package types

/*
	See https://yourbasic.org/golang/bitmask-flag-set-clear/ for more information.
	To use this, set constants like thus:
	
	const (
		OPT1 types.MaskBit = 1 << iota
		OPT2
		OPT3
		// ...
	)

	type Object struct {
		Opts BitMask
	}

	o := Object{
		BitMask: uint8(0)
	}

	o.AddFlag(OPT1)
	o.AddFlag(OPT3)


	This would return true:
		o.HasFlag(OPT1)
	As would this:
		o.HasFlag(OPT3)
	But this would return false:
		o.HasFlag(OPT2)

*/
type BitMask interface {
	HasFlag(bit MaskBit) bool
	AddFlag(bit MaskBit)
	ClearFlag(bit MaskBit)
	ToggleFlag(bit MaskBit)
}

// BitMasks
type MaskBit uint8

func (f MaskBit) HasFlag(flag MaskBit) (r bool) {
	if f&flag != 0 {
		r = true
	}
	return
}

func (f *MaskBit) AddFlag(flag MaskBit) {
	*f |= flag
	return
}

func (f *MaskBit) ClearFlag(flag MaskBit) {
	*f &= flag
	return
}

func (f *MaskBit) ToggleFlag(flag MaskBit) {
	*f ^= flag
	return
}