From 79d843524cf6b2f0f01f4f7649e24f6c8e8db41e Mon Sep 17 00:00:00 2001
From: aiongg <aiongtaigi@gmail.com>
Date: Thu, 22 Oct 2026 01:46:03 +0000
Subject: [PATCH] Integration: #2220 look up set-aside object numbers in a set

fill_xref_gaps scanned every xref oddity for each object header; a file with many offset-0 rows and many headers took quadratic time.
---
 crates/cos/src/document.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/crates/cos/src/document.rs b/crates/cos/src/document.rs
index b24bea637..6d39d53db 100644
--- a/crates/cos/src/document.rs
+++ b/crates/cos/src/document.rs
@@ -1968,9 +1968,10 @@ impl Document {
         } else {
             HashSet::new()
         };
+        let odd: HashSet<u32> = self.xref_oddities.iter().map(|(_, n)| *n).collect();
         let mut found = 0usize;
         for (&num, &(offset, generation)) in &located {
-            let left_out = past_shift.contains(&num) || self.xref_oddities.iter().any(|(_, n)| *n == num);
+            let left_out = past_shift.contains(&num) || odd.contains(&num);
             if num != 0 && !filled.contains_key(&num) && left_out {
                 filled.insert(num, XrefEntry::InFile { offset, generation });
                 found += 1;