[Minor] Move common hashing utils to a separate util header

diff --git a/src/libutil/cxx/hash_util.hxx b/src/libutil/cxx/hash_util.hxx
new file mode 100644 (file)
index 0000000..6d20ddb
--- /dev/null
+++ b/src/libutil/cxx/hash_util.hxx
@@ -0,0 +1,54 @@
+/*-
+ * Copyright 2021 Vsevolod Stakhov
+ *
+ * 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 RSPAMD_HASH_UTIL_HXX
+#define RSPAMD_HASH_UTIL_HXX
+
+#pragma once
+
+#include <string_view>
+#include <string>
+#include "contrib/robin-hood/robin_hood.h"
+
+
+namespace rspamd {
+
+/* Enable lookup by string view */
+struct smart_str_equal {
+       using is_transparent = void;
+       auto operator()(const std::string &a, const std::string &b) const {
+               return a == b;
+       }
+       auto operator()(const std::string_view &a, const std::string &b) const {
+               return a == b;
+       }
+       auto operator()(const std::string &a, const std::string_view &b) const {
+               return a == b;
+       }
+};
+
+struct smart_str_hash {
+       using is_transparent = void;
+       auto operator()(const std::string &a) const {
+               return robin_hood::hash<std::string>()(a);
+       }
+       auto operator()(const std::string_view &a) const {
+               return robin_hood::hash<std::string_view>()(a);
+       }
+};
+
+}
+
+#endif //RSPAMD_HASH_UTIL_HXX