use super::Tag;
const KEY_PHASE_MASK: u8 = 0x04;
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct ProtectedKeyPhase;
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum KeyPhase {
Zero,
One,
}
impl Default for KeyPhase {
#[inline]
fn default() -> Self {
Self::Zero
}
}
const PHASES: [KeyPhase; 2] = [KeyPhase::Zero, KeyPhase::One];
impl From<u8> for KeyPhase {
#[inline]
fn from(v: u8) -> Self {
PHASES[(v & 0x01) as usize]
}
}
impl KeyPhase {
#[inline]
pub fn from_tag(tag: Tag) -> Self {
let phase = (tag & KEY_PHASE_MASK) >> 2;
PHASES[phase as usize]
}
#[inline]
pub fn into_packet_tag_mask(self) -> u8 {
match self {
Self::One => KEY_PHASE_MASK,
Self::Zero => 0,
}
}
#[must_use]
#[inline]
pub fn next_phase(self) -> Self {
PHASES[(((self as u8) + 1) % 2) as usize]
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_keyphase_from_tag() {
for i in 0..255 {
let phase = KeyPhase::from_tag(i);
assert_eq!(phase.into_packet_tag_mask(), i & KEY_PHASE_MASK);
}
}
#[test]
fn test_next_phase() {
for i in 0..254 {
let phase = KeyPhase::from(i);
let next_phase = KeyPhase::from(i + 1);
assert_eq!(phase.next_phase(), next_phase);
}
}
}