Add utils for bech32 format address

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/Workiva/go-datastructures v1.0.50
 	github.com/allegro/bigcache v1.2.0 // indirect
 	github.com/aristanetworks/goarista v0.0.0-20190308231643-e9fb69a13f45 // indirect
+	github.com/btcsuite/btcutil v0.0.0-20190207003914-4c204d697803
 	github.com/cespare/cp v1.1.1
 	github.com/davecgh/go-spew v1.1.1
 	github.com/deckarep/golang-set v1.7.1
@@ -48,6 +49,7 @@ require (
 	github.com/smartystreets/goconvey v0.0.0-20190330032615-68dc04aab96a // indirect
 	github.com/stretchr/testify v1.3.0
 	github.com/syndtr/goleveldb v1.0.0
+	github.com/tendermint/tendermint v0.31.7
 	github.com/whyrusleeping/go-logging v0.0.0-20170515211332-0457bb6b88fc
 	golang.org/x/crypto v0.0.0-20190313024323-a1f597ede03a
 	golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3

internal/bech32/bech32.go

@@ -0,0 +1,29 @@
+package bech32
+
+import (
+	"github.com/btcsuite/btcutil/bech32"
+	"github.com/pkg/errors"
+)
+
+//ConvertAndEncode converts from a base64 encoded byte string to base32 encoded byte string and then to bech32
+func ConvertAndEncode(hrp string, data []byte) (string, error) {
+	converted, err := bech32.ConvertBits(data, 8, 5, true)
+	if err != nil {
+		return "", errors.Wrap(err, "encoding bech32 failed")
+	}
+	return bech32.Encode(hrp, converted)
+
+}
+
+//DecodeAndConvert decodes a bech32 encoded string and converts to base64 encoded bytes
+func DecodeAndConvert(bech string) (string, []byte, error) {
+	hrp, data, err := bech32.Decode(bech)
+	if err != nil {
+		return "", nil, errors.Wrap(err, "decoding bech32 failed")
+	}
+	converted, err := bech32.ConvertBits(data, 5, 8, false)
+	if err != nil {
+		return "", nil, errors.Wrap(err, "decoding bech32 failed")
+	}
+	return hrp, converted, nil
+}

internal/bech32/bech32_test.go

@@ -0,0 +1,31 @@
+package bech32_test
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"testing"
+
+	"github.com/tendermint/tendermint/libs/bech32"
+)
+
+func TestEncodeAndDecode(t *testing.T) {
+
+	sum := sha256.Sum256([]byte("hello world123\n"))
+
+	bech, err := bech32.ConvertAndEncode("shasum", sum[:])
+
+	if err != nil {
+		t.Error(err)
+	}
+	hrp, data, err := bech32.DecodeAndConvert(bech)
+
+	if err != nil {
+		t.Error(err)
+	}
+	if hrp != "shasum" {
+		t.Error("Invalid hrp")
+	}
+	if !bytes.Equal(data, sum[:]) {
+		t.Error("Invalid decode")
+	}
+}

