From 00238fc1f179e52a733f44b461792b6a698dc9a3 Mon Sep 17 00:00:00 2001
From: Simon Gardling <titaniumtown@proton.me>
Date: Thu, 27 Feb 2025 23:35:59 -0500
Subject: [PATCH] coords: use num::Integer::div_mod_floor for from_index

---
 src/repr/coords.rs | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/repr/coords.rs b/src/repr/coords.rs
index 11b9f97..af4e739 100644
--- a/src/repr/coords.rs
+++ b/src/repr/coords.rs
@@ -1,6 +1,5 @@
-use std::fmt::Display;
-
 use super::Board;
+use num::Integer;
 use static_assertions::const_assert;
 
 // PERF! having `Coord` be of type `u8` (instead of usize) increases
@@ -15,7 +14,7 @@ const_assert!(CoordPairInner::MAX as usize >= Board::BOARD_AREA as usize);
 #[derive(PartialEq, Eq, Copy, Clone, Hash)]
 pub struct CoordPair(pub CoordPairInner);
 
-impl Display for CoordPair {
+impl std::fmt::Display for CoordPair {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let (i, j) = (*self).into();
         write!(f, "({}, {})", i, j)
@@ -29,14 +28,12 @@ impl std::fmt::Debug for CoordPair {
 }
 
 /// Convert a row and column to an index in the board
-pub const fn get_index(row: CoordAxis, col: CoordAxis) -> CoordPair {
+const fn get_index(row: CoordAxis, col: CoordAxis) -> CoordPair {
     CoordPair(row * Board::BOARD_SIZE + col)
 }
 
-pub const fn from_index(index: CoordPair) -> (CoordAxis, CoordAxis) {
-    let row = index.0 % Board::BOARD_SIZE;
-    let col = (index.0 - row) / Board::BOARD_SIZE;
-    (col, row)
+fn from_index(index: CoordPair) -> (CoordAxis, CoordAxis) {
+    index.0.div_mod_floor(&Board::BOARD_SIZE)
 }
 
 impl From<(CoordAxis, CoordAxis)> for CoordPair {
@@ -56,7 +53,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn into_outof() {
+    fn into_out_of() {
         let a: CoordPair = (1, 3).into();
         let back: (CoordAxis, CoordAxis) = a.into();
         assert_eq!(back, (1, 3));