mirror of
https://github.com/superseriousbusiness/gotosocial.git
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49 lines
1.3 KiB
Go
49 lines
1.3 KiB
Go
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// Copyright 2022 Dolthub, Inc.
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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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// http://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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package maphash
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import "unsafe"
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// Hasher hashes values of type K.
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// Uses runtime AES-based hashing.
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type Hasher[K comparable] struct {
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hash hashfn
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seed uintptr
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}
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// NewHasher creates a new Hasher[K] with a random seed.
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func NewHasher[K comparable]() Hasher[K] {
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return Hasher[K]{
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hash: getRuntimeHasher[K](),
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seed: newHashSeed(),
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}
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}
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// NewSeed returns a copy of |h| with a new hash seed.
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func NewSeed[K comparable](h Hasher[K]) Hasher[K] {
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return Hasher[K]{
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hash: h.hash,
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seed: newHashSeed(),
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}
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}
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// Hash hashes |key|.
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func (h Hasher[K]) Hash(key K) uint64 {
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// promise to the compiler that pointer
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// |p| does not escape the stack.
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p := noescape(unsafe.Pointer(&key))
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return uint64(h.hash(p, h.seed))
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}
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