From 21ced6af62939e3f441efcd74ba95a87ed57270d Mon Sep 17 00:00:00 2001
From: Mehdi Bouaziz <mbouaziz@fb.com>
Date: Mon, 11 Jun 2018 08:47:09 -0700
Subject: [PATCH] PartialOrder

Reviewed By: ngorogiannis

Differential Revision: D8350238

fbshipit-source-id: 3ec4f34
---
 infer/src/bufferoverrun/itv.ml  | 14 +-------------
 infer/src/istd/PartialOrder.ml  | 25 +++++++++++++++++++++++++
 infer/src/istd/PartialOrder.mli | 14 ++++++++++++++
 3 files changed, 40 insertions(+), 13 deletions(-)
 create mode 100644 infer/src/istd/PartialOrder.ml
 create mode 100644 infer/src/istd/PartialOrder.mli

diff --git a/infer/src/bufferoverrun/itv.ml b/infer/src/bufferoverrun/itv.ml
index 447c090b4..b17bba3a5 100644
--- a/infer/src/bufferoverrun/itv.ml
+++ b/infer/src/bufferoverrun/itv.ml
@@ -690,19 +690,7 @@ module Bound = struct
 
   let eq : t -> t -> bool = fun x y -> le x y && le y x
 
-  let xcompare ~lhs ~rhs =
-    let ller = le lhs rhs in
-    let rlel = le rhs lhs in
-    match (ller, rlel) with
-    | true, true ->
-        `Equal
-    | true, false ->
-        `LeftSmallerThanRight
-    | false, true ->
-        `RightSmallerThanLeft
-    | false, false ->
-        `NotComparable
-
+  let xcompare = PartialOrder.of_le ~le
 
   let remove_max_int : t -> t =
    fun x ->
diff --git a/infer/src/istd/PartialOrder.ml b/infer/src/istd/PartialOrder.ml
new file mode 100644
index 000000000..a9f98c59a
--- /dev/null
+++ b/infer/src/istd/PartialOrder.ml
@@ -0,0 +1,25 @@
+(*
+ * Copyright (c) 2018-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+
+open! IStd
+
+type total = [`LeftSmallerThanRight | `Equal | `RightSmallerThanLeft]
+
+type t = [total | `NotComparable]
+
+let of_le ~le ~lhs ~rhs =
+  let ller = le lhs rhs in
+  let rlel = le rhs lhs in
+  match (ller, rlel) with
+  | true, true ->
+      `Equal
+  | true, false ->
+      `LeftSmallerThanRight
+  | false, true ->
+      `RightSmallerThanLeft
+  | false, false ->
+      `NotComparable
diff --git a/infer/src/istd/PartialOrder.mli b/infer/src/istd/PartialOrder.mli
new file mode 100644
index 000000000..bb27e24be
--- /dev/null
+++ b/infer/src/istd/PartialOrder.mli
@@ -0,0 +1,14 @@
+(*
+ * Copyright (c) 2018-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+
+open! IStd
+
+type total = [`LeftSmallerThanRight | `Equal | `RightSmallerThanLeft]
+
+type t = [total | `NotComparable]
+
+val of_le : le:('a -> 'a -> bool) -> lhs:'a -> rhs:'a -> t