Method to_string_lossy

crates/wtf8/src/lib.rs:877–899

Lossily converts the string to UTF-8. Returns a UTF-8 `&str` slice if the contents are well-formed in UTF-8. Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”). This only copies the data if necessary (if it contains any surrogate).

(&self)

    ///
    /// This only copies the data if necessary (if it contains any surrogate).
    pub fn to_string_lossy(&self) -> Cow<'_, str> {
        let Some((surrogate_pos, _)) = self.next_surrogate(0) else {
            return Cow::Borrowed(unsafe { str::from_utf8_unchecked(&self.bytes) });
        };
        let wtf8_bytes = &self.bytes;
        let mut utf8_bytes = Vec::with_capacity(self.len());
        utf8_bytes.extend_from_slice(&wtf8_bytes[..surrogate_pos]);
        utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
        let mut pos = surrogate_pos + 3;
        loop {
            match self.next_surrogate(pos) {
                Some((surrogate_pos, _)) => {
                    utf8_bytes.extend_from_slice(&wtf8_bytes[pos..surrogate_pos]);
                    utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER.as_bytes());
                    pos = surrogate_pos + 3;
                }
                None => {
                    utf8_bytes.extend_from_slice(&wtf8_bytes[pos..]);
                    return Cow::Owned(unsafe { String::from_utf8_unchecked(utf8_bytes) });
                }
            }
        }
    }

    /// Converts the WTF-8 string to potentially ill-formed UTF-16
    /// and return an iterator of 16-bit code units.