internal/common/address.go

@@ -0,0 +1,145 @@
+package common
+
+import (
+	"database/sql/driver"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/harmony-one/harmony/internal/bech32"
+	"github.com/harmony-one/harmony/internal/utils"
+	"golang.org/x/crypto/sha3"
+)
+
+// Lengths of addresses in bytes.
+const (
+	// AddressLength is the expected length of the address
+	AddressLength = 20
+)
+
+// Address represents the 20 byte address of an Harmony account.
+type Address [AddressLength]byte
+
+// 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
+}
+
+// BigToAddress returns Address with byte values of b.
+// If b is larger than len(h), b will be cropped from the left.
+func BigToAddress(b *big.Int) Address { return BytesToAddress(b.Bytes()) }
+
+// 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(utils.FromHex(s)) }
+
+// IsBech32Address verifies whether a string can represent a valid bech32-encoded
+// Harmony address or not.
+func IsBech32Address(s string) bool {
+	hrp, bytes, err := bech32.DecodeAndConvert(s)
+	if err != nil || (hrp != "one" && hrp != "tone") || len(bytes) != AddressLength {
+		return false
+	}
+	return true
+}
+
+// Bytes gets the string representation of the underlying address.
+func (a Address) Bytes() []byte { return a[:] }
+
+// Big converts an address to a big integer.
+func (a Address) Big() *big.Int { return new(big.Int).SetBytes(a[:]) }
+
+// Hash converts an address to a hash by left-padding it with zeros.
+func (a Address) Hash() Hash { return BytesToHash(a[:]) }
+
+// Bech32 returns an bip0173-compliant string representation of the address.
+func (a Address) Bech32() string {
+	unchecksummed := hex.EncodeToString(a[:])
+	sha := sha3.NewLegacyKeccak256()
+	sha.Write([]byte(unchecksummed))
+	hash := sha.Sum(nil)
+
+	result := []byte(unchecksummed)
+	for i := 0; i < len(result); i++ {
+		hashByte := hash[i/2]
+		if i%2 == 0 {
+			hashByte = hashByte >> 4
+		} else {
+			hashByte &= 0xf
+		}
+		if result[i] > '9' && hashByte > 7 {
+			result[i] -= 32
+		}
+	}
+	return "0x" + string(result)
+}
+
+// String implements fmt.Stringer.
+func (a Address) String() string {
+	return a.Bech32()
+}
+
+// Format implements fmt.Formatter, forcing the byte slice to be formatted as is,
+// without going through the stringer interface used for logging.
+func (a Address) Format(s fmt.State, c rune) {
+	fmt.Fprintf(s, "%"+string(c), a[:])
+}
+
+// SetBytes sets the address to the value of b.
+// If b is larger than len(a) it will panic.
+func (a *Address) SetBytes(b []byte) {
+	if len(b) > len(a) {
+		b = b[len(b)-AddressLength:]
+	}
+	copy(a[AddressLength-len(b):], b)
+}
+
+// MarshalText returns the hex representation of a.
+func (a Address) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(a[:]).MarshalText()
+}
+
+// UnmarshalText parses a hash in hex syntax.
+func (a *Address) UnmarshalText(input []byte) error {
+	return hexutil.UnmarshalFixedText("Address", input, a[:])
+}
+
+// UnmarshalJSON parses a hash in hex syntax.
+func (a *Address) UnmarshalJSON(input []byte) error {
+	return hexutil.UnmarshalFixedJSON(addressT, input, a[:])
+}
+
+// Scan implements Scanner for database/sql.
+func (a *Address) Scan(src interface{}) error {
+	srcB, ok := src.([]byte)
+	if !ok {
+		return fmt.Errorf("can't scan %T into Address", src)
+	}
+	if len(srcB) != AddressLength {
+		return fmt.Errorf("can't scan []byte of len %d into Address, want %d", len(srcB), AddressLength)
+	}
+	copy(a[:], srcB)
+	return nil
+}
+
+// Value implements valuer for database/sql.
+func (a Address) Value() (driver.Value, error) {
+	return a[:], nil
+}
+
+// UnprefixedAddress allows marshaling an Address without 0x prefix.
+type UnprefixedAddress Address
+
+// UnmarshalText decodes the address from hex. The 0x prefix is optional.
+func (a *UnprefixedAddress) UnmarshalText(input []byte) error {
+	return hexutil.UnmarshalFixedUnprefixedText("UnprefixedAddress", input, a[:])
+}
+
+// MarshalText encodes the address as hex.
+func (a UnprefixedAddress) MarshalText() ([]byte, error) {
+	return []byte(hex.EncodeToString(a[:])), nil
+}

