Add go implementation by tokuhirom

Makefile

@@ -17,4 +17,6 @@ null_server_epoll: null_server_epoll.cpp
 null_server_thread: null_server_thread.cpp
 	$(CXX) $(CXXFLAGS) -o $@ $<
 
-
+echo_server_go: echo_server_go.go
+	6g -o echo_server_go.6 $<
+	6l -o $@ echo_server_go.6

echo_server_go.go

@@ -0,0 +1,47 @@
+// Original: http://d.hatena.ne.jp/tokuhirom/20091112/1257995906
+
+package main
+import (
+    "net";
+    "os";
+    "fmt";
+)
+
+func Err(format string, v ...os.Error) {
+    fmt.Fprintf(os.Stderr, format + "\n", v)
+}
+
+func Handler(conn net.Conn) {
+    defer conn.Close();
+
+    buffer := make([]byte, 24);
+    for {
+        l, e := conn.Read(buffer);
+        switch {
+        case e == nil:
+            conn.Write(buffer[0:l])
+        case e == os.EOF:
+            return;
+        case e != os.EAGAIN:
+            Err("Err on receiving a header (%s)", e);
+            return;
+        }
+    }
+}
+
+func main() {
+    psock, e := net.Listen("tcp", ":5000");
+    if e != nil {
+        Err("an error occured(%s)", e);
+        return
+    }
+
+    for {
+        conn, e := psock.Accept();
+        if e != nil {
+            Err("an error occured(%s)", e);
+            return
+        }
+        go Handler(conn);
+    }
+}