package bytesconv

import "fmt"

type endian int

const (
	BigEndian endian = iota + 1
	LittleEndian
)

func (e endian) BytesToUInt64(data []byte) (uint64, error) {
	if len(data) > 8 {
		return 0, fmt.Errorf("bytes to uint64, bytes length is invaild")
	}

	var ret uint64
	var len int = len(data)

	if e == BigEndian {
		for i := 0; i < len; i++ {
			ret = ret | (uint64(data[len-1-i]) << (i * 8))
		}
	} else {
		for i := 0; i < len; i++ {
			ret = ret | (uint64(data[i]) << (i * 8))
		}
	}

	return ret, nil
}