initial

Author: goiste

.gitignore

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+.idea

README.md

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+# Bit Flags
+
+A simple package to store up to 64 boolean flags in one uint field.
+
+Requires Go version 1.18+ (uses generics)
+
+For usage example see [example dir](example)
+
+```go
+import (
+	"strings"
+
+	bf "github.com/goiste/bit_flags"
+)
+
+const (
+	Messages    = 1 << iota // 1
+	Replies                 // 2
+	Likes                   // 4
+	NewArticles             // ... powers of 2
+	News
+
+	ByEmail
+	BySms
+	ByTelegram
+
+	AllNotifications = Messages | Replies | Likes | NewArticles | News
+	AllMethods       = ByEmail | BySms | ByTelegram
+)
+
+type Notification struct {
+	SomeOtherFields string
+	Flags           bf.BitFlags[uint8]
+}
+
+func New() *Notification { ... }
+
+func (n *Notification) SetDefaultFlags() {
+	n.Flags.Set(Messages | Replies | Likes | ByEmail)
+}
+
+func (n *Notification) SetAll() {
+	n.Flags.Set(AllNotifications | AllMethods)
+}
+
+func (n *Notification) SetNone() {
+	n.Flags.Reset()
+}
+
+...
+```
+[full notification.go](example/notification.go)
+```go
+func main() {
+	ntf := notification.New()
+	fmt.Println(ntf.Flags.Get())     // 39
+	fmt.Println(ntf.FlagsToString()) // Messages, Replies, Likes, By email
+
+	ntf.Flags.Add(notification.News | notification.BySms)
+	ntf.Flags.Remove(notification.Replies | notification.Likes)
+	fmt.Println(ntf.FlagsToString())                // Messages, News, By email, By sms
+	fmt.Println(ntf.HasFlag(notification.Messages)) // true
+	fmt.Println(ntf.HasFlag(notification.Likes))    // false
+
+	ntf.Flags.Reset()
+	fmt.Println(ntf.Flags.Get())     // 0
+	fmt.Println(ntf.GetFlagsNames()) // []
+
+	ntf.SetAll()
+	fmt.Println(ntf.Flags.Get())     // 255
+	fmt.Println(ntf.FlagsToString()) // Messages, Replies, Likes, New articles, News, By email, By sms, By telegram
+}
+```
+[full main.go](example/main.go)

bit_flags.go

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+package bit_flags
+
+import "math/bits"
+
+type uints interface {
+	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64
+}
+
+// BitFlags stores boolean flags
+//
+// Use uintN type to store up to N flags, e.g. uint8 to <=8 flags
+type BitFlags[T uints] struct {
+	flags T
+}
+
+func New[T uints]() *BitFlags[T] {
+	return new(BitFlags[T])
+}
+
+// Set sets the stored flags from the specified
+func (f *BitFlags[T]) Set(flags T) {
+	f.flags = flags
+}
+
+// Get returns the stored flags
+func (f BitFlags[T]) Get() T {
+	return f.flags
+}
+
+// Add adds the specified flags to the stored
+func (f *BitFlags[T]) Add(flags T) {
+	f.flags |= flags
+}
+
+// Remove deletes the specified flags from the stored
+func (f *BitFlags[T]) Remove(flags T) {
+	f.flags ^= flags
+}
+
+// Reset sets the stored flags to zero
+func (f *BitFlags[T]) Reset() {
+	f.flags = 0
+}
+
+// Has checks if all the specified flags exists in the stored
+func (f BitFlags[T]) Has(flags T) bool {
+	return f.flags&flags == flags
+}
+
+// List returns a list of the stored flags
+func (f BitFlags[T]) List() []T {
+	result := make([]T, 0, bits.Len64(uint64(f.flags)))
+	for i := 0; i < cap(result); i++ {
+		pow := T(1 << i)
+		if f.flags&pow == pow {
+			result = append(result, pow)
+		}
+	}
+	return result
+}

