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tic tac toe

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nora 2022-11-21 09:23:31 +01:00
parent 43d39fba30
commit c7a6bdf3c0
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11 changed files with 149 additions and 40 deletions
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33
src/board.rs
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@ -58,24 +58,21 @@ impl Board {
Self(0x0002AAAA)
}
#[cfg(not(debug_assertions))]
fn validate(&self) {}
#[cfg(debug_assertions)]
fn validate(&self) {
let board = self.0;
for i in 0..16 {
let next_step = board >> (i * 2);
let mask = 0b11;
let pos = next_step & mask;
if pos >= 3 {
panic!("Invalid bits, self: {board:0X}, bits: {pos:0X}");
if cfg!(debug_assertions) {
let board = self.0;
for i in 0..16 {
let next_step = board >> (i * 2);
let mask = 0b11;
let pos = next_step & mask;
if pos >= 3 {
panic!("Invalid bits, self: {board:0X}, bits: {pos:0X}");
}
}
}
}
pub fn get(&self, index: usize) -> Option<Player> {
self.validate();
debug_assert!(index < 9);
let board = self.0;
@ -83,7 +80,13 @@ impl Board {
let shifted = board >> (index * 2);
let masked = shifted & 0b11;
Player::from_u8(masked as u8).unwrap()
// SAFETY: So uh, this is a bit unlucky.
// You see, there are two entire bits of information at our disposal for each position.
// This is really bad. We only have three valid states. So we need to do _something_ if it's invalid.
// We just hope that it will never be invalid which it really shouldn't be and also have a debug assertion
// here to make sure that it really is valid and then if it's not invalid we just mov it out and are happy.
self.validate();
unsafe { Player::from_u8(masked as u8).unwrap_unchecked() }
}
pub fn set(&mut self, index: usize, value: Option<Player>) {
@ -106,7 +109,7 @@ impl Board {
let mut i = 0;
let this = self.clone();
std::iter::from_fn(move || {
let result = (i < 8).then(|| this.get(i));
let result = (i < 9).then(|| this.get(i));
i += 1;
result
})
@ -121,7 +124,7 @@ mod win_table {
use super::{Board, Player, State};
const WIN_TABLE_SIZE: usize = 2usize.pow(2 * 9);
const WIN_TABLE: &[u8; WIN_TABLE_SIZE] = include_bytes!(concat!(env!("OUT_DIR"), "/win_table"));
static WIN_TABLE: &[u8; WIN_TABLE_SIZE] = include_bytes!(concat!(env!("OUT_DIR"), "/win_table"));
pub fn result(board: &Board) -> State {
match WIN_TABLE[board.0 as usize] {