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use crate::err::ValueTooBigError;
/// 3 bit unsigned integer containing the "Priority Code Point"
/// (present in the [`crate::SingleVlanHeader`]).
///
/// Refers to the IEEE 802.1p class of service and maps to the
/// frame priority level.
#[derive(Copy, Clone, Default, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
pub struct VlanPcp(u8);
impl VlanPcp {
/// VlanPcp with value 0.
pub const ZERO: VlanPcp = VlanPcp(0);
/// Maximum value of an vlan header PCP.
pub const MAX_U8: u8 = 0b0000_0111;
/// Tries to create an [`VlanPcp`] and checks that the passed value
/// is smaller or equal than [`VlanPcp::MAX_U8`] (3 bit unsigned integer).
///
/// In case the passed value is bigger then what can be represented in an 3 bit
/// integer an error is returned. Otherwise an `Ok` containing the [`VlanPcp`].
///
/// ```
/// use etherparse::VlanPcp;
///
/// let pcp = VlanPcp::try_new(2).unwrap();
/// assert_eq!(pcp.value(), 2);
///
/// // if a number that can not be represented in an 3 bit integer
/// // gets passed in an error is returned
/// use etherparse::err::{ValueTooBigError, ValueType};
/// assert_eq!(
/// VlanPcp::try_new(VlanPcp::MAX_U8 + 1),
/// Err(ValueTooBigError{
/// actual: VlanPcp::MAX_U8 + 1,
/// max_allowed: VlanPcp::MAX_U8,
/// value_type: ValueType::VlanPcp,
/// })
/// );
/// ```
#[inline]
pub const fn try_new(value: u8) -> Result<VlanPcp, ValueTooBigError<u8>> {
use crate::err::ValueType;
if value <= VlanPcp::MAX_U8 {
Ok(VlanPcp(value))
} else {
Err(ValueTooBigError {
actual: value,
max_allowed: VlanPcp::MAX_U8,
value_type: ValueType::VlanPcp,
})
}
}
/// Creates an [`VlanPcp`] without checking that the value
/// is smaller or equal than [`VlanPcp::MAX_U8`] (3 bit unsigned integer).
/// The caller must guarantee that `value <= VlanPcp::MAX_U8`.
///
/// # Safety
///
/// `value` must be smaller or equal than [`VlanPcp::MAX_U8`]
/// otherwise the behavior of functions or data structures relying
/// on this pre-requirement is undefined.
#[inline]
pub const unsafe fn new_unchecked(value: u8) -> VlanPcp {
debug_assert!(value <= VlanPcp::MAX_U8);
VlanPcp(value)
}
/// Returns the underlying unsigned 3 bit value as an `u8` value.
#[inline]
pub const fn value(self) -> u8 {
self.0
}
}
impl core::fmt::Display for VlanPcp {
#[inline]
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
self.0.fmt(f)
}
}
impl From<VlanPcp> for u8 {
#[inline]
fn from(value: VlanPcp) -> Self {
value.0
}
}
impl TryFrom<u8> for VlanPcp {
type Error = ValueTooBigError<u8>;
#[inline]
fn try_from(value: u8) -> Result<Self, Self::Error> {
use crate::err::ValueType;
if value <= VlanPcp::MAX_U8 {
Ok(VlanPcp(value))
} else {
Err(Self::Error {
actual: value,
max_allowed: VlanPcp::MAX_U8,
value_type: ValueType::VlanPcp,
})
}
}
}
#[cfg(test)]
mod test {
use super::*;
use core::hash::{Hash, Hasher};
use proptest::prelude::*;
use std::format;
#[test]
fn derived_traits() {
// copy & clone
{
let a = VlanPcp(2);
let b = a;
assert_eq!(a, b);
assert_eq!(a.clone(), a);
}
// default
{
let actual: VlanPcp = Default::default();
assert_eq!(actual.value(), 0);
}
// debug
{
let a = VlanPcp(2);
assert_eq!(format!("{:?}", a), format!("VlanPcp(2)"));
}
// ord & partial ord
{
use core::cmp::Ordering;
let a = VlanPcp(2);
let b = a;
assert_eq!(a.cmp(&b), Ordering::Equal);
assert_eq!(a.partial_cmp(&b), Some(Ordering::Equal));
}
// hash
{
use std::collections::hash_map::DefaultHasher;
let a = {
let mut hasher = DefaultHasher::new();
VlanPcp(2).hash(&mut hasher);
hasher.finish()
};
let b = {
let mut hasher = DefaultHasher::new();
VlanPcp(2).hash(&mut hasher);
hasher.finish()
};
assert_eq!(a, b);
}
}
proptest! {
#[test]
fn try_new(
valid_value in 0..=0b0000_0111u8,
invalid_value in 0b0000_1000u8..=u8::MAX
) {
use crate::err::{ValueType, ValueTooBigError};
assert_eq!(
valid_value,
VlanPcp::try_new(valid_value).unwrap().value()
);
assert_eq!(
VlanPcp::try_new(invalid_value).unwrap_err(),
ValueTooBigError{
actual: invalid_value,
max_allowed: 0b0000_0111,
value_type: ValueType::VlanPcp
}
);
}
}
proptest! {
#[test]
fn try_from(
valid_value in 0..=0b0000_0111u8,
invalid_value in 0b0000_1000u8..=u8::MAX
) {
use crate::err::{ValueType, ValueTooBigError};
// try_into
{
let actual: VlanPcp = valid_value.try_into().unwrap();
assert_eq!(actual.value(), valid_value);
let err: Result<VlanPcp, ValueTooBigError<u8>> = invalid_value.try_into();
assert_eq!(
err.unwrap_err(),
ValueTooBigError{
actual: invalid_value,
max_allowed: 0b0000_0111,
value_type: ValueType::VlanPcp
}
);
}
// try_from
{
assert_eq!(
VlanPcp::try_from(valid_value).unwrap().value(),
valid_value
);
assert_eq!(
VlanPcp::try_from(invalid_value).unwrap_err(),
ValueTooBigError{
actual: invalid_value,
max_allowed: 0b0000_0111,
value_type: ValueType::VlanPcp
}
);
}
}
}
proptest! {
#[test]
fn new_unchecked(valid_value in 0..=0b0000_0111u8) {
assert_eq!(
valid_value,
unsafe {
VlanPcp::new_unchecked(valid_value).value()
}
);
}
}
proptest! {
#[test]
fn fmt(valid_value in 0..=0b0000_0111u8) {
assert_eq!(format!("{}", VlanPcp(valid_value)), format!("{}", valid_value));
}
}
proptest! {
#[test]
fn from(valid_value in 0..=0b0000_0111u8,) {
let pcp = VlanPcp::try_new(valid_value).unwrap();
let actual: u8 = pcp.into();
assert_eq!(actual, valid_value);
}
}
}