add bytes utils

utils/bytes.go

@@ -0,0 +1,112 @@
+package utils
+
+import "encoding/hex"
+
+// ToHex returns the hex representation of b, prefixed with '0x'.
+// For empty slices, the return value is "0x0".
+//
+// Deprecated: use hexutil.Encode instead.
+func ToHex(b []byte) string {
+	hex := Bytes2Hex(b)
+	if len(hex) == 0 {
+		hex = "0"
+	}
+	return "0x" + hex
+}
+
+// FromHex returns the bytes represented by the hexadecimal string s.
+// s may be prefixed with "0x".
+func FromHex(s string) []byte {
+	if len(s) > 1 {
+		if s[0:2] == "0x" || s[0:2] == "0X" {
+			s = s[2:]
+		}
+	}
+	if len(s)%2 == 1 {
+		s = "0" + s
+	}
+	return Hex2Bytes(s)
+}
+
+// CopyBytes returns an exact copy of the provided bytes.
+func CopyBytes(b []byte) (copiedBytes []byte) {
+	if b == nil {
+		return nil
+	}
+	copiedBytes = make([]byte, len(b))
+	copy(copiedBytes, b)
+
+	return
+}
+
+// hasHexPrefix validates str begins with '0x' or '0X'.
+func hasHexPrefix(str string) bool {
+	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
+}
+
+// isHexCharacter returns bool of c being a valid hexadecimal.
+func isHexCharacter(c byte) bool {
+	return ('0' <= c && c <= '9') || ('a' <= c && c <= 'f') || ('A' <= c && c <= 'F')
+}
+
+// isHex validates whether each byte is valid hexadecimal string.
+func isHex(str string) bool {
+	if len(str)%2 != 0 {
+		return false
+	}
+	for _, c := range []byte(str) {
+		if !isHexCharacter(c) {
+			return false
+		}
+	}
+	return true
+}
+
+// Bytes2Hex returns the hexadecimal encoding of d.
+func Bytes2Hex(d []byte) string {
+	return hex.EncodeToString(d)
+}
+
+// Hex2Bytes returns the bytes represented by the hexadecimal string str.
+func Hex2Bytes(str string) []byte {
+	h, _ := hex.DecodeString(str)
+	return h
+}
+
+// Hex2BytesFixed returns bytes of a specified fixed length flen.
+func Hex2BytesFixed(str string, flen int) []byte {
+	h, _ := hex.DecodeString(str)
+	if len(h) == flen {
+		return h
+	}
+	if len(h) > flen {
+		return h[len(h)-flen:]
+	}
+	hh := make([]byte, flen)
+	copy(hh[flen-len(h):flen], h[:])
+	return hh
+}
+
+// RightPadBytes zero-pads slice to the right up to length l.
+func RightPadBytes(slice []byte, l int) []byte {
+	if l <= len(slice) {
+		return slice
+	}
+
+	padded := make([]byte, l)
+	copy(padded, slice)
+
+	return padded
+}
+
+// LeftPadBytes zero-pads slice to the left up to length l.
+func LeftPadBytes(slice []byte, l int) []byte {
+	if l <= len(slice) {
+		return slice
+	}
+
+	padded := make([]byte, l)
+	copy(padded[l-len(slice):], slice)
+
+	return padded
+}