From bb1ede3fa4f9c00fdb3f809356dcf6465781f74d Mon Sep 17 00:00:00 2001
From: oech3 <79379754+oech3@users.noreply.github.com>
Date: Sat, 7 Mar 2026 01:18:27 +0900
Subject: [PATCH] shuf: Reduce malloc

---
 src/uu/shuf/src/shuf.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/uu/shuf/src/shuf.rs b/src/uu/shuf/src/shuf.rs
index 5661ec2ee..757de639b 100644
--- a/src/uu/shuf/src/shuf.rs
+++ b/src/uu/shuf/src/shuf.rs
@@ -272,7 +272,10 @@ fn split_seps(data: &[u8], sep: u8) -> Vec<&[u8]> {
     // If data is empty (and does not even contain a single 'sep'
     // to indicate the presence of an empty element), then behave
     // as if the input contained no elements at all.
-    let mut elements: Vec<&[u8]> = data.split(|&b| b == sep).collect();
+    const PREDICTED_LINE_LENGTH: usize = 64;
+    let predicted_capacity = data.len() / PREDICTED_LINE_LENGTH;
+    let mut elements = Vec::with_capacity(predicted_capacity);
+    elements.extend(data.split(|&b| b == sep));
     if elements.last().is_some_and(|e| e.is_empty()) {
         elements.pop();
     }