github.com/muhammadn/cortex@v1.9.1-0.20220510110439-46bb7000d03d/pkg/ingester/client/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 client
    16  
    17  // Inline and byte-free variant of hash/fnv's fnv64a.
    18  
    19  const (
    20  	offset64 = 14695981039346656037
    21  	prime64  = 1099511628211
    22  	offset32 = 2166136261
    23  	prime32  = 16777619
    24  )
    25  
    26  // hashNew initializes a new fnv64a hash value.
    27  func hashNew() uint64 {
    28  	return offset64
    29  }
    30  
    31  // hashAdd adds a string to a fnv64a hash value, returning the updated hash.
    32  // Note this is the same algorithm as Go stdlib `sum64a.Write()`
    33  func hashAdd(h uint64, s string) uint64 {
    34  	for i := 0; i < len(s); i++ {
    35  		h ^= uint64(s[i])
    36  		h *= prime64
    37  	}
    38  	return h
    39  }
    40  
    41  // hashAdd adds a string to a fnv64a hash value, returning the updated hash.
    42  func hashAddString(h uint64, s string) uint64 {
    43  	for i := 0; i < len(s); i++ {
    44  		h ^= uint64(s[i])
    45  		h *= prime64
    46  	}
    47  	return h
    48  }
    49  
    50  // hashAddByte adds a byte to a fnv64a hash value, returning the updated hash.
    51  func hashAddByte(h uint64, b byte) uint64 {
    52  	h ^= uint64(b)
    53  	h *= prime64
    54  	return h
    55  }
    56  
    57  // HashNew32 initializies a new fnv32 hash value.
    58  func HashNew32() uint32 {
    59  	return offset32
    60  }
    61  
    62  // HashAdd32 adds a string to a fnv32 hash value, returning the updated hash.
    63  // Note this is the same algorithm as Go stdlib `sum32.Write()`
    64  func HashAdd32(h uint32, s string) uint32 {
    65  	for i := 0; i < len(s); i++ {
    66  		h *= prime32
    67  		h ^= uint32(s[i])
    68  	}
    69  	return h
    70  }
    71  
    72  // HashAddByte32 adds a byte to a fnv32 hash value, returning the updated hash.
    73  func HashAddByte32(h uint32, b byte) uint32 {
    74  	h *= prime32
    75  	h ^= uint32(b)
    76  	return h
    77  }
    78  
    79  // HashNew32a initializies a new fnv32a hash value.
    80  func HashNew32a() uint32 {
    81  	return offset32
    82  }
    83  
    84  // HashAdd32a adds a string to a fnv32a hash value, returning the updated hash.
    85  // Note this is the same algorithm as Go stdlib `sum32.Write()`
    86  func HashAdd32a(h uint32, s string) uint32 {
    87  	for i := 0; i < len(s); i++ {
    88  		h ^= uint32(s[i])
    89  		h *= prime32
    90  	}
    91  	return h
    92  }
    93  
    94  // HashAddByte32a adds a byte to a fnv32a hash value, returning the updated hash.
    95  func HashAddByte32a(h uint32, b byte) uint32 {
    96  	h ^= uint32(b)
    97  	h *= prime32
    98  	return h
    99  }