1/* Copyright 2016 The TensorFlow Authors. All Rights Reserved.
2
3Licensed under the Apache License, Version 2.0 (the "License");
4you may not use this file except in compliance with the License.
5You may obtain a copy of the License at
6
7 http://www.apache.org/licenses/LICENSE-2.0
8
9Unless required by applicable law or agreed to in writing, software
10distributed under the License is distributed on an "AS IS" BASIS,
11WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12See the License for the specific language governing permissions and
13limitations under the License.
14==============================================================================*/
15
16#ifndef TENSORFLOW_CORE_PLATFORM_STRONG_HASH_H_
17#define TENSORFLOW_CORE_PLATFORM_STRONG_HASH_H_
18
19#include "highwayhash/sip_hash.h" // from @highwayhash
20#include "highwayhash/state_helpers.h" // from @highwayhash
21#include "tensorflow/core/platform/platform.h"
22#include "tensorflow/core/platform/types.h"
23
24namespace tensorflow {
25
26// This is a strong keyed hash function interface for strings.
27// The hash function is deterministic on the content of the string within the
28// process. The key of the hash is an array of 2 uint64 elements.
29// A strong hash makes it difficult, if not infeasible, to compute inputs that
30// hash to the same bucket.
31//
32// Usage:
33// uint64 key[2] = {123, 456};
34// string input = "input string";
35// uint64 hash_value = StrongKeyedHash(key, input);
36//
37inline uint64 StrongKeyedHash(const tensorflow::uint64 (&key)[2],
38 const string& s) {
39 return highwayhash::StringHasher<highwayhash::SipHashState>()(
40 {key[0], key[1]}, s);
41}
42
43} // namespace tensorflow
44
45#endif // TENSORFLOW_CORE_PLATFORM_STRONG_HASH_H_
46