Function a2b_uu

crates/stdlib/src/binascii.rs:747–798

(s: ArgAsciiBuffer, vm: &VirtualMachine)

    #[pyfunction]
    fn a2b_uu(s: ArgAsciiBuffer, vm: &VirtualMachine) -> PyResult<Vec<u8>> {
        s.with_ref(|b| {
            // First byte: binary data length (in bytes)
            let length = if b.is_empty() {
                ((-0x20i32) & 0x3fi32) as usize
            } else {
                ((b[0] - b' ') & 0x3f) as usize
            };

            // Allocate the buffer
            let mut res = Vec::<u8>::with_capacity(length);
            let trailing_garbage_error =
                || Err(super::new_binascii_error("Trailing garbage".to_owned(), vm));

            for chunk in b.get(1..).unwrap_or_default().chunks(4) {
                let (char_a, char_b, char_c, char_d) = {
                    let mut chunk = chunk
                        .iter()
                        .map(|x| uu_a2b_read(x, vm))
                        .collect::<Result<Vec<_>, _>>()?;
                    while chunk.len() < 4 {
                        chunk.push(0);
                    }
                    (chunk[0], chunk[1], chunk[2], chunk[3])
                };

                if res.len() < length {
                    res.push((char_a << 2) | (char_b >> 4));
                } else if char_a != 0 || char_b != 0 {
                    return trailing_garbage_error();
                }

                if res.len() < length {
                    res.push(((char_b & 0xf) << 4) | (char_c >> 2));
                } else if char_c != 0 {
                    return trailing_garbage_error();
                }

                if res.len() < length {
                    res.push(((char_c & 0x3) << 6) | char_d);
                } else if char_d != 0 {
                    return trailing_garbage_error();
                }
            }

            let remaining_length = length - res.len();
            if remaining_length > 0 {
                res.extend(vec![0; remaining_length]);
            }
            Ok(res)
        })
    }

    #[derive(FromArgs)]
    struct BacktickArg {