devela::_dep::sdl3::sys::stdinc

Function SDL_StepUTF8

pub unsafe extern "C" fn SDL_StepUTF8(
    pstr: *mut *const i8,
    pslen: *mut usize,
) -> u32 ⓘ
Available on crate feature dep_sdl3 only.
Expand description

Decode a UTF-8 string, one Unicode codepoint at a time.

This will return the first Unicode codepoint in the UTF-8 encoded string in *pstr, and then advance *pstr past any consumed bytes before returning.

It will not access more than *pslen bytes from the string. *pslen will be adjusted, as well, subtracting the number of bytes consumed.

pslen is allowed to be NULL, in which case the string must be NULL-terminated, as the function will blindly read until it sees the NULL char.

if *pslen is zero, it assumes the end of string is reached and returns a zero codepoint regardless of the contents of the string buffer.

If the resulting codepoint is zero (a NULL terminator), or *pslen is zero, it will not advance *pstr or *pslen at all.

Generally this function is called in a loop until it returns zero, adjusting its parameters each iteration.

If an invalid UTF-8 sequence is encountered, this function returns SDL_INVALID_UNICODE_CODEPOINT and advances the string/length by one byte (which is to say, a multibyte sequence might produce several SDL_INVALID_UNICODE_CODEPOINT returns before it syncs to the next valid UTF-8 sequence).

Several things can generate invalid UTF-8 sequences, including overlong encodings, the use of UTF-16 surrogate values, and truncated data. Please refer to RFC3629 for details.

§Parameters

  • pstr: a pointer to a UTF-8 string pointer to be read and adjusted.
  • pslen: a pointer to the number of bytes in the string, to be read and adjusted. NULL is allowed.

§Return value

Returns the first Unicode codepoint in the string.

§Thread safety

It is safe to call this function from any thread.

§Availability

This function is available since SDL 3.2.0.