Function encoding_utf8_valid_up_to 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn encoding_utf8_valid_up_to(
    buffer: *const u8,
    buffer_len: usize,
) -> usize

Validates UTF-8.

Returns the index of the first byte that makes the input malformed as UTF-8 or buffer_len if buffer is entirely valid.

buffer must be non-NULL even if buffer_len is zero. When buffer_len is zero, it is OK for buffer to be something non-dereferencable, such as 0x1. This is required due to Rust’s optimization for slices within Option.

Undefined behavior

UB ensues if buffer and buffer_len don’t designate a valid memory block of if buffer is NULL.