internal/common/address_test.go

@@ -0,0 +1,223 @@
+// Copyright 2015 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package common
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"math/big"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestIsBech32Address(t *testing.T) {
+	tests := []struct {
+		str string
+		exp bool
+	}{
+		{"one1ay37rp2pc3kjarg7a322vu3sa8j9puahg679z3", true},
+		{"one1fdv7u7rll9epgcqv9xxh9lhwq427nsqldp8ua9", true},
+		{"tone1fdv7u7rll9epgcqv9xxh9lhwq427nsqlr5wca5", true},
+		{"tone1fdv7u7rll9epgcqv9xxh9lhwq427nsqlr5wca1", false},
+		{"xone1fdv7u7rll9epgcqv9xxh9lhwq427nsqlr5wca5", false},
+	}
+
+	for _, test := range tests {
+		if result := IsBech32Address(test.str); result != test.exp {
+			t.Errorf("IsBech32Address(%s) == %v; expected %v",
+				test.str, result, test.exp)
+		}
+	}
+}
+
+func TestHashJsonValidation(t *testing.T) {
+	var tests = []struct {
+		Prefix string
+		Size   int
+		Error  string
+	}{
+		{"", 62, "json: cannot unmarshal hex string without 0x prefix into Go value of type common.Hash"},
+		{"0x", 66, "hex string has length 66, want 64 for common.Hash"},
+		{"0x", 63, "json: cannot unmarshal hex string of odd length into Go value of type common.Hash"},
+		{"0x", 0, "hex string has length 0, want 64 for common.Hash"},
+		{"0x", 64, ""},
+		{"0X", 64, ""},
+	}
+	for _, test := range tests {
+		input := `"` + test.Prefix + strings.Repeat("0", test.Size) + `"`
+		var v Hash
+		err := json.Unmarshal([]byte(input), &v)
+		if err == nil {
+			if test.Error != "" {
+				t.Errorf("%s: error mismatch: have nil, want %q", input, test.Error)
+			}
+		} else {
+			if err.Error() != test.Error {
+				t.Errorf("%s: error mismatch: have %q, want %q", input, err, test.Error)
+			}
+		}
+	}
+}
+
+func TestAddressUnmarshalJSON(t *testing.T) {
+	var tests = []struct {
+		Input     string
+		ShouldErr bool
+		Output    *big.Int
+	}{
+		{"", true, nil},
+		{`""`, true, nil},
+		{`"0x"`, true, nil},
+		{`"0x00"`, true, nil},
+		{`"0xG000000000000000000000000000000000000000"`, true, nil},
+		{`"0x0000000000000000000000000000000000000000"`, false, big.NewInt(0)},
+		{`"0x0000000000000000000000000000000000000010"`, false, big.NewInt(16)},
+	}
+	for i, test := range tests {
+		var v Address
+		err := json.Unmarshal([]byte(test.Input), &v)
+		if err != nil && !test.ShouldErr {
+			t.Errorf("test #%d: unexpected error: %v", i, err)
+		}
+		if err == nil {
+			if test.ShouldErr {
+				t.Errorf("test #%d: expected error, got none", i)
+			}
+			if got := new(big.Int).SetBytes(v.Bytes()); got.Cmp(test.Output) != 0 {
+				t.Errorf("test #%d: address mismatch: have %v, want %v", i, got, test.Output)
+			}
+		}
+	}
+}
+
+func TestAddressHexChecksum(t *testing.T) {
+	var tests = []struct {
+		Input  string
+		Output string
+	}{
+		// Test cases from https://github.com/ethereum/EIPs/blob/master/EIPS/eip-55.md#specification
+		{"0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed", "0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed"},
+		{"0xfb6916095ca1df60bb79ce92ce3ea74c37c5d359", "0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359"},
+		{"0xdbf03b407c01e7cd3cbea99509d93f8dddc8c6fb", "0xdbF03B407c01E7cD3CBea99509d93f8DDDC8C6FB"},
+		{"0xd1220a0cf47c7b9be7a2e6ba89f429762e7b9adb", "0xD1220A0cf47c7B9Be7A2E6BA89F429762e7b9aDb"},
+		// Ensure that non-standard length input values are handled correctly
+		{"0xa", "0x000000000000000000000000000000000000000A"},
+		{"0x0a", "0x000000000000000000000000000000000000000A"},
+		{"0x00a", "0x000000000000000000000000000000000000000A"},
+		{"0x000000000000000000000000000000000000000a", "0x000000000000000000000000000000000000000A"},
+	}
+	for i, test := range tests {
+		output := HexToAddress(test.Input).Bech32()
+		if output != test.Output {
+			t.Errorf("test #%d: failed to match when it should (%s != %s)", i, output, test.Output)
+		}
+	}
+}
+
+func BenchmarkAddressBech32(b *testing.B) {
+	testAddr := HexToAddress("0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed")
+	for n := 0; n < b.N; n++ {
+		testAddr.Bech32()
+	}
+}
+
+func TestAddress_Scan(t *testing.T) {
+	type args struct {
+		src interface{}
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+	}{
+		{
+			name: "working scan",
+			args: args{src: []byte{
+				0xb2, 0x6f, 0x2b, 0x34, 0x2a, 0xab, 0x24, 0xbc, 0xf6, 0x3e,
+				0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+			}},
+			wantErr: false,
+		},
+		{
+			name:    "non working scan",
+			args:    args{src: int64(1234567890)},
+			wantErr: true,
+		},
+		{
+			name: "invalid length scan",
+			args: args{src: []byte{
+				0xb2, 0x6f, 0x2b, 0x34, 0x2a, 0xab, 0x24, 0xbc, 0xf6, 0x3e,
+				0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a,
+			}},
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			a := &Address{}
+			if err := a.Scan(tt.args.src); (err != nil) != tt.wantErr {
+				t.Errorf("Address.Scan() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			if !tt.wantErr {
+				for i := range a {
+					if a[i] != tt.args.src.([]byte)[i] {
+						t.Errorf(
+							"Address.Scan() didn't scan the %d src correctly (have %X, want %X)",
+							i, a[i], tt.args.src.([]byte)[i],
+						)
+					}
+				}
+			}
+		})
+	}
+}
+
+func TestAddress_Value(t *testing.T) {
+	b := []byte{
+		0xb2, 0x6f, 0x2b, 0x34, 0x2a, 0xab, 0x24, 0xbc, 0xf6, 0x3e,
+		0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+	}
+	var usedA Address
+	usedA.SetBytes(b)
+	tests := []struct {
+		name    string
+		a       Address
+		want    driver.Value
+		wantErr bool
+	}{
+		{
+			name:    "Working value",
+			a:       usedA,
+			want:    b,
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := tt.a.Value()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Address.Value() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Address.Value() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/common/hash.go

