Scalar charconv helpers

These functions are used by the parser and emitter to convert scalars to and from chars. More...

Functions
bool	c4::yml::scalar_is_null (csubstr s) noexcept
	YAML-sense query of nullity. More...
bool	c4::yml::scalar_is_plain_number_json (csubstr s) noexcept
	JSON-sense query of plain number. More...
bool	c4::yml::scalar_is_inf3 (const char *s) noexcept
	Query if a scalar is inf (inf, Inf, INF) More...
bool	c4::yml::scalar_is_nan3 (const char *s) noexcept
	Query if a scalar is nan (nan, NaN, Nan, NAN) More...
bool	c4::yml::scalar_is_inf_or_nan3 (const char *s) noexcept
	Same as scalar_is_inf3() || scalar_is_nan3() More...
bool	c4::yml::scalar_is_special_json (csubstr s) noexcept
	Query if a scalar is plain, eg, true, false, null, +-.inf or .nan. More...
template<class T >
bool	c4::yml::from_chars_float (csubstr scalar, T *val) RYML_NOEXCEPT
	Deserialize a floating point from string. More...
template<class T >
size_t	c4::yml::to_chars_float (substr buf, T val) RYML_NOEXCEPT
	Serialize a floating point value to a string. More...
template<class T >
bool	c4::yml::from_chars_integral (csubstr scalar, T *val) RYML_NOEXCEPT
	Deserialize an integral scalar. More...
template<class T >
bool	c4::yml::scalar_deserialize (csubstr str, T *val)
	Deserialize a scalar from its string representation, dispatching to one of from_chars(), from_chars_float() or from_chars_integral() as appropriate. More...
template<class T >
size_t	c4::yml::scalar_serialize (substr buf, T const &a)
	Serialize a scalar to the buffer, dispatching to to_chars() or to_chars_float() as appropriate. More...

Detailed Description

These functions are used by the parser and emitter to convert scalars to and from chars.

Function Documentation

bool c4::yml::scalar_is_null ( csubstr  s )

inlinenoexcept

YAML-sense query of nullity.

returns true if the scalar points to nullptr or is otherwise equal to one of the strings "~","null","Null","NULL"

Definition at line 28 of file scalar_charconv.hpp.

Referenced by c4::yml::Tree::key_is_null(), sample_empty_null_values(), and c4::yml::Tree::val_is_null().

{
    return s.str == nullptr ||
        (s.len == 1 && (s.str[0] == '~')) ||
        (s.len == 4 && ((0 == memcmp("null", s.str, 4))
                        || (0 == memcmp("Null", s.str, 4))
                        || (0 == memcmp("NULL", s.str, 4))));
}

bool c4::yml::scalar_is_plain_number_json ( csubstr  s )

inlinenoexcept

JSON-sense query of plain number.

Definition at line 39 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_style_choose_json().

{
    return s.is_number()
        &&
        (
            // quote integral numbers if they have a leading 0
            // https://github.com/biojppm/rapidyaml/issues/291
            (!(s.len > 1 && s.begins_with('0')))
            // do not quote reals with leading 0
            // https://github.com/biojppm/rapidyaml/issues/313
            || (s.find('.') != csubstr::npos)
        );
}

bool c4::yml::scalar_is_inf3 ( const char *  s )

inlinenoexcept

Query if a scalar is inf (inf, Inf, INF)

Warning

length must be 3

Definition at line 57 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_is_special_json().

{
    switch(s[0])
    {
    case 'i': return ((s[1] == 'n') && (s[2] == 'f'));
    case 'I': return ((s[1] == 'n') && (s[2] == 'f')) ||
                     ((s[1] == 'N') && (s[2] == 'F'));
    }
    return false;
}

bool c4::yml::scalar_is_nan3 ( const char *  s )

inlinenoexcept

Query if a scalar is nan (nan, NaN, Nan, NAN)

Warning

length must be 3

Definition at line 72 of file scalar_charconv.hpp.

{
    switch(s[0])
    {
    case 'n': return ((s[1] == 'a') && (s[2] == 'n'));
    case 'N': return ((s[1] == 'a') && (s[2] == 'N')) ||
                     ((s[1] == 'a') && (s[2] == 'n')) ||
                     ((s[1] == 'A') && (s[2] == 'N'));
    }
    return false;
}

bool c4::yml::scalar_is_inf_or_nan3 ( const char *  s )

inlinenoexcept

Same as scalar_is_inf3() || scalar_is_nan3()

Warning

length must be 3

Definition at line 88 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_is_special_json().

{
    switch(s[0])
    {
    case 'i': return ((s[1] == 'n') && (s[2] == 'f'));
    case 'I': return ((s[1] == 'n') && (s[2] == 'f')) ||
                     ((s[1] == 'N') && (s[2] == 'F'));
    case 'n': return ((s[1] == 'a') && (s[2] == 'n'));
    case 'N': return ((s[1] == 'a') && (s[2] == 'N')) ||
                     ((s[1] == 'a') && (s[2] == 'n')) ||
                     ((s[1] == 'A') && (s[2] == 'N'));
    }
    return false;
}

bool c4::yml::scalar_is_special_json ( csubstr  s )

inlinenoexcept

Query if a scalar is plain, eg, true, false, null, +-.inf or .nan.

