Initial stab at a buffer pool

test/test.rs

@@ -2,12 +2,14 @@ use rand::random;
 
 extern crate bytes;
 extern crate rand;
+extern crate byteorder;
 
 mod test_buf;
 mod test_buf_fill;
 mod test_buf_take;
 mod test_byte_buf;
 mod test_bytes;
+mod test_pool;
 mod test_ring;
 mod test_rope;
 mod test_seq_byte_str;

test/test_pool.rs

@@ -0,0 +1,85 @@
+use bytes::alloc::Pool;
+use bytes::{Buf, MutBuf};
+use rand::{self, Rng};
+use byteorder::{ByteOrder, BigEndian};
+
+#[test]
+fn test_pool_of_zero_capacity() {
+    let pool = Pool::with_capacity(0, 0);
+    assert!(pool.new_byte_buf().is_none());
+
+    let pool = Pool::with_capacity(0, 1_024);
+    assert!(pool.new_byte_buf().is_none());
+}
+
+#[test]
+fn test_pool_with_one_capacity() {
+    let pool = Pool::with_capacity(1, 1024);
+
+    let mut buf = pool.new_byte_buf().unwrap();
+    assert!(pool.new_byte_buf().is_none());
+
+    assert_eq!(1024, buf.remaining());
+
+    buf.write_slice(b"Hello World");
+    let mut buf = buf.flip();
+
+    let mut dst = vec![];
+
+    buf.copy_to(&mut dst).unwrap();
+
+    assert_eq!(&dst[..], b"Hello World");
+
+    // return the buffer to the pool
+    drop(buf);
+
+    let _ = pool.new_byte_buf().unwrap();
+}
+
+#[test]
+fn test_pool_stress() {
+    let pool = Pool::with_capacity(100, 4);
+    let mut bufs = Vec::with_capacity(100);
+    let mut rng = rand::thread_rng();
+
+    let mut s = [0; 4];
+
+    for i in 0..50_000u32 {
+        let action: usize = rng.gen();
+
+        match action % 3 {
+            0 if bufs.len() < 100 => {
+                let mut buf = pool.new_byte_buf().unwrap();
+                BigEndian::write_u32(&mut s, i);
+                buf.write_slice(&s);
+                bufs.push((i, buf.flip()));
+            }
+            1 if bufs.len() > 0 => {
+                // drop
+                let len = bufs.len();
+                let _ = bufs.remove(rng.gen::<usize>() % len);
+            }
+            2 if bufs.len() > 0 => {
+                // read
+                let len = bufs.len();
+                let (i, mut buf) = bufs.remove(rng.gen::<usize>() % len);
+                buf.mark();
+                buf.read_slice(&mut s);
+                buf.reset();
+                let v = BigEndian::read_u32(&s);
+                assert_eq!(i, v);
+                bufs.push((i, buf));
+            }
+            3 if bufs.len() > 0 => {
+                // write data
+                let len = bufs.len();
+                let (i, buf) = bufs.remove(rng.gen::<usize>() % len);
+                let mut buf = buf.flip();
+                BigEndian::write_u32(&mut s, i);
+                buf.write_slice(&s);
+                bufs.push((i, buf.flip()));
+            }
+            _ => {}
+        }
+    }
+}