bitflags

README

bitflags

This covers a specific use-case for bit flags where:

• You want the flags themselves defined separately.
• You want to iterate over set values, and rely on exhaustive-switch linters to make you account for everything.
• You want generic support for "safety" (convenience), and support any type with constraints.Unsigned storage.

A code block is worth 1000 words:

package main

import (
	"fmt"

	"github.com/coxley/bitflags"
)

type perms uint8

const (
	read perms = 1 << iota
	write
	exec
)

func main() {
	var flags bitflags.Set[perms]
	flags.Add(read, exec)    // alt: bitflags.NewSet(read, exec)
	flags.HasAll(read, exec) // true
	flags.Has(write)         // false

	// Output:
	//   read: set
	//   exec: set
	for flag := range flags.All() {
		switch flag {
		case read:
			fmt.Println("read: set")
		case write:
			fmt.Println("write: set")
		case exec:
			fmt.Println("exec: set")
		}
	}
}

Documentation

Index

• func ValidateFlags(enabled bool)
• type Set
  • func NewSet[T constraints.Unsigned](flag T, extra ...T) Set[T]
  • func (f *Set[T]) Add(flag T, extra ...T)
  • func (f Set[T]) All() iter.Seq[T]
  • func (f *Set[T]) Clear(flag T, extra ...T)
  • func (f Set[T]) Empty() bool
  • func (f Set[T]) Has(flag T) bool
  • func (f Set[T]) HasAll(flag T, extra ...T) bool
  • func (f Set[T]) Merge(flags Set[T]) Set[T]

Functions

func ValidateFlags

func ValidateFlags(enabled bool)

ValidateFlags will panic when flag values are not on bit boundaries when enabled.

Types

type Set

type Set[T constraints.Unsigned] struct {
	// contains filtered or unexported fields
}

Set is a helper for operating over a custom bit flag

The zero value is ready to use

func NewSet

func NewSet[T constraints.Unsigned](flag T, extra ...T) Set[T]

NewSet returns a set with the provided flags set

func (*Set[T]) Add

func (f *Set[T]) Add(flag T, extra ...T)

Add one or more flags to the set

Panics if any value is not on a bit-boundary to protect against misuse.

func (Set[T]) All

func (f Set[T]) All() iter.Seq[T]

All produces each flag that is currently set

func (*Set[T]) Clear

func (f *Set[T]) Clear(flag T, extra ...T)

Clear one or more flags from the set

Panics if any value is not on a bit-boundary to protect against misuse.

func (Set[T]) Empty

func (f Set[T]) Empty() bool

func (Set[T]) Has

func (f Set[T]) Has(flag T) bool

Has the flag been set?

Panics if any value is not on a bit-boundary to protect against misuse.

func (Set[T]) HasAll

func (f Set[T]) HasAll(flag T, extra ...T) bool

HasAll returns true if all provided flags are set

Panics if any value is not on a bit-boundary to protect against misuse.

func (Set[T]) Merge

func (f Set[T]) Merge(flags Set[T]) Set[T]

Merge flags together and return as a new value