from_chars: generalized chars to value

Read a value from the string, which must be trimmed to the value (ie, no leading/trailing whitespace). More...

Topics
	from_chars_first: generalized chars to value
	Read the first valid sequence of characters from the string, skipping leading whitespace, and convert it using from_chars: generalized chars to value .

Functions
bool	c4::from_chars (csubstr buf, uint8_t *v) noexcept
bool	c4::from_chars (csubstr buf, uint16_t *v) noexcept
bool	c4::from_chars (csubstr buf, uint32_t *v) noexcept
bool	c4::from_chars (csubstr buf, uint64_t *v) noexcept
bool	c4::from_chars (csubstr buf, int8_t *v) noexcept
bool	c4::from_chars (csubstr buf, int16_t *v) noexcept
bool	c4::from_chars (csubstr buf, int32_t *v) noexcept
bool	c4::from_chars (csubstr buf, int64_t *v) noexcept
bool	c4::from_chars (csubstr buf, float *v) noexcept
bool	c4::from_chars (csubstr buf, double *v) noexcept
template<class T>
auto	c4::from_chars (csubstr buf, T *v) noexcept -> bool::type
template<class T>
bool	c4::from_chars (csubstr buf, T **v) noexcept
bool	c4::from_chars (csubstr buf, bool *v) noexcept
bool	c4::from_chars (csubstr buf, char *v) noexcept
	extract a single character from a substring
bool	c4::from_chars (csubstr buf, csubstr *v) noexcept
bool	c4::from_chars (csubstr buf, substr *v) noexcept
template<class T>
bool	c4::from_chars (csubstr s, fmt::overflow_checked_< T > wrapper)
	read an integer type, detecting overflow (returns false on overflow)
template<class T>
bool	c4::from_chars (csubstr s, fmt::overflow_checked_< T > *wrapper)
	read an integer type, detecting overflow (returns false on overflow)
bool	c4::from_chars (csubstr buf, fmt::raw_wrapper *r)
	read a variable in raw binary format, using memcpy
bool	c4::from_chars (csubstr buf, fmt::raw_wrapper r)
	read a variable in raw binary format, using memcpy

Detailed Description

Read a value from the string, which must be trimmed to the value (ie, no leading/trailing whitespace).

return true if the conversion succeeded. There is no check for overflow; the value wraps around in a way similar to the standard C/C++ overflow behavior. For example, from_chars<int8_t>("128", &val) returns true and val will be set tot 0. See overflows: does a number string overflow a type and Check read for overflow for facilities enforcing no-overflow.

Dispatches to the most appropriate and efficient conversion function

See also

from_chars_first: generalized chars to value, atou, atoi, atof, atod

Function Documentation

from_chars() [1/20]

bool c4::from_chars ( csubstr buf, uint8_t * v )

inlinenoexcept

Definition at line 2382 of file charconv.hpp.

{ return atou(buf, v); }

from_chars() [2/20]

bool c4::from_chars ( csubstr buf, uint16_t * v )

inlinenoexcept

Definition at line 2383 of file charconv.hpp.

{ return atou(buf, v); }

from_chars() [3/20]

bool c4::from_chars ( csubstr buf, uint32_t * v )

inlinenoexcept

Definition at line 2384 of file charconv.hpp.

{ return atou(buf, v); }

from_chars() [4/20]

bool c4::from_chars ( csubstr buf, uint64_t * v )

inlinenoexcept

Definition at line 2385 of file charconv.hpp.

{ return atou(buf, v); }

from_chars() [5/20]

bool c4::from_chars ( csubstr buf, int8_t * v )

inlinenoexcept

Definition at line 2386 of file charconv.hpp.

{ return atoi(buf, v); }

from_chars() [6/20]

bool c4::from_chars ( csubstr buf, int16_t * v )

inlinenoexcept

Definition at line 2387 of file charconv.hpp.

{ return atoi(buf, v); }

from_chars() [7/20]

bool c4::from_chars ( csubstr buf, int32_t * v )

inlinenoexcept

Definition at line 2388 of file charconv.hpp.

{ return atoi(buf, v); }

from_chars() [8/20]

bool c4::from_chars ( csubstr buf, int64_t * v )

inlinenoexcept

Definition at line 2389 of file charconv.hpp.

{ return atoi(buf, v); }

from_chars() [9/20]

bool c4::from_chars ( csubstr buf, float * v )

inlinenoexcept

Definition at line 2390 of file charconv.hpp.

