Added fast-path, tests

Author: Lucretiel

src/libstd/net/addr.rs

@@ -600,17 +600,23 @@ impl fmt::Display for SocketAddr {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddrV4 {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- const IPV4_SOCKET_BUF_LEN: usize = 21;
- let mut buf = [0; IPV4_SOCKET_BUF_LEN];
- let mut buf_slice = &mut buf[..];
-
- // Unwrap is fine because writing to a buffer is infallible
- write!(buf_slice, "{}:{}", self.ip(), self.port()).unwrap();
- let len = IPV4_SOCKET_BUF_LEN - buf_slice.len();
-
- // This unsafe is OK because we know what is being written to the buffer
- let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
- f.pad(buf)
+ // Fast path: if there's no alignment stuff, write to the output buffer
+ // directly
+ if f.precision().is_none() && f.width().is_none() {
+ write!(f, "{}:{}", self.ip(), self.port())
+ } else {
+ const IPV4_SOCKET_BUF_LEN: usize = 21;
+ let mut buf = [0; IPV4_SOCKET_BUF_LEN];
+ let mut buf_slice = &mut buf[..];
+
+ // Unwrap is fine because writing to a buffer is infallible
+ write!(buf_slice, "{}:{}", self.ip(), self.port()).unwrap();
+ let len = IPV4_SOCKET_BUF_LEN - buf_slice.len();
+
+ // This unsafe is OK because we know what is being written to the buffer
+ let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
+ f.pad(buf)
+ }
  }
 }
 
@@ -624,21 +630,27 @@ impl fmt::Debug for SocketAddrV4 {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl fmt::Display for SocketAddrV6 {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- const IPV6_SOCKET_BUF_LEN: usize = (4 * 8) // The address
+ // Fast path: if there's no alignment stuff, write to the output
+ // buffer directly
+ if f.precision().is_none() && f.width().is_none() {
+ write!(f, "[{}]:{}", self.ip(), self.port())
+ } else {
+ const IPV6_SOCKET_BUF_LEN: usize = (4 * 8) // The address
  + 7 // The colon separators
  + 2 // The brackets
  + 1 + 5; // The port
 
- let mut buf = [0; IPV6_SOCKET_BUF_LEN];
- let mut buf_slice = &mut buf[..];
+  let mut buf = [0; IPV6_SOCKET_BUF_LEN];
+  let mut buf_slice = &mut buf[..];
 
- // Unwrap is fine because writing to a buffer is infallible
- write!(buf_slice, "[{}]:{}", self.ip(), self.port()).unwrap();
- let len = IPV6_SOCKET_BUF_LEN - buf_slice.len();
+  // Unwrap is fine because writing to a buffer is infallible
+  write!(buf_slice, "[{}]:{}", self.ip(), self.port()).unwrap();
+  let len = IPV6_SOCKET_BUF_LEN - buf_slice.len();
 
- // This unsafe is OK because we know what is being written to the buffer
- let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
- f.pad(buf)
+ // This unsafe is OK because we know what is being written to the buffer
+ let buf = unsafe { crate::str::from_utf8_unchecked(&buf[..len]) };
+ f.pad(buf)
+ }
  }
 }
 
@@ -1192,6 +1204,28 @@ mod tests {
  assert!(v6.is_ipv6());
  }
 
+ #[test]
+ fn socket_v4_to_str() {
+ let socket = SocketAddrV4::new(Ipv4Addr::new(192, 168, 0, 1), 8080);
+
+ assert_eq!(format!("{}", socket), "192.168.0.1:8080");
+ assert_eq!(format!("{:<20}", socket), "192.168.0.1:8080 ");
+ assert_eq!(format!("{:>20}", socket), " 192.168.0.1:8080");
+ assert_eq!(format!("{:^20}", socket), " 192.168.0.1:8080 ");
+ assert_eq!(format!("{:.10}", socket), "192.168.0.");
+ }
+
+ #[test]
+ fn socket_v6_to_str() {
+ let socket: SocketAddrV6 = "[2a02:6b8:0:1::1]:53".parse().unwrap();
+
+ assert_eq!(format!("{}", socket), "[2a02:6b8:0:1::1]:53");
+ assert_eq!(format!("{:<24}", socket), "[2a02:6b8:0:1::1]:53 ");
+ assert_eq!(format!("{:>24}", socket), " [2a02:6b8:0:1::1]:53");
+ assert_eq!(format!("{:^24}", socket), " [2a02:6b8:0:1::1]:53 ");
+ assert_eq!(format!("{:.15}", socket), "[2a02:6b8:0:1::");
+ }
+
  #[test]
  fn compare() {
  let v4_1 = "224.120.45.1:23456".parse::<SocketAddrV4>().unwrap();