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z.go
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z.go
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/*
* Copyright 2019 Dgraph Labs, Inc. and Contributors
*
* 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 z
import (
"github.com/cespare/xxhash"
)
// TODO: Figure out a way to re-use memhash for the second uint64 hash, we
// already know that appending bytes isn't reliable for generating a
// second hash (see Ristretto PR #88).
//
// We also know that while the Go runtime has a runtime memhash128
// function, it's not possible to use it to generate [2]uint64 or
// anything resembling a 128bit hash, even though that's exactly what
// we need in this situation.
func KeyToHash(key interface{}) (uint64, uint64) {
if key == nil {
return 0, 0
}
switch k := key.(type) {
case uint64:
return k, 0
case string:
raw := []byte(k)
return MemHash(raw), xxhash.Sum64(raw)
case []byte:
return MemHash(k), xxhash.Sum64(k)
case byte:
return uint64(k), 0
case int:
return uint64(k), 0
case int32:
return uint64(k), 0
case uint32:
return uint64(k), 0
case int64:
return uint64(k), 0
default:
panic("Key type not supported")
}
}