Golang - Determine if bitmask is set

bitmask.go

/*
fmt.Println(Bitmask(0x6).IsSet(0x2))
fmt.Println(Bitmask(f.FileHeader.Characteristics).ListDescriptions(charValues))
fmt.Println(Bitmask(f.FileHeader.Characteristics).ListValues(charValues))
*/

type Bitmask uint16

// BitValue is a value and a description
type BitValue struct {
	value       Bitmask
	description string
}

// Bitwise returns a string array of all set bits
func (value Bitmask) ListDescriptions(values []BitValue) []string {
	list := make([]string, 0)
	currentValue := value
	for currentValue > 0 {
		for _, bv := range values {
			if currentValue&bv.value != 0 {
				currentValue ^= bv.value
				list = append(list, bv.description)
			}
		}
	}	
	return list
}

// Bitwise returns a string array of all set bits
func (value Bitmask) ListValues(values []BitValue) []Bitmask {
	list := make([]Bitmask, 0)
	currentValue := value
	for _, bv := range values {
		if currentValue&bv.value != 0 {
			currentValue ^= bv.value
			list = append(list, bv.value)
		}
	}	
	return list
}

// IsSet returns true if a bit is set
func (value Bitmask) IsSet(test Bitmask) bool {
	return value&test != 0
}

The for currentValue > 0 { loops loop forever and the code seems to work just fine with them removed.

The for currentValue > 0 { loops loop forever and the code seems to work just fine with them removed.

Good catch - I updated it. Thanks!

func (value Bitmask) IsSet(test Bitmask) bool {
	if value&test != 0 {
		return true
	}
	return false
}

should be simplified to

func (value Bitmask) IsSet(test Bitmask) bool { return value&test != 0 }

Thanks, I updated it.