Function utf8_first_byte

crates/sre_engine/src/string.rs:315–317

(byte: u8, width: u32)

/// for width 3, and 3 bits for width 4.
#[inline]
const fn utf8_first_byte(byte: u8, width: u32) -> u32 {
    (byte & (0x7F >> width)) as u32
}

/// Returns the value of `ch` updated with continuation byte `byte`.
#[inline]