vendor/github.com/mitchellh/hashstructure/README.md

   1 # hashstructure [![GoDoc](https://godoc.org/github.com/mitchellh/hashstructure?status.svg)](https://godoc.org/github.com/mitchellh/hashstructure)
   2
   3 hashstructure is a Go library for creating a unique hash value
   4 for arbitrary values in Go.
   5
   6 This can be used to key values in a hash (for use in a map, set, etc.)
   7 that are complex. The most common use case is comparing two values without
   8 sending data across the network, caching values locally (de-dup), and so on.
   9
  10 ## Features
  11
  12   * Hash any arbitrary Go value, including complex types.
  13
  14   * Tag a struct field to ignore it and not affect the hash value.
  15
  16   * Tag a slice type struct field to treat it as a set where ordering
  17     doesn't affect the hash code but the field itself is still taken into
  18     account to create the hash value.
  19
  20   * Optionally specify a custom hash function to optimize for speed, collision
  21     avoidance for your data set, etc.
  22
  23   * Optionally hash the output of `.String()` on structs that implement fmt.Stringer,
  24     allowing effective hashing of time.Time
  25
  26 ## Installation
  27
  28 Standard `go get`:
  29
  30 ```
  31 $ go get github.com/mitchellh/hashstructure
  32 ```
  33
  34 ## Usage & Example
  35
  36 For usage and examples see the [Godoc](http://godoc.org/github.com/mitchellh/hashstructure).
  37
  38 A quick code example is shown below:
  39
  40 ```go
  41 type ComplexStruct struct {
  42     Name     string
  43     Age      uint
  44     Metadata map[string]interface{}
  45 }
  46
  47 v := ComplexStruct{
  48     Name: "mitchellh",
  49     Age:  64,
  50     Metadata: map[string]interface{}{
  51         "car":      true,
  52         "location": "California",
  53         "siblings": []string{"Bob", "John"},
  54     },
  55 }
  56
  57 hash, err := hashstructure.Hash(v, nil)
  58 if err != nil {
  59     panic(err)
  60 }
  61
  62 fmt.Printf("%d", hash)
  63 // Output:
  64 // 2307517237273902113
  65 ```