Abseil Common Libraries (C++) (grcp 依赖)
https://abseil.io/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
50 lines
1.8 KiB
50 lines
1.8 KiB
// Copyright 2020 The Abseil Authors |
|
// |
|
// 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 |
|
// |
|
// https://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. |
|
// |
|
// This file provides the Google-internal implementation of LowLevelHash. |
|
// |
|
// LowLevelHash is a fast hash function for hash tables, the fastest we've |
|
// currently (late 2020) found that passes the SMHasher tests. The algorithm |
|
// relies on intrinsic 128-bit multiplication for speed. This is not meant to be |
|
// secure - just fast. |
|
// |
|
// It is closely based on a version of wyhash, but does not maintain or |
|
// guarantee future compatibility with it. |
|
|
|
#ifndef ABSL_HASH_INTERNAL_LOW_LEVEL_HASH_H_ |
|
#define ABSL_HASH_INTERNAL_LOW_LEVEL_HASH_H_ |
|
|
|
#include <stdint.h> |
|
#include <stdlib.h> |
|
|
|
#include "absl/base/config.h" |
|
|
|
namespace absl { |
|
ABSL_NAMESPACE_BEGIN |
|
namespace hash_internal { |
|
|
|
// Hash function for a byte array. A 64-bit seed and a set of five 64-bit |
|
// integers are hashed into the result. |
|
// |
|
// To allow all hashable types (including string_view and Span) to depend on |
|
// this algorithm, we keep the API low-level, with as few dependencies as |
|
// possible. |
|
uint64_t LowLevelHash(const void* data, size_t len, uint64_t seed, |
|
const uint64_t salt[5]); |
|
|
|
} // namespace hash_internal |
|
ABSL_NAMESPACE_END |
|
} // namespace absl |
|
|
|
#endif // ABSL_HASH_INTERNAL_LOW_LEVEL_HASH_H_
|
|
|