Adding upstream version 2.2.0.upstream/2.2.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 57 insertions, 0 deletions

diff --git a/src/lib/util/hash.h b/src/lib/util/hash.h
new file mode 100644
index 0000000..45d6ba5
--- /dev/null
+++ b/src/lib/util/hash.h
@@ -0,0 +1,57 @@
+// Copyright (C) 2018 Internet Systems Consortium, Inc. ("ISC")
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#ifndef HASH_H
+#define HASH_H
+
+#include <cstddef>
+#include <cstdint>
+#include <string>
+
+namespace isc {
+namespace util {
+
+/// @brief Hash implementation based on Fowler-Noll-Vo hash function
+///
+struct Hash64 {
+    /// @brief Compute the hash
+    ///
+    /// FNV-1a hash function
+    ///
+    /// @param data data to hash
+    /// @param length length of data
+    /// @return the hash value
+    static uint64_t hash(const uint8_t* data, size_t length) {
+        uint64_t hash = FNV_offset_basis;
+        for (size_t i = 0; i < length; ++i) {
+            hash = hash ^ data[i];
+            hash = hash * FNV_prime;
+        }
+        return (hash);
+    }
+
+    /// @brief Compute the hash
+    ///
+    /// FNV-1a hash function
+    ///
+    /// @param str not empty string to hash
+    /// @return the hash value
+    static uint64_t hash(const std::string& str) {
+        return (hash(reinterpret_cast<const uint8_t*>(str.c_str()),
+                     str.size()));
+    }
+
+    /// @brief Offset basis
+    static const uint64_t FNV_offset_basis = 14695981039346656037ull;
+
+    /// @brief Prime
+    static const uint64_t FNV_prime = 1099511628211ull;
+};
+
+} // end of namespace isc::util
+} // end of namespace isc
+
+#endif