Extend address type (#67)

types/address.go

@@ -4,9 +4,57 @@ import (
 	"encoding/hex"
 )
 
+const AddressLength = 20
+
 // Address represents the 20 byte address of an Ethereum account.
-type Address [20]byte
+type Address [AddressLength]byte
 
 func (a Address) String() string {
-	return "0x" + hex.EncodeToString(a[:])
+	return "0x" + hex.EncodeToString(a.Bytes())
+}
+
+func (a Address) Bytes() []byte { return a[:] }
+
+// HexToAddress returns Address with byte values of s.
+// If s is larger than len(h), s will be cropped from the left.
+func HexToAddress(s string) Address { return BytesToAddress(FromHex(s)) }
+
+// BytesToAddress returns Address with value b.
+// If b is larger than len(h), b will be cropped from the left.
+func BytesToAddress(b []byte) Address {
+	var a Address
+	a.SetBytes(b)
+	return a
+}
+
+// SetBytes sets the address to the value of b.
+// If b is larger than len(a), b will be cropped from the left.
+func (a *Address) SetBytes(b []byte) {
+	if len(b) > len(a) {
+		b = b[len(b)-AddressLength:]
+	}
+	copy(a[AddressLength-len(b):], b)
+}
+
+// FromHex returns the bytes represented by the hexadecimal string s.
+// s may be prefixed with "0x".
+func FromHex(s string) []byte {
+	if has0xPrefix(s) {
+		s = s[2:]
+	}
+	if len(s)%2 == 1 {
+		s = "0" + s
+	}
+	return Hex2Bytes(s)
+}
+
+// has0xPrefix validates str begins with '0x' or '0X'.
+func has0xPrefix(str string) bool {
+	return len(str) >= 2 && str[0] == '0' && (str[1] == 'x' || str[1] == 'X')
+}
+
+// Hex2Bytes returns the bytes represented by the hexadecimal string str.
+func Hex2Bytes(str string) []byte {
+	h, _ := hex.DecodeString(str)
+	return h
 }

types/types_test.go

@@ -0,0 +1,31 @@
+package types
+
+import (
+	"math/big"
+	"testing"
+)
+
+func TestAddress_Convertation(t *testing.T) {
+	addrStr := "0x9c1a711a5e31a9461f6d1f662068e0a2f9edf552"
+	addr := HexToAddress(addrStr)
+
+	if addr.String() != addrStr {
+		t.Fatal("incorrect address conversion")
+	}
+}
+
+func TestHash_Compare(t *testing.T) {
+	a := big.NewInt(1)
+	b := big.NewInt(2)
+
+	h1 := BigToHash(a)
+	h2 := BigToHash(b)
+
+	if h1.Compare(h2) != -1 {
+		t.Fatal("incorrect comparing")
+	}
+
+	if h1.Uint64() != uint64(1) {
+		t.Fatal("incorrect uint64 conversion")
+	}
+}