github.com/sequix/cortex@v1.1.6/pkg/chunk/gcp/fnv.go (about)

     1  // Modified from github.com/prometheus/common/model/fnv.go
     2  // Copyright 2015 The Prometheus Authors
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  // http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gcp
    16  
    17  // Inline and byte-free variant of hash/fnv's fnv64a.
    18  
    19  const (
    20  	offset64 = 14695981039346656037
    21  	prime64  = 1099511628211
    22  )
    23  
    24  // hashNew initializies a new fnv64a hash value.
    25  func hashNew() uint64 {
    26  	return offset64
    27  }
    28  
    29  // hashAdd adds a string to a fnv64a hash value, returning the updated hash.
    30  func hashAdd(h uint64, s string) uint64 {
    31  	for i := 0; i < len(s); i++ {
    32  		h ^= uint64(s[i])
    33  		h *= prime64
    34  	}
    35  	return h
    36  }