From 678d8edb128c40d6ae5d4492e6b85c94867be80a Mon Sep 17 00:00:00 2001
From: Louis-Philippe Gauthier <lpgauth@gmail.com>
Date: Tue, 14 Jun 2016 08:42:25 -0400
Subject: [PATCH] Support OTP-19-rc2

---
 rebar.config             |  3 ++-
 src/statsderl_server.erl | 10 ++++-----
 src/statsderl_udp.erl    | 44 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 50 insertions(+), 7 deletions(-)
 create mode 100644 src/statsderl_udp.erl

diff --git a/rebar.config b/rebar.config
index 9a63404..49240fe 100644
--- a/rebar.config
+++ b/rebar.config
@@ -13,7 +13,8 @@
 ]}.
 
 {erl_opts, [
-  debug_info
+  debug_info,
+  {platform_define, "19", 'UDP_HEADER'}
 ]}.
 
 {profiles, [
diff --git a/src/statsderl_server.erl b/src/statsderl_server.erl
index 3fa4746..8154464 100644
--- a/src/statsderl_server.erl
+++ b/src/statsderl_server.erl
@@ -7,7 +7,7 @@
 ]).
 
 -record(state, {
-    header :: binary(),
+    header :: iodata(),
     socket :: inet:socket()
 }).
 
@@ -70,11 +70,9 @@ loop(State) ->
 udp_header(Hostname, Port, BaseKey) ->
     case statsderl_utils:getaddrs(Hostname) of
         {ok, {A, B, C, D}} ->
-            {ok, iolist_to_binary([
-                [((Port) bsr 8) band 16#ff, (Port) band 16#ff],
-                [A band 16#ff, B band 16#ff, C band 16#ff, D band 16#ff],
-                statsderl_utils:base_key(BaseKey)
-            ])};
+            Header = statsderl_udp:header({A, B, C, D}, Port),
+            BaseKey2 = statsderl_utils:base_key(BaseKey),
+            {ok, [Header, BaseKey2]};
         {error, Reason} ->
             {error, Reason}
     end.
diff --git a/src/statsderl_udp.erl b/src/statsderl_udp.erl
new file mode 100644
index 0000000..9c4f6bf
--- /dev/null
+++ b/src/statsderl_udp.erl
@@ -0,0 +1,44 @@
+-module(statsderl_udp).
+-include("statsderl.hrl").
+
+-compile(inline).
+-compile({inline_size, 512}).
+
+-export([
+    header/2,
+    send/3
+]).
+
+-define(INET_AF_INET, 1).
+-define(INT16(X), [((X) bsr 8) band 16#ff, (X) band 16#ff]).
+
+%% public
+-spec header(inet:ip_address(), inet:port_number()) -> iodata().
+
+-ifdef(UDP_HEADER).
+
+header(IP, Port) ->
+    [?INET_AF_INET, ?INT16(Port) | ip4_to_bytes(IP)].
+
+-else.
+
+header(IP, Port) ->
+    [?INT16(Port) | ip4_to_bytes(IP)].
+
+-endif.
+
+-spec send(inet:socket(), iodata(), iodata()) ->
+    ok | {error, term()}.
+
+send(Socket, Header, Data) ->
+    try
+        true = erlang:port_command(Socket, [Header, Data]),
+        ok
+    catch
+        Error:Reason ->
+            {error, {Error, Reason}}
+    end.
+
+%% private
+ip4_to_bytes({A, B, C, D}) ->
+    [A band 16#ff, B band 16#ff, C band 16#ff, D band 16#ff].