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-rw-r--r--vendor/github.com/dolthub/maphash/hasher.go48
1 files changed, 48 insertions, 0 deletions
diff --git a/vendor/github.com/dolthub/maphash/hasher.go b/vendor/github.com/dolthub/maphash/hasher.go
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+// Copyright 2022 Dolthub, Inc.
+//
+// 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
+//
+// http://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.
+
+package maphash
+
+import "unsafe"
+
+// Hasher hashes values of type K.
+// Uses runtime AES-based hashing.
+type Hasher[K comparable] struct {
+ hash hashfn
+ seed uintptr
+}
+
+// NewHasher creates a new Hasher[K] with a random seed.
+func NewHasher[K comparable]() Hasher[K] {
+ return Hasher[K]{
+ hash: getRuntimeHasher[K](),
+ seed: newHashSeed(),
+ }
+}
+
+// NewSeed returns a copy of |h| with a new hash seed.
+func NewSeed[K comparable](h Hasher[K]) Hasher[K] {
+ return Hasher[K]{
+ hash: h.hash,
+ seed: newHashSeed(),
+ }
+}
+
+// Hash hashes |key|.
+func (h Hasher[K]) Hash(key K) uint64 {
+ // promise to the compiler that pointer
+ // |p| does not escape the stack.
+ p := noescape(unsafe.Pointer(&key))
+ return uint64(h.hash(p, h.seed))
+}