bitwise ops and left padding added

base2.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"math"
 	"strconv"
+	"strings"
 )
 
 // binaryEncodeToString takes an array of bytes and returns
@@ -19,9 +20,9 @@ func binaryEncodeToString(src []byte) string {
 func encodeBinary(dst []byte, src []byte) {
 	for i := 0; i < len(src); i++ {
 		t := src[i]
-		for j := i * 8; j < (i*8)+8; j++ {
-			higherPower := math.Pow(2, float64(7-(j%8)))
-			if float64(t) >= higherPower {
+		for j := i << 3; j < (i<<3)+8; j++ {
+			higherPower := math.Pow(2, float64(7-(j&7)))
+			if t >= byte(higherPower) {
 				dst[j] = '1'
 				t = t - byte(higherPower)
 			} else {
@@ -34,12 +35,12 @@ func encodeBinary(dst []byte, src []byte) {
 // decodeBinaryString takes multibase binary representation
 // and returns a byte array
 func decodeBinaryString(s string) ([]byte, error) {
-	if len(s)%8 != 0 {
-		return nil, fmt.Errorf("cannot decode multibase: %s",
-			"length should be a multiple of 4")
+	if len(s)&7 != 0 {
+		// prepend the padding
+		s = strings.Repeat("0", 8-len(s)&7) + s
 	}
 
-	data := make([]byte, len(s)/8)
+	data := make([]byte, len(s)>>3)
 
 	for i, dstIndex := 0, 0; i < len(s); i = i + 8 {
 		value, err := strconv.ParseInt(s[i:i+8], 2, 0)