Method fromhex

crates/vm/src/bytes_inner.rs:436–482

(bytes: &[u8], vm: &VirtualMachine)

    }

    pub fn fromhex(bytes: &[u8], vm: &VirtualMachine) -> PyResult<Vec<u8>> {
        let mut iter = bytes.iter().enumerate();
        let mut result: Vec<u8> = Vec::with_capacity(bytes.len() / 2);
        // None means odd number of hex digits, Some(i) means invalid char at position i
        let invalid_char: Option<usize> = loop {
            let (i, &b) = match iter.next() {
                Some(val) => val,
                None => {
                    return Ok(result);
                }
            };

            if is_py_ascii_whitespace(b) {
                continue;
            }

            let top = match b {
                b'0'..=b'9' => b - b'0',
                b'a'..=b'f' => 10 + b - b'a',
                b'A'..=b'F' => 10 + b - b'A',
                _ => break Some(i),
            };

            let (i, b) = match iter.next() {
                Some(val) => val,
                None => break None, // odd number of hex digits
            };

            let bot = match b {
                b'0'..=b'9' => b - b'0',
                b'a'..=b'f' => 10 + b - b'a',
                b'A'..=b'F' => 10 + b - b'A',
                _ => break Some(i),
            };

            result.push((top << 4) + bot);
        };

        match invalid_char {
            None => Err(vm.new_value_error(
                "fromhex() arg must contain an even number of hexadecimal digits",
            )),
            Some(i) => Err(vm.new_value_error(format!(
                "non-hexadecimal number found in fromhex() arg at position {i}"
            ))),
        }
    }

    /// Parse hex string from str or bytes-like object
    pub fn fromhex_object(string: PyObjectRef, vm: &VirtualMachine) -> PyResult<Vec<u8>> {