bit_flags_test.go

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+package bit_flags
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+const (
+	testProperty1 = 1 << iota
+	testProperty2
+	testProperty3
+	testProperty4
+	testProperty5
+	testProperty6
+)
+
+func TestBitProperties_Set(t *testing.T) {
+	bf := New[uint8]()
+	bf.Set(testProperty1 | testProperty5)
+	require.Equal(t, uint8(17), bf.Get())
+}
+
+func TestBitProperties_Add(t *testing.T) {
+	bf := New[uint8]()
+	bf.Set(testProperty1 | testProperty5)
+	bf.Add(testProperty2 | testProperty3)
+	require.Equal(t, uint8(23), bf.Get())
+}
+
+func TestBitProperties_Remove(t *testing.T) {
+	bf := New[uint8]()
+	bf.Set(testProperty1 | testProperty5 | testProperty4 | testProperty6)
+	bf.Remove(testProperty5)
+	require.Equal(t, uint8(41), bf.Get())
+	require.Equal(t, false, bf.Has(testProperty5|testProperty1))
+	require.Equal(t, true, bf.Has(testProperty1))
+}
+
+func TestBitProperties_Reset(t *testing.T) {
+	bf := New[uint8]()
+	bf.Set(testProperty1 | testProperty5)
+	bf.Reset()
+	require.Equal(t, uint8(0), bf.Get())
+}
+
+func TestBitProperties_Has(t *testing.T) {
+	bf := New[uint8]()
+	bf.Set(testProperty1 | testProperty5 | testProperty4 | testProperty6)
+	require.Equal(t, true, bf.Has(testProperty5|testProperty1))
+	require.Equal(t, false, bf.Has(testProperty2))
+}
+
+func TestBitProperties_List(t *testing.T) {
+	bf := New[uint8]()
+	bf.Set(testProperty1 | testProperty5 | testProperty4 | testProperty6)
+	exp := []uint8{testProperty1, testProperty4, testProperty5, testProperty6}
+	require.Equal(t, exp, bf.List())
+}

example/main.go

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+package main
+
+import (
+	"fmt"
+)
+
+func main() {
+	ntf := New()
+	fmt.Println(ntf.Flags.Get())     // 39
+	fmt.Println(ntf.FlagsToString()) // Messages, Replies, Likes, By email
+
+	ntf.Flags.Add(News | BySms)
+	ntf.Flags.Remove(Replies | Likes)
+	fmt.Println(ntf.FlagsToString())   // Messages, News, By email, By sms
+	fmt.Println(ntf.HasFlag(Messages)) // true
+	fmt.Println(ntf.HasFlag(Likes))    // false
+
+	ntf.Flags.Reset()
+	fmt.Println(ntf.Flags.Get())     // 0
+	fmt.Println(ntf.GetFlagsNames()) // []
+
+	ntf.SetAll()
+	fmt.Println(ntf.Flags.Get())     // 255
+	fmt.Println(ntf.FlagsToString()) // Messages, Replies, Likes, New articles, News, By email, By sms, By telegram
+}

example/notification.go

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+package main
+
+import (
+	"strings"
+
+	bf "github.com/goiste/bit_flags"
+)
+
+const (
+	Messages    = 1 << iota // 1
+	Replies                 // 2
+	Likes                   // 4
+	NewArticles             // ... powers of 2
+	News
+
+	ByEmail
+	BySms
+	ByTelegram
+
+	AllNotifications = Messages | Replies | Likes | NewArticles | News
+	AllMethods       = ByEmail | BySms | ByTelegram
+)
+
+type Notification struct {
+	SomeOtherFields string
+	Flags           bf.BitFlags[uint8]
+}
+
+func New() *Notification {
+	n := &Notification{}
+	n.SetDefaultFlags()
+	return n
+}
+
+func (n *Notification) SetDefaultFlags() {
+	n.Flags.Set(Messages | Replies | Likes | ByEmail)
+}
+
+func (n *Notification) SetAll() {
+	n.Flags.Set(AllNotifications | AllMethods)
+}
+
+func (n *Notification) SetNone() {
+	n.Flags.Reset()
+}
+
+func (n Notification) HasFlag(flag uint8) bool {
+	return n.Flags.Has(flag)
+}
+
+func (n Notification) FlagsToString() string {
+	return strings.Join(n.GetFlagsNames(), ", ")
+}
+
+func (n Notification) GetFlagsNames() (names []string) {
+	for _, p := range n.Flags.List() {
+		name := getFlagName(p)
+		if name == "" {
+			continue
+		}
+		names = append(names, name)
+	}
+	return
+}
+
+func getFlagName(flag uint8) string {
+	switch flag {
+	case Messages:
+		return "Messages"
+	case Replies:
+		return "Replies"
+	case Likes:
+		return "Likes"
+	case NewArticles:
+		return "New articles"
+	case News:
+		return "News"
+	case ByEmail:
+		return "By email"
+	case BySms:
+		return "By sms"
+	case ByTelegram:
+		return "By telegram"
+	}
+	return ""
+}

go.mod

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+module github.com/goiste/bit_flags
+
+go 1.18
+
+require github.com/stretchr/testify v1.8.0
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,15 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
+github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
+github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=