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use crate::error::Error;
use std::mem::transmute;
use std::str::FromStr;
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Debug, Hash)]
pub enum Rank {
First,
Second,
Third,
Fourth,
Fifth,
Sixth,
Seventh,
Eighth,
}
pub const NUM_RANKS: usize = 8;
pub const ALL_RANKS: [Rank; NUM_RANKS] = [
Rank::First,
Rank::Second,
Rank::Third,
Rank::Fourth,
Rank::Fifth,
Rank::Sixth,
Rank::Seventh,
Rank::Eighth,
];
impl Rank {
#[inline]
pub fn from_index(i: usize) -> Rank {
unsafe { transmute((i as u8) & 7) }
}
#[inline]
pub fn down(&self) -> Rank {
Rank::from_index(self.to_index().wrapping_sub(1))
}
#[inline]
pub fn up(&self) -> Rank {
Rank::from_index(self.to_index() + 1)
}
#[inline]
pub fn to_index(&self) -> usize {
*self as usize
}
}
impl FromStr for Rank {
type Err = Error;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if s.len() < 1 {
return Err(Error::InvalidRank);
}
match s.chars().next().unwrap() {
'1' => Ok(Rank::First),
'2' => Ok(Rank::Second),
'3' => Ok(Rank::Third),
'4' => Ok(Rank::Fourth),
'5' => Ok(Rank::Fifth),
'6' => Ok(Rank::Sixth),
'7' => Ok(Rank::Seventh),
'8' => Ok(Rank::Eighth),
_ => Err(Error::InvalidRank),
}
}
}