)

var uint8arr [8]uint8

// ErrBadStringFormat represents a error of input string's format is illegal .

var ErrBadStringFormat = errors.New("bad string format")

// ErrEmptyString represents a error of empty input string.

var ErrEmptyString = errors.New("empty string")

func init() {

uint8arr[0] = 128

uint8arr[1] = 64

uint8arr[2] = 32

uint8arr[3] = 16

uint8arr[4] = 8

uint8arr[5] = 4

uint8arr[6] = 2

uint8arr[7] = 1

}

// append bytes of string in binary format.

func appendBinaryString(bs []byte, b byte) []byte {

var a byte

for i := 0; i < 8; i++ {

a = b

b <<= 1

b >>= 1

switch a {

case b:

bs = append(bs, zero)

default:

bs = append(bs, one)

}

b <<= 1

}

return bs

}

// ByteToBinaryString get the string in binary format of a byte or uint8.

func ByteToBinaryString(b byte) string {

buf := make([]byte, 0, 8)

buf = appendBinaryString(buf, b)

return string(buf)

}

// BytesToBinaryString get the string in binary format of a []byte or []int8.

func BytesToBinaryString(bs []byte) string {

l := len(bs)

bl := l*8 + l + 1

buf := make([]byte, 0, bl)

buf = append(buf, lsb)

for _, b := range bs {

buf = appendBinaryString(buf, b)

buf = append(buf, space)

}

buf[bl-1] = rsb

return string(buf)

}

// regex for delete useless string which is going to be in binary format.

var rbDel = regexp.MustCompile(`[^01]`)

// BinaryStringToBytes get the binary bytes according to the

// input string which is in binary format.

func BinaryStringToBytes(s string) (bs []byte) {

if len(s) == 0 {

panic(ErrEmptyString)

}

s = rbDel.ReplaceAllString(s, "")

l := len(s)

if l == 0 {

panic(ErrBadStringFormat)

}

mo := l % 8

l /= 8

if mo != 0 {

l++

}

bs = make([]byte, 0, l)

mo = 8 - mo

var n uint8

for i, b := range []byte(s) {

m := (i + mo) % 8

switch b {

case one:

n += uint8arr[m]

}

if m == 7 {

bs = append(bs, n)

n = 0

}

}

return