Add rotation functions and diagonal/orthogonal check functions to Direction #461
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src/constants/small_enums.rs
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| /// ``` | ||
| pub fn multi_rot(self, times: i8) -> Self { | ||
| let raw_dir = ((self as u8) - 1).wrapping_add_signed(times) % 8 + 1; | ||
| unsafe { std::mem::transmute(raw_dir) } |
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Note that Direction has FromPrimitive so you could instead use Direction::from_u8, and the compiler will prove that the unwrap is not necessary, except in debug mode, but that's fine to be slower.
Suggested change
| unsafe { std::mem::transmute(raw_dir) } | |
| Self::from_u8(raw_dir).unwrap() |
(you may need to use num_traits::FromPrimitive;)
But if you still want to keep the unsafe, at least add a safety comment:
Suggested change
| unsafe { std::mem::transmute(raw_dir) } | |
| // SAFETY: `x % 8 + 1` is in the range of the valid values for `Direction` of 1..=8. | |
| unsafe { std::mem::transmute(raw_dir) } |
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This is the assembly generated by the from_u8 version, it's as good as you can get and identical to the transmute.
lea eax, [rdi + rsi]
dec al
and al, 7
inc al
ret
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