var srcString = "1234"
var srcBytes = []byte(srcString)
var dst uint64

// BenchmarkIdeal is the ideal performance parsing a string.
func BenchmarkIdeal(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		dst, _ = strconv.ParseUint(srcString, 0, 64)
	}
}

// BenchmarkCopy is the performance after copying the input bytes as a string.
// Performance loss is expected.
func BenchmarkCopy(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		dst, _ = strconv.ParseUint(string(srcBytes), 0, 64)
	}
}

// BenchmarkCast is the performance when using unsafe to cast bytes as a string.
func BenchmarkCast(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		dst, _ = strconv.ParseUint(UnsafeString(srcBytes), 0, 64)
	}
}

type stringHeader struct {
	Data unsafe.Pointer
	Len  int
}
type sliceHeader struct {
	Data unsafe.Pointer
	Len  int
	Cap  int
}

func UnsafeString(b []byte) (s string) {
	bp := (*sliceHeader)(unsafe.Pointer(&b))
	sp := (*stringHeader)(unsafe.Pointer(&s))
	sp.Data = bp.Data
	sp.Len = bp.Len
	return s
}