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use core::mem;
#[allow(dead_code)]
#[derive(Debug, Copy, Clone)]
pub enum State {
Anywhere = 0,
CsiEntry = 1,
CsiIgnore = 2,
CsiIntermediate = 3,
CsiParam = 4,
DcsEntry = 5,
DcsIgnore = 6,
DcsIntermediate = 7,
DcsParam = 8,
DcsPassthrough = 9,
Escape = 10,
EscapeIntermediate = 11,
Ground = 12,
OscString = 13,
SosPmApcString = 14,
Utf8 = 15,
}
impl Default for State {
fn default() -> State {
State::Ground
}
}
#[allow(dead_code)]
#[derive(Debug, Clone, Copy)]
pub enum Action {
None = 0,
Clear = 1,
Collect = 2,
CsiDispatch = 3,
EscDispatch = 4,
Execute = 5,
Hook = 6,
Ignore = 7,
OscEnd = 8,
OscPut = 9,
OscStart = 10,
Param = 11,
Print = 12,
Put = 13,
Unhook = 14,
BeginUtf8 = 15,
}
/// Unpack a u8 into a State and Action
///
/// The implementation of this assumes that there are *precisely* 16 variants for both Action and
/// State. Furthermore, it assumes that the enums are tag-only; that is, there is no data in any
/// variant.
///
/// Bad things will happen if those invariants are violated.
#[inline(always)]
pub fn unpack(delta: u8) -> (State, Action) {
unsafe {
(
// State is stored in bottom 4 bits
mem::transmute(delta & 0x0f),
// Action is stored in top 4 bits
mem::transmute(delta >> 4),
)
}
}
#[inline(always)]
pub const fn pack(state: State, action: Action) -> u8 {
(action as u8) << 4 | state as u8
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn unpack_state_action() {
match unpack(0xee) {
(State::SosPmApcString, Action::Unhook) => (),
_ => panic!("unpack failed"),
}
match unpack(0x0f) {
(State::Utf8, Action::None) => (),
_ => panic!("unpack failed"),
}
match unpack(0xff) {
(State::Utf8, Action::BeginUtf8) => (),
_ => panic!("unpack failed"),
}
}
#[test]
fn pack_state_action() {
match unpack(0xee) {
(State::SosPmApcString, Action::Unhook) => (),
_ => panic!("unpack failed"),
}
match unpack(0x0f) {
(State::Utf8, Action::None) => (),
_ => panic!("unpack failed"),
}
match unpack(0xff) {
(State::Utf8, Action::BeginUtf8) => (),
_ => panic!("unpack failed"),
}
}
}
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