blob: ceb44b2c30b855e15444a537a29e86c07bdf44cf [file] [log] [blame]
use super::Error;
use bytes::Bytes;
/// Strip padding from the given payload.
///
/// It is assumed that the frame had the padded flag set. This means that the
/// first byte is the length of the padding with that many
/// 0 bytes expected to follow the actual payload.
///
/// # Returns
///
/// A slice of the given payload where the actual one is found and the length
/// of the padding.
///
/// If the padded payload is invalid (e.g. the length of the padding is equal
/// to the total length), returns `None`.
pub fn strip_padding(payload: &mut Bytes) -> Result<u8, Error> {
let payload_len = payload.len();
if payload_len == 0 {
// If this is the case, the frame is invalid as no padding length can be
// extracted, even though the frame should be padded.
return Err(Error::TooMuchPadding);
}
let pad_len = payload[0] as usize;
if pad_len >= payload_len {
// This is invalid: the padding length MUST be less than the
// total frame size.
return Err(Error::TooMuchPadding);
}
let _ = payload.split_to(1);
let _ = payload.split_off(payload_len - pad_len - 1);
Ok(pad_len as u8)
}