@@ -0,0 +1,135 @@
+package common
+
+import (
+	"database/sql/driver"
+	"encoding/hex"
+	"fmt"
+	"math/big"
+	"math/rand"
+	"reflect"
+
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/harmony-one/harmony/internal/utils"
+)
+
+// Lengths of hashes in bytes.
+const (
+	// HashLength is the expected length of the hash
+	HashLength = 32
+)
+
+var (
+	hashT    = reflect.TypeOf(Hash{})
+	addressT = reflect.TypeOf(Address{})
+)
+
+// Hash represents the 32 byte Keccak256 hash of arbitrary data.
+type Hash [HashLength]byte
+
+// BytesToHash sets b to hash.
+// If b is larger than len(h), b will be cropped from the left.
+func BytesToHash(b []byte) Hash {
+	var h Hash
+	h.SetBytes(b)
+	return h
+}
+
+// BigToHash sets byte representation of b to hash.
+// If b is larger than len(h), b will be cropped from the left.
+func BigToHash(b *big.Int) Hash { return BytesToHash(b.Bytes()) }
+
+// HexToHash sets byte representation of s to hash.
+// If b is larger than len(h), b will be cropped from the left.
+func HexToHash(s string) Hash { return BytesToHash(utils.FromHex(s)) }
+
+// Bytes gets the byte representation of the underlying hash.
+func (h Hash) Bytes() []byte { return h[:] }
+
+// Big converts a hash to a big integer.
+func (h Hash) Big() *big.Int { return new(big.Int).SetBytes(h[:]) }
+
+// Hex converts a hash to a hex string.
+func (h Hash) Hex() string { return hexutil.Encode(h[:]) }
+
+// TerminalString implements log.TerminalStringer, formatting a string for console
+// output during logging.
+func (h Hash) TerminalString() string {
+	return fmt.Sprintf("%x…%x", h[:3], h[29:])
+}
+
+// String implements the stringer interface and is used also by the logger when
+// doing full logging into a file.
+func (h Hash) String() string {
+	return h.Hex()
+}
+
+// Format implements fmt.Formatter, forcing the byte slice to be formatted as is,
+// without going through the stringer interface used for logging.
+func (h Hash) Format(s fmt.State, c rune) {
+	fmt.Fprintf(s, "%"+string(c), h[:])
+}
+
+// UnmarshalText parses a hash in hex syntax.
+func (h *Hash) UnmarshalText(input []byte) error {
+	return hexutil.UnmarshalFixedText("Hash", input, h[:])
+}
+
+// UnmarshalJSON parses a hash in hex syntax.
+func (h *Hash) UnmarshalJSON(input []byte) error {
+	return hexutil.UnmarshalFixedJSON(hashT, input, h[:])
+}
+
+// MarshalText returns the hex representation of h.
+func (h Hash) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(h[:]).MarshalText()
+}
+
+// SetBytes sets the hash to the value of b.
+// If b is larger than len(h), b will be cropped from the left.
+func (h *Hash) SetBytes(b []byte) {
+	if len(b) > len(h) {
+		b = b[len(b)-HashLength:]
+	}
+
+	copy(h[HashLength-len(b):], b)
+}
+
+// Generate implements testing/quick.Generator.
+func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value {
+	m := rand.Intn(len(h))
+	for i := len(h) - 1; i > m; i-- {
+		h[i] = byte(rand.Uint32())
+	}
+	return reflect.ValueOf(h)
+}
+
+// Scan implements Scanner for database/sql.
+func (h *Hash) Scan(src interface{}) error {
+	srcB, ok := src.([]byte)
+	if !ok {
+		return fmt.Errorf("can't scan %T into Hash", src)
+	}
+	if len(srcB) != HashLength {
+		return fmt.Errorf("can't scan []byte of len %d into Hash, want %d", len(srcB), HashLength)
+	}
+	copy(h[:], srcB)
+	return nil
+}
+
+// Value implements valuer for database/sql.
+func (h Hash) Value() (driver.Value, error) {
+	return h[:], nil
+}
+
+// UnprefixedHash allows marshaling a Hash without 0x prefix.
+type UnprefixedHash Hash
+
+// UnmarshalText decodes the hash from hex. The 0x prefix is optional.
+func (h *UnprefixedHash) UnmarshalText(input []byte) error {
+	return hexutil.UnmarshalFixedUnprefixedText("UnprefixedHash", input, h[:])
+}
+
+// MarshalText encodes the hash as hex.
+func (h UnprefixedHash) MarshalText() ([]byte, error) {
+	return []byte(hex.EncodeToString(h[:])), nil
+}

