From c091b8e892657f0f92a2db76ca4b5aad7ce4497b Mon Sep 17 00:00:00 2001
From: Samuel Tardieu <sam@rfc1149.net>
Date: Sun, 11 Feb 2024 16:31:48 +0100
Subject: [PATCH] fix(matrix): use bitvec-rs instead of hand-crafted bit
 manipulation

---
 Cargo.toml    | 1 +
 src/matrix.rs | 7 ++++---
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 4e3ee124..ad718d3d 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,6 +28,7 @@ rustc-hash = "2.0.0"
 integer-sqrt = "0.1.5"
 thiserror = "1.0.63"
 deprecate-until = "0.1.1"
+bitvec-rs = "0.2.1"
 
 [dev-dependencies]
 codspeed-criterion-compat = "2.0.0"
diff --git a/src/matrix.rs b/src/matrix.rs
index 61215267..4a434583 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -3,6 +3,7 @@
 use crate::directed::bfs::bfs_reach;
 use crate::directed::dfs::dfs_reach;
 use crate::utils::{constrain, in_direction, move_in_direction, uint_sqrt};
+use bitvec_rs::BitVec;
 use deprecate_until::deprecate_until;
 use num_traits::Signed;
 use std::collections::BTreeSet;
@@ -727,10 +728,10 @@ impl<C> Matrix<C> {
         let mn1 = m * n - 1;
 
         // Scratch array for recording visited locations
-        let mut visited = vec![0u8; (m * n + 7) / 8];
+        let mut visited = BitVec::from_elem(m * n, false);
 
         for s in 1..self.data.len() {
-            if visited[s / 8] & (1 << (s % 8)) != 0 {
+            if visited[s] {
                 continue;
             }
 
@@ -746,7 +747,7 @@ impl<C> Matrix<C> {
                     x = (n * x) % mn1;
                 }
                 self.data.swap(x, s);
-                visited[x / 8] |= 1 << (x % 8);
+                visited.set(x, true);
 
                 // Stop when we're back at the start of the cycle
                 if x == s {