Add == and < operators on CassUuid-s to make them usable in std::set, std::map, etc. containers

Author: lgeorget

include/cassandra.h

@@ -144,6 +144,11 @@ typedef struct CassUuid_ {
   cass_uint64_t clock_seq_and_node;
 } CassUuid;
 
+#ifdef __cplusplus
+// If the current project is a C++ one, expose C++ operators on CassUuid.
+#include "uuid_operators.hpp"
+#endif
+
 /**
  * A cluster object describes the configuration of the Cassandra cluster and is used
  * to construct a session instance. Unlike other DataStax drivers the cluster object

include/uuid_operators.hpp

@@ -0,0 +1,48 @@
+/*
+  Copyright (c) DataStax, Inc.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+*/
+
+#ifndef __UUID_OPERATORS_HPP_INCLUDED__
+#define __UUID_OPERATORS_HPP_INCLUDED__
+
+#ifdef __cplusplus
+#include "cassandra.h"
+
+/**
+ * Compare two UUIDs for ordering
+ *
+ * This operator is useful to use CassUuid variables as std::map keys, for
+ * instance.
+ *
+ * @param uuid1 A UUID
+ * @param uuid2 Another UUID
+ * @return true if, and only if, uuid1 is numerically less or equal than uuid2
+ */
+bool operator<(const CassUuid& uuid1, const CassUuid& uuid2);
+
+/**
+ * Compare two UUIDs for equality
+ *
+ * This operator is useful to use CassUuid variables as std::map keys, for
+ * instance.
+ *
+ * @param uuid1 A UUID
+ * @param uuid2 Another UUID
+ * @return true if, and only if, uuid1 is numerically less or equal than uuid2
+ */
+bool operator==(const CassUuid& uuid1, const CassUuid& uuid2);
+#endif
+
+#endif /* __UUID_OPERATORS_HPP_INCLUDED__ */

src/uuids.cpp

@@ -44,6 +44,18 @@ static uint64_t set_version(uint64_t timestamp, uint8_t version) {
   return (timestamp & 0x0FFFFFFFFFFFFFFFLL) | (static_cast<uint64_t>(version) << 60);
 }
 
+bool operator<(const CassUuid& uuid1, const CassUuid& uuid2) {
+  if (uuid1.time_and_version == uuid2.time_and_version)
+    return uuid1.clock_seq_and_node < uuid2.clock_seq_and_node;
+  else
+    return uuid1.time_and_version < uuid2.time_and_version;
+}
+
+bool operator==(const CassUuid& uuid1, const CassUuid& uuid2) {
+  return uuid1.time_and_version == uuid2.time_and_version
+    && uuid1.clock_seq_and_node == uuid2.clock_seq_and_node;
+}
+
 extern "C" {
 
 CassUuidGen* cass_uuid_gen_new() { return CassUuidGen::to(new UuidGen()); }

tests/src/unit/tests/test_uuids.cpp

@@ -167,3 +167,35 @@ TEST(UuidUnitTest, FromStringInvalid) {
   EXPECT_EQ(cass_uuid_from_string_n("00-00-00-00-11-11-11-11-22-22-22-22-deadbeaf", 36, &uuid),
             CASS_ERROR_LIB_BAD_PARAMS);
 }
+
+TEST(UuidUnitTest, Operators) {
+  CassUuid uuid1 = { 0x0000112233445566LL, 0x0000112233445566LL };
+  CassUuid uuid2 = { 0x0000112233445566LL, 0x0000112233445566LL };
+  CassUuid uuid3 = { 0x9988776655443322LL, 0x0000112233445566LL };
+  CassUuid uuid4 = { 0x9988776655443322LL, 0x9988776655443322LL };
+
+  // uuid1 == uuid2
+  EXPECT_TRUE(uuid1 == uuid2);
+  // uuid1 != uuid3
+  EXPECT_FALSE(uuid1 == uuid3);
+  // uuid1 != uuid4
+  EXPECT_FALSE(uuid1 == uuid4);
+  // uuid2 != uuid3
+  EXPECT_FALSE(uuid2 == uuid3);
+  // uuid2 != uuid3
+  EXPECT_FALSE(uuid2 == uuid4);
+  // uuid3 != uuid4
+  EXPECT_FALSE(uuid3 == uuid4);
+  // uuid1 >= uuid2
+  EXPECT_FALSE(uuid1 < uuid2);
+  // uuid1 < uuid3
+  EXPECT_TRUE(uuid1 < uuid3);
+  // uuid1 < uuid4
+  EXPECT_TRUE(uuid1 < uuid4);
+  // uuid2 < uuid3
+  EXPECT_TRUE(uuid2 < uuid3);
+  // uuid2 < uuid3
+  EXPECT_TRUE(uuid2 < uuid4);
+  // uuid3 < uuid4
+  EXPECT_TRUE(uuid3 < uuid4);
+}