Abseil Common Libraries (C++) (grcp 依赖)
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49 lines
1.6 KiB
49 lines
1.6 KiB
4 years ago
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// Copyright 2020 The Abseil Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// https://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// This file provides the Google-internal implementation of the Wyhash
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// algorithm.
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//
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// Wyhash is a fast hash function for hash tables, the fastest we've currently
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// (late 2020) found that passes the SMHasher tests. The algorithm relies on
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// intrinsic 128-bit multiplication for speed. This is not meant to be secure -
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// just fast.
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#ifndef ABSL_HASH_INTERNAL_WYHASH_H_
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#define ABSL_HASH_INTERNAL_WYHASH_H_
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#include <stdint.h>
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#include <stdlib.h>
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#include "absl/base/config.h"
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namespace absl {
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ABSL_NAMESPACE_BEGIN
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namespace hash_internal {
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// Hash function for a byte array. A 64-bit seed and a set of five 64-bit
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// integers are hashed into the result.
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//
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// To allow all hashable types (including string_view and Span) to depend on
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// this algoritm, we keep the API low-level, with as few dependencies as
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// possible.
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uint64_t Wyhash(const void* data, size_t len, uint64_t seed,
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const uint64_t salt[5]);
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} // namespace hash_internal
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ABSL_NAMESPACE_END
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} // namespace absl
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#endif // ABSL_HASH_INTERNAL_WYHASH_H_
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