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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 File {
A,
B,
C,
D,
E,
F,
G,
H,
}
pub const NUM_FILES: usize = 8;
pub const ALL_FILES: [File; NUM_FILES] = [
File::A,
File::B,
File::C,
File::D,
File::E,
File::F,
File::G,
File::H,
];
impl File {
#[inline]
pub fn from_index(i: usize) -> File {
unsafe { transmute((i as u8) & 7) }
}
#[inline]
pub fn left(&self) -> File {
File::from_index(self.to_index().wrapping_sub(1))
}
#[inline]
pub fn right(&self) -> File {
File::from_index(self.to_index() + 1)
}
#[inline]
pub fn to_index(&self) -> usize {
*self as usize
}
}
impl FromStr for File {
type Err = Error;
fn from_str(s: &str) -> Result<Self, Self::Err> {
if s.len() < 1 {
return Err(Error::InvalidFile);
}
match s.chars().next().unwrap() {
'a' => Ok(File::A),
'b' => Ok(File::B),
'c' => Ok(File::C),
'd' => Ok(File::D),
'e' => Ok(File::E),
'f' => Ok(File::F),
'g' => Ok(File::G),
'h' => Ok(File::H),
_ => Err(Error::InvalidFile),
}
}
}