package util

import (
	"crypto/md5"
	"io"
)

// big endian

func BytesToUint64(b []byte) (v uint64) {
	length := uint(len(b))
	for i := uint(0); i < length-1; i++ {
		v += uint64(b[i])
		v <<= 8
	}
	v += uint64(b[length-1])
	return
}
func BytesToUint32(b []byte) (v uint32) {
	length := uint(len(b))
	for i := uint(0); i < length-1; i++ {
		v += uint32(b[i])
		v <<= 8
	}
	v += uint32(b[length-1])
	return
}
func BytesToUint16(b []byte) (v uint16) {
	v += uint16(b[0])
	v <<= 8
	v += uint16(b[1])
	return
}
func Uint64toBytes(b []byte, v uint64) {
	for i := uint(0); i < 8; i++ {
		b[7-i] = byte(v >> (i * 8))
	}
}
func Uint32toBytes(b []byte, v uint32) {
	for i := uint(0); i < 4; i++ {
		b[3-i] = byte(v >> (i * 8))
	}
}
func Uint16toBytes(b []byte, v uint16) {
	b[0] = byte(v >> 8)
	b[1] = byte(v)
}
func Uint8toBytes(b []byte, v uint8) {
	b[0] = byte(v)
}

// returns a 64 bit big int
func HashStringToLong(dir string) (v int64) {
	h := md5.New()
	io.WriteString(h, dir)

	b := h.Sum(nil)

	v += int64(b[0])
	v <<= 8
	v += int64(b[1])
	v <<= 8
	v += int64(b[2])
	v <<= 8
	v += int64(b[3])
	v <<= 8
	v += int64(b[4])
	v <<= 8
	v += int64(b[5])
	v <<= 8
	v += int64(b[6])
	v <<= 8
	v += int64(b[7])

	return
}