uutils · sylvestre · Oct 4, 2025 · Oct 3, 2025
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/src/uu/expand/Cargo.toml b/src/uu/expand/Cargo.toml
@@ -24,6 +24,15 @@ uucore = { workspace = true }
 thiserror = { workspace = true }
 fluent = { workspace = true }
 
+[dev-dependencies]
+divan = { workspace = true }
+tempfile = { workspace = true }
+uucore = { workspace = true, features = ["benchmark"] }
+
 [[bin]]
 name = "expand"
 path = "src/main.rs"
+
+[[bench]]
+name = "expand_bench"
+harness = false
diff --git a/src/uu/expand/benches/expand_bench.rs b/src/uu/expand/benches/expand_bench.rs
@@ -0,0 +1,48 @@
+// This file is part of the uutils coreutils package.
+//
+// For the full copyright and license information, please view the LICENSE
+// file that was distributed with this source code.
+
+use divan::{Bencher, black_box};
+use std::fmt::Write;
+use uu_expand::uumain;
+use uucore::benchmark::{create_test_file, run_util_function};
+
+/// Helper function to run expand benchmark with generated data
+fn bench_expand(bencher: Bencher, data: impl AsRef<[u8]>, args: &[&str]) {
+    let temp_dir = tempfile::tempdir().unwrap();
+    let file_path = create_test_file(data.as_ref(), temp_dir.path());
+    let file_path_str = file_path.to_str().unwrap();
+
+    let mut all_args = vec![];
+    all_args.extend_from_slice(args);
+    all_args.push(file_path_str);
+
+    bencher.bench(|| {
+        black_box(run_util_function(uumain, &all_args));
+    });
+}
+
+/// Benchmark expanding tabs on files with many short lines
+#[divan::bench(args = [100_000])]
+fn expand_many_lines(bencher: Bencher, num_lines: usize) {
+    let data = (0..num_lines).fold(String::new(), |mut acc, i| {
+        writeln!(&mut acc, "line{i}\tvalue{}\tdata{}", i * 2, i * 3).unwrap();
+        acc
+    });
+    bench_expand(bencher, data, &[]);
+}
+
+/// Benchmark expanding tabs with custom tab stops
+#[divan::bench(args = [50_000])]
+fn expand_custom_tabstops(bencher: Bencher, num_lines: usize) {
+    let data = (0..num_lines).fold(String::new(), |mut acc, i| {
+        writeln!(&mut acc, "a\tb\tc\td\te{i}").unwrap();
+        acc
+    });
+    bench_expand(bencher, data, &["--tabs=4,8,12"]);
+}
+
+fn main() {
+    divan::main();
+}