrip/roundtrip22.json",
"test/json_roundtrip/roundtrip23.json",
//"test/json_roundtrip/roundtrip24.json",
//"test/json_roundtrip/roundtrip25.json",
//"test/json_roundtrip/roundtrip26.json",
//"test/json_roundtrip/roundtrip27.json"
"test/json_roundtrip/roundtrip24.json",
"test/json_roundtrip/roundtrip25.json",
"test/json_roundtrip/roundtrip26.json",
"test/json_roundtrip/roundtrip27.json",
"test/json_roundtrip/roundtrip28.json",
"test/json_roundtrip/roundtrip29.json",
"test/json_roundtrip/roundtrip30.json",
"test/json_roundtrip/roundtrip31.json",
"test/json_roundtrip/roundtrip32.json"
})
{
CAPTURE(filename);