internal/common/hash_test.go

@@ -0,0 +1,110 @@
+package common
+
+import (
+	"database/sql/driver"
+	"reflect"
+	"testing"
+)
+
+func TestBytesConversion(t *testing.T) {
+	bytes := []byte{5}
+	hash := BytesToHash(bytes)
+
+	var exp Hash
+	exp[31] = 5
+
+	if hash != exp {
+		t.Errorf("expected %x got %x", exp, hash)
+	}
+}
+
+func TestHash_Scan(t *testing.T) {
+	type args struct {
+		src interface{}
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr bool
+	}{
+		{
+			name: "working scan",
+			args: args{src: []byte{
+				0xb2, 0x6f, 0x2b, 0x34, 0x2a, 0xab, 0x24, 0xbc, 0xf6, 0x3e,
+				0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+				0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+				0x10, 0x00,
+			}},
+			wantErr: false,
+		},
+		{
+			name:    "non working scan",
+			args:    args{src: int64(1234567890)},
+			wantErr: true,
+		},
+		{
+			name: "invalid length scan",
+			args: args{src: []byte{
+				0xb2, 0x6f, 0x2b, 0x34, 0x2a, 0xab, 0x24, 0xbc, 0xf6, 0x3e,
+				0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+				0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+			}},
+			wantErr: true,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			h := &Hash{}
+			if err := h.Scan(tt.args.src); (err != nil) != tt.wantErr {
+				t.Errorf("Hash.Scan() error = %v, wantErr %v", err, tt.wantErr)
+			}
+
+			if !tt.wantErr {
+				for i := range h {
+					if h[i] != tt.args.src.([]byte)[i] {
+						t.Errorf(
+							"Hash.Scan() didn't scan the %d src correctly (have %X, want %X)",
+							i, h[i], tt.args.src.([]byte)[i],
+						)
+					}
+				}
+			}
+		})
+	}
+}
+
+func TestHash_Value(t *testing.T) {
+	b := []byte{
+		0xb2, 0x6f, 0x2b, 0x34, 0x2a, 0xab, 0x24, 0xbc, 0xf6, 0x3e,
+		0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+		0xa2, 0x18, 0xc6, 0xa9, 0x27, 0x4d, 0x30, 0xab, 0x9a, 0x15,
+		0x10, 0x00,
+	}
+	var usedH Hash
+	usedH.SetBytes(b)
+	tests := []struct {
+		name    string
+		h       Hash
+		want    driver.Value
+		wantErr bool
+	}{
+		{
+			name:    "Working value",
+			h:       usedH,
+			want:    b,
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := tt.h.Value()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Hash.Value() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("Hash.Value() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/utils/bytes.go

@@ -27,13 +27,18 @@ func CopyBytes(b []byte) (copiedBytes []byte) {
 	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 {
+// IsHex validates whether each byte is valid hexadecimal string.
+func IsHex(str string) bool {
 	if len(str)%2 != 0 {
 		return false
 	}

internal/utils/bytes_test.go

@@ -64,7 +64,7 @@ func TestIsHex(t *testing.T) {
 		{"0xHELLO_MY_NAME_IS_STEVEN_@#$^&*", false},
 	}
 	for _, test := range tests {
-		if ok := isHex(test.input); ok != test.ok {
+		if ok := IsHex(test.input); ok != test.ok {
 			t.Errorf("isHex(%q) = %v, want %v", test.input, ok, test.ok)
 		}
 	}