{ return atof(buf, v); }

from_chars() [10/20]

bool c4::from_chars ( csubstr buf, double * v )

inlinenoexcept

Definition at line 2391 of file charconv.hpp.

{ return atod(buf, v); }

from_chars() [11/20]

template<class T>

auto c4::from_chars ( csubstr buf, T * v )->bool::type

inlinenoexcept

Definition at line 2393 of file charconv.hpp.

{ return atoi(buf, v); }

from_chars() [12/20]

template<class T>

bool c4::from_chars ( csubstr buf, T ** v )

inlinenoexcept

Definition at line 2396 of file charconv.hpp.

{ intptr_t tmp; bool ret = from_chars(buf, &tmp); if(ret) { *v = (T*)tmp; } return ret; }

from_chars() [13/20]

bool c4::from_chars ( csubstr buf, bool * v )

inlinenoexcept

Definition at line 2465 of file charconv.hpp.

{
    if(buf.len == 1)
    {
        if(buf.str[0] == '0')
        {
            *v = false; return true;
        }
        else if(buf.str[0] == '1')
        {
            *v = true; return true;
        }
    }
    else if(buf.len == 4)
    {
        if(((buf.str[0] == 't') && (0 == memcmp(buf.str + 1, "rue", 3)))
           ||
           ((buf.str[0] == 'T') && (0 == memcmp(buf.str + 1, "rue", 3) ||
                                    0 == memcmp(buf.str + 1, "RUE", 3))))
        {
            *v = true; return true;
        }
    }
    else if(buf.len == 5)
    {
        if(((buf.str[0] == 'f') && (0 == memcmp(buf.str + 1, "alse", 4)))
           ||
           ((buf.str[0] == 'F') && (0 == memcmp(buf.str + 1, "alse", 4) ||
                                    0 == memcmp(buf.str + 1, "ALSE", 4))))
        {
            *v = false; return true;
        }
    }
    // fallback to c-style int bools
    int val = 0;
    bool ret = from_chars(buf, &val);
    if(C4_LIKELY(ret))
    {
        *v = (val != 0);
    }
    return ret;
}

from_chars() [14/20]

bool c4::from_chars ( csubstr buf, char * v )

inlinenoexcept

extract a single character from a substring

Note

to extract a string instead and not just a single character, use the csubstr overload

Definition at line 2536 of file charconv.hpp.

{
    if(buf.len != 1)
        return false;
    C4_XASSERT(buf.str);
    *v = buf.str[0];
    return true;
}

from_chars() [15/20]

bool c4::from_chars ( csubstr buf, csubstr * v )

inlinenoexcept

Definition at line 2576 of file charconv.hpp.

{
    *v = buf;
    return true;
}

from_chars() [16/20]

bool c4::from_chars ( csubstr buf, substr * v )

inlinenoexcept

Definition at line 2614 of file charconv.hpp.

{
    C4_ASSERT(!buf.overlaps(*v));
    // is the destination buffer wide enough?
    if(v->len >= buf.len)
    {
        // calling memcpy with zero len is undefined behavior
        // and will wreak havoc in calling code's branches.
        // see https://github.com/biojppm/rapidyaml/pull/264#issuecomment-1262133637
        if(buf.len)
        {
            C4_ASSERT(buf.str != nullptr);
            C4_ASSERT(v->str != nullptr);
            memcpy(v->str, buf.str, buf.len);
        }
        v->len = buf.len;
        return true;
    }
    return false;
}

from_chars() [17/20]

template<class T>

bool c4::from_chars ( csubstr s, fmt::overflow_checked_< T > wrapper )

inline

read an integer type, detecting overflow (returns false on overflow)

Definition at line 322 of file format.hpp.

{
    if(C4_LIKELY(!overflows<T>(s)))
        return atox(s, wrapper.val);
    return false;
}

from_chars() [18/20]

template<class T>

bool c4::from_chars ( csubstr s, fmt::overflow_checked_< T > * wrapper )

inline

read an integer type, detecting overflow (returns false on overflow)

Definition at line 331 of file format.hpp.

{
    if(C4_LIKELY(!overflows<T>(s)))
        return atox(s, wrapper->val);
    return false;
}

from_chars() [19/20]

bool c4::from_chars	(	csubstr	buf,
		fmt::raw_wrapper *	r )

read a variable in raw binary format, using memcpy

from_chars() [20/20]

bool c4::from_chars ( csubstr buf, fmt::raw_wrapper r )

inline

read a variable in raw binary format, using memcpy

Definition at line 465 of file format.hpp.

{
    return from_chars(buf, &r);
}