Jenkins hash function

jenkins.go

package jenkins

import "hash"

// Jenkins hash function
type jenkins uint32

func New32() hash.Hash32 {
    var j jenkins = 0
	return &j;
}

func (j *jenkins) Write(data []byte) (int, error) {
	hash := *j
	for _, e := range data {
		hash += jenkins(e)
		hash += (hash << 10)
		hash ^= (hash >> 6)
	}
	*j = hash
	return len(data), nil
}

func (j *jenkins) Reset() {
	*j = 0
}

func (j *jenkins) Size() int {
	return 4
}

func (j *jenkins) BlockSize() int {
	return 1
}

func (j *jenkins) Sum32() uint32 {
	sum := uint32(*j)
	sum += sum << 3
	sum ^= sum >> 11
	sum += sum << 15
	return sum
}

func (j *jenkins) Sum(b []byte) []byte {
	s := j.Sum32()
	b = append(b, byte(s>>24))
	b = append(b, byte(s>>16))
	b = append(b, byte(s>>8))
	b = append(b, byte(s))
	return b
}