unformat: formatted read from string

Functions
template<class Arg , class... Args>
size_t	c4::unformat (csubstr buf, csubstr fmt, Arg &a, Args &...more)
	using a format string, deserialize the arguments from the given buffer. More...

Detailed Description

Function Documentation

template<class Arg , class... Args>

size_t c4::unformat	(	csubstr	buf,
		csubstr	fmt,
		Arg &	a,
		Args &...	more
	)

using a format string, deserialize the arguments from the given buffer.

This is the inverse function to c4::format().

Returns

the number of characters read from the buffer, or npos if a conversion failed.

See also

c4::format().

Definition at line 987 of file format.hpp.

Referenced by from_chars(), and sample_formatting().

{
    const size_t pos = fmt.find("{}");
    if C4_UNLIKELY(pos == csubstr::npos)
        return unformat(buf, fmt);
    size_t num = pos;
    size_t out = num;
    buf  = buf.len >= num ? buf.sub(num) : substr{};
    num  = from_chars_first(buf, &a);
    if C4_UNLIKELY(num == csubstr::npos)
        return csubstr::npos;
    out += num;
    buf  = buf.len >= num ? buf.sub(num) : substr{};
    num  = unformat(buf, fmt.sub(pos + 2), more...);
    if C4_UNLIKELY(num == csubstr::npos)
        return csubstr::npos;
    out += num;
    return out;
}