sort: Add random_ints()

sort/Cargo.toml

@@ -6,3 +6,10 @@ publish = false
 
 [dependencies]
 rand = "0.8.5"
+
+[dev-dependencies]
+criterion = "0.5.1"
+
+[[bench]]
+name = "bubble_sort"
+harness = false

sort/benches/bubble_sort.rs

@@ -0,0 +1,10 @@
+// Copyright (c) 2024 Xu Shaohua <shaohua@biofan.org>. All rights reserved.
+// Use of this source is governed by General Public License that can be found
+// in the LICENSE file.
+
+use criterion::{Criterion, criterion_group, criterion_main};
+
+fn criterion_benchmark(_c: &mut Criterion) {}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);

sort/src/util.rs

@@ -3,7 +3,8 @@
 // in the LICENSE file.
 
 use std::fmt;
-use std::io::{self, BufRead, BufReader};
+use std::fs::File;
+use std::io::{self, BufRead, BufReader, Read};
 
 pub fn is_sorted<T>(list: &[T]) -> bool
 where
@@ -74,3 +75,34 @@ pub fn read_strings() -> Vec<String> {
     }
     v
 }
+
+/// Generate random integers.
+///
+/// # Errors
+/// Returns error if failed to rand system random file.
+pub fn random_ints(len: usize) -> Result<Vec<i32>, io::Error> {
+    let mut file = File::open("/dev/urandom")?;
+    let mut buf = vec![0; len * 4];
+    file.read_exact(&mut buf)?;
+
+    let mut nums = Vec::with_capacity(len);
+    for i in 0..len {
+        let array: [u8; 4] = [buf[4 * i], buf[4 * i + 1], buf[4 * i + 2], buf[4 * i + 3]];
+        // let mut array: [u8; 4] = [0; 4];
+        // array.swap_with_slice(&mut buf[(i * 4)..(i * 4 + 4)]);
+        nums.push(i32::from_le_bytes(array));
+    }
+    Ok(nums)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::util::random_ints;
+
+    #[test]
+    fn test_random_ints() {
+        let len = 100;
+        let nums: Vec<i32> = random_ints(len).unwrap();
+        assert_eq!(nums.len(), len);
+    }
+}