Definition at line 105 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_style_choose_json().

{
    if(s.len == 4)
        return 0 == memcmp("true", s.str, 4)
            || 0 == memcmp("null", s.str, 4)
            || ((s[0] == '.') && scalar_is_inf_or_nan3(s.str + 1))
            || ((s[0] == '-' || s[0] == '+') && scalar_is_inf3(s.str + 1));
    else if(s.len == 5)
        return 0 == memcmp("false", s.str, 5)
            || ((s[0] == '-' || s[0] == '+') && s[1] == '.' && scalar_is_inf3(s.str + 2));
    else if(s.len == 3)
        return scalar_is_inf_or_nan3(s.str);
    return false;
}

template<class T >

bool c4::yml::from_chars_float	(	csubstr	scalar,
		T *	val
	)

Deserialize a floating point from string.

Accepts special values: .nan, .inf, -.inf, with upper-case variations.

Unlike non-floating types, only the leading part of the string that may constitute a number is processed. This happens because the float parsing is delegated to fast_float, which is implemented that way. Consequently, for example, all of "34", "34 " "34hg" "34 gh" will be read as 34. If you are not sure about the contents of the data, you can use csubstr::first_real_span() to check before deserializing, for example like this:

 {c++}
csubstr val = node.val();
if(val.first_real_span() == val)
    node >> v; // or call from_chars_float(val, &v);
else
    ERROR("not a real")

Definition at line 183 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_deserialize().

{
    static_assert(std::is_floating_point<T>::value, "must be floating point");
    if C4_LIKELY(scalar.len > 0)
    {
        if(scalar.str[0] == '+')
            scalar = scalar.sub(1);
        if C4_LIKELY(from_chars(scalar, val))
            return true;
        else if(scalar.len == 4 || scalar.len == 5)
            return detail::from_chars_float_yaml_special(scalar, val);
    }
    return false;
}

template<class T >

size_t c4::yml::to_chars_float	(	substr	buf,
		T	val
	)

Serialize a floating point value to a string.

Definition at line 202 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_serialize().

{
    static_assert(std::is_floating_point<T>::value, "must be floating point");
    C4_SUPPRESS_WARNING_GCC_CLANG_WITH_PUSH("-Wfloat-equal");
    if C4_UNLIKELY(std::isnan(val))
        return to_chars(buf, csubstr(".nan"));
    else if C4_UNLIKELY(val == std::numeric_limits<T>::infinity())
        return to_chars(buf, csubstr(".inf"));
    else if C4_UNLIKELY(val == -std::numeric_limits<T>::infinity())
        return to_chars(buf, csubstr("-.inf"));
    return to_chars(buf, val);
    C4_SUPPRESS_WARNING_GCC_CLANG_POP
}

template<class T >

bool c4::yml::from_chars_integral ( csubstr  scalar, T *  val  )

inline

Deserialize an integral scalar.

Trims leading +, and then dispatches to from_chars<T>(). The full string is used.

Note

Unlike with the floating case (see to_chars_float()), there is no need for an analogous to_chars_integral(), because the lower-level atoi() and atou() functions used by to_chars() do not produce leading + characters.

Definition at line 227 of file scalar_charconv.hpp.

Referenced by c4::yml::scalar_deserialize().

{
    if C4_LIKELY(scalar.len > 0)
    {
        if(scalar.str[0] == '+')
            scalar = scalar.sub(1);
        return from_chars(scalar, val);
    }
    return false;
}

template<class T >

bool c4::yml::scalar_deserialize ( csubstr  str, T *  val  )

inline

Deserialize a scalar from its string representation, dispatching to one of from_chars(), from_chars_float() or from_chars_integral() as appropriate.

Note

When using a standard older than C++17, if constexpr is not available, and the implementation reverts to SFINAE to achieve the compile-time dispatch.

Returns

true if the deserialization succeeded

Definition at line 254 of file scalar_charconv.hpp.

Referenced by c4::yml::read(), and c4::yml::read_key().

{
    if constexpr (std::is_floating_point<T>::value)
        return from_chars_float(str, val);
    else if constexpr (std::is_arithmetic<T>::value)
        return from_chars_integral(str, val);
    else
        return from_chars(str, val);
}

template<class T >

size_t c4::yml::scalar_serialize ( substr  buf, T const &  a  )

inline

Serialize a scalar to the buffer, dispatching to to_chars() or to_chars_float() as appropriate.

Note

When using a standard older than C++17, if constexpr is not available, and the implementation reverts to SFINAE to achieve the compile-time dispatch.

Returns

the size of the serialization, (the buffer size is strictly respected and never overflowed)

Definition at line 308 of file scalar_charconv.hpp.

Referenced by c4::yml::serialize_to_arena_scalar().

{
    if constexpr (std::is_floating_point<T>::value)
        return to_chars_float(buf, a);
    else
        return to_chars(buf, a);
}