Function decode

crates/common/src/encodings.rs:506–549

(
        ctx: Ctx,
        errors: &E,
        final_decode: bool,
    )

    }

    pub fn decode<Ctx: DecodeContext, E: DecodeErrorHandler<Ctx>>(
        ctx: Ctx,
        errors: &E,
        final_decode: bool,
    ) -> Result<(Wtf8Buf, usize), Ctx::Error> {
        decode_utf8_compatible(
            ctx,
            errors,
            |v| {
                core::str::from_utf8(v).map_err(|e| {
                    // SAFETY: as specified in valid_up_to's documentation, input[..e.valid_up_to()]
                    //         is valid utf8
                    unsafe { make_decode_err(v, e.valid_up_to(), e.error_len()) }
                })
            },
            |rest, err_len| {
                let first_err = rest[0];
                if matches!(first_err, 0x80..=0xc1 | 0xf5..=0xff) {
                    HandleResult::Error {
                        err_len: Some(1),
                        reason: "invalid start byte",
                    }
                } else if err_len.is_none() {
                    // error_len() == None means unexpected eof
                    if final_decode {
                        HandleResult::Error {
                            err_len,
                            reason: "unexpected end of data",
                        }
                    } else {
                        HandleResult::Done
                    }
                } else if !final_decode && matches!(rest, [0xed, 0xa0..=0xbf]) {
                    // truncated surrogate
                    HandleResult::Done
                } else {
                    HandleResult::Error {
                        err_len,
                        reason: "invalid continuation byte",
                    }
                }
            },
        )
    }
}

pub mod latin_1 {