github.com/m3db/m3@v1.5.0/src/x/hash/jump/example_test.go (about)

     1  // Copyright (c) 2017 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package jump_test
    22  
    23  import (
    24  	"fmt"
    25  	"hash/fnv"
    26  	"log"
    27  
    28  	"github.com/m3db/m3/src/x/hash/jump"
    29  )
    30  
    31  func ExampleHash() {
    32  	var (
    33  		numBuckets int64 = 10
    34  		key              = []byte("foo")
    35  		hasher           = fnv.New64()
    36  	)
    37  
    38  	// Create hash of the key using whatever hash function you wish.
    39  	if _, err := hasher.Write(key); err != nil {
    40  		log.Fatal(err)
    41  	}
    42  	keyHash := hasher.Sum64()
    43  
    44  	// Get which bucket the key is assigned to.
    45  	bucket := jump.Hash(keyHash, numBuckets)
    46  
    47  	fmt.Printf("Key '%s' is assigned to bucket %d.\n", string(key), bucket)
    48  	// Output: Key 'foo' is assigned to bucket 9.
    49  }