From e8acfd44ac6fb1cf46bf64fc7b6706b6fc35dced Mon Sep 17 00:00:00 2001
From: "Benjamin A. Beasley" <code@musicinmybrain.net>
Date: Wed, 8 May 2024 09:10:53 -0400
Subject: [PATCH] Fix integer overflow in midpoint calculation

Fixes #2 as suggested by @kaltu (Yulin Liu) in the issue.

See also:

https://research.google/blog/extra-extra-read-all-about-it-nearly-all-binary-searches-and-mergesorts-are-broken/
---
 src/lib.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 3089e54..63a6c09 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -137,7 +137,7 @@ where
 {
     let (mut lo, mut hi) = bounds_to_indices(a, within);
     while lo < hi {
-        let mid = (lo + hi) / 2;
+        let mid = lo + (hi - lo) / 2;
         if f(&a[mid]) == Ordering::Less {
             hi = mid;
         } else {
@@ -278,7 +278,7 @@ where
 {
     let (mut lo, mut hi) = bounds_to_indices(a, within);
     while lo < hi {
-        let mid = (lo + hi) / 2;
+        let mid = lo + (hi - lo) / 2;
         let cmp = f(&a[mid]);
         if cmp == Ordering::Less {
             lo = mid + 1;