Add implementation for std::hash<MacAddress>

Summary: Add implementation for std::hash<MacAddress> so that it can be used in maps. Reviewed By: yfeldblum Differential Revision: D10004544 fbshipit-source-id: 46cb177577123b1248cd8ff679f0fbe286596819
facebook · Sep 24, 2018 · 07f9076 · 07f9076
1 parent b7ac6b7
commit 07f9076
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diff --git a/folly/MacAddress.h b/folly/MacAddress.h
@@ -231,3 +231,15 @@ typename std::enable_if<IsSomeString<Tgt>::value>::type toAppend(
 std::ostream& operator<<(std::ostream& os, MacAddress address);
 
 } // namespace folly
+
+namespace std {
+
+// Provide an implementation for std::hash<MacAddress>
+template <>
+struct hash<folly::MacAddress> {
+  size_t operator()(const folly::MacAddress& address) const {
+    return std::hash<uint64_t>()(address.u64HBO());
+  }
+};
+
+} // namespace std
diff --git a/folly/test/MacAddressTest.cpp b/folly/test/MacAddressTest.cpp
@@ -167,3 +167,12 @@ TEST(MacAddress, ordering) {
   testCmp("01:00:00:00:00:00", "02:00:00:00:00:00");
   testCmp("00:00:00:00:00:01", "00:00:00:00:01:00");
 }
+
+TEST(MacAddress, hash) {
+  EXPECT_EQ(
+      std::hash<MacAddress>()(MacAddress("00:11:22:33:44:55")),
+      std::hash<MacAddress>()(MacAddress("00-11-22-33-44-55")));
+  EXPECT_NE(
+      std::hash<MacAddress>()(MacAddress("00:11:22:33:44:55")),
+      std::hash<MacAddress>()(MacAddress("00:11:22:33:44:56")));
+}